Abstract: A technique for fingerprint classification and/or identification, in which a fingerprint is defined by areas containing patterns of ridges and valleys. At least one local pattern is determined using locations and characterizations of the fingerprint, which are indicated by a rapid change in direction of the ridges and valleys. The fingerprint is classified into types based upon the relative locations and characterizations of said local pattern(s). The fingerprint identification process can utilize minutiae location and angles as well as local pattern characterizations. Neural networks are utilized in determining the local patterns. The amount of data required to store data defining the fingerprints using the local pattern and/or minutiae techniques is significantly reduced.

Abstract: A space communication system incorporating a concatenated Reed Solomon Viterbi coding channel is disclosed for transmitting compressed and uncompressed data from a spacecraft to a data processing center on Earth. Imaging (and other) data is first compressed into source blocks which are then coded by a Reed Solomon coder and interleaver with parameters J=8, E=16, I=16, followed by a convolutional encoder of parameters k=7, .nu.=2. The received data is first decoded by a Viterbi decoder, followed by a Reed Solomon decoder and deinterleaver. The output of the latter is then decompressed, based on the compression criteria used in compressing the data in the spacecraft. The decompressed data is processed to reconstruct an approximation of the original data-producing condition or images.