Image processing apparatus

Abstract

Apparatus for processing images which have been sampled on a rectangular grid and which have been binary digitized with one bit per pixel, each pixel being considered in relation to at least some of the eight surrounding pixels in the rectangular grid. The apparatus includes a control unit (4), a random access memory (5) for storing the pixel bits, and a feedback loop connecting the image memory output to its input via at least one feedback assembly (6) comprising shift register unit (6A, 6B), a function memory (7) and a selector (8). The shift register units comprises at least one write unit (6A) and at least one read unit (6B), with the read unit being connected to the output of the image memory and being connected to supply nine bits simultaneously to the input of the function memory. The nine bits correspond to a pixel under examination and to the eight surrounding pixels, and are changed at each shift of the shift register units. The function memory provides new values for the bit of the pixel under examination on the basis of thenine bits applied to its inputs and in accordance with a plurality of predetermined criteria. The selector receives the new values from the function memory and selects one under control of the control unit. The selected on of the bits is then written back into the image memory via the write unit.