Quantifying the perceived interest of objects in images: effects of size, location

This paper presents the results of two psychophysical experiments designed to investigate the effects of size, location, blur, and contrast on the perceived visual interest of objects within images. In the first experiment, digital composting was used to create images containing objects (humans, animals, and non-living objects) which varied in controlled increments of size, location, blur, and contrast. Ratings of perceived interest were then measured for each object. We found that: (1) As object size increases, perceived interest increases but exhibits diminished gains for larger sizes; (2) As an object moves from the center of the image toward the image’s edge, perceived interest decreases nearly linearly with distance; (3) Blurring imposes a substantial initial decrease in perceived interest, but this drop is relatively lessened for highly blurred objects; (4) As an object’s RMS contrast is increased, perceived interest increases nearly linearly. Furthermore, these trends were quite similar for all three categories (human, animal, non-living object). To determine whether these data can predict the perceived interest of objects in real, non-composited images, a second experiment was performed in which subjects rated the visual interest of each of 562 objects in 150 images. Based on these results, an algorithm is presented which, given a segmented image, attempts to generate an object-level interest map. 1