Measuring perceptual contrast in digital images

  • Authors:
  • Gabriele Simone;Marius Pedersen;Jon Yngve Hardeberg

  • Affiliations:
  • The Norwegian Color Research Laboratory, Faculty of Computer Science and Media Technology, Gjøvik University College, P.O. Box 191, N-2802 Gjøvik, Norway;The Norwegian Color Research Laboratory, Faculty of Computer Science and Media Technology, Gjøvik University College, P.O. Box 191, N-2802 Gjøvik, Norway;The Norwegian Color Research Laboratory, Faculty of Computer Science and Media Technology, Gjøvik University College, P.O. Box 191, N-2802 Gjøvik, Norway

  • Venue:
  • Journal of Visual Communication and Image Representation
  • Year:
  • 2012

Quantified Score

Hi-index 0.00

Visualization

Abstract

In this paper we present a novel method to measure perceptual contrast in digital images. We start from a previous measure of contrast developed by Rizzi et al. [26], which presents a multilevel analysis. In the first part of the work the study is aimed mainly at investigating the contribution of the chromatic channels and whether a more complex neighborhood calculation can improve this previous measure of contrast. Following this, we analyze in detail the contribution of each level developing a weighted multilevel framework. Finally, we perform an investigation of Regions-of-Interest in combination with our measure of contrast. In order to evaluate the performance of our approach, we have carried out a psychophysical experiment in a controlled environment and performed extensive statistical tests. Results show an improvement in correlation between measured contrast and observers perceived contrast when the variance of the three color channels separately is used as weighting parameters for local contrast maps. Using Regions-of-Interest as weighting maps does not improve the ability of contrast measures to predict perceived contrast in digital images. This suggests that Regions-of-Interest cannot be used to improve contrast measures, as contrast is an intrinsic factor and it is judged by the global impression of the image. This indicates that further work on contrast measures should account for the global impression of the image while preserving the local information.