I am pleased to announce that the following paper has been accepted
to the Mirage 2007 (
http://acivs.org/mirage2007/) an international
conference on Computer Vision / Computer Graphics Collaboration
Techniques and Applications.
J. Darbon. A Note on the Dicerete Binary Mumford-Shah Model.
This paper is concerned itself with the analysis of the twophase
Mumford-Shah model also known as the active contour without
edges model introduced by Chan and Vese. It consists of approximating
an observed image by a piecewise constant image which can take only
two values. First we show that this model with the L1-norm as data
fidelity yields a contrast invariant filter which is a well known property
of morphological filters. Then we consider a discrete version of the original
problem. We show that an inclusion property holds for the minimizers.
The latter is used to design an efficient graph-cut based algorithm which
computes an exact minimizer. Some preliminary results are presented
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I am also pleased to announce that the following twin papers have
been published in the Journal of Mathmematical Imaging and Vision
(
http://www.springerlink.com/content/u8388810354q/?p=e3972a8e80d5433daf4bc20…)
J. Darbon and M. Sigelle
Image Restoration with Discrete Constrained Total Variation Part I: Fast and
Exact Optimization
Journal of Mathematical Imaging and Vision. Journal of Mathematical Imaging and
Vision. Vol 26 n.3, pp. 277-291, December 2006.
This paper deals with the total variation minimization problem in image
restoration for convex data fidelity functionals. We propose a new and fast
algorithm which computes an exact solution in the discrete framework. Our
method relies on the decomposition of an image into its level sets. It maps the
original problems into independent binary Markov Random Field optimization
problems at each level. Exact solutions of these binary problems are found
thanks to minimum cost cut techniques in graphs. These binary solutions are
proved to be monotone increasing with levels and yield thus an exact solution
of the discrete original problem. Furthermore we show that minimization of
total variation under L1 data fidelity term yields a self-dual contrast
invariant filter. Finally we present some results.
J. Darbon and M. Sigelle
Image Restoration with Discrete Constrained Total Variation Part II: Levelable
Functions, Convex and Non-Convex Cases
In Part II of this paper we extend the results obtained in Part I for total
variation minimization in image restoration towards the following directions:
first we investigate the decomposability property of energies on levels, which
leads us to introduce the concept of levelable regularization functions (which
TV is the paradigm of). We show that convex levelable posterior energies can be
minimized exactly using the level-independant cut optimization scheme seen in
Part I. Next we extend this graph cut scheme to the case of non-convex
levelable energies.We present convincing restoration results for images
corrupted with impulsive noise. We also provide a minimum-cost based algorithm
which computes a global minimizer for Markov Random Field with convex priors.
Last we show that non-levelable models with convex local conditional posterior
energies such as the class of generalized Gaussian models can be exactly
minimized with a generalized coupled Simulated Annealing.
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