Open Access

Spatially Adaptive Intensity Bounds for Image Restoration

  • Kaaren L. May1Email author,
  • Tania Stathaki2 and
  • Aggelos K. Katsaggelos3
EURASIP Journal on Advances in Signal Processing20032003:250181

https://doi.org/10.1155/S1110865703308066

Received: 9 December 2002

Published: 20 November 2003

Abstract

Spatially-adaptive intensity bounds on the image estimate are shown to be an effective means of regularising the ill-posed image restoration problem. For blind restoration, the local intensity constraints also help to further define the solution, thereby reducing the number of multiple solutions and local minima. The bounds are defined in terms of the local statistics of the image estimate and a control parameter which determines the scale of the bounds. Guidelines for choosing this parameter are developed in the context of classical (nonblind) image restoration. The intensity bounds are applied by means of the gradient projection method, and conditions for convergence are derived when the bounds are refined using the current image estimate. Based on this method, a new alternating constrained minimisation approach is proposed for blind image restoration. On the basis of the experimental results provided, it is found that local intensity bounds offer a simple, flexible method of constraining both the nonblind and blind restoration problems.

Keywords

image resolution blur identification blind image restoration set-theoretic estimation

Authors’ Affiliations

(1)
Liss Research Centre, Snell and Wilcox Ltd.
(2)
Communications and Signal Processing Group, Department of Electrical and Electronic Engineering, Imperial College London
(3)
Department of Electrical and Computer Engineering, Northwestern University

Copyright

© Copyright © 2003 Hindawi Publishing Corporation 2003