A process for thinning an image, comprising the steps of defining an image in terms of a plurality of discrete picture elements (pixels), convolving each horizontal string of pixels of the image with itself shifted a predetermined number of pixels, weighting each shifted position of each horizontal string, selecting certain of the pixels of the weighted horizontally convolved pixel strings which correspond to predetermined descriptors, convolving each vertical string of pixels of the image with itself shifted a predetermined number of pixels, weighting each shifted position of each vertical string, selecting certain of the pexels of the weighted vertically convolved pixel strings which correspond to predetermined descriptors, adding thee selected pixels from the weighted vertical and horizontal convolutions and the pixels of the original image, retaining those pixels which are common to the original image and the selected pixels of both the horizontal and vertical weighted convolutions, discarding those pixels which are absent from the original image, filtering those pixels which are common to the original image and the original image and only one of the selected pixels of the horizontal and vertical weighted convolutions, further retaining certain of the filtered pixels and discarding others in accordance with a predetermined filter matrix, and providing an output signal of the retained pixels which represents a thinned image.