ABSTRACT
The eyes of most insects are comparatively close together and lack focusing mechanisms, so that they must use cues other than stereopsis or accommodation to gauge the distances of objects in the environment. This chapter describes experiments designed to explore this “centering response” quantitatively, in an attempt to discover the parameters of image motion that are used to extract range information, and to probe the mechanisms by which these parameters are measured. It describes the results that suggest that the estimation of range by the bee’s visual system does, indeed, involve movement-sensitive mechanisms that measure the apparent speed of an image largely independently of its structure. Flight trajectories, recorded at 25 frames per second by the camera and video recorder, were subsequently analyzed frame by frame to measure average positions along the width of the tunnel, average flight velocities, etc.
