Region-based anisotropic diffusion with soft shock filter for adaptive image enhancement

A region-based anisotropic diffusion with soft shock filter is presented for image noise removal and edge sharpening. Two image processing steps are performed successively: smoothing and sharpening. An image is divided into different regions according to image features: edges, textures and details, and flat areas. For edges, a shock- type backward diffusion is performed in the gradient direction to the isophote line (edge), incorporating a forward diffusion in the isophote line direction; while for textures and details, a soft backward diffusion is done to enhance image features preserving a natural transition. Experiments on real images show that this method produces better visual results of the enhanced images than some relevant equations.