부산대학교 도서관

This research shows that insects employ several strategies to estimate object range. Earlier work has shown that insects, while orienting with respect to a familiar landmark, adjust their distance to the landmark by matching the retinal image with a preformed template or mental image of the landmark. With unfamiliar objects, other strategies are brought to bear. At least some insects with large interocular separations, such as the mantis, use for of steropsis to gauge the distance of objects at close range. With more distant objects, however, insects have to resort to cues obtained from the optical flow experienced by the moving eye. The ranges of distant objects are measured in terms of the angular speed of their images on the retina. Flies, bees and probably many other insects are able to segregate a figure from a more distant background purely on the basis of relative motion between the two. In the case of the bee, this task seems to accomplished by detecting the discontinuity in image speed at the figure boundary. At present, however, we know little about the neural mechanisms by which insects exploit motion cues to refer range and more generally to obtain a three-dimensional appreciation of their visual environment.