Device for the dynamic adjustment of a black/white discrimination threshold for the processing of images containing grey values

摘要

A device for binarizing an image consisting of grey values by means of a dynamically adjusted black/white discrimination threshold comprises: a. a generator (74) for determining a discrimination threshold each time for a first local sub-set of pixels; b. an edge detector (90) for determining a local edge between darker and lighter pixels from a second local sub-set of pixels, associated with a first local sub-set of pixels, in order to form an accept signal, and otherwise a reject signal; and c. a discriminator (64) for presenting, on the basis of a grey value and the relevant discrimination threshold, alternatively a black or a white signal.