Restoration of video imagery by intensity-dependent spatial summation
Phillip G. Harnden, Franklin F. Holly, Dale R. Shires · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1992
A contrast-enhancement algorithm is described which avoids the 'flat', noisy appearance often produced by histogram equalization. This algorithm is based upon the Intensity-dependent spatial summation (IDS) model proposed by Cornsweet and Yellott to explain certain effects in human vision. However, where IDS collapses quantization levels except at edges and histogram equalization collapses some quantization levels in the process of expanding others, our algorithm largely preserves the original brightness gradations as it expands them. Thus, the shape-from-shading cues so important to the perception of form and contour are preserved. Also, this technique, in some cases, enhances high frequency noise to a far lesser extent than does histogram equalization.