Improved color edge preserving smoothing
An edge preserving smoothing algorithm is presented. To prevent smoothing over edges, the algorithm requires that diffusion in a direction should not result in an increase in neighbouring gradients. Intuitively, we think that smoothing reduces gradients. This is, however, not true in the vicinity of strong edges where smoothing over the edge results in surface deformation. The possibility of reducing the calculation cost is explored by reducing the frequency of calculating the edge strength.