A New Technique for Displaying Continuous Tone Images on a Bilevel Display

A new technique for the display of continuous tone images on a bilevel graphical output device is described. This technique belongs to the general class of algorithms that convey intensity information by the spatial arrangement of lit and unlit cells which are in a one-to-one correspondence with the picture elements (PEL´s) in the original image. Besides the rendition of a gray scale in the processed image, the new algorithm also incorporates edge emphasis to increase the legibility of textual information and other areas of high detail. A simple theory of the algorithm, derived from an intensity distribution function, is given, along with the details of an implementation and results obtained using the new technique. The technique is interesting as it requires a nonzero noise component in the image signal being processed in order to generate a gray scale.