A model for simultaneous computation of heading and depth in the presence of rotations

The effect of monocular depth cues on the detection of moving objects by moving observers

An observer moving through the world must be able to identify and locate moving objects in the scene. In principle, one could accomplish this task by detecting object images moving at a different angle or speed than the images of other items in the optic flow field. While angle of motion provides an unambiguous cue that an object is moving relative to other items in the scene, a difference in speed could be due to a difference in the depth of the objects and thus is an ambiguous cue. We tested whether the addition of information about the distance of objects from the observer, in the form of monocular depth cues, aided detection of moving objects. We found that thresholds for detection of object motion decreased as we increased the number of depth cues available to the observer.

Detecting moving objects in an optic flow field using direction- and speed-tuned operators

An observer moving through a scene must be able to identify moving objects. Psychophysical results have shown that people can identify moving objects based on the speed or direction of their movement relative to the optic flow field generated by the observer's motion. Here we show that a model that uses speed- and direction-tuned units, whose responses are based on the response properties of cells in the primate visual cortex, can successfully identify the borders of moving objects in a scene through which an observer is moving.

Use of speed cues in the detection of moving objects by moving observers

When an observer moves through an environment containing stationary and moving objects, he or she must be able to determine which objects are moving relative to the others in order to navigate successfully and avoid collisions. We investigated whether image speed can be used as a cue to detect a moving object in the scene. Our results show that image speed can be used to detect moving objects as long as the object is moving sufficiently faster or slower than it would if it were part of the stationary scene.