Learning device for digital signal pattern recognition

Abstract

A device for recognizing overall patterns of digital signals which are arranged according to at least one coordinate comprises: first storage means for the storage of a pattern to be presented for comparison; a window device for selecting a local pattern of a number of digital signals from the overall pattern; a stepping mechanism for coordinate-wise adjustment of the window device over a step; a gradient determining device for determining, for predetermined coordinate values within the window, the absolute value of the coordinate-wide gradient of the values of the digital signals prevailing at said coordinate values; a moment generator for receiving these absolute values, for determining the moment therefrom with respect to a focussing point of the window, and for generating an output signal when a predetermined minimum value of said moment is reached in order to indicate the reaching of a local maximum in said coordinate-wise gradient; second storage means for the storage of a number of reference patterns; and a difference determining device for comparing, under control of the output signal of the moment generator, a local pattern selected by the window device with the reference patterns and for alternatively forming a non-correspondence/correspondence signal. If the difference is too large, the 'new' pattern is stored as a further reference, so that the learning phase and the use phase occur simultaneously. The comparison does not take into account a difference near substantially coincident acute amplitude gradients.