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: The invention is an optical feature extraction apparatus which uses video display, spatial light modulation, and detection components in conjunction with microlenslet replicating optics, to expedite the recognition of DNA sequences based on their symmetry properties and, specifically, to classify short (6 bases in length) sequences of DNA as palindrome or nonpalindrome. The DNA sequences are symbolically encoded using a novel method. Multichannel operation is achieved through the replication of input scenery, making possible a higher throughput rate than for single channel systems.

Abstract: A multiple quantum well spatial light modulator combines both optically addressed and electrically addressed portions on a single wafer. The electrically and optically addressed portions may be physically distinct or combined. To fabricate the modulator, a portion of an optically addressed multiple quantum well spatial light modulator is configured as an electrically addressed portion by pixellating that portion of the multiple quantum well wafer. The frequency of the applied voltage to the electrically addressed portion is increased such that the voltage switches faster than both the dark and illuminated screening time. The electrically and optically addressed portions may be combined or positioned side-by-side. The spatial light modulator has applications in a wide variety of low-cost, high performance pattern recognition systems. In one system, a first infrared beam impinges the electrically addressed portion of the modulator and picks up the pattern electrically written thereon (i.e., the template image).

Abstract: In a spatial light modulator of the present invention, a photoconductive layer formed of photoconductive material receives write light having a spatial distribution in its intensity and changes resistivity of the photoconductive material dependently on the spatial distribution in the intensity of the received write light. A liquid crystal layer formed of liquid crystal molecules of nematic phase receives read light and presents birefringence with respect to the received read light. An electric voltage is applied through the photoconductive layer and the liquid crystal layer to thereby produce an electric field in the liquid crystal layer. The photoconductive layer changes the electric field produced in the liquid crystal layer in accordance with the resistivity of the photoconductive material so as to electrically control the birefringence of the liquid crystal molecules.

Abstract: In an individual identification apparatus, a hologram 11 recorded on a card is irradiated with laser light to read out a fingerprint image of a specific person. A finger of an arbitrary person to be identified with the specific person is irradiated with laser light to obtain a fingerprint image. Thus obtained fingerprint images are jointly written in a first SLM. Then, the joint image is read out and Fourier transformed to obtain a Joint Fourier Transform image, which is then written in a second SLM. The Joint Fourier Transform image is then read out and Fourier transformed to obtain a pair of output correlation peaks. A photodetector detects the intensity of the output correlation peaks and outputs a signal indicative of the intensity. A threshold processor compares the value of the signal with a predetermined threshold value to positively or negatively identify the arbitrary person with the specific person.

Abstract: A joint Fourier transform optical correlator is disclosed which can have varying degrees of nonlinearity and yet employ a readily available binary spatial light modulator for producing the correlation output light signal in conjunction with a Fourier transform lens. The nonlinearly transformed joint power spectrum is binarized utilizing a multiple level threshold function which can vary from one pixel to the next.

Abstract: An apparatus and method for detecting anomalies morphologically detecting regions of interest. The apparatus and method include a region of interest (ROI) detection unit which morphologically detects anomalies in two dimensional input images or morphologically detects regions of interest based on structuring elements which can be set by a user using a modified hit and miss transform which includes a thresholding feature. The thresholding feature makes it possible to vary how much the shape of features within the input images can deviate from the shape of structuring elements and still be detected as a region of interest. One application of this involves detection of abnormal cells in a cervical Pap-smear.

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: An image processing method and apparatus in which a range image of a three-dimensional object is obtained, and the inclination of a plane contained in the range image and an approximate area of the plane are instantaneously detected, thereby realizing high-speed recognition of a three-dimensional object.

Abstract: In an image sensing apparatus, an array of two-dimensional matrix of photosensitive devices is used to detect an image. Each photosensitive device comprises a photosensor accumulating carriers when exposed to a light, control terminals, and an output terminal. A signal generator supplies a vector or a one-dimensional data to the control terminals in the array to output pixel data of the two-dimensional matrix, and the pixel signal is output through the output terminal. The control terminals of the photosensors arranged along each line are connected commonly, while the output terminals thereof arranged along each column are connected commonly. A controller supplies control signals to the control terminals. Then, pixel signal for columns designated by a control signal are output through an output circuit connected to the control terminals.

Abstract: A optical processor facilitates the alignment between an original image and transformation patterns, thus improving the operation accuracy, and, if a fixed transmission mask is to be used, facilitates the fabrication of the fixed transmission mask. The optical processor includes an original image display to display an original image and a pattern display to display the patterns for a transformation on the original image displayed on the original image display. In the optical processor, the original image display is os made as to have pixels with a smaller aperture ratio than that of the pixels of the pattern display.

Abstract: A process and device for automatic recognition of an object such as a road sign includes a laser beam source providing a laser beam capable of passing through a modulator on which an intensity spectrum of reference signs and a sign to be recognized has been pre-recorded. A converging lens positioned downstream of the modulator, as well as devices for observing and/or analyzing the spectrum occurring at the focal plane of the lens. These devices include apparatus for detecting peaks indicating that a reference sign is identical to a sign to be recognized, as well as apparatus to separate those peaks from spurious peaks. As an example, this device can automatically recognize speed limit signs on roads or freeways.

Abstract: An high-speed, high-resolution optical pattern recognition system which automatically recognizes or measures a specified pattern from two-dimensional images comprises an image display device for displaying at least one reference image including at least one target and at least one input image, a device including a laser diode having an oscillation wavelength less than 900 nm for converting the at least one reference image and the at least one input image into a coherent image, a Fourier transform lens for optically Fourier transforming the coherent image to produce a joint Fourier-transformed image, an optically addressed ferroelectric liquid crystal spatial light modulator having no light reflection layer, a device for converting the joint Fourier-transformed image into an intensity distribution image and displaying the intensity distribution image on the optically addressed spatial light modulator, and a device including a laser diode having an oscillation wavelength longer than 660 nm for reading the inten

Abstract: An arrangement for optical autocorrelation of laser speckle photography (LSP) photographs or particle image velocimetry (PIV) photographs using optical Fourier transforms is disclosed. The object of providing an electro-optical arrangement for optical correlation of LSP film recordings and PIV film recordings which is simple to produce and accurate is met by using an optically addressable liquid crystal SLM (spatial light modulator) for producing the Young's fringe patterns which contains a uniaxial double-refracting liquid crystal layer and is read out with linearly polarized light of a laser light source, wherein the polarization direction of the laser light source on the readout side coincides with the extraordinary semi-axis of the refractive index ellipsoid of the liquid crystal layer.

Abstract: An optical pattern recognition apparatus has an optical coordinate converter unit which simultaneously and in parallel converts an entered reference image and an entered input image from an entered coordinate system to a desired coordinate system to produce a coordinate-converted reference image and a coordinate-converted input image. A joint transform correlator receives the coordinate-converted reference image and the coordinate-converted input image and generates a correlation coefficient between the coordinate-converted reference image and the coordinate-converted input image so that a correlation between each entered reference and each entered input image is obtained to effect pattern recognition in real time. A feedback circuit normalizes the generated correlation coefficient between the coordinate-converted reference image and the coordinate-converted input image with a maximum correlation coefficient.

Abstract: An input image of an object is optically Fourier-transformed and after coordinate-transforming the Fourier-transformed input image optically to obtain a rotation-invariant and scale-invariant image, the resultant image is pattern-matched with a computer generated hologram of a reference image. The coordinate-transformation of the Fourier-transformed input image is made using an optical phase filter represented as a computer generated hologram.