Abstract: An image compression method based on symbol matching is disclosed. Precompression of the image is performed prior to symbol matching to improve efficiency. A voting scheme is used in conjunction with a plurality of novel similarity tests to improve symbol matching accuracy. A template composition scheme achieves image enhancement. Other disclosed features provide further advantages. Apparatus for implementing the image compression method for image transmission, storage, and enhancement are included.

Abstract: In order to efficiently controlling a compressing feeder of refuse, a novel detector system for existence or non-existence of refuse, a novel detector system for stagnation of refuse, and a novel system for preventing stagnation of refuse, are disclosed. The refuse existence detector system comprises an image pick-up device, an A/D converter for an analog image signal, a background image memory, a luminance variation detector, a background image selector, a subtractor for subtracting a background image signal from a digitized image signal, a binary encoder for issuing binary-coded image difference signal, an area calculator for calculating an area of an image region where the binary-coded image difference signal is binary "1", and a determinator device for determining whether existence or non-existence of refuse on the basis of the output of the area calculator. The refuse stagnation detector system and the refuse stagnation preventing system are constructed on the basis of a similar inventive concept.

Abstract: An image data coding apparatus includes a coder for coding input binary data in a predetermined coding algorithm and for outputting coded data, a conversion circuit for repeatedly performing a converting operation with respect to binary image data supplied from an external unit, a determination circuit for determining a number of times which the converting operation should be repeated in the conversion circuit based on a condition in which, when data obtained by repeating the converting operation the number of times in the conversion circuit is coded by the coder, a number of codes representing coded data output from the coder is minimum; and a circuit, for supplying to the coder, as the input data, converted data obtained by repeating the conversion operation the number of times determined by the determination circuit. The image coding apparatus outputs the coded data and data representing the number of times the converting operation is repeated.

Abstract: An apparatus and a method for identifying a person by making use of his fingerprint. The uneven fingerprint surface of a finger is scanned by a laser beam through a transparent plate. The distance between positions of the surface of the transparent plate serving as a reference surface of reflection and of the uneven surface of the fingerprint is detected as a deviation value due to the scanning. Pattern information obtained from the deviation value is indicative of undulation of the uneven surface of the fingerprint. The pattern information is collated with registered fingerprint data so as to determine whether or not the person whose fingerprint has been detected is registered or not.