PATTERN MATCHING DEVICE OPERABLE WITH SIGNALS OF A COMPRESSED DYNAMIC RANGE

A pattern matching device generally comprises a first circuit (36) for calculating an elementary similarity measure between two feature vectors, one and the other selected from two feature vector sequences representative of two patterns, respectively, and a second circuit (37) for iteratively calculating a recurrence formula which defines a recurrence value by a sum of such an elementary similarity measure and an extremum of a prescribed number of previously calculated recurrence values. The recurrence formula eventually gives an overall similarity measure between the two patterns. The elementary similarity measure is now calculated by calculating a primitive similarity measure by a conventional circuit (15) and subtracting a predetermined value therefrom by a compensation circuit (31). Preferably, the second circuit (37) comprises circuitry (41, 42) for preventing the sum from overflowing outwardly of a preselected range.