Abstract: The present invention provides for a compression scheme tailored to the compression of large radiological images processed with image processing workstations. The compression scheme is a variation of the CCITT JPEG compression scheme with special care taken to suppress blocking effects of the 8.times.8 discrete cosine transform used therein. In accordance with the present invention, an original image is downsampled, then interpolated back to its original size, resulting in a smoothed image. The difference between the smoothed image and the original image is then compressed using an 8.times.8 discrete cosine transform with 12 bit data. Major artifacts present in the original image are due to the mismatching of the low frequency components of the image at the edges of the blocks. When the low frequencies are removed by subtracting out the low frequency components, the artifacts disappear except in areas having very large dynamic changes.

Abstract: A filter which uses both an analog portion and a digital portion to optimize the filter performance. A simple analog filter provides a rough filtering of the input signal. The output of the analog filter is converted into digital form and supplied to a digital filter. The coefficients of the digital filter are changed by a digital computer in order to correct for the errors in the filtered signal produced by the analog filter. The coefficients necessary for the digital filter to provide an error offset are determined by comparing the filtered value of a test signal through the analog filter to an ideal filtered value of such test signal.

Abstract: This invention relates to a system and method for determining velocity, direction, position, profile and confidence information of a target such as an intruder from alarms generated by the intruder passing by an array of spaced sensors. The system comprises a processor, the primary element of which is a velocity-position matrix comprising a plurality of information storage cells in the form of counters. The cells are arranged in a plurality of adjacent rows and adjacent columns corresponding to target velocity and position, respectively. Each sensor alarm is entered as a count into cells in those columns which correspond to sensor deployment and the count in each cell is shifted to the adjacent cell in the same row by auxiliary equipment at different rates for the different rows to provide a velocity determination capability. Counts are subtracted from the cells in the columns corresponding to sensor locations when no alarm is given by the particular sensor.

Abstract: A feed pawl antibounce device that prevents jamming of a round feed appars when the pawl clears the round and is moved into position to feed the round from its feed position to its chambering position in front of the open bolt.