Apparatus for detecting relative motion between contents of successive fields of a video signal

Claim 1

A motion amount detection apparatus for operating on successive picture element values of an input digital video signal to detect amounts of relative motion between picture contents of sequentially occurring fields of said input digital video signal, comprising: representative point specifying means (53, 52) for specifying respective positions of a plurality of representative points within each field of said input digital video signal; a first memory circuit (51) controlled by said representative point specifying means for operating during a current field of said input digital video signal to store respective picture element values of said plurality of representative points of said current field while outputting each representative point value of a preceding field during a corresponding comparison interval, said corresponding comparison interval extending prior to and subsequent to the corresponding representative point; first operational circuit means (55) operating during each said corresponding comparison interval for comparing successive picture element values of the input digital video signal with the preceding field representative point value corresponding to said each corresponding comparison interval, to obtain respective sets of operational result values in each said corresponding comparison interval; second operational circuit means (61) for deriving, for each of said sets of operational result values, a corresponding set of relative distance values, wherein each relative distance value is a binary number representing a relative distance between a picture element corresponding to an operational result value and the corresponding representative point; a second memory circuit (63) formed of a plurality of memory circuit sections each having an identical number of addresses and each functioning to cumulatively store successive operational result values supplied thereto in respective addresses, each address for storing a result value being specified by a fixed set of low-order bits of the relative distance value corresponding to said result value; selector circuit means (59) for transferring each of said operational result values to one of said plurality of memory circuit sections selected in accordance with a combination of states of a set of high-order bits of a corresponding one of said corresponding set of relative distance values, said set of high-order bits comprising at least the most significant bit of said corresponding one of the corresponding set of relative distance values; and motion amount detection circuit means (65) for periodically deriving an amount of relative picture motion, based on cumulative stored values contained in said second memory circuit.