Visual attention: Effects of blur

The detection of salient regions in images is of great interest for a lot of computer vision applications as adaptive content delivery, smart resizing and auto-cropping, content based image retrieval or visually impaired people assistance. In this paper we focus on the effect of blurriness on human visual attention when observers see images with no prior knowledge. We investigate the hypothesis that sharp objects tend to capture attention irrespective of intensity, color or contrast. Eye movements of 17 subjects were recorded with an eye-tracker in free viewing conditions. Observers were asked to watch a collection of 122 color and grayscale images selected according to criteria driven by basic features of visual perception. The results of the experimental study clearly demonstrate the influence of the sharp/blur aspect of an image part on its saliency. These results indicate that blur information might be integrated in models of attention to efficiently improve the extraction of salient regions.