[IPOL announce] new article: Parameter-Free Fast Pixelwise Non-Local Means Denoising

[announcements about the IPOL journal]

A new article is available in IPOL: http://www.ipol.im/pub/art/2014/120/

Jacques Froment,
Parameter-Free Fast Pixelwise Non-Local Means Denoising,
Image Processing On Line, 4 (2014), pp. 300–326.
http://dx.doi.org/10.5201/ipol.2014.120

Abstract
This article proposes a fast and open-source implementation of the 
well-known Non-Local Means (NLM) denoising algorithm, in its original 
pixelwise formulation. The fast implementation is based on the 
computation of patch distances using sums of lines that are invariant 
under a patch shift. The optimal parameters of NLM (in the average peak 
signal to noise ratio - PSNR - sense) are computed from an image 
database, thereby leading to a parameter-free NLM implementation. 
Comparison is performed with the parameter-free blockwise NLM 
implementation already proposed in IPOL journal by Buades, Coll and 
Morel. As expected the blockwise implementation offers better PSNR, at 
least when the noise standard deviation is large enough, but there is no 
significant difference in quality when performing visual inspection. The 
highlight is that the proposed parameter-free pixelwise NLM 
implementation is faster than the patchwise one by a factor of 6 to 49.