  Among the patch-based image denoising processing methods, smooth ordering of
local patches (patch ordering) has been shown to give state-of-art results. For
image denoising the patch ordering method forms two large TSPs (Traveling
Salesman Problem) comprised of nodes in N-dimensional space. Ten approximate
solutions of the two large TSPs are then used in a filtering process to form
the reconstructed image. Use of large TSPs makes patch ordering a
computationally intensive method. A modified patch ordering method for image
denoising is proposed. In the proposed method, several smaller-sized TSPs are
formed and the filtering process varied to work with solutions of these smaller
TSPs. In terms of PSNR, denoising results of the proposed method differed by
0.032 dB to 0.016 dB on average. In original method, solving TSPs was observed
to consume 85% of execution time. In proposed method, the time for solving TSPs
can be reduced to half of the time required in original method. The proposed
method can denoise images in 40% less time.
