1. An imaging system, comprising: a memory for storing an image frame of pixel values; an image data processor programmed to perform the steps of: (a) segregating m pixel.times.n pixel blocks of pixel values having an expected high resolution from m pixel.times.n pixel blocks of pixel values having an expected low resolution, where m and n are positive even integers .gtoreq.4; (b) classifying each pixel block as a function of the brightness and the contrast of respective quadrants within each pixel block; (c) substituting a high-resolution block having a predetermined brightness class and a predetermined contrast class in place of a low-resolution block having said predetermined brightness class and said predetermined contrast class in said image frame to form an enhanced image frame; and a display device comprising a multiplicity of pixels for displaying said enhanced image frame.