pierrepaleo / ChambollePock

A Python implementation of the Chambolle-Pock algorithm for image processing applications examples
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Chambolle-Pock algorithm for Total Variation minimization

This repository is a Python implementation of the Chambolle-Pock algorithm [1] for minimizing an objective function with Total Variation (TV) regularization. It is mainly written for a didactic purpose.

Two examples are implemented :

There is also an implementation of conjugate gradient using a smoothed TV described in [2].

Installation

Simply download and execute the sample scripts. For tomographic reconstruction, the ASTRA toolbox version 1.6 should be installed beforehand.

Usage

The file CP.py implements the Chambolle-Pock algorithm for minimizing

where K can be any linear operator (here, convolution or tomographic projection).

The file CG.py implements a conjugate gradient algorithm for solving the previous problem, where the TV is approximated by

with

Both of these files can be executed.

The other files contain functions implementing various operators.

Example of deconvolution Example of tomographic reconstruction

[1] Antonin Chambolle, Thomas Pock, A First-Order Primal-Dual Algorithm for Convex Problems with Applications to Imaging, 2011, Journal of Mathematical Imaging and Vision, Vol. 40 Issue 1, pp. 120-145

[2] Pierre Weiss, Laure Blanc-Féraud, and Gilles Aubert, Efficient Schemes for Total Variation Minimization Under Constraints in Image Processing, 2008, SIAM J. Sci. Comput., 31(3), 2047–2080