10 November 2017 Artifact reduction for separable nonlocal means
Author Affiliations +
Abstract
It was recently demonstrated that one can perform fast nonlocal means (NLM) denoising of one-dimensional (1-D) signals using a method called lifting. The cost of lifting is independent of the patch length, which dramatically reduces the run-time for large patches. Unfortunately, it is difficult to directly extend lifting for NLM denoising of images. To bypass this, the authors proposed a separable approximation in which the image rows and columns are filtered using lifting. The overall algorithm is significantly faster than NLM, and the results are comparable in terms of PSNR. However, the separable processing often produces vertical and horizontal stripes in the image. This problem was previously addressed using a bilateral filter-based postsmoothing, which was effective in removing some of the stripes. We demonstrate that stripes can be mitigated in the first place simply by involving the neighboring rows (or columns) in the filtering. In other words, we use a two-dimensional (2-D) search (similar to NLM), while still using 1-D patches (as in the previous proposal). The innovation is in the observation that one can use lifting for performing 2-D searches. The proposed approach produces artifact-free images, whose quality and PSNR are comparable to NLM, while being significantly faster.
© 2017 SPIE and IS&T
Sanjay Ghosh, Sanjay Ghosh, Kunal N. Chaudhury, Kunal N. Chaudhury, } "Artifact reduction for separable nonlocal means," Journal of Electronic Imaging 26(6), 063012 (10 November 2017). https://doi.org/10.1117/1.JEI.26.6.063012 . Submission: Received: 12 August 2017; Accepted: 24 October 2017
Received: 12 August 2017; Accepted: 24 October 2017; Published: 10 November 2017
JOURNAL ARTICLE
6 PAGES


SHARE
RELATED CONTENT

Adaptive contrast enhancement for underexposed images
Proceedings of SPIE (January 24 2011)
Image decomposition and enhancement using rank filtering
Proceedings of SPIE (March 09 1998)
Block List Transform (BLT) Coding Of Images
Proceedings of SPIE (October 12 1987)
Edge-and-corner-directed interpolation
Proceedings of SPIE (February 28 2005)
Adaptive bilateral filtering for image denoising
Proceedings of SPIE (September 30 2011)

Back to Top