U.S. patent application number 10/922394 was filed with the patent office on 2005-01-27 for optical processor architecture.
This patent application is currently assigned to Lenslet Ltd.. Invention is credited to Konforti, Naim, Mendlovic, David, Sariel, Aviram.
Application Number | 20050018295 10/922394 |
Document ID | / |
Family ID | 26323841 |
Filed Date | 2005-01-27 |
United States Patent
Application |
20050018295 |
Kind Code |
A1 |
Mendlovic, David ; et
al. |
January 27, 2005 |
Optical processor architecture
Abstract
Apparatus for optically applying a transform to data,
comprising: a spatially modulated light source, that generates a
spatially modulated light beam; a diffractive element that
replicates said light beam; and a lens that applies a Fourier
transform to said replicated light beam.
Inventors: |
Mendlovic, David;
(Petach-Tikva, IL) ; Konforti, Naim; (Holon,
IL) ; Sariel, Aviram; (Ramot-Hashavim, IL) |
Correspondence
Address: |
William H. Dippert, Esq.
c/o Reed Smith LLP
29th Floor
599 Lexington Avenue
New York
NY
10022-7650
US
|
Assignee: |
Lenslet Ltd.
Herzeliya
IL
|
Family ID: |
26323841 |
Appl. No.: |
10/922394 |
Filed: |
August 19, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10922394 |
Aug 19, 2004 |
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09979183 |
Jul 15, 2002 |
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09979183 |
Jul 15, 2002 |
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PCT/IL00/00283 |
May 19, 2000 |
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Current U.S.
Class: |
359/558 ;
375/E7.226 |
Current CPC
Class: |
G06T 7/262 20170101;
G06K 9/58 20130101; H04N 19/60 20141101; G06E 3/005 20130101 |
Class at
Publication: |
359/558 |
International
Class: |
G03H 001/12; G02B
005/18 |
Foreign Application Data
Date |
Code |
Application Number |
May 19, 1999 |
IL |
130038 |
Jul 25, 1999 |
IL |
131094 |
Sep 5, 1999 |
WO |
PCT/IL99/00479 |
Claims
1. Apparatus for optically applying a transform to data,
comprising: a spatially modulated light source, that generates a
spatially modulated light beam encoding said data by said
modulation; a diffractive element that replicates said light beam;
and a lens that applies a Fourier transform to said replicated
light beam.
2. Apparatus according to claim 1, comprising a detector that
detects said transformed light.
3. Apparatus according to claim 2, comprising electronic circuitry
that converts said detected signals into a discrete transform of
said data.
4. Apparatus according to claim 3, wherein said transform is a
linear transform.
5. Apparatus according to claim 3, wherein said transform is a DCT
transform.
6. Apparatus according to claim 1, wherein said replicating
comprises replicating said beam to a two dimensional
arrangement.
7. Apparatus according to claim 1, wherein said diffractive element
comprises a Dammann grating.
8. Apparatus according to claim 1, wherein said diffractive element
comprises a Ronchi grid.
9. Apparatus according to claim 1, wherein said spatially modulated
light encodes said data as an array of blocks.
Description
RELATED APPLICATIONS
[0001] This application is a Divisional filing of U.S. application
Ser. No. 09/979,183, filed on Jul. 15, 2002 which is a U.S.
national filing of PCT Application No. PCT/IL00/00283, filed on May
19, 2000, which is a continuation-in-part of U.S. application Ser.
No. 09/926,547, filed on Mar. 5, 2002 which is a U.S. national
filing of PCT Application No. PCT/IL99/00479, filed on Sep. 5,
1999, the disclosures of all of which are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of optical
processor architectures
BACKGROUND OF THE INVENTION
[0003] A general linear transformation (GLT) in its discrete form
is defined by its kernel function W. The transformed function G as
a function of a two dimensional input g(x,y) is thus:
G(.xi., .eta.)=.SIGMA..SIGMA.g(x,y)W(x, y; .xi., .eta.) (1)
[0004] For a two dimensional object having the size of 1000 by 1000
pixels, a general linear transformation requires 10.sup.12
multiplications.
[0005] The equation (1) for a one dimensional vector is:
G(.xi.)=.SIGMA.g(x)W(x; .xi.) (2)
[0006] In matrix formulation, equation (2) becomes 1 [ G 1 G 2 G N
] = [ g 1 g 2 g N ] [ W 11 W 12 W 1 N W 21 W 22 W N1 W NN ] ( 3
)
[0007] , showing that a GLT can be performed as a vector-matrix
multiplication.
[0008] Dammann gratings are described, for example in "High
Efficiency In-Line Multiple Imaging by Means of Multiple Phase
Holograms", H. Damman, K. Gortler, Optics communications, 3(5),
321-315
[0009] The following is a partial list of publications that
describe one or more of optical processing methods, optical
processors and cross-bar switches: For example: "Cosinusoidal
transforms in white light," by N. George and S. Wang, in Applied
Optics, Vol. 23, No 6, 1984; "Hartley transforms in hybrid pattern
matching," by Nomura, K. Itoh and Y. Ichioka, in Applied Optics,
Vol. 29, No. 29, 1990; "Lens design for a white light cosine
transform achromat," by K. B. Farr and S. Wang, in Applied Optics,
Vol. 34, No. 1, 1995; "Optical computing," by Feitelson in a
chapter titled, "Optical image and signal processing," pp. 102-104
(general discrete linear transforms using lenslet array) and pp.
117-129 (which describe matrix multiplication), MIT press 1988;
"Optical crossbar interconnected digital signal processor with
basic algorithms," by A. D. McAulay, in Optical engineering, Vol.
25, P. 25, 1986; "Historical perspectives: Optical crossbars and
optical computing," by R. Arrathoon, in Proc. SPIE, Vol. 752, P. 2,
1987; "Optoelectronic parallel computing system with optical image
crossbar switch," by M. Fukui, in Applied Optics 32, 6475-6481,
1993; "Optical crossbar elements used for switching networks," by
Y. Wu, L. Liu and Z. Wang, in Applied Optics, Vol. 33, No. 2,
175-178, 1994; "Implementation of an optical crossbar network based
on directional switches," by KH. Brenner and T. M. Merklein, in
Applied Optics, Vol. 31, No. 14, 2446-2451, 1992; "Fully parallel,
high-speed incoherent optical method for performing discrete
Fourier transforms," by J. W. Goodman, A. R. Dias and L. M. Woody,
in Optics Letters, Vol. 2, No. 1, 1-3, 1978; "High throughput
optical image crossbar switch that uses a point light source
array," by M. Fukui and K. Hitayama, Optics Letters, Vol. 18, No.
5, 376-378, 1993; "Performance of 4.times.4 optical crossbar switch
utilising acousto optic deflector," by P. C. Huang, W. E. Stephens.
C. Banwell, and L. A. Reith, Electronics Letters, Vol. 25, No.4,
252-253, 1989; "Link analysis of a deformable mirror device based
optical crossbar switch," by R. W. Cohn, Optical Engineering Vol.
31, No. 1, 134-140, 1992; "Compact optical crossbar switch," S.
Reinhorn, Y. Amitai, A. A. Friesem, A. W. Lohmann and S.
Gorodeisky, Applied Optics, Vol. 36, No. 5, 1039-1044, 1997;
"Microlens array processor with programmable weight mask and direct
optical input," by V. Schmid, E. Lueder, G. Bader, G. Maier and J.
Siegordner, Proc. SPIE Vol. 3715, 175-184, 1999; and European
patent application publication 0577258 by Nakajima et. al.
entitled: "Picture compressing and restoring system and record
pattern forming method for a spatial light modulator." The
disclosures of all of the above publications are incorporated
herein by reference.
SUMMARY OF THE INVENTION
[0010] An aspect of some embodiments of the invention relates to
using a diffractive optical replicator, for example a Dammann grid,
or a Ronchi grating to replicate a light source. The replicated
light source may be used, for example, to perform a DCT transform
using a Fourier transforming system. In one exemplary embodiment,
the light source comprises an array of VCELs or an SLM image. The
replicated light is transformed using a lenslet array and the
transformed light is detected by a photo-electric detector.
[0011] An aspect of some embodiments of the invention relates to
applying a transform to a linear one dimensional source, by
spreading the source in a direction perpendicular to the extent of
the light source and optically processing the spread light. In one
embodiment, the source, for example a one-dimensional array of
VCELs is spread using a lens or a reflector, such as a parabolic
reflector. In another embodiment, the source is spread using
non-imaging optics, for example light guides.
[0012] In some embodiments of the invention the light source is
spatially and/or temporally coherent. In other embodiments, an
incoherent light source is used. Also, instead of electro-optical
detection, in some embodiments the transformed light is used for
further processing, optionally being detected by an array of
optical fibers or by a lens or lenslet array.
[0013] There is thus provided in accordance with an exemplary
embodiment of the invention, apparatus for optically applying a
transform to data, comprising:
[0014] a spatially modulated light source, that generates a
spatially modulated light beam encoding said data by said
modulation;
[0015] a diffractive element that replicates said light beam;
and
[0016] a lens that applies a Fourier transform to said replicated
light beam. Optionally, the apparatus comprises a detector that
detects said transformed light. Optionally, the apparatus comprises
electronic circuitry that converts said detected signals into a
discrete transform of said data. Optionally, said transform is a
linear transform. Optionally, said transform is a DCT
transform.
[0017] In an exemplary embodiment of the invention, said
replicating comprises replicating said beam to a two dimensional
arrangement. Alternatively or additionally, said diffractive
element comprises a Dammann grating. Alternatively, said
diffractive element comprises a Ronchi grid.
[0018] There is also provided in accordance with an exemplary
embodiment of the invention, apparatus for optically applying an
transform to data, comprising:
[0019] a linear array of light sources;
[0020] at least one first optical element for converting light from
said arrays into a two dimensional array of light, wherein each
light source is a line in said two dimensional array of light;
[0021] at least one transforming optical element that applies a
transform to said spread light; and
[0022] at least one second optical element that combines said
transformed spread light onto a linear detector array,
[0023] wherein said first optical element is one of reflective,
anamorphic or non-imaging. Optionally, said first optical element
is an anamorphic cylindrical lens having different focal lengths in
two directions. Alternatively, said first optical element is an
anamorphic reflector having different focal lengths in two
directions. Alternatively, said first optical element is a curved
reflector. Optionally, said first optical element is a parabolic
reflector. Alternatively or additionally, said first optical
element comprises a non-imaging optics element. Optionally, said
first optical element comprises a leaky light guide.
[0024] In an exemplary embodiment of the invention, said second
optical element comprises a lens. Optionally, said second optical
element comprises an anamorphic lens.
[0025] In an exemplary embodiment of the invention, said second
optical element comprises a reflector.
[0026] In an exemplary embodiment of the invention, said second
optical element comprises a non-imaging optics light collector.
[0027] In an exemplary embodiment of the invention, said first
optical element comprises an array of light guiding slabs.
Alternatively or additionally, said transforming optical element
comprises a mask. Alternatively or additionally, said transforming
optical element comprises an SLM (spatial light modulator).
Alternatively or additionally, said transforming optical element
comprises a lenslet array. Alternatively or additionally, said
detector is an electro-optic detector.
BRIEF DESCRIPTION OF THE FIGURES
[0028] Some embodiments of the present invention will be now be
described in the following detailed description and with reference
to the attached drawings, in which:
[0029] FIG. 1 is a general flowchart showing a processing method in
accordance with an exemplary embodiment of the invention;
[0030] FIG. 2 is a general flowchart showing a fan-out and fan-in
section of the method of FIG. 1;
[0031] FIG. 3 is a schematic flowchart of a combined optical and
electronic processing method in accordance with an exemplary
embodiment of the invention;
[0032] FIG. 4 is a schematic diagram of an optical processing
system using a Dammann grating in accordance with an exemplary
embodiment of the invention;
[0033] FIGS. 5A and 5B are a top and a side schematic views of a
linear source optical processing system in accordance with an
exemplary embodiment of the invention;
[0034] FIGS. 6A and 6B are a top and a side schematic views of a
non-imaging optics optical processing system in accordance with an
exemplary embodiment of the invention; and
[0035] FIG. 7 is a schematic view of a two dimensional optical
processing system, in accordance with an exemplary embodiment of
the invention.
DETAILED DESCRIPTION OF SOME EMBODIMENTS
[0036] FIG. 1 is a general flowchart 100 showing a processing
method in accordance with an exemplary embodiment of the invention.
Stored data (102) is transferred to a processor (104), processed,
preferably optically (106), transferred back to a memory (108) and
stored again (110).
[0037] In accordance with some embodiments of the invention,
optical means are used to parallelize the processing (106). FIG. 2
is a general flowchart 200 showing a fan-in and fan-out section of
the method of FIG. 1. Many processes can be made parallel by
fanning out the input (202), processing the fanned-out input in
parallel (204) and the collating the results (fan in 206). In
particular, a GLT can be performed as a plurality of simultaneous
multiplications of various elements, followed by adding together of
the multiplication results. In some exemplary embodiments of the
invention, optical means are used to provide efficient fan in or
fan out mechanisms.
[0038] FIG. 3 is a schematic flowchart 300 of a combined optical
and electronic processing method in accordance with an exemplary
embodiment of the invention. Prior to any optical processing,
electronic preprocessing may be performed (302), for example to
perform calculations more efficiently carried out electronically,
calculations that utilize existing hardware, to match the data to
the processing system and/or the processing to be performed and/or
to prepare the data for parallel processing. However, in some
embodiments, no pre-processing is performed, for example, an
optical input image may be directly optically processed. The
electronic data is then converted to an optical representation
(304), for example using an SLM or an array of individually
controllable light sources. The light is then optically processed
(306), using various means, such as lens, holograms, SLMs, masks
and/or lenslet arrays. The processed light may be directly
utilized, for example in optical communications systems or for
displaying or printing an image. Alternatively or additionally, the
light is detected (308), for example using a CCD. Optionally, the
detected signals are further electronically processed (310), for
example to perform addition or other post processing more
conveniently carried out using electrical circuitry. Alternatively
or additionally, the detected signals are provided to an electronic
circuitry.
[0039] In an exemplary application of the invention, a linear
transform implemented is a Fourier based transform, for example
JPEG-DCT. However, the following described optical processor
architectures may be used for other linear transforms as well
and/or for processing, such as switching, error correction and
signal compression, for example using a ID wavelet transform.
Alternatively or additionally, non-linear transforms and processing
may also use a similar architecture or elements from the
architectures described herein.
[0040] GLT can be used in many fields, including, for example,
image compression, image enhancement, pattern recognition, signal
identification, signal compression, optical interconnects and
crossbar systems, morphologic operations, logical operations, image
and signal transformation and modeling neural networks.
[0041] Although not required, in some embodiments of the invention,
the input data set is processed as a series of bit planes, with the
results of the transform of each bit plane being added together to
yield the required transform of the input data. The following
equation describes the relationship between the Fourier
transforming of bit plane separated and unseparated data: 2 F ( i 2
i a i ) = i 2 i F ( a i )
[0042] This equation is correct for all linear transformations and
enables translation of a gray level (with M gray levels) linear
transformation to a set of log.sub.2M transforms of binary input
data. It should be noted that in many cases, modulation of binary
signals provides faster operation rates and better performance.
[0043] FIG. 4 is a schematic diagram of an optical processing
system 400 using a Dammann grating 408 for image replication, in
accordance with an exemplary embodiment of the invention.
Alternatively, other diffractive elements may be used for
replication, for example a Ronchi grating. The input source is a
one or two dimensional array 404, which can be for example, a VCSEL
array, a LED array, a laser array, and/or a light source combined
with a spatial light modulator (SLM), for example, acousto-optic,
liquid crystal, mechanical or MQW (multi quantum wells)
modulators.
[0044] In an exemplary embodiment an 8 by 8 array of light sources
is used for array source 404. Driver circuitry 402, which is
typically electronic, but may also be of other types, such as
optical, drives array source 404 in correspondence with the input
data to system 400.
[0045] The image on array 404 is collimated a lens 406 and
replicated by a replicating structure, for example a Dammann
grating 408. The replicated images are then processed, for example
using a masking convolution or using a lenslet array. One example
of a masking convolution uses a mask array 410. Th results of the
processing are optionally collected, for example using a lenslet
array 412 onto an array of detectors 414. The signals generated by
the detectors may be further processed by circuitry 416. Array 410
can be a standard half-tone mask or it may be a gray scale mask. A
passive element may be used. Alternatively, an actively
controllable element, such as an SLM (spatial light modulator) may
be used. Although a linear response mask is preferred, in some
embodiments, a non-linear response mask is used instead. Also it is
noted that in some uses, such as JPEG image compression, not all
the coefficients are strictly required, so they may be omitted from
the mask.
[0046] A potential advantage of a Dammann grating is that the
replication is almost identical to the original even if the input
illumination is not uniform. A potential advantage of VCSELs is
that even though each one of the sources is coherent, the sources
are not coherent between themselves, so there may be fewer
interference effects. However, neither a Darnmann grating nor a
VCSEL are strictly required and they may be replaced by other
elements, in accordance with some embodiments of the invention.
[0047] Typically, the GLT function W(x,y;.xi.,.eta.) to be
performed is determined by masks 410 and/or lenslet array 412.
Although fixed masks 410 may be used, in some embodiments of the
invention, masks 410 are controllable, for example being SLMs,
binary or gray level.
[0048] An analysis of an exemplary system 400 is as follows:
[0049] The imaging relation of the main lens provides: 3 1 u + 1 v
= 1 f ,
[0050] where U is the distance between array source 404 and lens
406 and v is the distance between Dammann grating 408 and mask
array 410.
[0051] The magnification ratio is: 4 M = u v
[0052] The resolution condition: 5 2.44 f # < 250 m M
[0053] when 250 .mu.m is the pitch of the laser sources (in other
embodiments, a different pitch may be available). A field of view
(FOV) restriction in order to avoid spherical lens distortions may
be applied as: 6 F O V = x v < 0.8 [ rad ]
[0054] where .DELTA.x is the transaxial extent of detector array
414. Although system 400 is not rectangular, in some embodiments,
it may be. Optionally, a reflective optical element is used to fold
optical paths and/or shorten the system.
[0055] A volume V restriction condition may be defined, for example
arbitrarily requiring a volume of less than 4000 cubic mm:
V=(u+v).multidot.[max{.DELTA.x,D}].sup.2<4000 [mm.sup.3]
[0056] where D is the diameter of the lens.
[0057] A cross talk condition can be defined as the interference
between two neighbored replica: 7 2.44 f # 20 < a 250 m M
[0058] where "a" is the required separation ratio between replica
and 20 is an empirical constant. The "a" ratio may be extracted
from this equation, assuming that each block is 8.times.8 pixels in
size: 8 x = 2 a 8 8 250 m M
[0059] In a particular implementation f=8 mm, f#=1, the light
wavelength is 1 .mu.m and M=5, a following setup configuration can
be achieved:
[0060] .DELTA.x=6.4 mm
[0061] v=9.6 mm, u=48 mm
[0062] FOV=38 [deg].
[0063] V=3686.4 [mm.sup.3]
[0064] In another particular implementation: M=4, f=8 mm, f#=1, and
the light wavelength is 1 .mu.m. Resulting in:
[0065] .DELTA.x=8 mm
[0066] v=10 mm, u=40 mm
[0067] FOV=46 [deg].
[0068] V=3200 [mm.sup.3]
[0069] In some embodiments, the Dammann grating is a multi channel
Dammann grating that replicates block portions of the input image,
rather than the entire input image as a whole, which may be
associated with a lenslet array instead of lens 406, for
implementing a multi-channel system.
[0070] Another potential advantage of using a diffractive element
is that a spatial shifting of the output can be achieved by varying
the input wavelength. In one exemplary embodiment, a tunable laser
input is used, with different wavelengths being used for different
output positions and/or scales. Alternatively or additionally, a
wavelength responsive reflector, lens or additional optical element
may be used to shift the results for different wavelengths. Other
wavelength shifting techniques can be used as well, for example,
very fast modulators in combination with sensitive detection
systems.
[0071] FIGS. 5A and 5B are a top and a side schematic views of a
linear source optical processing system 500 in accordance with an
exemplary embodiment of the invention.
[0072] In system 500, a linear light source 504, for example an
array of VCSELs is driven by electronic circuitry 502 to generate a
one dimensional pattern. Although a discrete source array is shown,
in some embodiments, a continuous source array may be provided. It
should be noted that although a straight one dimensional source is
shown, the source may also be curved and/or folded with
corresponding changes in other elements and/or their positioning.
Alternatively, other methods of providing a one-dimensional light
source may be provided. The spatially modulated light is spread in
a transaxial direction by at least one lens 506, for example a
single cylindrical lens. Optionally, the lens is an anamorphic
lens, with different focal lengths for its two axes. The spread
light is then processed by a two dimensional optical element 510,
for example an array of masks. Alternatively or additionally, an
active element may be used instead, for example an LCD or other
type of light valve array. A second lens system 512, also
optionally anamorphic collects the light onto a linear detector
array 514, which is, for example, perpendicular to source array
504, so that it collects processed light from all of the sources
together. Optional post processing may be performed by a processor
516 connected to detectors 514. The arrays may be, for example, 64
element long, to support an 8.times.8 block operation.
[0073] One possibly restriction of system 500 is generated by the
resolution available in the Fourier plane. Assume a 256 gray level
transformation mask 510 with a spatial production resolution of
.delta.=0.5 .mu.m. Then, the size of each pixel in the
transformation mask ought to be: .delta.L=.delta.{square
root}{square root over (256)}=0.5 .mu.g.multidot.16=8 [cm]
[0074] This size typically defines the maximal resolution in the
Fourier plane. Such a resolution requires: 9 f 64 x = L
[0075] where .delta.ox is the size of the VCSEL cell and f is the
lens focal length.
[0076] In an exemplary embodiment of system 500, using a VCSEL
vector of 64 pixels, .delta.x=50 .mu.m and .lambda.=1 .mu.m (the
wavelength of the light):
[0077] f=50.multidot.64.multidot.8 .mu.m=2.56 [cm]
[0078] resulting in a system length of 4f=10.24 [m]. If a f#=1 lens
is used, a lens aperture of 10 D = f f # = 2.56 [ cm ]
[0079] is obtained. A typical volume V of this exemplary system
is:
V=(4f).multidot.D.sup.2=10.24.multidot.(2.56).sup.2=6710
[mm.sup.3]
[0080] It should be noted that in this and other exemplary
estimated measurements, different manufacturing and/or design
constrains will yield different results.
[0081] FIGS. 6A and 6B are a top and a side schematic views of a
non-imaging optics optical processing system 600 in accordance with
an exemplary embodiment of the invention. System 600 is
characterized in that the light from a point source is spread using
non-imaging means.
[0082] In system 600, an array of point sources 604, driven by
circuitry is spread by non-imaging means, for example an array of
planar light guides 606, which widen from a point to a line.
Optionally, the use of light guides prevents or reduces cross-talk
between channels. Alternatively, other means, such as mirrors or
diffuse reflectors, may be used. Light sources 604 may be behind
the effective linear source or they may be at a different angle,
for example to the side. In one embodiment, the light is spread by
scattering along a light guide to outside of the light guide. In
another example, the light is conveyed along a light guide using
total internal reflections, and exists the light guide via a
diffraction grating or other non-uniformity of the surface. In a
particular embodiment of the invention, each of light guides 606
comprises a distorted parabolic reflector, with a light source 604
so located in it that the light from the source is reflected by the
reflector to extend the entire width of the light guide, at its
end. In one dimension, the parabolic reflector generates a parallel
beam of light from a point source placed in its focal point, so
that the light does not exit the light guide. In some embodiments,
no physical light guide is provided beyond a parabolic or other
design reflector. The expansion of light in the other dimension may
be supported by a distortion of the parabola or by using other
suitable curves as known in the art of light reflecting.
Alternatively or additionally, non-imaging optics techniques are
used to spread the light, for example a suitably designed light
guide. It should be noted that parabolic or other reflectors may
also be used in conjunction with the embodiment of FIGS. 5A and 5B,
for example for light collection.
[0083] Light exiting from light guides 606 is processed by an
optical element 610, for example a mask or an SLM. The results of
the processing are collected by a second set of light guides 612,
to an array 614 of detectors. Alternatively, a lens may be used to
collect the processed light. Optionally, a diffuser is placed
adjacent element 610, to assist in imaging the processed light. In
an alternative embodiment (also suitable for system 500) detectors
614 may be an array of linear detectors, for example, each element
having a length equal to the width of the system. Alternatively or
additionally, the light sources may be an array of linear light
sources.
[0084] A potential advantage of not having imaging elements is that
the resulting system may be more robust.
[0085] In an exemplary parametric design, if IL.sub.FOV denotes the
illumination field of view of the light source, then: 11 y = 2 y 0
= 2 1 4 p
[0086] where .DELTA.y is the width of the optical processor.
Assuming that .delta. is the size of the VCSEL: 12 p ( 64 ) = tan (
IL FOV 4 ) Thus : y = 64 2 tan ( IL FOV 4 )
[0087] For an exemplary IL.sub.FOV of 30 degrees and .delta.250
.mu.m, a value of .DELTA.y=60 mm is obtain. An approximate volume
for such an element is:
V=(64.multidot..epsilon.).sup.2.DELTA..sub.y=15.5 [cm.sup.3]
[0088] FIG. 7 is a schematic view of a two dimensional optical
processing system 700, in accordance with a n exemplary embodiment
of the invention.
[0089] A 2-D input (702) having N*N pixels requires a kernel having
N.sup.2*N.sup.2 pixels. In this case the space multiplexing may be
more complex than the one in the 1-D input case. The transformation
may be written as: 13 I o ( k , l ) = m n I in ( m , n ) K ( m , n
; k , l )
[0090] In an exemplary embodiment, the kernel mask is divided into
2-D blocks and the index of each block will represent the output
coordinate k,l while the location within each block m,n will
represent the required kernel matrix. In this notation in order to
perform the transformation the input I.sub.in(m,n) is replicated to
each block, multiplied by the value of the kernel there and summed
to a single value k,l in the output plane.
[0091] In an incoherent illumination embodiment, the 2-D summation
may be obtained using a lens attached to each block of the kernel,
for example a lenslet array 710. The replication of the input may
be done via a Dammann grating 706 or an array of prisms which are
attached to the aperture of an imaging lens 704 (at 706, for
example, instead of the grating). A direction correcting prism
array may be provided at a replicated image plane 708.
[0092] In an embodiment using an incoherent illumination pattern,
the kernel mask may be limited to being positive since the phase
information is lost by the incoherence. Thus, in order to implement
a general transformation kernel three or more parallel processing
paths are optionally used. Each pixel of the input as well of the
kernel may be represented in the following manner:
I.sub.in(m,n)=a.sub.0.sup.I(m,n)+a.sub.1.sup.I(m,n)e.sup.2.pi.i/3+a.sub.2.-
sup.I(m,n)e.sup.4.pi.i/3
K(k,l,m,n)=a.sub.0.sup.K(k,l;m,n)+a.sub.1.sup.K(k,l;m,n)e.sup.2.pi.i/3+a.s-
ub.2.sup.K(k,l;m,n)e.sup.4.pi.i/3
[0093] The splitting into the three processing paths can be
performed, for example, using a Dammann grating or a prisms set
attached to an imaging lens. The transformation of each path is
performed and then the three paths are summed to obtain the total
output according to: 14 I o ( k , l ) = m n a 0 I ( m , n ) a 0 K (
k , l ; m , n ) + a 1 I ( m , n ) a 2 K ( m , n ) + a 2 I ( m , n )
a 1 K ( m , n ) + 2 / 2 m n [ a 0 I ( m , n ) a 1 K ( k , l ; m , n
) + a 1 I ( m , n ) a 0 K ( m , n ) + a 2 I ( m , n ) a 2 K ( m , n
) ] + 4 / 3 m n [ a 0 I ( m , n ) a 2 K ( k , l ; m , n ) + a 1 I (
m , n ) a 1 K ( m , n ) + a 2 I ( m , n ) a 0 K ( m , n ) ]
[0094] It should be noted that within each one of the three
processing paths three sub processing operations are applied when
the most general input representation is used. For a positive input
each path contains only one sub-processing path.
[0095] It is noted that instead of three spatial processing paths,
one or more of the three "paths" may be implemented by using a
single system 700 multiple times, one for each processing path.
[0096] For a real input/kernel an embodiment with two main
processing paths can be used: for the positive and the negative
values. In this case the output distribution should be obtained as:
15 I o ( k , l ) = m n [ a 0 I ( m , n ) a 0 K ( k , l ; m , n ) +
a 1 I ( m , n ) a 1 K ( m , n ) ] - m n [ a 0 I ( m , n ) a 1 K ( k
, l ; m , n ) + a 1 I ( m , n ) a 0 K ( m , n ) ]
[0097] where a.sub.0 represents the positive values and a.sub.1 the
negative ones.
[0098] It should be noted that the subtraction of the previous
equation may be performed by using the same detector and performing
the processing in two cycles. In the second cycle the voltage of
the output detector is inverted. The first path is done in the
first processing cycle and it loads the capacitor of the detector.
In the second cycle the inversion starts to unload the capacitor
and thus a subtraction between the two results is obtained.
[0099] The present application is related to the following four PCT
applications filed on same date as the instant application in the
IL receiving office, by applicant JTC2000 Development (Delaware),
Inc.: attorney docket 141/01582 which especially describes matching
of discrete and continuous optical elements, attorney docket
141/01541 which especially describes reflective and incoherent
optical processor designs, attorney docket 141/01581 which
especially describes a method of optical sign extraction and
representation, and attorney docket 141/01542 which especially
describes a method of processing by separating a data set into
bit-planes and/or using feedback. The disclosures of all of these
applications are incorporated herein by reference.
[0100] It will be appreciated that the above described methods and
apparatus for optical processing may be varied in many ways,
including, changing the order of steps, which steps are performed
using electrical components and which steps are performed using
optical components, the representation of the data and/or the
hardware design. In addition, various distributed and/or
centralized hardware configurations may be used to implement the
above invention. In addition, a multiplicity of various features,
both of methods and of devices, have been described. It should be
appreciated that different features may be combined in different
ways. In particular, not all the features shown above in a
particular embodiment are necessary in every similar embodiment of
the invention. Further, combinations of the above features are also
considered to be within the scope of some embodiments of the
invention. In addition, the scope of the invention includes methods
of using, constructing, calibrating and/or maintaining the
apparatus described herein. When used in the following claims, the
terms "comprises", "comprising", "includes", "including" or the
like mean "including but not limited to".
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