NLM algorithm with weight update

The nonlocal means (NLM) filter is one of the most popular denoising approaches and there have been many improvements regarding its weight function and parameter optimisation. However, those improvements have not removed artifacts such as the false texture pattern, which occurs when the smoothing parameter in the weight function is small. The smoothness in the flat region and the sharpness in the texture region without the artifacts can be ensured by accurately estimated weights, which can be calculated with sufficient similar patches. In this reported work, a NLM algorithm with weight update is used to exploit the weights from relatively similar locations as well as the weights from the centre location. Experimental results demonstrate that the proposed method performed well.