42 research outputs found
Deblurring by Solving a TV p
Image deblurring is formulated as an unconstrained minimization problem, and its penalty function is the sum of the error term and TVp-regularizers
with 0<p<1. Although TVp-regularizer is a powerful tool that can significantly promote the sparseness of image gradients, it is neither convex nor smooth, thus making the
presented optimization problem more difficult to deal with. To solve this minimization
problem efficiently, such problem is first reformulated as an equivalent constrained minimization problem by introducing new variables and new constraints. Thereafter, the split
Bregman method, as a solver, splits the new constrained minimization problem into subproblems. For each subproblem, the corresponding efficient method is applied to ensure
the existence of closed-form solutions. In simulated experiments, the proposed algorithm
and some state-of-the-art algorithms are applied to restore three types of blurred-noisy
images. The restored results show that the proposed algorithm is valid for image deblurring and is found to outperform other algorithms in experiments
A Fast Splitting Method for efficient Split Bregman Iterations
In this paper we propose a new fast splitting algorithm to solve the Weighted
Split Bregman minimization problem in the backward step of an accelerated
Forward-Backward algorithm. Beside proving the convergence of the method,
numerical tests, carried out on different imaging applications, prove the
accuracy and computational efficiency of the proposed algorithm
Image Restoration Using Joint Statistical Modeling in Space-Transform Domain
This paper presents a novel strategy for high-fidelity image restoration by
characterizing both local smoothness and nonlocal self-similarity of natural
images in a unified statistical manner. The main contributions are three-folds.
First, from the perspective of image statistics, a joint statistical modeling
(JSM) in an adaptive hybrid space-transform domain is established, which offers
a powerful mechanism of combining local smoothness and nonlocal self-similarity
simultaneously to ensure a more reliable and robust estimation. Second, a new
form of minimization functional for solving image inverse problem is formulated
using JSM under regularization-based framework. Finally, in order to make JSM
tractable and robust, a new Split-Bregman based algorithm is developed to
efficiently solve the above severely underdetermined inverse problem associated
with theoretical proof of convergence. Extensive experiments on image
inpainting, image deblurring and mixed Gaussian plus salt-and-pepper noise
removal applications verify the effectiveness of the proposed algorithm.Comment: 14 pages, 18 figures, 7 Tables, to be published in IEEE Transactions
on Circuits System and Video Technology (TCSVT). High resolution pdf version
and Code can be found at: http://idm.pku.edu.cn/staff/zhangjian/IRJSM
Preservation of Piecewise Constancy under TV Regularization with Rectilinear Anisotropy
A recent result by Lasica, Moll and Mucha about the -anisotropic
Rudin-Osher-Fatemi model in asserts that the solution is
piecewise constant on a rectilinear grid, if the datum is. By means of a new
proof we extend this result to . The core of our proof consists
in showing that averaging operators associated to certain rectilinear grids map
subgradients of the -anisotropic total variation seminorm to
subgradients
A regularization approach to blind deblurring and denoising of QR barcodes
QR bar codes are prototypical images for which part of the image is a priori known (required patterns). Open source bar code readers, such as ZBar, are readily available. We exploit both these facts to provide and assess purely regularization-based methods for blind deblurring of QR bar codes in the presence of noise
Total variation denoising in anisotropy
We aim at constructing solutions to the minimizing problem for the variant of
Rudin-Osher-Fatemi denoising model with rectilinear anisotropy and to the
gradient flow of its underlying anisotropic total variation functional. We
consider a naturally defined class of functions piecewise constant on
rectangles (PCR). This class forms a strictly dense subset of the space of
functions of bounded variation with an anisotropic norm. The main result shows
that if the given noisy image is a PCR function, then solutions to both
considered problems also have this property. For PCR data the problem of
finding the solution is reduced to a finite algorithm. We discuss some
implications of this result, for instance we use it to prove that continuity is
preserved by both considered problems.Comment: 34 pages, 9 figure