Title of Invention

METHOD OF CHARACTERIZING IMAGE FOR SHAPE CONTENT AND OPTICAL IMAGE SHAPE CONTENT ANALYZER

Abstract There is disclosed a method of characterizing an image for shape content, comprising producing a Fourier transform optic pattern of the image with light energy; spatial filtering the light energy from the Fourier transform optic pattern by selecting light energy from discrete portions of the Fourier transform optic pattern at a plurality of angular orientations and separating such discrete portions from other portions of the Fourier transform optic pattern to create a plurality of filtered patterns of light energy from those discrete portions; projecting the light energy of said discrete portions that have been spatially filtered in the Fourier transform optic pattern in the respective angular orientations to inverse Fourier transform such light energy to where such light energy locates in the same spatially related sites as the features in the image from which such light energy emanated; detecting intensities of light energy as it is distributed in the filtered and then inverse Fourier transformed patterns for the respective angular orientations; and storing the intensities of light energy detected in the filtered and then inverse Fourier transformed patterns along with the respective angular orientations.
Full Text METHOD OF CHARACTERIZING IMAGE FOR SHAPE CONTENT AND
OPTICAL IMAGE SHAPE CONTENT ANALYZER
Related Patent Application
This patent application is a continuation-in-part of U.S. patent application serial
no. 09/536,426, filed in the U.S. Patent and Trademark Office on March 27, 2000
(corresponding Indian Patent No. 199001).
Technical Field
This invention relates generally to spatial light modulators and, more particularly, to
a spatial light modulator with radially oriented active light modulating sectors for radial and
angular analysis of beams of light, including Fourier transform optic patterns, for uses such
as characterizing, searching, matching or identifying shape content of images. Background
Art
There are situations in which useful information can be derived from spatially
dispersed portions of light beams. In particular, when an image is being carried or
propagated by a light beam, it may be useful to gather and use or analyze information from
a particular portion of the image, such as from a particular portion of a cross-section of a
beam that is carrying an image.
For example, in my co-pending U.S. Patent Application, serial no. 09/536,426,
which is incorporated herein by reference, narrow, radially oriented portions of a Fourier
transform of an image are captured, detected, and used to characterize and encode images
by shape for storage, searching, and retrieval. As explained therein, such radially oriented,
angularly or rationally spaced portions of a Fourier transform of an image are captured
sequentially by positioning a rotating, opaque mask or wheel with a radially oriented slit in
the Fourier transform plane of a light beam carrying the image after passing the light beam
through a Fourier transform lens and detecting the light that passes through the slit at
various angular orientations, i.e., degrees of rotation. The light energy detected at each
angular orientation is characteristic of the portions of the image content that are generally
linearly aligned in the same angular orientation as the slit in the rotating mask when the
light energy is detected.
That system with the rotating, radially oriented, slit does perform the task of
characterizing and encoding images by shape content of the images quite well and quite
efficiently. However, it still has several shortcomings. For example, resolution of spatial
frequency of an image at each angular orientation of the rotating slit is not as good as some
applications or uses of such a system might require. Also, the spinning mask or wheel with
an associated drive mechanism, like all mechanical devices, has stability and long term
reliability issues, not to mention size and weight requirements.
Disclosure of Invention
Accordingly, it is a general object of this invention to provide an improved
apparatus and method for capturing and recording optical information from portions of
optical images.
A more specific object of this invention is to provide an improved apparatus and
method for spatial analysis of Fourier transform optical patterns of images for shape content
of such images.
Another specific object of this invention is to provide an improved apparatus and
method for characterizing and encoding images by shape content for storing, searching,
comparing, matching, or identifying images.
This and other objects, advantages, and novel features of the invention shall be set
forth in part in the description that follows, and in part will become apparent to those skilled
in the art upon examination of the following description or may be learned by the practice
of the invention. The objects and the advantages may be realized and attained by means of
the instrumentalities and in combinations particularly pointed out in the appended claims.
To further achieve the foregoing objects, the apparatus of this invention includes a
spatial light modulator with a plurality of addressable, active optic elements that extend
radially at various angular orientations in relation to an axis. The active optic elements are
preferably shaped to modulate portions of light beams incident on discrete sectors of an
active optic area on which the beam of light can be focused. Therefore, active optic
modulators in the shape of individual sectors, i.e., essentially wedge-shaped, are preferred,
although other shapes are also feasible and, in special circumstances, possibly even more
desirable, such as rectangular for better resolution or curved for detection of curved shape
content of an image. For better resolution of spatial frequency of shape content, the radially
extending wedges or rectangles of the active optic area can be comprised of individually
addressable segments, which can be activated separately or in groups, depending on the
resolution desires. Wedge-shaped sectors can comprise segments of smaller, truncated
wedge-shaped active optic elements or groups of sensors in pixel arrays that, in composite,
form such shapes. Rectangular areas can also comprise smaller rectangular segments or
composited groups of sensors in pixel arrays to form such radially extending, angularly
spaced, active optic components or areas. For shape content characterization of an image,
an optic pattern that is a Fourier transform of the image is focused on the active optic area,
and radially disposed portions of the Fourier transform optic pattern at various angular
orientations are selected and isolated by the spatial light modulator for detection of shape
content of the image that is aligned with such angular orientations. The intensities of light
detected from such respective portions are characteristic of such shape content and can be
recorded, stored, or used to compare with similarly analyzed shape content of other images
to find and identify matches or near matches of images with such shape content. Optional
image pre-processing to add ghost images at various radial and angular relationships to the
image and at various light intensities can enhance detectability of shape content and can
enable near matching of images with similar shape content.
Brief Description Of The Accompanying Drawings
The accompanying drawings, which are incorporated in and form a part of the
specification, illustrate the preferred embodiments of the present invention, and together
with the descriptions serve to explain the principles of the invention.
In the Drawings
Figure 1 is an isometric view of a segmented radial spatial light modulation device
according to this invention illustrated with a beam of light focused on the light modulating
components in the active optic area of the device;
Figure 2 is a front elevation view of the preferred light modulating components in
the active optic area of the segmented radial spatial light modulator device of this invention
in the shape of segmented modulator sectors that are oriented to extend radially at various
angular orientations in relation to a central axis;
Figure 3 is an enlarged, front elevation view of one sector of the active, light
modulating components of the segmented radial spatial light modulator device;
Figure 4 is a cross-sectional view of a portion of an active optic sector of a
segmented radial spatial light modulator of the present invention taken substantially along
section line 4-4 of Figure 3;
Figure 5 is a schematic diagram of an optical image characterizer in which a
segmented radial optical analyzer device according to this invention is illustrated in an
application for characterizing and encoding optical images by shape content to exemplify its
structure and functional capabilities;
Figures 6a-c include diagrammatic, elevation view of the active light modulating
components of the segmented radial spatial light modulator device to illustrate a use of an
outer segment of a vertically oriented sector of the light modulation components of the
segmented radial spatial light modulator device of this invention along with diagrammatic
views of an image being characterized and a resulting detectable optic pattern that is
characteristic of some of the vertically oriented shape content of the image;
Figures 7a-c include diagrammatic, elevation views similar to Figures 6a-c, but
illustrating a use of a near inner segment of the vertical sector;
Figures 8a-b include diagrammatic, elevation views similar to Figures 6a-c, but
illustrating a use of a near outer segment of an active optic sector that is oriented 45 degrees
from vertical;
Figures 9a-c include diagrammatic, elevation views similar to Figures 6a-c, but
illustrating a use of the outer segment of the horizontal oriented active optic sector;
Figures l0a-c include diagrammatic, elevation views similar to Figures 6a-c, but
illustrating a use of the outer segment of the active optic sector that is oriented 191.25
degrees from vertical;
Figure 11 is a diagrammatic elevation view similar to Figure 6a, but illustrating a
modified embodiment in which the active optic segments are rectangular instead of wedge-
shaped;
Figure 12 is a diagrammatic elevation view of another embodiment in which groups
of individually addressable light sensors in a pixel array of sensors can be activated together
in locations that simulate sectors or segments of sectors to achieve angular and/or spatial
analysis of a light beam for characterization of an image by shape content according to this
invention;
Figure 13 is a cross-section view similar to Figure 4, but illustrating a modification
in which a modulated light beam passes through, instead of being reflected by, a segmented
radial spatial light modulator in accordance with this invention;
Figures 14a-c illustrates an optional ghosting technique for enhancing optical power
transmission to improve shape information detection capability and to provide graded shape
content characterization to enable identification of near matches of shape content in various
images; and
Figures 15a-c illustrate the ghosting technique of Figures 14a-c applied to a slightly
more complex image.
Best Mode for Carrying Out the Invention
A segmented radial spatial light modulator (SLM) device SO according to the present
invention is illustrated diagrammatically in Figure 1 with a beam of light 27(p) focused on
the active optic area 54 in the center portion of the segmented radial SLM device 50. As
illustrated diagrammatically in Figure 1, the segmented radial SLM device 50 is preferably,
but not necessarily, constructed as an integrated circuit 52 mounted on a chip 56 equipped
with a plurality of electrical pins 58 configured to be plugged into a correspondingly
configured receptacle (not shown) on a printed circuit board (not shown). In such a
preferred embodiment, the pins 58 are connected electrically by a plurality of wires 59
soldered to contact pads 55 of the integrated circuit 52 to enable addressing and operating
optic components in the active optic area 54, as will be discussed in more detail below.
An enlarged elevation view of the active optic area 54 of the integrated circuit 52 is
illustrated in Figure 2, and an even more enlarged view of the active optic segments 502,
504, 506, 508 of one modulator sector 500 (sometimes hereinafter "sector" for convenience)
of the active optic area 54 is illustrated in Figure 3. Essentially, the segmented radial SLM
device 50 is capable of selectively isolating radially disposed portions of the incident light
energy at various angular orientations in relation to a central axis 40 for detection, as will be
explained in more detail below. One way of accomplishing such isolation is by reflecting,
as well as rotating plane of polarization of, the selected radially disposed portions of the
light beam 27(p) that is incident on the active optic area 54, while other portions of the light
beam 27(p) are reflected, but without rotation of the plane of polarization, or vice versa. In
the preferred embodiment, each of the active optic segments, such as segments 502, 504,
506, 508 of sector 500 in Figure 3, are addressable individually through electrically
conductive traces 503, 505, 507, 509, respectively, although the invention also can be
implemented, albeit with less spatial frequency resolution, by a sector 500 comprising only
one active optic modulator or by activating one or more of the individual segments
simultaneously.
The selection and isolation of a portion of the incident light beam 27(p) is illustrated
in Figure 4, which is a partial cross-section of active optic segments 506, 508. An incident
light beam 27(p), which is designated, for examples as being p-polarized, i.e., polarized in
the p-plane, will be reflected by, and will emerge from, segment 508 as s-polarized light
27(s), i.e., light polarized in the s-plane, or vice versa, when the segment 508 is activated by
a voltage V+ on trace 509, while the unactivated segment 506 reflects, but does not rotate
plane of polarization of, the incident light 27(p). In Figure 4, the light reflected by the
activated segment 508 is designated as 61 (s) to indicate its s-plane polarization, while light
reflected by the non-activated segment 506 is designated as 61(p) to indicate its p-plane
polarization. The structure and function of the segments 506, 508, which are typical of all
the segments of all the sectors 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610,
620, 630, 640, 650 of the active optic area 54, will be explained in more detail below.
Suffice it to say at this point that a s-polarization plane is orthogonal to i.e., rotated 90° in
relation to, a p-polarization plane and that such rotation of plane of polarization of a portion
of a light beam 61 (p) (see Figure 1) enables filtration or separation of that portion from the
remainder of the light beam 61 (p), as will be explained in more detail below.
The system 10 for characterizing, encoding, and storing images by shape content of
such images, as illustrated diagrammatically in Figure 5, is an example application of the
segmented radial SLM device 50 described above and is a part of this invention. In this
system 10, any number n of images 12, 14,..., n, can be characterized and encoded by the
shape content in such images, and such encoded shape information about each image can be
stored, for example, in database 102 for subsequent searching, retrieval, and comparison to
shape content of other images that is characterized and encoded in the same manner.
The images 12, 14,..., n can be in virtually any form, for example, visual images
on photographs, films, drawings, graphics, arbitrary patterns, ordered patterns, or the like.
They can also be stored and/or generated in or from digital formats or analog formats. Such
images can have content that is meaningful in some manner when viewed by humans, or
they can be meaningless or not capable of being interrupted by humans but characteristic of
some other content, e.g., music, sounds, text, software, and the like. Essentially, any optic
pattern of light energy intensities that can be manifested or displayed with discernable shape
content can be characterized and encoded with this system 10.
A sample image 12, which can be obtained from any source (e.g., Internet,
electronic data base, web site, library, scanner, photograph, film strip, radar image,
electronic still or moving video camera, and other sources) is entered into the optical image
shape characterizer 10, as will be described in more detail below. Any number n of other
sample images 14,..., n, are shown in Figure 5 queued for entry in sequence into the
optical image characterizer 10. Entry of any number n of such sequential images 12, 14,...
, n can be done manually or, preferably, in an automated manner, such as a mechanical slide
handler, a computer image generator, a film strip projector, an electronic still or video
camera, or the like. The computer 20 in Figure 5 is a preferred embodiment, but is also
intended to be symbolic of any apparatus or system that is capable of queuing and moving
images 12, 14,..., n into the image characterizer 10. The example image 12 of an
automobile displayed on the video monitor 22 represents and is symbolic of any image that
is placed in a process mode for characterizing and encoding its shape content according to
this invention, although it should be understood that such display of the image being
processed is not an essential feature of this invention. The description that follows will, for
the most part, refer only to the first image 12 for convenience and simplicity, but with the
understanding that it could apply as well to any image 12,14,..., n etc.
In the embodiment of the system 10 illustrated in Figure 5, the image 12 is inserted
into the optical image characterizer 10 in an image plane 19 that is perpendicular to the
beam of light 27 emanating from the E-SLM 26, i.e., perpendicular to the plane of the view
in Figure 5. However, to facilitate explanation, illustration, and understanding of the
invention, the images 12, 14,..., n are also shown in phantom lines in the plane of the
view in Figure 5, i.e., in the plane of the paper. This same convention is also used to project
image 12' produced by the E-SLM 26, the Fourier transform optic pattern 32, the active
optic area 54, isolated and filtered optic pattern 60, and the detector grid 82 from their
respective planes perpendicular to the light beams into the plane of the paper for purposes of
explanation, illustration, and understanding. These components and their functions in the
invention will be explained in more detail below.
As mentioned above, the image 12 can be entered into the optical image
characterizer 10 by the computer 20 and E-SLM 26, as will be described in more detail
below. However, the image 12 will undergo a significant transformation upon passing
through the thin, positive lens 30, also called the Fourier transform (FT) lens. A Fourier
transform (FT) of the sample image 12' rearranges the light energy of the optic pattern of
image 12' into a Fourier transform (FT) optic pattern 32, which is unique to the image 12',
even though it is not recognizable as the image 12' to the human eye and brain, and which
can be characterized by intensities, i.e., amplitudes, of light energy distributed spatially
across the optic pattern 32. The complex amplitude distribution of light energy 34 in the
optic pattern 32 is the Fourier transform of the complex light distribution in the image 12'.
Image 12' is a recreation of the image 12 in monochromatic, preferably coherent, light
energy, as will be described in more detail below, although white light will also work.
Concentrations of intense light energy in the Fourier transform (FT) optic pattern 32
generally correspond to spatial frequencies of the image 12', i.e., how closely together or far
apart features in the image 12' change or remain the same. In other words, spatial
frequencies are also manifested by how closely together or far apart light energy intensities
across the light beam 27 change or remain the same. For example, a shirt with a plaid fabric
in an image (not shown), i.e., having many small squares, would have a higher spatial
frequency, i.e., changes per unit of distance, than a plain, single-color shirt (not shown) in
the image. Likewise, portions of an image, such as the bumper and grill parts 35 of the
automobile in image 12', would have a higher spatial frequency than the side panel 36
portion of the automobile image 12', because the bumper and grill parts 35 comprise many
small pieces with various edges, curves, and other intricate changes within a small spatial
distance, whereas the side panel 36 is fairly smooth and uniform over a large spatial
distance. Light energy from the finer and sharper details of an image (more spatial
frequency), such as the more intricate bumper and grill parts 35 of the image 12', tend to be
dispersed farther radially outward from the optical center or axis 40 in the Fourier
transformed image than light energy from more course or plain details of an image (less
spatial frequency), such as the side panel 36 of the image 12'. The amplitude of light energy
34 dispersed radially outward in the Fourier transform optic pattern 32 is related to the light
energy of the corresponding portions of the optic pattern of image 12' from which such light
energy emanates, except that such light energy is concentrated into areas or bands 34 at the
plane of the Fourier transform (FT) optic pattern 32 after they are refracted by the FT lens
30, i.e., into bands of intense light energy separated by bands of little or no light energy,
which result from constructive and destructive interference of the diffracted light energy. If
the high spatial frequency portions of the image 12', such as the bumper and grill portion 35,
are bright, then the intensity or amplitude of light energy from those high spatial frequency
portions of the image 12', which are dispersed by the FT lens 30 to the more radially
outward bands of light energy 34 in the Fourier transform optic pattern 32, will be higher,
i.e., brighter. On the other hand, if the high spatial frequency portions of the optic pattern of
image 12' are dim, then the intensity or amplitude of light energy from those high spatial
frequency portions of the optic pattern of image 12', which are dispersed by the FT lens 30
to the more radially outward bands of light energy 34 in the Fourier transform optic pattern
32, will be lower, i.e., not so bright. Likewise, if the low spatial frequency portions of the
optic pattern of image 12', such as the side panel portion 36, arc bright, then the intensity or
amplitude of light energy from those low spatial frequency portions of the optic pattern of
image 12' which are dispersed by the FT lens to the less radially outward bands of light
energy 34 in the Fourier transform optic pattern 32 (i.e., closer to the optical axis 40), will
be higher, i.e., brighter. However, if the low spatial frequency portions of the optic pattern
of image 12' are dim, then the intensity or amplitude of light energy from those low spatial
frequency portions of the optic pattern of image 12", which are dispersed by the FT lens 30
to the less radially outward bands of light energy 34 in the Fourier transform optic pattern
32, will be lower, i.e., not so bright.
In summary, the Fourier transform optic pattern 32 of the light emanating from the
image 12': (i) is unique to the image 12'; (ii) comprises areas or bands of light energy 34
concentration, which are dispersed radially from the center or optical axis 40, that represent
spatial frequencies, i.e., fineness of details, in the image 12'; (iii) the intensity or amplitudes
of light energy 34 at each spatial frequency area or band in the Fourier transform optic
pattern 32 corresponds to brightness or intensity of light energy emanating from the
respective fine or course features of the image 12'; and (iv) such light energy 34 in the areas
or bands of the Fourier transform optic pattern 32 are detectable in intensity and in spatial
location by this invention.
Since this optical image characterizer 10 of this invention is designed to characterize
an image 12 by shapes that comprise the image 12, additional spatial filtering of the Fourier
transform light energy pattern 32 is used to detect and capture light energy emanating from
the finer or sharper details or parts of such finer or sharper details in the image 12', which
are aligned linearly in various specific angular orientations. Such spatial filtering can be
accomplished in any of a number of different ways, as will be explained in more detail
below, but an exemplary spatial filter arrangement for this function is included in a
combination of the segmented radial spatial light modulator device 50 with the polarizing
beam splitter 70. Essentially, the segmented radial SLM device 50 rotates the plane of
polarization of selected portions of the Fourier transform optic pattern 32 from p-plane
polarization to s-plane polarization, or vice versa, as explained above, and the polarizing
beam splitter 70 separates light energy of those portions that is isolated and polarized in one
plane from the light energy of the rest of the Fourier transform optic pattern 32 that remains
polarized in the other plane so that such light energy of the selected and isolated portions
can be detected separately.
Only the portions of the light energy 34 in the Fourier TRANSFORM pattern 32 that
align linearly with selected active optic segments, for example, segment 502, 504, 506,
and/or 508 (Figure 3), have the plane of polarization rotated in the reflected light 61 (s) by
the segmented radial SLM 50. Such selected portions 61(s) of the beam 27(p) represent,
i.e., emanated largely from, details or features of the image 12', such as straight lines and
short segments of curved lines, that align linearly with the angular orientation of the
respective sectors 500, 510,520, 530, 540, 550, 560, 570, 580, 590,600, 610, 620, 630,
640,650 in which selected segments are located in the active optic area 54 of the segmented
radial SLM 50. For example, if one or more of the segments 502, 504, 506,508 in sector
500 is selected and activated to rotate plane of polarization of light energy reflected from
such segments(s), the reflected light energy 61 (s) will have emanated largely from details or
features of the image 12' that align linearly with the vertical orientation of the sector 500 in
which segments 502, 504, 506, 508 are positioned. Further, since the light energy 34 from
higher spatial frequency content of the image 12', e.g., closely spaced bumper and grill parts
35, are dispersed farther radially outward in the Fourier transform optic pattern 32 than light
energy 34 from lower spatial frequency content, e.g., side panel 36, the light energy in
reflected light beam 61 (s) will also be characteristic of a confined range of such spatial
frequency content of image 12', depending on which segment of a sector is selected. For
example, activation of outer segment 508 of sector 500 (Figure 3), which is positioned
farther radially outward from the optic axis 40 of the incident beam 27(p) than segment 502,
will cause the light energy in reflected beam 61(s) to be characteristic of higher spatial
frequency content of vertically oriented features in image 12', e.g., vertical edges of bumper
and grill parts 35. In contrast, activation of inner segment 502 of sector 500, will cause the
light energy in reflected beam 61(s) to be more characteristic lower spatial frequency
content of vertically oriented features in the image 12', e.g., the vertical rear edge of the
trunk lid 37. The result is a filtered pattern 60 of light energy bands 62 that represent or are
characteristic of the unique combination of features or lines in the content of image 12' that
corresponds to light energy of the FT optic pattern 32 at the radial distance of the selected
segment and that align linearly with the sector in which the selected segment is positioned.
Therefore, in addition to being able to provide rotational spatial filtering of the FT optic
pattern 32 at different angular orientations about the optic axis, the segments of each sector,
such as segments 502, 504, 506, 508 of sector 500, provided the additional capability of
scalar spatial filtering FT optic pattern 32 at different radial distances from the optic axis.
Of course, segments in different sectors of different angular orientations about the
optic axis 40 will align linearly with features or lines in the image 12' that have different
angular orientations, as will be described in more detail below. Thus, the light energy bands
62 in the filtered pattern 60 will change, as active optic segments in different sectors are
selected and activated, to represent different features, details, edges, or lines in the optical
pattern of image 12' at various angular orientations, intricateness or fineness, and
brightness, as will be explained in more detail below. In general, however, the light energy
bands 62, if inverse Fourier transformed from the FT optic pattern 32 after the above-
described spatial filtering 54, will be located in the same spatially-related sites as the
features in the original image 12' from which such light energy emanated. For example,
light energy in a band 62 in pattern 60 that originally emanated from bumper and grill parts
35 in image 12', after spatial filtering with the vertical sector of the spatial filter SLM 5
and inverse transmission, as explained above, will correspond to the vertical bumper an
grill parts 35 in image 12'.
The spatially filtered light energy in bands 62 of the filtered pattern 60 can be
detected by a photodetector 80 at any of the various angular orientations of the activated
sectors and fed electronically to a computer 20 or other microprocessor or computer for
processing and encoding. While only one photodetector 80 with an example 16x16 array 82
of individual photosensitive energy transducers 84 is illustrated in Figure 5 and is sufficient
for many purposes of this invention, other detector arrangements, for example, the two
offset detector arrays described in co-pending patent application, serial no. 09/536,426, or
one or more larger detector arrays, could also be used.
The computer 20, with input of information about the filtered optical patterns 60,
i.e., light energy intensity (I) distribution, from the detector array 82, along with information
about the image 12 (e.g., identification number, source locator, and the like), information
about the angular orientation (R) of the sector in which a segment is activated, and
information about the radial distance or scale (S) of the activated segment relating to spatial
frequency, can be programmed to encode the characteristics of the image 12 relating to the
shape content of the image 12. One useful format for encoding such information is by pixel
of the filtered image 60, including information regarding x, y coordinate location of each
pixel, Rotation (i.e., angular orientation of the sector in which a segment is activated, thus
of the linear features of the image 12 that align with such angular orientation), and Intensity
(i.e., amplitude of light energy from the filtered pattern 60 that is detected at each pixel at
the angular orientation R. A searchable flag, such as a distortion factor X, can also be
provided, as explained in more detail co-pending patent application, serial no. 09/536,426 or
by the ghost image pre-processing feature of this invention, which will be explained in more
detail below. Such combination of angular orientation or rotation R, light energy intensity I
for each pixel, and distortion factor X can be called a "RIXcl" for short. Scale (i.e., spatial
frequencies of image 12 content at such angular orientations) can also be included in such
encoding, if desired. When including a scale factor S, the combination can be called a
"RIXScl". Each RlXel or RJXSel can then be associated with some identifier for the image
12 from which it was derived (e.g., a number, name, or the like), the source location of the
image 12 (e.g., Internet URL, data base file, book title, owner of the image 12, and the like),
and any other desired information about the image, such as format, resolution, color,
texture, content description, search category, or the like. Some of such other information,
such as color, texture, content description, and/or search category, can be information input
from another data base, from human input, or even from another optical characterizer that
automatically characterizes the same image 12 as to color, texture, or the like—whatever
would be useful for searching, finding, or retrieving image 12 or for comparing image 12 to
other images.
Some, all, or additional combinations of such information about each image 12, 14 .
.., n characterized for shape and encoded, as described above, can be sent by the computer
20 to one or more data base(s) 102. Several example data base architectures 104, 106, 108
for storing RIXel or RlXSel information about each image 12, 14.....n are shown in
Figure 5, but many other architectures and combinations of information could also be used.
In the optical image characterizer 10 illustrated in Figure 5, the image 12 has to be
recreated with monochromatic, preferably coherent, light energy, e.g., at image 12', with a
spatial light modulator (SLM) 26 illuminated with a beam of monochromatic light 24 from
a light source 23, such as a laser diode or gas diode. This feature of the invention could also
be implemented with white light, although the resultant Fourier transform optic patterns and
spatially filtered optic patterns would be more blurred than with monochromatic light.
Therefore, while this description of the invention will proceed based on monochromatic,
preferably coherent, light, it should be understood that white light is a suitable, albeit not a
preferred, substitute. The spatial light modulator (SLM) 26 can be optically addressable (0-
SLM), such as the one illustrated in co-pending patent application 09/536,426, or it can be
electrically addressable (E-SLM) and driven, for example, by a computer 20 in Figure 5 or
by a video camera (not shown). As is known by persons skilled in the art, a spatial light
modulator (SLM) can "write" an image into a polarized beam of light 25 by rotating or
partially rotating the polarization plane of the light on a spatial basis across the beam 25 so
that, upon reflection as beam 27, it is either transmitted through, or reflected by, the
polarization beam splitter 116, depending on what is needed to create the image 12' in
monochromatic light. In an optically addressed SLM (not shown), the image plane is
addressed on a spatial basis by incident light energy on a semiconductor material adjacent
the polarization rotating material (usually a liquid crystal material), whereas, in an
electrically addressable SLM 26, the liquid crystal, polarization rotating material is
addressed electrically on a pixel by pixel basis. The pixel portions of the polarized light that
have the plane of polarization rotated 45 degrees as they pass once through the liquid crystal
material, whereupon such light is reflected and passed back through the liquid crystal again,
where it is rotated another 45 degrees. Thus, the pixels of light in polarized beam 25 that
have their plane of polarization rotated in the SLM 26 are reflected and emerge from the
SLM along the optical path 27, which has an optic axis 40 that coincides with the optic axis
of the incident beam 25 but in an optic pattern imposed by the E-SLM 26 that forms an
image 12' and with its plane of polarization rotated 90 degrees from the plane of
polarization of the incident beam 25. The remaining pixels of light, which do not undergo
rotation of the plane of polarization, are also reflected, but they can be separated from those
that have undergone rotation of plane of polarization, as will be explained below. Various
light intensities or brightnesses of the image 12 can be recreated in gray scales in image 12'
by partial rotations of plane of polarization.
In the Figure 5 embodiment, the coherent light beam 24 from laser source 23 is
passed first through a polarizer 28 to create a polarized beam of coherent light 25 with all
the light polarized in one plane, such as, for example, but not for limitation, in the s-plane,
as indicated by 25(s). The s-polarized beam 25(s) is then passed through a spatial filter 110
comprised essentially of a pin hole 112 and a lens 114 to focus the beam 25(s) on the pin
hole 112. This spatial filter 110 is provided primarily to condition the beam 25(s) to get a
good Gaussian wavefront and, if necessary, to limit the power of the beam 25(s). Lens 114a
then columnates the light.
The beam 25(s) is then passed through a polarizing beam splitter 116, which reflects
light polarized in one direction at plane 118 and transmits light polarized in the orthogonal
direction. In this example, the polarizing beam splitter 116 reflects s-polarized light and
transmits p-polarized light, and it is oriented to reflect the s-polarized beam 25(s) toward the
electrically addressed spatial light modulator (E-SLM) 16. the monochromatic, preferably
coherent, light beam 25(s) incident on the E-SLM 36 provides the light energy that is
utilized to carry the shape content of the image 12' for further analysis, characterization, and
encoding according to this invention.
As mentioned above, there are many ways of "writing" images 12, 14,..., n into a
light beam, one of which is with an E-SLM 16. In this example, computer 20 has the
content of image 12 digitized, so the computer 20 can transmit digital signals via link 21 to
the E-SLM 26 in a manner that addresses and activates certain pixels in the E-SLM 26 to
"write" the image 12' into reflected light beam 27(p), as is understood by persons skilled in
the art. Essentially, the addressed pixels rotate the plane of polarization by 90 degrees from
the s-plane of incident beam 25(s) to the p-plane of reflected beam 27(p), or by some lesser
amount for gray-scales, in a manner such that the reflected light energy with partially or
fully 90-degree polarization plane rotation is in an optical pattern of the image 12'. Of
course, persons skilled in the art will also understand that the image 12' could also be
created with an E-SLM that operates in an opposite manner, i.e., the plane of polarization is
rotated in reflected light, except where pixels are activated, in which case the computer 20
would be programmed to activate pixels according to a negative of the image 12 in order to
write the image 12' into reflected beam 27. Either way, the emerging beam 27(p) of
coherent light, carrying image 12', is p-polarized instead of s-polarized or vice versa.
Consequently, in the above example, the monochromatic light beam 27(p), with its light
energy distributed in an optic pattern that forms the image 12', is transmitted by the
polarizing beam splitter 116 to the FT lens 30, instead of being reflected by it.
The positive Fourier transform (FT) lens 30, as explained above is positioned in the
light beam 27(p) and redistributes the monochromatic light energy from the image 12' into
its Fourier transform optic pattern 32, which occurs at the focal plane of the FT lens 30.
Therefore, the segmented radial SLM SO of this invention has to be positioned in the focal
plane of the FT lens 30, as indicated by the focal distance F in Figure 5, and the FT lens 30
is also positioned the same focal distance F from the E-SLM 26, so that the E-SLM 26 is
also in a focal plane of the lens 30. As also explained above, the complex amplitude
distribution of light energy 34 in the Fourier transform optic pattern 32 at the focal plane of
the FT lens 30 is the Fourier transform of the complex amplitude distribution in the image
12'. The Fourier transform optic pattern 32 has all of the light energy from the image 12'
distributed into the symmetrical pattern 32 based on the spatial frequencies of the image 12',
with intensities of the light energy in the various spatial frequency distributions 34 based on
the light energy in the corresponding portions of the image 12' where those respective
spatial frequencies occur.
The Fourier transform optic pattern 32, as mentioned above, is symmetrical from top
to bottom and from left to right, so that each semicircle of the Fourier transform optic
pattern 32 contains exactly the same distribution and intensity of light energy as its opposite
semicircle. Light energy from lower spatial frequencies in the image 12' are distributed
toward the center or optical axis 40 of the Fourier transform optic pattern 32, while the light
energy from higher spatial frequencies in the image 12' are distributed farther away from the
optical axis 40 and toward the outer edge of the pattern 32, i.e., farther radially outward
from the optic axis 40. Light energy from features in the image 12' that are distributed
vertically in the image 12' to create those various spatial frequencies is likewise distributed
vertically in the Fourier transform optic pattern 32. At the same time, light energy from
features in the image 12' that are distributed horizontally in the image 12' to create those
various spatial frequencies is distributed horizontally in the Fourier transform optic pattern
32. Therefore, in general, light energy from features in the image 12' that are distributed in
any angular orientation with respect to the optical axis 40 to create the various spatial
frequencies in the image 12' is also distributed at those same angular orientations in the
Fourier transform optic pattern 32. Consequently, by detecting only light energy distributed
at particular angular orientations with respect to the optical axis 40 in the Fourier transform
optic pattern 32, such detections are characteristic of features or details in the image 12' that
are aligned linearly in such particular angular orientations. The radial distributions of such
detected light energy at each such angular orientation indicate the intricateness or sharpness
of such linear features or details in the image 12', i.e., spatial frequency, while the intensities
of such detected light energy indicate the brightness of such features or details in the image
12'.
Therefore, a composite of light energy detections at all angular orientations in the
Fourier transform optic pattern 32 creates a composite record of the shapes, i.e., angular
orientations, intricateness or sharpness, and brightness, of linear features that comprise the
image 12'. However, for most practical needs, such as for encoding shape characteristics of
images 12, 14,..., n for data base storing, searching, retrieval, comparison and matching to
other images, and the like, it is not necessary to record such light energy detections for all
angular orientations in the Fourier transform pattern 12'. It is usually sufficient to detect
and record such light energy distributions and intensities for just some of the angular
orientations in the Fourier transform optic pattern 32 to get enough shape characterization to
be practically unique to each image 12, 14,..., n for data base storage, searching, and
retrieval of such specific images 12, 14,..., n. For purposes of explanation, but not for
limitation, use of 11.25-degree angular increments is convenient and practical, because
there are sixteen (16) 11.25-degree increments in 180 degrees of rotation, which is sufficient
characterization for most purposes and has data processing and data storage efficiencies, as
explained in co-pending U.S. patent application, serial no. 09/536,426. However, other
discrete angular increments could also be used, including constant increments or varying
increments. Of course, varying increments would require more computer capacity and more
complex software to handle the data processing, storing, and searching functions.
In the preferred embodiment of this invention, the segmented radial SLM 50, shown
in Figure 1, with its active optic sectors 500, 510, 520, 530, 540, 550, 560, 570, 580, 590,
600, 610, 620, 630, 640, 650 shown in Figure 2, is used to select only light energy from
specific angular orientations in the Fourier transform optic pattern 32 for detection at any
instant in time or increment of time on the detector array 82. As explained above with
reference to the sector 500 in Figure 3, which, except for angular orientation, is typical of all
the other sectors 510, 520, 530, 540, 550, 560, 570, 580, 590,600, 610, 620, 630, 640, 650
in Figure 2, any active optic segment, e.g., segments 502, 504, 506, 508, in vertical sector
500, can be addressed via respective electric traces, e.g., traces 503, 505, 507, 509 for sector
500, so that the detector array 82 can detect light energy distribution and intensity (I) in the
Fourier transform optic pattern 32 at any angular orientation (R) of a sector 500, 510, 520,
530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650 and at selected radial
distances from the optic axis 40. For example, sector 500 is oriented substantially vertical
in relation to the optic axis 40. If all of the active optic segments 502, 504, 506, 508 of
sector 500 are selected and activated simultaneously, virtually all of the light energy that is
distributed vertically in the Fourier transform optic pattern 32 will be incident on, and
detected by, the photodetector array 82 (Figure 5). However, if only one of the active optic
segments, for example, outer segment 508, is selected and activated, then only the light
energy in the Fourier transform optic pattern 32 that is distributed vertically and the farthest
radially outward from the optic axis 40 will be detected by the photodetector array 82.
Thus, any one, all, or combination of the active optic segments, e.g., 502, 504, 506, 508, can
be activated sequentially or simultaneously to detect and record various distributions of
light energy in the Fourier transform optic pattern 32. Also, any one or more sectors 500,
510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630,640,650 can be selected
and activated sequentially, simultaneously, or in various combinations, depending on the
detail or particular light energy distributions in the FT optic pattern 32 it is desired to detect.
The preferred, but not essential, shape of the active optic sectors, e.g., sector 500, in
the segmented radial SLM 50 is a narrow, elongated wedge. The width of the wedge will
depend on the light energy available or needed and the optic resolution desired. A wider
sector will direct more light energy 34 to the detector 80, but precision of line or feature
resolution of the image 12' will degrade slightly. A narrower sector will get better line
resolution, but with a corresponding increase in the complexity of the resulting pattern
shape generalization and complexity and a decrease in light energy directed to the detector
80. There may also be a practical limitation as to how narrow and close the wedges can be
made with the connecting electric traces in a limited active optic area 54 in an economic and
efficient manner. Therefore, a desirable balance between these resolution, detectability, and
size considerations may be struck in choosing sector size. Also, for specialized
applications, sectors of different shapes (not shown), such as ovals, or other shapes could be
used to capture shapes other than lines from the image 12.
The number of active optic segments in a sector, e.g., the four segments 502, 504,
506, 508 sector 500, also has similar constraints. Smaller segments direct less light energy
to the detector 80, but may provide more resolution of shape characteristics of the image
12', whereas larger segments direct more light to the detector 80, thus are more easily
detectable, but resolution decreases. For lower resolution applications or requirements, the
sectors may not even need to be divided into segments, and this invention includes radial
spatial light modulators in which each sector 500, 510, 520, 530, 540, 550, 560,570, 580,
590,600, 610, 620, 630, 640,650 is not segmented, thus comprises a single active optic
element for each sector. However, the same lower resolution effect can be achieved in the
illustrated embodiment 50 in Figures 1 - 3 by activating all the segments 502, 504, 506, 508
in a sector simultaneously, as described above.
In the preferred embodiment 50, each sector, e.g., sector 500, comprises four
individually addressable, active optic segments, e.g., segments 502, 504, 506, 508, as shown
in Figure 3, although any number of segments other than four can also be used according to
this invention. The length of each successive radial outward segment is twice as long as the
next adjacent radially inward segment. Thus, in sector 500, the near inner segment 504 is
about twice as long as the inner segment 502. Likewise, the near outer segment 506 is
about twice as long as the near inner segment 504, and the outer segment 508 is about twice
as long as the near outer segment 506. Expressed another way, if the radial length of inner
segment 502 is L, the radial length of near inner segment 504 is 2L, the radial length of the
near outer segment 506 is 4L, and the radial length of the outer segment 508 is 8L. The
distance d between the optic axis 40 and the inner edge 501 of inner segment 502 is about
the same as the length L of inner segment 502, so the diameter of the center area 57 is about
2L. These proportional lengths of the active optic segments enable the inner segments (e.g.,
502) to capture shape features of the image 12' that have sizes] in a range of about 25 - 50
percent of the size of the image 12' produced by the spatial light modulator 26 in Figure 5,
the near inner segments (e.g., 504) to capture shape features of the image 12' that have sizes
in a range of about 12'/j - 25 percent of the size of image 12', the near outer segments (e.g.,
506) to capture shape features of the image 12' that have sizes in a range of about 614 - 12'/i
percent of the size of image 12, and the outer segments (e.g., 508) to capture shape features
of the image 12' that have sizes in a range of about 3 1/8-6^4 percent of the size of the
image 12". Therefore, any features of the image 12' that have sizes over 50 percent of the
size of image 12', which light energy is incident on the center area portion 41, can either be
captured and detected as an indicator of general brightness of the image 12' for intensity
control or calibration purposes or just ignored and not captured or detected at all, because
there is little, if any, useable shape information or content in the light energy that comprises
that 50 percent of the size of the image 12'. Likewise, the approximately 3 1/8 percent of
the size content of the image 12' that is radially outward beyond the outer segments is not
detected and can be ignored in this preferred configuration. The light in the center 41 can
be made optically active to capture light energy incident thereon, if it is desired to capture
and detect such light energy for general brightness indication, intensity control, or
calibration purposes, as will be understood and within the capabilities of persons skilled in
the art, once they understand this invention. Of course, other configurations of the
segmented radial SLM 50 could also be made and used within the scope of this invention.
While the radial configuration of the active optic sectors with or without the
multiple, active optic segments in each sector in the spatial light modulator 50 is a
significant feature of this invention, persons skilled in the art of designing and fabricating
spatial light modulators can readily understand how such a spatial light modulator 50 can be
constructed and function, once they become familiar with the features and principles of this
invention, and there are many known materials, fabrication techniques, and the like, known
to persons skilled in the art that could be used to design, make, and use state-of-the-art
spatial light modulators that are applicable to the specialized spatial light modulator
embodiments of this invention. Therefore, a detailed recitation of such available materials
is not necessary to enable a person skilled in the art to make and use this invention. Never-
the-less, reference is now made to Figure 4 in combination with Figures 1 - 3 and 5 to
illustrate how selection and activation of any particular active optic segment, for example,
near outer segment 506 and outer segment 508, function to selectively enable detection of
light energy from the Fourier transform optic pattern 32 that is incident on such segments.
As illustrated in Figure 4, the optic active segments 506, 508, which are typical of
other active optic segments, are part of an integrated circuit 52, which is mounted on a chip
base or platform 56. The integrated circuit 52 has a variable birefringent material 180, such
as a liquid crystal material, sandwiched between two transparent substrates 182, 184, such
as high quality glass. The variable birefringent material 180 is responsive to a voltage to
change its birefringence in the area of the voltage, which results in rotation of the plane of
polarization of the light that passes through the material 180. The division between near
outer segment 506 and outer segment 508 is made by a separation of respective metal layers
186, 188. An intervening dielectric or electrical insulation material 185 can be used to
maintain electrical separation of these metal layers 186, 188. As shown by a combination of
Figures 3 and 4, electrically conductive trace 507 is connected to the metal layer 186 of near
outer segment 506, and trace 509 is connected to the metal layer 188 of outer segment 508.
In fact, the electric traces 507, 509 and metal layers 186, 188 can be deposited the same
metal and can be on the back substrate 184 concurrently with their respective metal layers
186, 188 during fabrication of the integrated circuit 52, as would be understood and within
the capabilities of persons skilled in the art of designing and fabricating spatial light
modulators, once they are informed of the principles of this invention. Therefore, the metal
layers 186, 188 can be addressed individually through their respective connected traces 507,
509 by connecting positive (+) or negative (-) voltages Vt and V2, respectively, to traces
507, 509.
A transparent conductive layer 190 deposited on the front substrate 182 is connected
by another lead 513 to another voltage V3. Therefore, a voltage can be applied across the
portion of the liquid crystal material 180 that is sandwiched between the metal layer 186
and the transparent conductive layer 190 by, for example, making V1 positive and V3
negative and vice versa. Likewise, when a voltage can be applied across the portion of the
liquid crystal material 180 that is sandwiched between the metal layer 188 and the
transparent conductive layer 190 by, for example, making V2 positive and V3 negative and
vice versa.
As mentioned above, the function of the respective segments 506, 508 is to rotate
the plane of polarization of selective portions of the incident light beam 27(p) so that those
portions of the light beam 27(p), which carry corresponding portions of the Fourier
transform optic pattern 32, can be separated and isolated from the remainder of the light
beam 27(p) for detection by the photodetector array 82 (Figure 5). As understood by
persons skilled in the art, there are a number of spatial light modulator variations, structures,
and materials that can yield the desired functional results, some of which have advantages
and/or disadvantages over others, such as switching speeds, light transmission efficiencies,
costs, and the like, and many of which would be readily available and satisfactory for use in
this invention. Therefore, for purposes of explanation, but not for limitation, the segmented
radially spatial light modulator illustrated in Figure 4 can have respective alignment layers
192, 194 deposited on the transparent conductive layer 190 on substrate 182 and on the
metal layers 186, 188 on substrate 184. These alignment layers 192, 194 are brushed or
polished in a direction desired for boundary layer crystal alignment, depending on the type
of liquid crystal material 180 used, as is well-understood in the art. See, e.g., J.Goodman,
"Introduction to Fourier Optics, 2nd ed., chapter 7 (The McGraw Hill Companies, Inc.)
1996. An antireflective layer 196 can be deposited on the outside surface of the glass
substrate 182 to maintain optical transmissive efficiency.
One example system, but certainly not the only one, can use a liquid crystal material
180 that transmits light 27(p) without affecting polarization when there is a sufficient
voltage across the liquid crystal material 180 and to act as a 1/4-wave retarder when there is
no voltage across the liquid crystal material. An untwisted crystal material 180 that is
birefringent in its untwisted state can function in this manner. Thus, for example, when no
voltage is applied across the liquid crystal material 180 in segment 508, there is no
molecular rotation of the liquid crystal material 180 in outer segment 508, and the liquid
crystal material in outer segment 108, with the proper thickness according to the liquid
crystal manufacturer's specifications, will function as a 1/4-wave plate to convert p-polarized
light 27(p) incident on outer segment 508 to circular polarization as the light passes through
the untwisted liquid crystal material 180. Upon reaching the metal layer 188, which is
reflective, the light is reflected and passes back through the liquid crystal material to
undergo another 1/4-wave retardation to convert the circular polarization to linear
polarization, but in the s-plane, which is orthogonal to the p-plane. The reflected light
61(s), therefore, has its plane of polarization effectively rotated by 90 degrees in relation to
the incident light 27(p).
Meanwhile, if there is a sufficient voltage on, for example, the near outer segment
506, to rotate the long axes of the liquid crystal molecules into alignment with the direction
of propagation of the incident light waves 27(p), thereby eliminating the birefringence of
the liquid crystal material 180, then there is no change of the linear polarization of the light
on either its first pass through the liquid crystal material 180 or on its second pass through
the liquid crystal material after being reflected by metal layer 186. Consequently, under this
condition with a voltage applied across the liquid material 180 in ear outer segment 506, the
reflected light 61(p) is still polarized in the p-plane, i.e., the same plane as the incident light
27(p).
Many liquid crystal materials require an average DC voltage bias of zero, which can
be provided by driving the voltage V3 with a square wave function of alternating positive
and negative voltages for equal times. Therefore, for no voltage across the liquid crystal
material 180, the other voltages V1, V2, etc., can be driven in phase with equal voltages as
V3. However, to apply a voltage across the liquid crystal material 180 adjacent a particular
metal layer 186, 188, etc., to activate that particular segment 506, 508, etc., as described
above, the respective voltage V1 or V2, etc., can be driven out of phase with V3. If the
frequency of the square wave function is coordinated with the switching speed of the liquid
crystal material 180, one-half cycle out of phase for a voltage V1, V2, etc., will be enough to
activate the liquid crystal material 180 to rotate the plane of polarization of the light as
described above.
As mentioned above, other alternate arrangements and known liquid crystal
materials can reverse the results from an applied voltage. For example, a twisted liquid
crystal material 180 may be used to rotate plane of polarization under a voltage and to not
affect plane of polarization when there is no voltage.
Referring again primarily to Figure 5 with continuing secondary reference to Figure
4, the light energy in the beam 27'(p), which passes through the polarizing beam splitter 116
and 70 without reflection by planes 116 and 72, is focused as the Fourier transform optic
pattern 32 on the segmented radial SLM 50. Selected active optic segments, for example,
segments 502, 504, 506, 508, in the segmented radial SLM, can rotate the plane of
polarization of portions of the incident light beam 27(p), as described above, in order to
separate and isolate light energy from selected portions of the FT optic pattern 32 for
detection by photodctector 80. The computer 20 can be programmed to provide signals via
link 198 to the segmented radial SLM 50 to select and coordinate activation of particular
segments, for example, segments 502, 504, 506, 508, with displays of particular images 12,
14,..., n. The computer 20 can also be programmed to coordinate laser source 23 via a
link 29 to produce the required light energy 24, when the selected segment of the segmented
radial SLM 50 is activated.
The reflected light 61 (s) from the segmented radial SLM 50, e.g., light polarized in
the s-plane reflected from an activated segment, as explained above, does not pass back
through the polarizing beam splitter 70 along with p-polarized reflected light. Instead, the
s-polarized reflected light 61(s) is reflected by the plane 72 in the polarizing beam splitter
70 to the detector 80. The lens 78 magnifies and focuses the isolated beam 61 (s) in a
desired size on the detector array 82 of photodetector 80.
The photodetector array 82, as mentioned above, can be a 16 x 16 array of individual
light sensors 84, such as charge coupled devices (CCDs), as shown in Figure 5, or any of a
variety of other sizes and configurations. The x, y coordinates of individual sensors 84 in
the array 82 that detect light 61(s) can be communicated, along with light intensity (I)
information, to the computer 20 or other controller or recording device via a link 86, where
it can be associated with information bout the image 12, 14,..., n and the angular
orientation and/or radial position of the activated segment(s) in the segmented radial SLM
50 that provided the beam 61(s) to the detector 80.
The spatial filtering process described above and its characterization of the image 12
by shape content is illustrated in more detail in Figures 6a-c, 7a-c, 8a-c, 9a-c, and l0a-c.
With reference first to Figure 6a, the active optic area 54 from Figures 1 and 2 is shown in
Figure 6a with the example sectors 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600,
610, 620, 630,640,650, but, to avoid unnecessary clutter, without the electric traces that
were described above and shown in Figures 1-3. As mentioned above, the sectors can be
any desired width or any desired angular orientation, but a convenient, efficient, and
effective configuration is to provide sectors of 11.25°. For example, a circle of 360° divides
into 32 sectors of 11.25° each, and a semicircle of 180° divides into sixteen sectors of 11.25°
each. Further, as mentioned above, the light energy distribution in any semicircle of a
Fourier transform optic pattern 32 is symmetric with its opposite semicircle. Therefore,
detection of the light energy pattern in one semicircle of the FT optic pattern 32, for
example, in the semicircle extending from 0° to 180°, provides effective information for the
entire image 12', and detection of the light energy pattern in the opposite semicircle
extending from 180° to 360° provides the same information. Consequently, to alleviate
clutter and better accommodate the electric traces (shown in Figures 1 - 3, some of sectors
can be positioned in one semi-circle of the optic area 54 with intervening spaces to
accommodate the electric traces (shown in Figures 1 - 3), while others of the sectors can be
positioned in the opposite semicircle of the optic area 54 diametrically opposite to the
intervening spaces. For example, when the circle is divided into 32 sectors of 11.25° each,
only 16 of those sectors, such as sectors 500,510, 520, 530, 540, 550, 560, 570, 580, 590,
600, 610,620, 630, 640, 650 have to be optically active to detect all of the light energy
incident on the area 54. All 16 of such optically active sectors could be positioned in one
semicircle of the area 54, or, as explained above, it is more convenient and less cluttered to
position some of the optically active sectors in one semicircle with intervening spaces and
others in the opposite semicircle diametrically opposite to the intervening spaces. In the
example of Figure 6a, any eight of the sectors, e.g., sectors 640,650, 500, 510, 520, 530,
540, 550, separated by non-active areas 641,651, 501, 511, 521, 531, 541, are positioned in
one semicircle of the area 54, while the remaining eight of the sectors 560, 570, 580, 590,
600, 610, 620, 630, also separated by non-active areas 561, 571, 581, 591, 601, 611,621,
can be positioned in the opposite semicircle, as shown in Figure 6a. When each of the 16
active optic sectors 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630,
640,650 in this arrangement is positioned diametrically opposite a non-active area, the
symmetry of the FT optic pattern 32 (Figure 5) effectively allows all of the light energy
distribution in FT optic pattern 32 to be directed with these sectors.
This principle also facilitates design and fabrication of an effective segmented radial
SLM 50, because, for every active optic sector, there can be an adjacent inactive sector or
area available for placement of electrically conductive traces to the segments, as shown by
reference back to Figures 2 and 3. For example, the inactive area 651 between active optic
segments 500 and 650 accommodates placement of traces 503, 505, and 507 (shown in
Figure 3) to respective segments 502, 504, 506 of active optic sector 500. To provide active
optic sectors to detect light energy incident on the non-active areas, for example, the non-
active area 501 in Figure 6a between active optic sectors 500, 510, the above-described
symmetry principle is applied by providing an active optic sector 590 in a position
diametrically opposite the said non-active area 501. Therefore, detection of light energy
detected in the active optic sector 590 is effectively detecting light energy incident on the
non-active area 501 between sectors 500, 510. In order to have an active optic sector
positioned diametrically opposite a non-active area, two of the active optic sectors, e.g.,
sectors 550, 560 are positioned adjacent each other without any significant intervening non-
active area, so the diametrically opposite non-active area 631 is twice as big as other non-
active areas. Therefore, according to the above-described symmetry principle, substantially
all light energy 34 of FT optic pattern 32 (Figure 5) is detectable by the sixteen 11.25°
active optic sectors 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620,630,
640,650.
Returning now to Figure 6a, vertical angular orientation is arbitrarily designated as
0°, so horizontal angular orientation is at 90°. Each active optic sector 500, 510, 520, 530,
540, 550, 560, 570, 580, 590, 600, 610, 620,630, 640, 650 is about 11.25°. Active optic
sectors from sector 640 clockwise to sector 550 are each separated by respective non-active
areas 641, 651, 501, 511, 521, 531, 541 of 11.25°. Therefore, each active optic sector from
sector 560 clockwise to sector 630 is positioned diametrically opposite a respective non-
active area 561, 571, 581, 591,601,611, 621. Therefore, to detect all the light energy
distribution in the FT optic pattern 32 (Figure 4) incident on the active area 54 can be
detected in 11.25° intervals by the 11.25° sectors 500, 510, 520, 503, 504, 550, 560, 570,
580, 590, 600, 610, 620, 630,640, 650 positioned as described above.
For example, light energy characteristic of that incident on both the vertical 11.25°
sector 500 centered at 0° as well as on the non-active area 581 centered at 180° can be
detected by effectively activating the active optical segments 502, 504, 506, 508 of sector
500. Light energy characteristic of that incident on the 11.25° sector 590 centered at
191.25" as well as on the non-active area 501 centered at 11.25° can be detected effectively
by activating the active optic segments of sector 590, because the active optic sector 590 is
centered diametrically opposite the non-active area of 11.25°. Light energy characteristic of
that incident on either the 11.25° sector 510 centered at 22.5° or the non-active area 591
centered at 202.5° can be detected by activating the active optic segments of sector 510.
Light energy characteristic of that incident on either the 11.25° non-active area centered at
33.75° or active sector 600 centered at 213.75° can be detected by activating the active optic
segments of sector 600, which is centered diametrically opposite 33.75° at 213.75". Light
energy characteristic of that incident on either the 11.25° sector 520 centered at 45° or non-
active area 601 centered at 225° can be detected by activating the active optic segments of
sector 520. Light energy characteristic of that incident on either the 11.25° non-active area
521 centered at 56.25° or the active sector 610 centered at 236.25° can be detected by
activating the active optic segments of sector 610, which is centered diametrically opposite
56.25° at 256.25°. Light energy characteristic of that incident on either the 11.25° sector
530 centered at 67.5° or the non-active area 611 centered at 247.5° can be detected by
activating the active optic segments of sector 530. Light energy characteristic of that
incident on either the 11.25° non-active area 531 centered at 78.75° or active sector 620
centered at 258.75° can be detected by activating the active optic segments of sector 620,
which is centered diametrically opposite 78.75" at 258.75". Light energy characteristic of
that incident on either the 11.25° sector 540 centered at 90° or non-active area 621 centered
at 270° can be detected by activating the active optic segments of sector 540. Light energy
characteristic of that incident on either the 11.25° non-active area 541 centered at 101.25° or
the active sector 630 centered at 281.25° can be detected by activating the active optic
segments of sector 630, which is centered diametrically opposite 101.25° at 281.25°. Light
energy characteristic of that incident on either the 11.25° sector 550 centered at 112.5° the
diametrically opposite portion of non-active area 631 that is centered at 292.5° can be
detected by activating the active optic segments of sector 550. Light energy characteristic
of that incident on the 11.25° sector 560 centered at 123.75°. The diametrically opposite
portion of non-active area 631 that is centered at 303.75° can be detected by activating the
active optic segments of sector 560. Light energy characteristic of that incident on the
11.25° non-active area 561 centered at 135° or active sector 640 centered at 315° can be
detected by activating the active optic segments of sector 640, which is centered
diametrically opposite 135° at 315°. Light energy characteristic of that incident on the
11.25° sector 570 centered at 146.25° or non-active area 641 centered at 326.25° can be
detected by activating the active optic segments of sector 570. Light energy characteristic
of that incident on the 11.25° non-active area 571 centered at 157.5° or active sector 650
centered at 337.5° can be detected by activating the active optic segments of sector 650,
which is centered diametrically opposite 157.5° at 337.5°. Finally, light energy
characteristic of that incident on the 11.25° sectors 580 centered at 168.75° or non-active
area 651 centered at 348.75° can be detected by activating the active optic segments of
sector 580.
While it would be unnecessarily cumbersome to illustrate and describe the shape
detecting and characterizing functionality of all the active optic segments of all the sectors
500, 510, 520, 530, 540, 550, 560, 570, 580,590, 600, 610, 620, 630,640, 650, it may be
helpful for an understanding of the invention to illustrate and describe the functionality and
results of activating several representative examples of the active optic segments in the
active optic area 54. Therefore, Figure 6a illustrates activation of the outer segment 508 of
the active optic sector 500 by depicting bands of light energy 34 from the FT optic pattern
32 that are incident on and reflected by the outer segment 508. These bands of light energy
34, which are dispersed fartherest radially outward in the vertical direction in the FT optic
pattern 32, emanated originally from, and correspond to, substantially vertically oriented
lines, edges, features, or details in the image 12' that have a higher spatial frequency, such
as the substantially vertical lines of the bumper and grill parts 35 in Figure 6b. As
explained above, the light energy 34 from the more intricate or closely spaced vertical parts
or lines 66 (i.e., higher spatial frequency), such as those in the front bumper and grill
portion 35 of image 12', are dispersed farther radially outward from the optical center or
axis 40, thus detectable by activating outer segments 506, 508 of vertical sector 500, while
the light energy 34 from the less intricate, more isolated and semi-isolated or farther spaced
apart vertical parts, edges, or lines (i.e., lower spatial frequency), such as the substantially
vertical parts or lines 66' in the trunk and rear bumper portions of the image 12' in Figure
6b, are dispersed not so far radially from the optical center or axis 40 and would be more
detectable by inner segments 502, 504. The intensity of the light energy 34 in those
respective dispersion bands, as explained above, depends on the brightness of the
corresponding respective vertical features 35,66, 66' in the image 12'. Again, the central
portion 41 of the active optic area 54 can be ignored, if desired, because the light energy 54
in and near the center or axis 40 of the Fourier transform 32 (Figure 5) emanates from
features in image 12' with very low or virtually no spatial frequencies, such as the overall
brightness of the image, which do very little, if anything, to define shapes. On the other
hand, as also explained above, the center portion 41 can be fabricated as an active optic
component to capture and reflect the light energy incident on the center portion 41 to the
detector 80 as a measure of overall brightness, which may be useful in calibrating, adjusting
brightness of the source light 25(s) (Figure 5), calibrating intensity (I) measurements of
sensors 84 in detector 80, and the like.
The light energy bands 34, when reflected by the activated outer segment 508, are
filtered through the polarizing beam splitter 70 and projected in the filtered optic pattern 60,
which is comprised primary of vertical lines or bands 62 of light energy illustrated
diagrammatically in Figure 6c, to the photodetector 80 (Figure 5). As discussed above, the
light energy in the filtered optic pattern 60 is detected by the light sensors 84 in detector
array 82. The intensity (I) of light energy on each sensor 84 is recorded along with the
sensor (pixel) location, preferably by x-y coordinates, and the angular orientation (R) of the
sector 500. The radial position or scale (S) of the activated segment 508 is also recorded,
for example, as RIXSel values described above. These values can be stored in a database
102 in association with information about the characterized image 12, such as image
identification (ID), source location (URL, database address, etc.) of the image 12, digital
format, resolution, colors, texture, shape, subject matter category, and the like.
To illustrate further, the near inner segment 504 of active optic sector 500 is shown
in Figure 7a as being selected to rotate plane of polarization of selected portions of the light
energy bands 34 from the FT optic pattern 32 for isolation by the polarizing beam splitter 70
and then detection by the photodetector 80. This near inner segment 504 is also in the
vertically oriented sector 500, but it is positioned or scaled radially closer to the optic axis
40 than the outer segment 508, which was activated in the previous example. Therefore,
this near inner segment 504, when activated, captures light energy 34 in the FT optic pattern
32 that also corresponds to vertical lines, edges, etc., of the image 12', but to such lines,
edges, etc., of lesser spatial frequency than those selected by the outer segment 508. For
example, instead of the closely spaced, vertically oriented bumper and grill parts 35, the
light energy 34 from the FT optic pattern 32 selected by the near inner segment 504 may be
more characteristic of the more spatially semi-isolated vertical edge 66' of the trunk lid and
other vertical lines and edges 66 of similar semi-isolation in the automobile image 12' in
Figure 6b. Therefore, the light energy bands 62 in the resulting filtered beam 61(s), as
shown in optic pattern 60 in Figure 7c, are characteristic of such vertical shape content 66,
66'in the image 12'.
Another example angular orientation of light energy 34 from the FT optic pattern 32
is illustrated by Figures 8a-c. The near outer segment 526 in this example is activated to
capture light from lines, edges, or features extending radially at an angular orientation of 45°
from vertical. Such light energy 34 is characteristic of lines, edges, or features in the image
12' that extend at about 45° and that have some spatial frequency, i.e., are not isolated, such
as, perhaps, the window post and roof support 67 in Figure 8b. Such 45° oriented lines in
the image 12' with even less spatial frequency, i.e., even more isolated, for example, the
portions of the fender and hood edges 67' might be captured more by the near inner segment
524 or inner segment 522, although it is possible that some of such light energy could also
be captured by near outer segment 506. The reflected and filtered beam 61(s) with the
optical pattern 60 for these 45° angular oriented shape contents have bands 62 of the light
energy oriented at about 45°, as illustrated diagrammatically in Figure 8c. Such light energy
bands 62 are detected by sensors 84 for photodetector 80 (Figure 5) and are recorded and
stored as characteristic of the spatial frequency of 43"-oriented shape content of the image
12".
Capture and detection of horizontal portions of lines, edges, and features 68, 68' of
the image 12' is accomplished by activation of one or more segments 542, 544, 546, 548 of
Horizontal sector 540, which is oriented 90° from the vertical 0°. The portion of the light
energy 34 that is reflected by any activated segment 542, 544, 546, 548 of the horizontal
sector 540 is characteristic of all of the substantially horizontal features, parts, and lines 68
of the image 12', as shown in Figure 9b. Some curved features, parts, or lines in the image
12' have portions or line segments 68' that are also substantially horizontal, so those
horizontal portions or line segments 68' also contribute to the light energy 34 that gets
reflected by the horizontal sector 540 in Figure 9a. The bands 62 of light energy in the
filtered pattern 60, shown in Figure 9c, resulting from the horizontal orientation of an
activated segment 542, 544, 546, 548 in Figure 9a, are also oriented substantially horizontal
and are indicative of some or all of the shape characteristics 68, 68" of image 12' that arc
oriented substantially horizontal. Again, the inner segments 542, 544 are activated to detect
light energy bands 34 from the FT optic pattern 32 that are dispersed closer to the optic axis
40, thus are characteristic of lower spatial frequency, horizontal shape content of the image
12", while higher spatial frequency, horizontal shape content can be detected by activating
the outer segments 546, 548 of the horizontal sector 540. Thus, detection of the light energy
bands 62 in Figure 9c by detector array 82 (Figure 5) facilitates encoding and recording of
the horizontal shape characteristics of the image 12', as was described above.
One more example activated segment 598 in sector 590, is illustrated in Figure 10a
to describe the symmetric light energy detection feature described above. As explained
above, the light energy bands 34 of the FT optic pattern 32 that are incident on the non-
active area between the active optic sectors 500, 510 are symmetric with the diametrically
opposite light energy bands 34, which are incident on the active optic segments 529, 594,
569, 598 in sector 590. Therefore, activation of a segment, for example, outer segment 598,
as illustrated in Figure 10a, will enable effective detection of the diametrically opposite,
equivalent light energy 34 that is incident between the segments 508, 518 of respective
sectors 500, 510. Likewise, activation of any other segment 592, 594, 596 enables effective
detection of other diametrically opposite portions of light energy that is incident in the non-
active area 501 between active sectors 500 and 510. Therefore, detecting light energy 34
incident on the sector 590, which is centered at 191.25° in the example of Figure 10a, is the
equivalent of detecting light energy 34 that is incident on the non-active area 501 centered
at 11.25°. The opposite also holds, i.e., detection of light energy 34 incident on the vertical
sector 500, as illustrated in Figures 6a and 7a and described above, is the equivalent to
detecting light energy from the FT optic pattern 32 that is incident on the non-active area
581 between active sectors 580 and 590.
Referring again to Figures lOa-c, the light energy 34 detected in the sector 590
corresponds to shape content 69, such as lines, edges, portions of curves, and the like in the
image 12' that are oriented substantially at about 191.25°, which, being linear, can also be
expressed as oriented at about 11.25°. The light energy bands 62 in the reflected and
filtered optic pattern 60 also have that same angular orientation, which is characteristic of
the linear shape content of the image 12' that has that angular orientation and that has higher
spatial frequency if reflected by outer segments 596, 598 or lower spatial frequency if
reflected by inner segments 592, 594. The optic patterns 60 resulting from such various
reflected portions of the FT optic pattern 32 are detected by the sensors 84 in detector array
82 for recording and storage, as described above.
It should be clear by now that any particular angular orientation R of segments of
sectors in the active optic area 54 will allow detection of all the shape characteristics of
image 12' that have substantially that same angular orientation R. It should also be clear
that radial outward spacing or scale (S) of the segments relates to spatial frequency of such
shape characteristics. Thus, all of the shape characteristics of the image 12' can be detected
by detecting the bands 62 of the respective filtered patterns 60 with the segments at all
angular orientations. However, as mentioned above, it is sufficient for most purposes to
detect some, preferably most, but not necessarily all, of the shape characteristics of the
image 12' by choosing to detect the light energy bands 34 of filtered patterns 60 at certain
selected increments of or angular orientation or rotation R. Obviously, the bigger the
increments of angular orientation of the sectors where light energy bands 34 are detected,
the less precise the detected shape characteristics or contents of the image 12' will be. On
the other hand, the smaller the increments of angular orientation, the more data that will
have to be processed. Therefore, when selecting the angular increments of sectors at which
light energy bands 34 will be detected and recorded, it may be desirable to strike some
balance between preciseness of shape characteristics needed or wanted and the speed and
efficiency of data processing and storage required to handle such preciseness. For example,
but not for limitation, it is believed that detection and recording of the shape characteristics
at angular increments of in a range of about 5 to 20 degrees, preferably about 11.25-degrees,
will be adequate for most purposes. Also, the angular area of detection can be varied. For
example, even if active optic sectors are oriented to detect shape characteristics at angular
increments of 11.25°, the active optic areas could be narrow, such as in a range of 3° to 8°,
more or less, which would filter out some of the optic energy from the FT optic pattern 32
between the sectors. However, such loss of light energy from non-active areas between
sectors or other radially extending sensors, as described elsewhere in this specification, may
not be detrimental shape characterization by this invention, depending on specific
applications of the technology to particular problems or goals.
Instead of the radially extending, wedge-shaped active optic sectors and segments of
sectors described above, an alternate configuration can be comprised of radially extending,
rectangular-shaped active optic modulators as illustrated diagrammatically in Figure 11.
These rectangular-shaped modulators 500',510', 520', 530', 540', 550', 560', 570', 580', 590',
600', 610', 620', 630', 640', 650' can be at the same or different angular orientations as the
wedge-shaped sectors described above, and each angular orientation can comprise several
rectangular, active optic segments, such as segments 502', 504', 506', 508' of the modulator
500'. This arrangement does not capture as much of the light energy of an incident FT optic
pattern 32 (Figure 5) as the wedge-shaped segments and sectors described above, but shape
resolution may be greater.
Another, albeit less efficient embodiment, is illustrated in Figure 12, where the
desired sectors and segments, which are shown in phantom lines, can be formed by
activating selected groups of light modulator elements 702 in a pixel array 700 type of
spatial light modulator simultaneously. For example, a virtual outer segment 508" of a
vertical sector 500" can be activated by activating simultaneously a segment group 508" of
the light modulator pixel elements 602. While there are versatility advantages to this type
of implementation, such advantages may be outweighed by the complexity and cost as
compared to the simpler configurations described above.
While the reflective spatial light modulator structure described above in connection
with the cross-sectional view of Figure 4 may be applicable to all of the segmented radial
SLM 50 configurations described above, an alternative transmissive spatial light modulator
structure 50' illustrated in Figure 13 could also be used with each of the configurations. In
this embodiment 50', the metal reflective layers 186, 188 are replaced by transparent
conducting layers 186', 188', such as indium tin oxide (ITO) or any of a number of other
well-known transparent conducting materials. Therefore, incident 27(p) may or may not
have its plane of polarization rotated, depending on whether a voltage V+ is applied to
either layer 186' or 188', but, instead of being reflected, the light is transmitted through the
device 50' to emerge as light energy 61 (s) or 61 (p), as indicated in Figure 13. this device is
mounted around its periphery in a base 56, so the base 56 does not interfere with the light
61(s) and 61(p) propagation. A different liquid crystal material 180' and/or a different
thickness of liquid crystal material than the liquid crystal material 180 for the Figure 4
embodiment would be required, since the light passes only once through the liquid crystal
material 180'. However, such materials and their applications are readily available and
well-known in the art and can be implemented by persons skilled in the art, once the
understand the principles of this invention. Also, since the light 61 (s) is transmitted rather
than reflected, the polarizing beam splitter 70 (Figure 5) would also have to be positioned
behind the segmented radial SLM 50' of Figure 13 instead of in front of it. However, this
modification could also be implemented quite easily by persons skilled in the art, thus is not
shown explicitly in Figure 5.
The accuracy, versatility, and efficiency of shape characterizing, processing, storing,
searching, comparing, and matching images according to this invention can be enhanced by
some pre-processing of the images 12, 14,..., n when creating the optical patterns for the
images 12', 14',. .., n' at the SLM 26 in Figure 5. One particularly beneficial method of
such pre-processing is "ghosting" the image to allow more light energy into the optic
pattern 12', thus also allowing more light energy into the FT optic pattern 32.
With reference now to Figures 14a-c, the ghosting process of this invention is
illustrated first with an image content of a simple dot, such as a typed period 600, which is
illustrated as greatly enlarged in Figure 14a. The computer 20 (Figure 5) or other
microprocessor can first create an image of only the edge 602 of the dot 600, as illustrated
in Figure 14b. Myriad edge-finding software programs are available commercially to
perform such edge-finding tasks, such as Labview IMAQ™ available from National
Instrument Corporation, of 11500 Mopac Expressway, Austin, Texas. More complex
images 12, 14,..., n would, of course, have more edge content. Elimination of non-edge
content of the images 12, 14,..., n does not degrade the shape characterizing function or
performance of this invention, because the edges define the shape characteristics and
produce the detectable FT optic patterns 32. As was explained above, plain, uniform,
unchanging portions of images, such as the side panel 36 of the automobile in image 12' or
the clear blue sky in a landscape picture 14 do not contribute significant detectable shape
content to such images. As also explained above, light energy from such plain, uniform,
unchanging portions of images tends to focus on or very near the optic axis 40 in Fourier
transform optic patterns 32, thus would be incident primarily on the center section 41 of the
segmented radial SLM SO (see Figure 2) and is either not detected at all or detected only to
determine background brightness of the image, as explained above.
After the image 600 is converted to an optic pattern of the edge content 602 of the
image 600, as illustrated in Figure 14b, it is ghosted by creating a plurality of ghost images
602 the edge content 602. For example, as illustrated in Figure 14c, a plurality of ghost
images 602A, 602b 602c are created and added to the optic pattern of the edge image 602.
In this example, a first set of eight ghost images 602a is added a first radial distance r1
outward from the original edge image 602 at 45° angular increments. A second set of eight
more ghost images 602b are added another radial distance r2 outward from the ghost images
602A and at 45° angular increments, and a third set of eight ghost images 602c are added
another radial distance r3 outward and at 45° increments. Each of the ghost images 602 a,
602b, 602c have the same shape and are of the same size as the original edge image 602.
Therefore, while there is more light energy and more spatial frequency in the ghosted image
602' of Figure 14c than in the edge image 602 of Figure 14b, there is no new shape content.
Consequently, there will be both a wider radial dispersement and increased intensity of light
energy 34 in the FT optic pattern 32 (Figure 5), which can be detected with the segmented
radial SLM SO and detector 80. the higher intensity light energy makes it easier for the
sensors 84 in detector 80 to detect the light energy diverted by the segmented radial SLM 50
to the detector 80
The wider radial dispersion of light energy in FT optic pattern 32 due to the higher
spatial frequency content in the ghosted image 602' of Figure 14c, as compared to the non-
ghosted image 602 of Figure 14b, would also make the recorded pixels of detected light
energy by the sensors 84 (Figure 5) somewhat less precise, thus less unique to the image
600 or 602 than would be obtained by producing the image 600 or 602 on the SLM 26
instead of the ghosted image 602'. However, this decrease in resolution capability can
actually be turned to an advantage for search and comparison applications, where near
matches as well as matches are desired. As illustrated in Figure 14c, the initial edge image
pattern 602 is bright, the nearest ring of ghost edge images 602A is less bright, the next ring
of ghost edge images 602b is even less bright, and the outermost ring of ghost edge images
602c is less bright yet. However, the ghost images 602a, 602b, 602c increase the spatial
frequency of the image 602', thus cause more radial dispersion of the light energy bands 34
in the FT optic pattern 32, so the portions of the light energy bands 34 that originate from
the initial edge image 602 in the center of the ghosted pattern 602' are brighter, i.e., more
intense, than portions of the light energy bands 34 that originate from the ghost images
602A, 602b, 602c. Therefore, while more sensors 84 of the detector array 82 will detect
light energy reflected by the segmented radial SLM SO to the detector 80 for a ghosted
image 602', the sensors 84 that sense the highest intensity (I) light energy will be the sensors
84 that correspond to the initial edge image 602, and those intensities can be recorded and
stored for future access, analysis, searching, matching, and/or retrieving, as described
above. The lesser intensities detected by other sensors 84 for light energy emanating from
the nearest ring of ghost images 602A are also recorded and stored, as are those even lesser
light intensities emanating from the other rings of ghost images 602b, 602c sensed by still
other sensors 84. Therefore, in a search and matching process with other images, matches
to the brightest or highest intensities of both images would indicate the highest probability
that the respective images are the same. If no such match can be found to the brightest or
highest intensity pixels, RIXels, or other records of optic patterns that are characterized as
described above, then comparisons to lesser intensities corresponding to ghost images 602A,
602b, 603c can be attempted to find near matches.
The ghosting process is quite simple and can be scaled to achieve a desired result.
Essentially, a software program can simply be applied to reproduce each pixel of an image
at selected locations at selected distances and at selected angular orientations in relation to
such pixel, as illustrated in the simple example of the dot 600 in Figures 14a-c. An example
of this ghosting process in a slightly more complex image 610 in the shape of a house is
illustrated in Figures 15a-c. The edges of the uniform or featureless areas of the house
image 610 are found and produced in an edge image 612,, which maintains the shape
content of the image 610, as explained above. Then the ghosting process described above is
applied to the edge image 612, as illustrated in Figure 14c, to create ghost images 612A,
612b, 612c at selected distances, angular orientations, and decreasing brightnesses the
farther the ghost images 612a, 612b, 612c are from the initial edge image 612.
The ghosting process of this invention can also be applied to images for which edges
have not been found or produced, as described above. However, more pixel processing by
the computer 20 or other processor would be required, and resulting shape resolution may
not be as sharp.
Since these and numerous other modifications and combinations of the above-
described method and embodiments will readily occur to those skilled in the art, it is not
desired to limit the invention to the exact construction and process shown and described
above. For example, Accordingly, resort may be made to all suitable modifications and
equivalents that fall within the scope of the invention as defined by the claims which follow.
The words "comprise," "comprises," "comprising," "include," "including," and "includes"
when used in this specification and in the following claims are intended to specify the
presence of stated features or steps, but they do not preclude the presence or addition of one
or more other features, steps, or groups thereof.
WE CLAIM:
1. A method of characterizing an image for shape content, comprising:
producing a Fourier transform optic pattern of the image with light energy: spatial
filtering the light energy from the Fourier transform optic pattern by selecting light energy
from discrete portions of the Fourier transform optic pattern at a plurality of angular
orientations and separating such discrete portions from other portions of the Fourier
transform optic pattern to create a plurality of filtered patterns of light energy from those
discrete portions;
projecting the light energy of said discrete portions that have been spatially
filtered in the Fourier transform optic pattern in the respective angular orientations to
inverse Fourier transform such light energy to where such light energy locates in the same
spatially related sites as the features in the image from which such light energy emanated;
detecting intensities of light energy as it is distributed in the filtered and then
inverse Fourier transformed patterns for the respective angular orientations; and
storing the intensities of light energy detected in the filtered and then inverse
Fourier transformed patterns along with the respective angular orientations.
2. The method as claimed in claim 1, which involves :
focusing the Fourier transform optic pattern onto an active optic area of a spatial
light modulator:
selectively activating portions of the spatial light modulator at selected angular
orientations to rotate plane of polarization of the discrete portions of the light energy of
the Fourier transform optic pattern;
separating light with rotated plane of polarization from light without rotated plane
of polarization; and
detecting the intensities of light that has rotated plane of polarization.
3. The method as claimed in claim 2, which involves selectively activating portions
of the spatial light modulator at selected segments positioned at different radial distances
from an optic axis of the Fourier transform optic pattern as well as in said angular
orientations.
4. The method as claimed in claim 2, which involves selectively activating portions
of the spatial light modulator to rotate plane of polarization of light energy in the Fourier
transform optic pattern that is incident on selected sectors of the active optic area of the
spatial light modulator.
5. The method as claimed in claim 4, which involves selectively activating portions
of the spatial light modulator to rotate plane or polarization of light energy in the Fourier
transform optic pattern that is incident on selected segments of the selected sectors.
6. The method as claimed in claim I, which involves :
producing a plurality of ghost images around the image that is being characterized,
each ghost image having shape content that is substantially the same as the image being
characterized; and
producing the Fourier transform optic image from the ghost images along with the
image being characterized.
7. The method as claimed in claim 6, which involves producing the ghost images
with each ghost image having less light energy than the image being characterized.
8. The method as claimed in claim 6, which involves replicating original pixels that
comprise the image being characterized and offsetting each such replicated pixel from its
corresponding original pixel by an equal distance and angular orientation to the original
pixel to create a ghost image.
9. The method as claimed in claim 8, which involves dispersing the plurality of ghost
images in a symmetrical manner around the image being characterized.
10. The method as claimed in claim 6, which involves :
findings edges of the shape content in the image being characterized and edge
image of the shape content;
replicating original pixels that comprise the edge image; and offsetting each such
replicated pixel from its corresponding original pixel by an equal distance and angular
orientation to the original pixel to create a ghost image.
11. The method as claimed in claim 10, which involves replicating the pixels that
comprise the ghost image with less light energy than the corresponding pixels of the edge
image.
12. An optical image shape content analyzer, comprising:
a Fourier transform lens having a focal point in a focal plane at a focal distance;
a spatial light filter comprising: (i) a filter spatial light modulator that has an
active optic area around a central axis positioned in the focal plane of the Fourier
transform lens with the central axis coincident with the focal point, said active optic area
comprising discrete active optic components that are capable of selective activation to
selectively rotate or not rotate plane of polarization of light incident at various angular
orientations in relation to the central axis; and (ii) a polarization analyzer thai is capable
of separating light polarized in one plane from light polarized in another plane;
an image producing spatial light modulator with an associated monochromatic
light source, wherein the image producing spatial light modulator is addressable to
produce an image in an optic pattern with light from the associated monochromatic light
source, said image producing spatial light modulator being positioned to project such an
image optic pattern of monochromatic light though the Fourier transform lens to form a
Fourier transform optic pattern of the image optic pattern at the focal plane of the Fourier
transform lens; and
a photodetector positioned to receive light filtered by the spatial light filter after
the light filtered by the spatial light filter projects out of the facal plane of the Fourier
transform lens to inverse Fourier transform said light filtered by the spatial light filter to
where such light locates in the same spatially-related sites as the features in the image
optic pattern from which such light emanated, said photodetector including an array of
sensors that are capable of detecting filtered patterns of light energy intensities in the
filtered light after such inverse Fourier transformation of the filtered light.
13. The optical image shape content analyzer as claimed in claim 12, wherein the
discrete active components arc disposed in the active optic area in a manner that extends
radially outward at various angular orientations in relation to the central axis.
14. The optical image shape content analyzer as claimed in claim 13, wherein the
discrete active components comprise individual sectors of the active optic area.
15. The optical image shape content analyzer as claimed in claim 14, wherein the
discrete active components comprise individually addressable segments of the sectors.
16. The optical image shape content analyzer as claimed in claim 15, wherein the
individually addressable segments are disposed radially in relation to the central axis to
form the active optic sectors.
17. The optical image shape content analyzer in claim 13, wherein the discrete active
components comprise rectangular components extending radially in relation to the central
axis.
18. The optical image shape content analyzer as claimed in claim 13, wherein the
active optic area comprises a rectangular spatial light modular array of active optic
elements and the discrete active components comprise active optic elements of a
rectangular array of such elements that are activatable in distance groups of such elements
that extend radially outward in relation to the central axis.
There is disclosed a method of characterizing an image for shape content,
comprising producing a Fourier transform optic pattern of the image with light energy;
spatial filtering the light energy from the Fourier transform optic pattern by selecting light
energy from discrete portions of the Fourier transform optic pattern at a plurality of
angular orientations and separating such discrete portions from other portions of the
Fourier transform optic pattern to create a plurality of filtered patterns of light energy
from those discrete portions; projecting the light energy of said discrete portions that have
been spatially filtered in the Fourier transform optic pattern in the respective angular
orientations to inverse Fourier transform such light energy to where such light energy
locates in the same spatially related sites as the features in the image from which such
light energy emanated; detecting intensities of light energy as it is distributed in the
filtered and then inverse Fourier transformed patterns for the respective angular
orientations; and storing the intensities of light energy detected in the filtered and then
inverse Fourier transformed patterns along with the respective angular orientations.

Documents:

1174-KOLNP-2004-FORM 15.pdf

1174-kolnp-2004-granted-abstract.pdf

1174-kolnp-2004-granted-assignment.pdf

1174-kolnp-2004-granted-claims.pdf

1174-kolnp-2004-granted-correspondence.pdf

1174-kolnp-2004-granted-description (complete).pdf

1174-kolnp-2004-granted-drawings.pdf

1174-kolnp-2004-granted-examination report.pdf

1174-kolnp-2004-granted-form 1.pdf

1174-kolnp-2004-granted-form 18.pdf

1174-kolnp-2004-granted-form 3.pdf

1174-kolnp-2004-granted-form 5.pdf

1174-kolnp-2004-granted-gpa.pdf

1174-kolnp-2004-granted-letter patent.pdf

1174-kolnp-2004-granted-reply to examination report.pdf

1174-kolnp-2004-granted-specification.pdf


Patent Number 223041
Indian Patent Application Number 1174/KOLNP/2004
PG Journal Number 36/2008
Publication Date 05-Sep-2008
Grant Date 03-Sep-2008
Date of Filing 13-Aug-2004
Name of Patentee LOOK DYNAMICS, INC
Applicant Address 2500 TRADE CENTRE, LONGMONT, CO
Inventors:
# Inventor's Name Inventor's Address
1 CRILL RIKK 2942 BOW LINE PLACE, LONGMONT, CO 80501
PCT International Classification Number G02F
PCT International Application Number PCT/US03/01281
PCT International Filing date 2003-01-16
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10/051,364 2002-01-18 U.S.A.