A novel partial differential equation method for image denoising is proposed based on graph theory.In the process of constructing graph,the small world model is introduced into the graph topology to decrease the diameter of graph,which speeds up the denoisng algorithm.Meanwhile,the optimal parameter selection in graph weighting function is studied.After that,the heat diffusion equation and Lapician matrix on the graph are used to filter the noisy image.Experiments illustrate that compared with some existing...