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: An image of the object remains in the field of view of the camera, thereby generating a continuously changing image signal. The images are captured and digitized in a continual sequence S of discrete images of the scenes at a respective sequence T of points in time. During this capture sequence, a first plurality of reference signals are established corresponding to a plurality of respective captured images. In this manner, a plurality of reference images are generated on-line, during movement of the object or cameras. A second plurality of detected signals corresponding to a second plurality of captured images, are individually correlated with the respective next previous reference signal of the sequence, thereby establishing a relative position of the object or camera, for each detected signal. The absolute position of the camera or object, is determined by accumulating these relative positions.

Abstract: System for identification of a person (P, P') or an object with an informon carrier (1; G, 20), including at least one identification (IA, IB, IC; K) not perceptible with a human sense organ characteristic for a certain person (P, P') or an object (G), a device (2; 22, 23) for the inscription of the identification (IA, IB, IC; K) on to the information carrier (1; G, 20) and a device (8) to the read and evaluate the identification, wherein the information carrier (1; G, 20) carries a recording detectable only in ultraviolet light of a predestined range of wavelengths which is containing the identification (IA, IB, IC; K) and that the device for the inscription (2; 22, 23) includes means for the generation (7) and the device (8) for reading and evaluating includes means for reading the recording by means ultraviolet light.

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 of verifying the authenticity of an object is disclosed employing a spatial integrating optical correlator. An unreadable and hence non-counterfeitable mask (e.g., a. complex mask or a phase mask) is coupled to the object and the optical correlator compares the mask with a reference mask on which it is scanned over. The correlator produces a correlation spot or image having an intensity which exceeds a given level if the mask is genuine. An alternate embodiment includes a fingerprint or other personalized pattern bonded to the mask, and the fingerprint or other personalized pattern on the card is compared to a reference fingerprint or other personalized pattern of the card holder for added security.

Abstract: The invention relates to a method of spatial filtering a point distribution representing a structure buried in noise and each of the points of which are defined by n coordinate values of an n-dimensional space, wherein for each point the function representing the number of the points in an area around the point concerned as a function of a dimension of the area is established, and a scaling coefficient equal to the exponent (a) of a simple power function is determined which approximates as near as possible the function determined in step a) in a certain area having the dimension (d), furthermore the scaling coefficients of the points of a n-dimensional stochastic point distribution of a type equivalent to the point distribution to be filtered are determined, the difference between the scaling coefficients of the point distribution to be filtered and the scaling coefficients of the stochastic point distribution are determined, and the points, the scaling coefficients of which are contained in the difference an

Abstract: Pattern-recognition computing can be accomplished using wave-type or other types pf energy. In pattern-recognition computing which uses a plurality of wave-type energy input patterns modulated with quantized information, energy from the patterns combines to produce interference-based dynamic images. Component parts of a dynamic image are separated and recombined to produce logic and other computing process outputs. To produce a coordinated set of optics for pattern-recognition computing, waveforms at pixel-sized image components of the dynamic image are chosen to become contributors to the combined output if they will contribute (or can be modified to contribute) in a positive manner to a combined output waveform that obeys the logic rules of the device being produced. Iterative changes in input pattern characteristics are used to optimize the coordinated optics. Pattern-recognition computing can also use special interference and frequency-multiplexed logic.

Abstract: A method is provided for normalizing correlation data from a holographic correlator. After a sequence of object image patterns are recorded in an angularly multiplexed hologram, the entire volume hologram contents are read out with a uniform (plane wave) object beam. The plane wave readout produces an array of spots at a correlation plane, with the intensity of each spot representing the strength of the recorded hologram for the corresponding stored image pattern. The spot intensity values are accurately detected and stored as normalization factors. Holographic correlation output array values produced by parallel comparison of an input object pattern with the stored image patterns are then divided by the corresponding normalization factors. The resulting normalized correlation output accurately represents the true degree of correlation between the input object pattern and the stored image patterns by eliminating the uncertainty factor.

Abstract: The present invention is directed to a method for recognizing and classifying one or more unknown patterns, such as letters or numerals, by comparing these unknown patterns to a set of reference patterns. The unknown patterns, as well as the reference patterns, are irradiated by a coherent or incoherent beam, and correlation outputs are measured which would be at peak value of an auto-correlation output or a cross-correlation output between the unknown patterns and the reference patterns. Membership functions are created for each of the reference patterns, and a membership value is estimated or calculated on the basis of the output correlation between the unknown patterns and the reference patterns. Based upon this membership value, the specific unknown pattern is determined.

Abstract: A method using a fingerprint image as a cipher for optical encrypting and decrypting information which is presented in the form of an analogous signal. The method includes recording a Fourier hologram, the complex amplitude of the spatial grating of the hologram being a Fourier transform of the information image divided by a Fourier transform of the fingerprint image. To prepare the hologram, a full-complex spatial light modulator (SLM) may be used. The parameters of the Fourier transforms are chosen such that the optical spatial frequencies of the information image and the cipher lie in the same physical range. In another embodiment, the intensity distribution of the Fourier spectrum of the fingerprint image is captured. The cipher image is obtained by illuminating a phase-only SLM which is addressed with a function derived from this intensity distribution. The hologram may be amplitude or phase; thin, thick or volume; transparent or reflective; prepared optically or computer-generated.

Abstract: A method and apparatus for reconstructing holographic images is disclosed. A holographic image is recreated from a holographic storage media (10) by passing a reference beam (38) therethrough, which holographic image comprises a composite data image of discrete binary images arranged in an array. A reconstructed data beam (58) is then directed onto a detector array (42), resulting in a reconstructed composite data image (62) formed on the surface thereof. The detector (42) is comprised of a plurality of detector elements or pixels (92) arranged in an array corresponding to the original array of binary data images that are associated with the reconstructed composite data image (62). The reconstructed composite data image is oversampled such that each discrete binary image in the reconstructed composite data image is associated with, for example, four of the detector elements (92) which define pixels. Each group of pixels that is associated with an image is defined as a bixel. A 2.times.

Abstract: An edge detecting device with an image pickup unit for preparing an electric image signal from an optical signal from an object having edge information, a sampling device for converting the image signal into digital image data, a Fourier transformation device for converting the image data to data in the spatial frequency region, a filter for cutting off at least the zero order spatial frequency components, an inverse Fourier transformation device for converting the filtered spatial frequency data to real space data, a rough edge detecting device for obtaining rough edge data in a simplified form, an edge detector for detecting ultimate edge information on the basis of the data obtained by the inverse Fourier transformation device and the data obtained by the rough edge detecting device, and a display unit for displaying the ultimate edge information in a predetermined form.

Abstract: A method and system for searching for a given sequence in a data base having a multitude of reference sequences stored or identified therein. In accordance with this method, a light beam is modulated with patterns representing the reference sequences, and with a pattern representing the given sequence, and a correlation signal is generated representing the correlation of the reference and given sequences.Optical diffraction patterns may be used to represent the given and reference sequences. In one embodiment, a multitude of first diffraction patterns, each one representing the given sequence, are formed in an optical medium, and a light beam is modulated with each of those multitude of diffraction patterns to form a multi-channel signal beam. Each channel of that beam is then modulated with a respective one second diffraction pattern representing one of the reference sequences to form a multi-channel correlation beam.

Abstract: An amplitude encoded lens function signal, similar to a zone plate, is formed in the transform plane of a chirp encoded joint transform correlator. CCD correlation spot light sensor is separated from the transform plane by the focal length of the encoded lens function, and generates the desired output correlation spot. As a result, no prior art inverse transform lens need be provided, which simplifies the design. Further simplification is attainable in a low noise commercial image matching environment by eliminating the CCD correlation spot sensor entirely, and verifying an input image/reference image close match by using the eye of an operator to check for the presence of the visible zone plate, indicative of such a match.

Abstract: An object of the invention is to provide a method and a apparatus for optical pattern recognition capable of accurately comparing and identifying a reference image accurately at a real-time even when the input image rotates or its size changes by being compared with a reference image that is a desirous target. The method and apparatus comprise the processes of; steps (6, 11) for independently obtaining a lower-frequency component and a higher-frequency component from a joint Fourier transform image 5 of the reference image 4 and the input image 3; steps (10, 15) for calculating correlation coefficients respectively from the lower-frequency component and the higher-frequency component; step (16) for obtaining a ratio of the respective correlation coefficients; and step (19) for identifying and comparing a correlation coefficient ratio of the two same reference images to be required with a correlation coefficient ratio obtained from step (16).

Abstract: The fiber optic-based correlating and sensing system (the System) utilizes length of optical fiber through which the object beam travels prior to being incident on the holographic plate. First, a matched filter is created on the holographic plate of the initial condition of the environment. Then when the plate is re-placed in its original position in the System and the reference beam is blocked from reaching the plate, a correlation peak appears as the object beam passes through the holographic plate. To use the System as a correlator, the object beam is transmitted through an input scene prior to its travel through the optical fiber. The changes in the input scene from the initial scene causes broadening of the shape of and degradation of intensity of the correlation peak. To use the System as a sensor, the object beam travels through the optical fiber acquiring information regarding the environment surrounding the fiber, such as pressure, temperature, sound, electric and magnetic fields.

Abstract: A method for detecting the location of a human being in three dimensions from a spatial image of an area that is generated using a lens. Portions of the image having density values within a predetermined range are labeled, those density values corresponding to brightness levels of the pixels in the image. A labeled portion corresponding to a part of the head is selected when the top region of that portion forms the shape of an arch. The width of the selected portion is then determined. Assuming that the part of the head having hair on all persons has a constant horizontal width, the distance from a lens to a human being is calculated based on the determined width of the selected portion. The coordinates of the person are determined based on that distance.

Abstract: A computer system with an image reader and nerual network is provided for determining whether an image of text has been generated by a machine or by hand. This serves the useful purpose of allowing one to use speciallized recognition techiques that are more suited to one form of printing, thus achieving a higher recognition accuracy than by using a single recognition technique for both types of printing. The method is based on the premise that the spatial spectra for an image of machine text will have more higher frequency components than one generated by hand, because of the nonregular, nonuniform slant of the handprint. The method proposed generates this spectra by convolving spatial templates with vertical histograms from each line of text, and uses a neural network to classify the resulting spectra.

Abstract: An all-optical nonlinear joint transform correlator has been implemented for the first time without using a spatial light modulator and digital processing in the Fourier plane. The correlator utilizes energy transfer from two-beam coupling in the Fourier plane. A compressional nonlinearity in the hard-clipped regime is implemented by pumping a weak plane wave with the intense joint spectrum of the reference and signal images. Operation of this device rivals or exceeds that of the phase-only filter for detecting objects in cluttered noise. Experimental results are compared with both plane wave and beam propagation simulations.

Abstract: A method of verifying the authenticity of an object is disclosed preferrably employing a joint transform coherent optical processor. An unreadable and hence non-counterfeitable phase mask is coupled to the object and the optical processor compares the phase mask with a reference phase mask having the same phase code thereon. The processor produces a correlation spot having an intensity which exceeds a given level if the phase mask is genuine. A highly secure ID or credit card also carries a fingerprint bonded to the phase mask, and the fingerprint on the card is compared to a reference fingerprint of the card holder for added security.

Abstract: An object position detecting method and apparatus whereby even an image subjected to deformation such as shift, rotation, scaling, etc., can be recognized with high accuracy. Also disclosed is an image processing system that uses the object position detecting method and apparatus.

Abstract: A system for optically generating expansion coefficients for an image processing function. The invention (10) includes a first optical element (18) for providing a transform of an image provided at a first image plane (16). A second optical arrangement (20) provides a product of the transform of the image and a transform of a convolving function. This product is transformed by a lens (22) to provide an image intensity distribution representative of expansion coefficients resulting from a convolution of the image by the convolving function. In a specific implementation, the convolving function is a wavelet and the intensity distribution is detected to provide the expansion coefficients.

Abstract: In an optical correlator system having reflective and transmissive optical components positioned along a folded and segmented optical axis or path, one or more optical path extenders are provided for selected optical path segments that require operative path length adjustment so that an electromagnetic radiation beam, which traverses the folded optical path with selected information imparted into and detected from the beam, can be imaged upon a defined and maximum usable area or region both on the reflective components and on an end detector component.

Abstract: A technique for all-optical Code Division Multiple Access (CDMA) system based on optical holography is disclosed. In this technique the energy of an incoming information light signal is spread over a spatial domain by a two-dimensional spatial encoder which includes a mask having regions of first and second transmission characteristics corresponding to the unique code assigned to a particular source. Subsequent decoding, which is accomplished by an optical matched filter through the use of a hologram, spatially despreads the energy of the information light signal and produces a focused light beam which serves as input to a code division detector.