A thinned output image is generated from an input image. Values of pixels surrounding a pixel of interest in the input image are determined, and first and second neighboring pixel patterns surrounding the pixel of interest are established based on the values of the pixels surrounding the pixel of interest. The first neighboring pixel pattern may be compared to each of a set of purge patterns to determine whether to eliminate the pixel, and the second neighboring pixel pattern may be compared to each of a set of conservation patterns to determine whether to conserve the pixel. The comparisons to the purge and conservation patterns are performed for each pixel independently, and in parallel for all pixels of the input image.