Abstract: A low-cost star-coupler assembly primarily for use in optical data networks is fabricated from three modular components. The first component is a support plate having at least two sets of grooves into which polymer optical fibers may be placed and a central aperture. The second component is a waveguide plate which is designed to fit in the aperture. The third component is a cover plate having alignment means for aligning the components in fixed relationship and for holding polymer optical fibers in the grooves securely in place. The coupling structure is most useful with large-core polymer optical fibers. The modular design facilitates replacement of fibers. The components may be fabricated by injection molding thereby reducing the cost.

Abstract: A subwavelength-resolution optical imaging device is provided for conveying light having a wavelength .lambda. that is emitted, reflected or transmitted by a sample. The device comprises a coherent fiber bundle, which itself comprises a plurality of optical fibers disposed substantially coaxially along their lengths. Each optical fiber also comprises a core having an index of refraction n.sub.1 and a cladding having an index of refraction n.sub.2 thereby providing a value .DELTA., where: ##EQU1## Light is effectively confined within the core of each fiber without need for a separate coating applied to the fibers by selecting the values of n.sub.1 and n.sub.2 for each optical fiber so as to provide a value for .DELTA.

Abstract: A method for rectifying first and second images of a single scene for stereoscopic analysis is provided. The method has first and second steps of providing the first and second images from first and second cameras. The first camera having a first optical center and a first geometry relative to the scene, the second camera having a second optical center and a second geometry relative to the scene. The first and second images each comprise a plurality of epipolar lines wherein each point on each of the epipolar lines is expressed in a first and second image coordinate system, respectively. Third and fourth steps are provided wherein each point on each epipolar line of the first and second images are rotated to be parallel to a line connecting the first and second optical centers of the first and second cameras.

Abstract: A method for generating a complete scene structure from a video sequence that provides incomplete data. The method has a first step of building a first matrix consisting of point locations from a motion sequence by acquiring a sequence of images of a fixed scene using a moving camera; identifying and tracking point features through the sequence; and using the coordinates of the features to build the first matrix with some missing elements where some features are not present in some images. In a second step an approximate solution is built by selecting triples of columns from the first matrix; forming their nullspaces into a second matrix; and taking the three smallest components of the second matrix. In a third step, an iterative algorithm is applied to the three smallest components to build a third matrix and to improve the estimate. Lastly, in a fourth step the third matrix is decomposed to determine the complete scene structure.

Abstract: A multistage database search method includes a first stage that only considers textual polygraphic frequencies and a second stage that considers the location of the polygraphs and coarsely approximates the proper alignment between the query and the database strings and a third stage that provides a better approximation of the alignment. The final output is a listing of suggested database records ranked by their similarity to the query.

Abstract: A metallic film has apertures located therein in an array arranged in a pattern so that when light is incident on the apertures, surface plasmons on the metallic film are perturbed resulting in an enhanced transmission of the light emitted from individual apertures in the array. The aperture array is used: to filter light of predetermined wavelength traversing the apertures, to collect light over a distance after traversing the apertures, to improve operation of near-field scanning optical microscopes, and to enhance light transmission through masks useable in photolithography.

Abstract: The low-field magnetoresistance of a high carrier mobility semiconductor with inhomogeneities which are more conducting than the surrounding semiconductor material matrix is significantly enhanced compared to the magnetoresistance of the homogeneous material. The enhancement results from a magnetic field induced geometric effect in which current is expelled from the conducting inhomogeneity. The enhanced giant magnetoresistance is demonstrated at low field in (near) zero-band-gap material, such as Hg.sub.1-x Cd.sub.x Te(x.about.0.1). The effect is applied to the fabrication of magnetic read head sensors such as Corbino disc, bar magnetoresistance sensors and thin film sensors.

Abstract: A quantum-dot cascade laser which eliminates undesirable single phonon decays associated with quantum-well devices. The elimination of single phonon decays is realized by a three-dimensional confinement resulting in a several-order-of-magnitude reduction in the threshold current. Vertical radiative transitions are employed within single quantum dots contained by Bragg reflectors. Dot size, dot density and dot uniformity requirements are presented along with several embodiments.

Abstract: A switching network that utilizes at least three degrees of freedom, time, wavelength and space. In one embodiment that involves point-to-point switching, each space channel between an input and an output is assigned a time slot and wavelength coordinate characteristic of the output and the input transmitter and output receiver are tuned to the appropriate time and wavelength coordinates and selective switching is used to complete the space channel between the input and output. In another embodiment for generalized switching, each input channel is assigned a set of space, time slot and wavelength coordinates and an input signal is broadcast to all of the outputs which selectively makes connection to those inputs with an appropriate set of coordinates.

Abstract: Based on the encoding of deterministic finite-state automata (DFA) in discrete-time, second-order recurrent neural networks, an algorithm constructs an augmented recurrent neural network that encodes a FFA and recognizes a given fuzzy regular language with arbitrary accuracy.

Abstract: A multi-mode oriented polynomial transformation based defuzzification strategy uses a Kalman filter in a parameter leaning procedure defuzzification application where two or more distinct possibility peaks exist in its membership function distribution.

Abstract: A multiresolution method and apparatus for searching of a database of images where the search is performed on compressed images, without first decompressing them. The method searches the database of compressed images first at a low resolution to obtain the relative quality of a match between a search template and a candidate image. If the match is below a particular threshold, the search is terminated without committing any further computational resources to the search. Conversely, if the match is above a particular threshold, the method enhances the resolution of the candidate image and then performs another match. As long as the relative quality of the match is above the particular threshold, the resolution of the candidate image is successively enhanced, until a match determination is made at a full resolution of the candidate image.

Abstract: Digital watermarking of audio, image, video or multimedia data is achieved by inserting the watermark into the perceptually significant components of a decomposition of the data in a manner so as to be visually imperceptible. In a preferred method, a frequency spectral image of the data, preferably a Fourier transform of the data, is obtained. A watermark is inserted into perceptually significant components of the frequency spectral image. The resultant watermarked spectral image is subjected to an inverse transform to produce watermarked data. The watermark is extracted from watermarked data by first comparing the watermarked data with the original data to obtain an extracted watermark. Then, the original watermark, original data and the extracted watermark are compared to generate a watermark which is analyzed for authenticity of the watermark.

Abstract: A compound semiconductor that is suitably doped to exhibit the DX effect is irradiated with an optical beam of spatially varying intensity whereby localized regions of persistently higher conductivity and lower refractive index are created in the semiconductor where sufficient intensity of the beam was incident. The persistently higher conductive region can be used to bridge selected gaps in conductive paths on a support member use in memory device and the regions of lower refractive index can be used to providing guiding in a wave guide, to form high resolution gratings, or to form holograms.

Abstract: A method for finding a match between a pattern of data of relatively small size in a base of related data or relatively large size in the presence of occlusions which are gaps or noise that obscure portions, either of the pattern or of the base. The method involves masking out occluded points in both the base data and the pattern so that correlation can be computed only at those points that are not occluded.

Abstract: A watermark is embedded into audio/video/image/multimedia data using spread spectrum methodology. The watermark is extracted from watermarked data without the use of an original or unwatermarked version of the data by using spatial or temporal local averaging of the frequency coefficients of the watermarked data.

Abstract: A computer technique for bipartite matching of objects of one subset with objects of a different subset where multiple choices are permitted. A bipartite graph is formed in which the objects form nodes and the edges connecting pairs of nodes represent costs of matching the nodes connected. The original tour or graph is decomposed into a plurality of quasi-convex subtours or subgraphs and the minimum cost match of each subtour is found and the union of all such matches of the subtours is used as the desired match.

Abstract: A number of layered vanadium oxide crystalline compositions are prepared by simple hydrothermal reactions. Generally, the compositions comprise parallel layers of mixed valence vanadium oxides with guest cations intercalated between the layers. The guest cations may comprise metal coordination complexes with bidentate ligands, monomeric ammonium or diammonium cations, or mixtures of alkali metal cations with monomeric ammonium cation or diammonium cations.

Abstract: A computer system that includes a plurality of processing elements for parallel computation utilizes a free-space optical network for communication between the processing elements. Such a network employs an optoelectronic switch that includes a binary H-type tree for routing signals to selected ones of an array of lasers. Hybrid repeaters are included in the optical paths to generate output optical beams colinear that are with incident input beams.

Abstract: A modular building block for supporting arrays of microlenses, microlasers and microphotodetectors, etc. in an optical beam relay system used as an optical interconnection network. The building block includes a frame member on which is mounted the array. The frame member includes a base portion that is press fitted to the smooth top surface of a plate member. The bottom surface of the plate member includes a rail portion that is secured into a groove in the support structure, such as a table, that also supports various elements of the optical interconnection network.