A Black-White Representation of a Gray-Scale Picture
T.H. Morrin · IEEE Transactions on Computers · 1974
A hardware-implemented algorithm combining dynamic thresholding and edge detection allows black-white representation of gray-scale images for computer storage. The output resembles a highly detailed sketch, with resolution and contrast superior to a halftone representation. The same algorithm can be applied to text and line drawings, so that all three types of images can be stored using the same compression algorithm.