Modeling Frog and Toad Depth Perception

Abstract

In this chapter we review the reasons why previous theoretical models do not provide an adequate explanation for the depth perception process in frogs and toads. We begin with a survey of earlier depth models and a review of experimental evidence from behavioral, anatomical, and physiological experiments relating to depth perception in frogs and toads. We conclude by contrasting the assumptions made in the models with observations about the animals. We note that all of the previous depth models based on stereopsis are restricted to the consideration of binocular matching on a pair of static images, and that their purpose is to produce a depth-mapping from the image pair. These models also depend upon assumptions concerning vergence and image granularity. We show that these restrictions and assumptions are not applicable to the depth resolution problem in frogs and toads.