[IPOL announce] new article: Multi-Scale DCT Denoising

[announcements about the IPOL journal]

A new article is available in IPOL: http://www.ipol.im/pub/art/2017/201/

Nicola Pierazzo, Jean-Michel Morel, and Gabriele Facciolo,
Multi-Scale DCT Denoising,
Image Processing On Line, 7 (2017), pp. 288–308.
https://doi.org/10.5201/ipol.2017.201

Abstract
DCT denoising is a classic low complexity method built in the JPEG 
compression norm. Once made translation invariant, this algorithm was 
still proven to be competitive at the beginning of this century. Since 
then, it has been outperformed by patch based methods, which are far 
more complex. This paper proposes a two-step multi-scale version of the 
algorithm that boosts its performance and reduces its artifacts. The 
multi-scale strategy decomposes the image in a dyadic DCT pyramid, which 
keeps noise white at all scales. The single scale denoising is then 
applied to all scales, thus giving multiple denoised versions of the low 
frequency coefficients of the denoised image. A 'multi-scale fusion' of 
these multiple estimates avoids the ringing artifacts resulting from the 
pyramid recomposition. The final algorithm attains a good PNSR and much 
improved visual image quality. It is shown to have a deficit of only 1dB 
with respect to state of the art algorithms, but its complexity is two 
orders of magnitude lower.