Perception of saturation in natural scenes.

We measured how well perception of color saturation in natural scenes can be predicted by different measures that are available in the literature. We presented 80 color images of natural scenes or their gray-scale counterparts to our observers, who were asked to choose the pixel from each image that appeared to be the most saturated. We compared our observers' choices to the predictions of seven popular saturation measures. For the color images, all of the measures predicted perception of saturation quite well, with CIECAM02 performing best. Differences between the measures were small but systematic. When gray-scale images were viewed, observers still chose pixels whose counterparts in the color images were saturated above average. This indicates that image structure and prior knowledge can be relevant to perception of saturation. Nevertheless, our results also show that saturation in natural scenes can be specified quite well without taking these factors into account.