Nonlinear diffusion filters based on partial differential equations can well preserves the edge information while de-noise effectively

but the corners gradually become rounded and vanish while filtering. A corner preserving nonlinear diffusion filter is proposed

whose diffusion coefficient is the function of the gradient and the curvature. The new model behaves as a Gaussian filter inside the regions and smoothes less across regions； and the smoothing effect is even decreased in the corner points. These effects ensure better preservation of the corner. Visual effect with data analysis of the experiment result proves simultaneous protection of the edge and corner information.