Abstract: To provide a magnetic sensor element and a magnetic sensor device that can be easily manufactured and can reduce a loss of light to the extent possible. The above-described problem is solved by a magnetic sensor element comprising a planar lightwave circuit (11) provided with a light branching part (12), an input optical fiber (19) and an output optical fiber (20) connected to the planar lightwave circuit (11), a metal magnetic body type light transmitting film (30) that is provided on one end surface of the planar lightwave circuit (11) and transmits light entered from the input optical fiber (19), and a reflecting film (40) that is provided on the metal magnetic body type light transmitting film (30) and reflects the transmitted light. The output optical fiber (20) is a polarization-plane maintaining optical fiber, and the input optical fiber (19) and the output optical fiber (20) are aligned and connected to the planar lightwave circuit (11).

Abstract: Systems and methods which provide iterative multi-directional image searching are described. Embodiments utilize a multi-directional searching pattern for defining one or more searching areas within a source image. A searching area of embodiments provides a searching area within a source image for searching for a template image in the multiple directions of the multi-directional searching pattern. A location of the searching area within the source image may be updated iteratively, such as based upon motion vectors derived from the searching, until a template image match position is identified within the source image. Embodiments transform the template image and the searching area within a source image to 1D representations corresponding to each direction of the multi-directional image search. Embodiments accommodate rotation and scale variance of the subject (e.g., object of interest) of the template image within the source image.

Abstract: A computer device tracks a field of view of a user wearing augmented reality eyewear, wherein within the field of view of the user the user utilizes one or more computing devices. The computing device identifies an orientation of the one or more computing devices. The computing device determines whether to present a holographic display to the user in two dimensions (2-D) or three dimensions (3-D) based, at least in part, on the orientation of the one or more computing devices. The computing device generates the holographic display and displays the holographic display to the user via the augmented reality eyewear, wherein the holographic display extends beyond a boundary of the one or more computing devices. The computing device updates the holographic display based, at least in part, on activity of the user.

Abstract: Provided are a projection apparatus and an interface apparatus that have a small size and low power consumption and can perform high-resolution multicolor display, without color breakup. The projection apparatus includes a light source emitting laser beams of a plurality of colors, a modulation means that has a phase-modulation-type modulation element including display regions corresponding to each color of the laser beams of the plurality of colors emitted from the light source and modulates incident laser beams, an unnecessary component removal means that removes the unnecessary components, which are generated by the modulation of laser beams of other colors mixed in the display regions corresponding to the laser beams of the plurality of colors, from the laser beams modulated by the modulation means using wavelength selection; and a projection means that projects light from which the unnecessary components have been removed by the unnecessary component removal means.

Abstract: An electronic-component assembly system is provided in the invention. The electronic-component assembly system includes a gripping device, a light-source device, a photographing device, and an image-processing device. The gripping device grips an electronic component, wherein the electronic component includes at least one pin. The light-source device includes a light source and emits light of the light source. The photographing device senses the light and generates a plurality of first one-dimensional images corresponding to the pins at different rotation angles. The image-processing device is coupled to the photographing device to receive the plurality of first one-dimensional images.

Abstract: Techniques for extracting phase data of off-axis interferogram images are disclosed. At least one sample-related interferogram image associated with a sample is spectrally decomposed to obtain a set of frequency components thereof, and a portion of the set of frequency components is used to generate at least one complex image having a reduced size being smaller in size than the sample-related interferogram image and being indicative of the phase data of the at least one sample-related interferogram image. The reduced size complex image is then used to generate a phase image of the least one sample-related interferogram image.

Abstract: A Wiener filter for equalizing an effect of a first filter on an input signal which is subject to the first filter and to noise and/or interference, wherein: the first filter is dependent on at least one unknown quantity; and the Wiener filter is configured based on an averaged representation of the first filter averaged over the at least one unknown quantity, in place of a representation of the first filter being assumed to be known.

Abstract: A quantum memory system includes a chalcogenide optical fiber link, a magnetic field generation unit and a pump laser. The chalcogenide optical fiber link includes a photon receiving end opposite a photon output end and is positioned within a magnetic field of the magnetic field generation unit when the magnetic field generation unit generates the magnetic field. The pump laser is optically coupled to the photon receiving end of the chalcogenide optical fiber link. The chalcogenide optical fiber link includes a core doped with a rare-earth element dopant. The rare-earth element dopant is configured to absorb a storage photon traversing the chalcogenide optical fiber link upon receipt of a first pump pulse output by the pump laser. Further, the rare-earth element dopant is configured to release the storage photon upon receipt of a second pump pulse output by the pump laser.

Abstract: The design method for complex electromagnetic materials is expanded from form-invariant coordinate transformations of Maxwell's equations to finite embedded coordinate transformations. Embedded transformations allow the transfer of electromagnetic field manipulations from the transformation-optical medium to another medium, thereby allowing the design of structures that are not exclusively invisible. A topological criterion for the reflectionless design of complex media is also disclosed and is illustrated in conjunction with the topological criterion to design a parallel beam shifter and a beam splitter with unconventional electromagnetic behavior.

Abstract: A system and method for uniform light generation in projection display systems. An illumination source comprises a light source to produce colored light, and a scrolling optics unit optically coupled to the light source, the scrolling optics unit configured to create lines of colored light from the colored light, and to scroll the lines of colored light along a direction orthogonal to a light path of the illumination source. The scrolling optics unit comprises a single light shaping diffuser to transform the colored light into the lines of colored light, an optical filter positioned in the light path after the light shaping diffuser, and a scrolling optics element positioned in the light path after the optical filter. The single light shaping diffuser is capable of simultaneously transforming colored light into lines of colored light having substantially uniform intensity to provide uniform illumination.

Abstract: A channel estimation method and system using linear correlation based interference cancellation combined with decision-feedback-equalization (LCIC-DFE) are provided. The channel estimation method includes generating a first correlation sequence by calculating a linear correlation between a baseband sampled complex signal and a locally stored pseudo-noise signal and obtaining a second correlation sequence by iteratively removing inter-path interference from the first correlation sequence and generating a first channel impulse response (CIR) sequence based on the second correlation sequence. And, obtaining a third correlation sequence by removing random-data interference from the second correlation sequence based on the first CIR sequence and a feedback signal and generating a second CIR sequence based on the third correlation sequence.

Abstract: A holographic data storage system that includes a write head that includes a pixellated spatial light modulator and a separate or integral phase mask that varies the phase depending on the location in the phase mask that light passes through. The phase variation can be changed over time in a random, pseudo-random, or predetermined fashion. The spatial light modulator and phase mask can be implemented in a liquid crystal SLM (nematic, ferroelectric, or other), in a DMD SLM, in a magneto-optical SLM, or in any other suitable manner.

Abstract: A system for encrypting a set of data may include a signal source, and a first, second, third, and fourth subsystem. The first subsystem may receive a first signal from the signal source and provide as output therefrom a first output signal. The second subsystem may receive a second signal from the signal source and provide as output therefrom a second output signal. The third subsystem may combine the first and second output signals. The fourth subsystem may acquire a set of encrypted data.

Abstract: A method of verifying the authenticity of an object is disclosed. The method may include encoding a primary image, convolving the encoded primary image with a random code, generating thereby a first reference image, transforming the first reference image, and correlating the first reference image with a second reference image.

Abstract: An optical surface substrate. The optical substrate features a three-dimensional surface. The optical substrate is defined by a first surface structure function modulated by a second surface structure function, the first surface structure function producing at least one specular component from a first input beam of light. The second surface structure function has a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate produces specular and diffuse light from the first input beam of light. The optical substrate is suitable for use in a variety of applications, including brightness enhancement and projection devices.

Abstract: A method and apparatus for enhancing the receiving and information identification functions of multiple access communications systems by employing one or more optical processors configured as a bank of 1-D correlators. The present invention is particularly useful in a DS/SS CDMA communications system, resulting in a multiuser CDMA system that approaches carrier to noise performance (C/N) as opposed to being limited by multiple access interference (MAI). The correlators are arranged in parallel to detect and/or demodulate the received signal, in conjunction with one or more complex algorithms to perform near-optimum multiuser detection, perform multipath combining and/or perform carrier Doppler compensation.

Abstract: A method of verifying the authenticity of an object is presented. The method comprises providing a primary image; providing a secondary image; encoding the primary image; providing a random code; convolving the encoded primary image with the random code, providing thereby a reference image; affixing the reference image to the object to be authenticated; transforming the reference image; and comparing the transformed reference image with the secondary image. A system for verifying the authenticity of an object is presented. The system comprises a signal source; a first subsystem receiving a first signal from the signal source and providing as output therefrom a first output signal; a second subsystem receiving a second signal from the signal source and providing as output therefrom a second output signal; a third subsystem receiving the first and second output signals for comparing the first output signal with the second output signal.

Abstract: An optical surface substrate. The optical substrate features a three-dimensional surface having a correlation length of about 1 cm or less. The optical substrate is defined by a first surface structure function modulated by a second surface structure function, the first surface structure function producing at least one specular component from a first input beam of light. The optical substrate is suitable for use in a variety of applications, including brightness enhancement and projection devices.

Abstract: An authentication system using a correlator that correlates an input with a reference wherein at least one of the input and reference comprises a phase volume mask having structures, preferably points, that are each less than about six microns in size and can have an aspect ratio (AR) greater than 1:1 so as to produce a phase encoded random pattern having millions of combinations in a mask that is as small as one square millimeter. The random pattern can be convolved with a second pattern, such as a biometric pattern, to produce a phase convolved mask. The correlator preferably is a nonlinear joint transform correlator that can use “chirp” encoding to permit the input to be located in a different plane than the reference. The correlator optically Fourier transforms images of the reference and input that are thereafter nonlinearly transformed and inverse Fourier transformed by a processor to determine the presence or absence of a correlation spike indicative of authenticity.

Abstract: In a method for influencing and measuring pulsed electromagnetic illumination, e.g. parallel laser light (L), said illumination or light can be spatially divided, in particular, in an autocorrelator comprising a beam receptor (12), can be recombined behind said beam receptor by a superposition or focusing device (18 or 58) and can be detected in the recombinant area by a detector (20). As the transmission system (52), the beam receptor comprises beam profile dividers in a penetrable housing (50), in the form of at least two transmission parts (54; 56), with or in which separate, preferably parallel component beams (S, T) can be modified in their time-based beam characteristics, before being recombined.

Abstract: A matched amplification correlator transforms input images projecting a real time hologram upon a holographic storage device and a spatial light modulator, optically coupled to the storage device, modulates the hologram with a correlation filter, and the modulated signal is Fourier transformed to produce an output correlation signal. Alternatively, Fourier transforms of beams bearing the signals to be correlated are projected upon a beam controlled semi-conductor absorption modulator for selectively switching the Fourier transform of the noisy cluttered image through the device, and a spatial light modulator, modulates the hologram with a correlation filter, and the transform produces an output correlation signal. These compact adaptive, noise robust correlators can be made as small as one cubic centimeter. In a correlation system of exemplary figure one, nearly one hundred million correlations per second (0.1 Ghz) are possible. Front end components of the correlators can be used to clean noisy images.

Abstract: An optical coherent processor or correlator for processing an input image produced by an imaging device illuminated by a coherent light source utilizes an optical key for preventing unauthorized use of the processor. The principle underlying processing apparatus and method according to the invention uses an optical lock in combination with an encoded software key superimposed on a filter image. The optical lock, which is preferably in hardware form, consists of a first optical mask implementing a locking mask function that is preferably complex (phase and/or amplitude), which first optical mask is included in the optical path of the processor. The mask is fixed during assembly of the processor or correlator and a unique pattern is encoded thereon. The software key consists of a pattern defined by a key mask function that is displayed preferably using a spatial light modulator as part of a second optical mask included on the processor optical path.

Abstract: An optical wavelength selection apparatus containing a surface-relief transmission diffraction grating, a collimating lens for collimating a beam incident to the diffraction grating, and a focusing lens for focusing the beams diffracted by the diffraction grating. The diffraction grating, after having been subjected to a test condition of 85 degrees centigrade and a relative humidity of 85 percent for at least 500 hours, has diffraction efficiency performance within 6 percent of that achieved before being subjected to these test conditions.

Abstract: A system for performing real time optical comparisons using an optical correlator permits comparing a sampled image to a wide variety of reference images through the utilization of a multiple quantum well spatial light modulator which is utilized to rapidly present a large number of reference images for correlation. The utilization of the multiple quantum well spatial light modulator as the spatial light modulator in a van der Lugt image correlator in combination with a spectrometer permits optical comparisons at 300,000 frames per second versus 10,000 frames per second, the best case for liquid crystal based spatial light modulators.

Abstract: A collimator optical system collimates light from the coherent light source. A reflection type spatial light modulator returns collimated light from the collimator optical system to the collimator optical system. A Fourier transformation optical system Fourier-transforms light from the reflection type spatial light modulator and shares at least partial optical system with the collimator optical system. An emission light from another coherent light source passes through an incident light path composed of another collimator optical system, spatial modulator and polarized beam splitter in this order and reaches the reflection type spatial light modulator. Then, a reflection light from the reflection type spatial light modulator passes through a reflection light path which is reverse to the incident light path and reaches a polarized beam splitter. That is, the incident light path and reflection light path are split by the polarized beam splitter.

Abstract: In a light unit that converts a false linear light into which a light from a point light source has been converted by a columnar light guide, into a planar light by a plate-shaped light guide, the point light source is arranged only at an end of the columnar light guide at which an angle between a longitudinal direction of the columnar light guide and ridge lines of recesses and projections forming a prism surface is obtuse. Thus, a positional relationship between the point light source and the ridge lines is set so that a main irradiation direction of band-shaped light emitted from the columnar light guide and which has been obtained by converting the light from the point light source to a false linear light is not substantially orthogonal to the ridge lines of the recesses and projections forming the prism surface of the plate-shaped light guide. Consequently, light obtained by totally reflecting this band-shaped light is unlikely to be viewed.

Abstract: An optically implemented wide bandwidth correlation system (10) that employs a multi-mode imaging device (42) and a particular modulation format to provide both in-phase and quadrature phase correlation components in a single correlation process. The correlation system (10) includes an optical source (12) that generates a laser beam (14) that is split into a first beam path (18) and a second beam path (20). The first split beam and a first electrical signal are applied to a first modulator (22) in the first path (18) and the second split beam and the second electrical signal are applied to a second modulator (24) in the second path (20). The modulated beams are then applied to the optical imaging device (42) that causes the beams to interfere with each other within an optical cavity (48).

Abstract: A system for performing real time optical comparisons using an optical correlator permits comparing a sampled image to a wide variety of reference images through the utilization of a multiple quantum well spatial light modulator which is utilized to rapidly present a large number of reference images for correlation. The utilization of the multiple quantum well spatial light modulator as the spatial light modulator in a van der Lugt image correlator in combination with a spectrometer permits optical comparisons at 300,000 frames per second versus 10,000 frames per second, the best case for liquid crystal based spatial light modulators.

Abstract: In accordance with the present invention, a multi-wavelength cross-correlator for two radiation pulses is disclosed. In one embodiment, a method for operating the cross-correlator is disclosed. A first radiation pulse is focused upon the photodiode. A second radiation pulse is also focused on the photodiode where the first and second radiation pulses illuminate a common point on the photodiode. The first and second radiation pulses, which have different wavelengths, are converted into a photocurrent using the photodiode where the product of the first and second intensities is proportional to the photocurrent. An amplitude of the photocurrent is detected while varying the delay of at least one of the first and second radiation pulses. In another embodiment, a multi-wavelength cross-correlator includes a radiation detector and a current detector. The radiation detector converts energy from the first and second radiation pulses, which have different wavelengths, into a current.

Abstract: An improved optical correlator using a coherent light beam employs a method of adaptive alignment. A test pattern modulates an input spatial light modulator. The modulated beam propagates through passive transforming optical elements to a filter spatial light modulator, which is simultaneously modulated with an independently transformed frequency domain reference. The resulting correlation or coincidence of the optically transformed pattern with the independently transformed reference is processed to yield a feedback signal indicative of any optical misalignment of the optical correlator. The feedback signal drives a beam deflector to compensate by adjusting the path of the coherent beam, thereby improving and maintaining optical alignment of the correlator.

Abstract: A method is disclosed by which filters are created optically in real time—and tested. This technique is made possible by recent advances in Charge Couple Detector (CCD) detector array technology. Pixel (picture element) size has decreased to the point that real fringes can be detected and displayed. The fringes result from the interference of the optical Fourier transform of a displayed scene with a specified plane wave. Phase information is thus preserved. This is the critical information required in producing a hologram or a holographic matched filter.

Abstract: A method and an apparatus capable of filtering based on desired spatial frequency characteristics without loss of Fourier spectrum frequency components, and of matched filtering of high recognition capability without losing functions of data recording and reconstruction as well as high-speed transmission and retrieval features and mass storage capacity characteristic of a holographic memory. Fourier transformed object light with 0° polarization of a target image is stored as a hologram using reference light having a spatial polarization distribution such that a daughter wavelet on scale m has 90° polarization. The hologram is retrieved using the Fourier transformed object light with 0° polarization. The hologram yields diffracted light in the form of a spatial frequency component which corresponds to scale m and is polarized 90° with respect to the other spatial frequency components. A polarizing element is used to extract only the spatial frequency component corresponding to scale m.

Abstract: A planar optical correlator including at least first and second optical substrates (30, 32), through which light propagates by means of total internal reflection, at least first and second holographic lenses (20, 22) on the first optical substrate and optical third and fourth holographic lenses (24, 26) on the second optical substrate, each of the first and second and third and fourth holographic lenses performing a Fourier transformation on the input light to their respective optical substrates, the substrates positioned such that the second and third holographic lenses at least partially face each other. A filter (36) is positioned between the second and third holographic lenses.

Abstract: An optical correlator system having a plurality of both active and passive reflective optical components between a source of electromagnetic radiation, such a visible coherent light, and an output detector array in a planar support body along a folded optical axis beam path within the body uses a grayscale spatial light modulator as the input sensor and the correlating filter to provide enhanced optical detection of an unknown object at a CCD detector array.

Abstract: Methods and apparatus are provided for the recognition of an optical signal that is encoded with a specified temporal pattern. Nonlinear optical interactions and time-integrating optical detectors are used to identify temporally short correlation peaks in an optical signal in an optical communication system without temporally resolving the correlation signal. The apparatus includes means for decoding an encoded optical waveform, a time-integrating nonlinear detection system, a time-integrating linear detection system for proper normalization, and thresholding electronics that produce voltage pulses corresponding to the presence of specified waveforms at the detector input.

Abstract: A holographic grating is written into a photorefractive erasable holographic member and a light beam having a first wavelength which includes the joint power spectrum of a pair of joint images to be correlated is directed at the photorefractive member to partially erase the grating. A phase conjugate signal from the partially erased grating is then readout and Fourier transformed to produce the correlation output spots.

Abstract: A real time fingerprint verification system includes a recording device and a verification device each having a fingerprint scanner for generating a flat, dimensionally undistorted, high contrast, fingerprint image, and an intensity sensitive, spatial light modulator (SLM) for receiving and transforming the flat fingerprint image into a planar, coherent light image. In the recording device, the planar coherent light image beam of the fingerprint from the SLM is Fourier transformed, and input into a microscope objective lens system which expands the Fourier transformed beam image sufficiently to allow mechanical blocking of its central portion or order, whereupon it is directed to interact as an object beam with a reference beam from the particular coherent light source to record a holographic matched filter.

Abstract: A pattern collation apparatus is designed to identify a registration pattern and a collation pattern as identical patterns or not even with a rotation offset between the registration pattern and the collation pattern. The image data of a registration fingerprint is rotated through m.multidot.a degrees, and two-dimensional discrete Fourier transform is performed for the resultant image data to obtain registration Fourier image data. The registration Fourier image data with m=-90 to +90 are filed as registration Fourier image data. In collation processing, registration Fourier image data are read out from the registration Fourier image data in units of patterns, and each registration Fourier image data is synthesized with the collation Fourier image data, thereby performing collation between the registration fingerprint and the collation fingerprint.

Abstract: An optical correlator system having a plurality of both active and passive reflective optical components between a source of electromagnetic radiation, such a visible coherent light, and an output detector array in a planar support body along a folded optical axis beam path within the body uses a ferro-electric liquid crystal spatial light modulator as the input sensor and the correlating filter to provide enhanced optical detection of an unknown object at a CCD detector array.

Abstract: A method and apparatus for modulating a light beam in an optical processing system is described. Preferably, an electrically-controlled polarizer unit and/or an analyzer unit are utilized in combination with a spatial light modulator and a controller. Preferably, the spatial light modulator comprises a pixelated birefringent medium such as a liquid crystal video display. The combination of the electrically controlled polarizer unit and analyzer unit make it simple and fast to reconfigure the modulation described by the Jones matrix of the spatial light modulator. A particular optical processing objective is provided to the controller. The controller performs calculations and supplies control signals to the polarizer unit, the analyzer unit, and the spatial light modulator in order to obtain the optical processing objective.

Abstract: A constituent unit for an optical information processing system comprises an input information displaying device, which one-dimensionally, two-dimensionally, or three-dimensionally displays presented information as an optical pattern. Each of optical correlation operation devices located close to the input information displaying device detects only an optical pattern falling within a predetermined range among the optical pattern displayed on the input information displaying device, and carries out an optical correlation operation in order to calculate correlation between information representing the detected optical pattern and predetermined information having been stored in each optical correlation operation device. Each optical correlation operation device thereafter feeds out the results of the correlation operation.

Abstract: The invention is a pattern defect inspection system and method for improving the inspection speed, simplifying the system, and enlarging the inspection object, in which a correlation circuit (24) selects from a plurality of reference images in reference image storing means (22) one having the highest correlation with a detection image in detection image storing means (23) and inputs it to a difference circuit (25); the difference circuit (25) forms a difference image based on a reference image from the correlation circuit (24) and a detection image from the detection image storing means (23); a defect decision circuit (26) decides the position and size of a defect in a wafer under test 41, based on the difference image from the difference circuit (25); and the result is inputted to defect information processing means (27) to output as a defect information.

Abstract: A real time fingerprint verification system includes a recording device and a verification device each having a fingerprint scanner for generating a flat, dimensionally undistorted, high contrast, fingerprint image, and an intensity sensitive, spatial light modulator (SLM) for receiving and transforming the flat fingerprint image into a planar, coherent light image. In the recording device, the planar coherent light image beam of the fingerprint from the SLM is Fourier transformed, and input into a microscope objective lens system which expands the Fourier transformed beam image sufficiently to allow mechanical blocking of its central portion or order, whereupon it is directed to interact as an object beam with a reference beam from the particular coherent light source to record a holographic matched filter.

Abstract: A method for pattern recognition and localization using a joint transform correlator and joint transform correlator. The method includes providing a joint image of a reference image and an input scene image at the input plane of the correlator, receiving the joint image and providing a Fourier transform interference field of the reference image and the input scene image, receiving the Fourier transform interference field and providing a joint power spectrum, compensating for noise prevailing within the input scene image by processing the joint power spectrum to produce a noise compensated joint power spectrum, and receiving the noise compensated joint power spectrum and providing a noise tolerant correlation signal so as to enhance pattern recognition and localization capabilities.

Abstract: A lensless joint transform correlator optically determines the relative position of two pinholes placed in parallel arms of a Mach-Zehnder interferometer. The Fraunhaufer diffraction patterns combine to form a joint power spectrum signal in the joint transform plane. Because of the interference of the two pinhole signals, an encoded lens comprising a Fresnel zone is formed in the joint Fraunhaufer diffraction pattern which is illuminated with a plane wave, and the output signal is taken in the focal plane of the Fresnel zone and magnifies the input pinhole displacement by a factor of ten, enhancing its use in precision positioning servo systems for mask alignment.

Abstract: An all optical photorefractive holographic joint transform correlator provides a first correlation plane output port using two-beam coupling, and a second correlation plane output port employing four-wave mixing. With appropriate input beam intensity ratios, the first port output is capable of high discrimination, while simultaneously the second port offers a low discrimination output.

Abstract: A module, capable of being mounted on a printed circuit board, containing optical components necessary for optical correlation and a unique folded light path technique for conversion from a Vander Lugt optical correlator to a joint-transform optical correlator, or visa versa, with no electronic changes required. The folded optical path permits a polarizing filter to be positioned in the beam path reflected by a filter SLM but before a correlation detector means when the correlator is in a Vander Lugt mode and permits the polarizing filter to be removed, and an auxilliary mirror or other optical components positioned in the beam path to eliminate the filter SLM and to direct the beam path toward the correlation detector means when the optical correlator is to become a two-cycle joint-transform optical correlator and simultaneously match the Fourier transform plane to the detector plane of the detector means.

Abstract: New on-axis, optically addressable spatial light modulators (SLMs) and methods of use are described. The new SLMs include a film of a photochromic material and a non-polarizing beam splitter arranged such that read and write beams counterpropagate with one another, and the read beam is separated from the path of the write beam after being transmitted through the photochromic material film without losing any polarization information encoded on the read beam. The new SLMs are advantageously implemented in incoherent-to-coherent optical converters and all-optical joint transform correlators.

Abstract: A pair of matched filters describing a pre-selected category of objects is ade, each of the filters having a center located at a unique place in the filter. When incorporated into a MACE filter and used in an optical correlator, a line drawn through the correlation peaks caused by the centers of the matched filter pair and a pre-selected axis together produce an angle that is indigenous to that particular category of objects, thus identifying the category of objects.

Abstract: A method and apparatus for modulating a light beam in an optical processing system is described. Preferably, an electrically-controlled polarizer unit and/or an analyzer unit are utilized in combination with a spatial light modulator and a controller. Preferably, the spatial light modulator comprises a pixelated birefringent medium such as a liquid crystal video display. The combination of the electrically controlled polarizer unit and analyzer unit make it simple and fast to reconfigure the modulation described by the Jones matrix of the spatial light modulator. A particular optical processing objective is provided to the controller. The controller performs calculations and supplies control signals to the polarizer unit, the analyzer unit, and the spatial light modulator in order to obtain the optical processing objective.