Title
Efficient Nonsmooth Nonconvex Optimization for Image Restoration and Segmentation
Abstract
In this article, we introduce variational image restoration and segmentation models that incorporate the $$L^1$$L1 data-fidelity measure and a nonsmooth, nonconvex regularizer. The $$L^1$$L1 fidelity term allows us to restore or segment an image with low contrast or outliers, and the nonconvex regularizer enables homogeneous regions of the objective function (a restored image or an indicator function of a segmented region) to be efficiently smoothed while edges are well preserved. To handle the nonconvexity of the regularizer, a multistage convex relaxation method is adopted. This provides a better solution than the classical convex total variation regularizer, or than the standard $$L^1$$L1 convex relaxation method. Furthermore, we design fast and efficient optimization algorithms that can handle the non-differentiability of both the fidelity and regularization terms. The proposed iterative algorithms asymptotically solve the original nonconvex problems. Our algorithms output a restored image or segmented regions in the image, as well as an edge indicator that characterizes the edges of the output, similar to Mumford---Shah-like regularizing functionals. Numerical examples demonstrate the promising results of the proposed restoration and segmentation models.
Year
DOI
Venue
2015
10.1007/s10915-014-9860-y
J. Sci. Comput.
Keywords
Field
DocType
nonconvex regularizer,multistage convex relaxation,image segmentation,image restoration,$$l^1$$l1 fidelity measure,augmented lagrangian method
Mathematical optimization,Segmentation,Indicator function,Outlier,Regular polygon,Image segmentation,Augmented Lagrangian method,Regularization (mathematics),Image restoration,Mathematics
Journal
Volume
Issue
ISSN
62
2
1573-7691
Citations 
PageRank 
References 
9
0.55
36
Authors
2
Name
Order
Citations
PageRank
Miyoun Jung112510.72
Myungjoo Kang2141.66