Title
Linearized ADMM and Fast Nonlocal Denoising for Efficient Plug-and-Play Restoration.
Abstract
In plug-and-play image restoration, the regularization is performed using powerful denoisers such as nonlocal means (NLM) or BM3D. This is done within the framework of alternating direction method of multipliers (ADMM), where the regularization step is formally replaced by an off-the-shelf denoiser. Each plug-and-play iteration involves the inversion of the forward model followed by a denoising step. In this paper, we present a couple of ideas for improving the efficiency of the inversion and denoising steps. First, we propose to use linearized ADMM, which generally allows us to perform the inversion at a lower cost than standard ADMM. Moreover, we can easily incorporate hard constraints into the optimization framework as a result. Second, we develop a fast algorithm for doubly stochastic NLM, originally proposed by Sreehari et al. (IEEE TCI, 2016), which is about 80× faster than brute-force computation. This particular denoiser can be expressed as the proximal map of a convex regularizer and, as a consequence, we can guarantee convergence for linearized plug-and-play ADMM. We demonstrate the effectiveness of our proposals for super-resolution and single-photon imaging.
Year
DOI
Venue
2018
10.1109/GlobalSIP.2018.8646599
2018 IEEE Global Conference on Signal and Information Processing (GlobalSIP)
Keywords
DocType
Volume
image restoration,ADMM,plug-and-play,non-local means,convergence
Conference
abs/1901.06110
ISSN
ISBN
Citations 
2376-4066
978-1-7281-1295-4
2
PageRank 
References 
Authors
0.36
15
3
Name
Order
Citations
PageRank
V. S. Unni121.03
Ghosh, S.293.85
Kunal N. Chaudhury39915.56