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

The purpose of the article is to give an analysis of the anisotropic diffusion (AD) and propose 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