This paper presents an equivalent formation via wavelet threshold of the diffusion equation defined by Lin-shi operator.Based on the equivalent formation

there are some revisions made for the diffusion coefficient by replacing the Gaussian filtered image with the translational-invariant nonlinear wavelet thresholded image when do estimation of all the derivation levels.This revision will be able to avoid the over-smoothness and edge movement resulting from the Gaussian filter.Finally

experimental results show that the new diffusion equation is effective to eliminate noise while maintaining the edge locations.