CONTRAST ENHANCEMENT VIA IMAGE EVOLUTION FLOWS

A framework for contrast enhancement via image evolution hows and vari ational formulations is introduced in this paper. First, an algorithm for histogram modification via image evolution equations is presented. We show that the image histogram can be modified to achieve any given distribution as the steady state solution of this differential equati on. We then prove that the proposed evolution equation solves an energ y minimization problem. This gives a new interpretation to histogram m odification and contrast enhancement in general. This interpretation i s completely formulated in the image domain, in contrast with classica l techniques for histogram modification which are formulated in a prob abilistic domain. From this, new algorithms for contrast enhancement, including, for example, image and perception models, can be derived, B ased on the energy formulation and its corresponding differential form , we show that the proposed histogram modification algorithm can be co mbined with image regularization schemes, This allows us to perform si mulations contrast enhancement and denoising, avoiding common noise sh arpening effects in classical schemes, Theoretical results regarding t he existence of solutions to the proposed equations are presented. (C) 1997 Academic Press.