Abstract: A receiver receives a signal which contains a code vector. The code vector is a member of a predetermined set of code vectors. The code vectors may be Kerdock code vectors. The receiver produces a transform, such as a Walsh transform, of the received signal. The transform contains a coefficient corresponding to each of at least some of the code vectors of the predetermined set of code vectors. The receiver determines data elements transmitted as the received code vector based upon the magnitudes of the coefficients of the transform. When plural code vectors are transmitted, the receiver determines data elements transmitted as a first code vector based upon the magnitudes of the coefficients of the transform, subtracts the first code vector from the received signal, produces a new transform of the subtraction results, and determines data elements transmitted as another code vector based upon the magnitudes of the coefficients of the new transform, and so on.

Abstract: In a synchronous code division multiple access (SCDMA) system, a set of substantially orthogonal code words is selected such that each code word in the set of substantially orthogonal code words is minimally correlated with a channel characteristic such as noise. When a station transmits a data signal, it multiplies the data signal by its assigned code word in order to produce a spread data signal. The spread data signal is transmitted over the channel of the SCDMA system.

Abstract: A specimen to be tested for resistance to abrasion is optically scanned prior to abrasion to produce a first array of pixels. The specimen then is abraded under controlled conditions and scanned again after abrasion to produce a second array of pixels. The sections of the two arrays which relate to the specimen are registered to each other. Corresponding pixels for the specimen in each array are compared to produce plurality of values indicating the difference between the pixels. The difference values are used to quantify the abrasion in various defined regions of the specimen. The quantifying employs the difference values to determine an average magnitude, a mean square energy, and an average voltage of the abrasion. A contour map of the specimen is displayed to graphically show the degree of abrasion in the regions.

Abstract: A peaking system for a compressed digital video signal includes a transform coder for converting 8.times.8 blocks of video pixels into corresponding groups of transform coefficients and supplying the coefficients to an image classifier where the coefficients are classified according to their perceptual nature or image types, e.g. edge, flat area, texture, etc. of the video represented thereby. Control signals for horizontal and vertical perceptual classifications are developed and applied to a peaking filter for selectively peaking the video signal in accordance with the horizontal and vertical control signals. A receiver operates to recover the selectively peaked compressed video signal. In another embodiment, the transmitter supplies the video signal with the developed control signals for use by a receiver in selectively peaking the recovered video signal in accordance with the control signals.

Abstract: A video signal having a bandwidth on the order of 37 MHz is subjected to adaptive sub-band coding for transmission through a standard 6 MHz NTSC television channel. During each frame of the video signal a plurality of blocks of sub-band coefficients, each block representing the spectral content of a corresponding portion of the video image, are derived. The energy distribution of each block of coefficients is analyzed in a plurality of different spatial directions to establish a perceptual coding classification for each coefficient block. The coefficients are then variably quantized, e.g. truncated, in dependence upon the classification established for the corresponding block to reduce the required transmission bandwidth without introducing significant visible artifacts in the reproduced video image.

Abstract: A video image signal is transform coded to derive a plurality of blocks of transform coefficients, the coefficients of each block being separated into horizontal, vertical and diagonal spatially related regions. A plurality of values each representing the degree to which a portion of the video image is characterized by a respective image related perceptual characteristic are derived in responsee to the estimated energy in the three regions. The derived perceptual values are combined and weighted to provide a single output value corresponding to each coefficient block.

Abstract: A video signal comprising a successive series of frames is sub-band coded to derive a plurality of groups of coefficients for each frame. Each group of coefficients comprises a spectral representation of the video content of a respective portion of the frame, which portions are spatially decorrelated relative to the corresponding portions of the immediately preceding and immediately following frames to reduce block artifacts in the reproduced image.