new interpretation and improvement of the nonlinear anisotropic diffusion for image enhancement

Abstract—The purpose of this article is to give a new analysis of the Anisotropic Diffusion (AD) and propose an adaptive nonlinear filtering based on a judicious choice of the Conductance Function (CF) and the edgeness threshold. A new undesirable effect, which we call the “pinhole effect, ” may result when AD is introduced for the first time. A robust solution to this effect is proposed and evaluated through experimental data. The evolution of the diffused signal is analyzed through a physical model using the Optical Flow Technique (OFT). The overall strategy is evaluated through experimental results obtained on synthetic and actual images. Index Terms—Nonlinear anisotropic diffusion, fluid mechanics, homogeneity, image enhancement, noise smoothing, optical flow. æ