Stimuli Design for Identification of Spatially Distributed Motion Detectors in Biological Vision Systems

Visual motion perception in biological vision systems is typically modeled via a set of elementary motion detectors (EMDs) forming a spatially distributed network. This paper addresses the problem of estimating the weights of such an EMD construct from a linear combination of their output signals. This challenge arises in e.g. mathematical modeling of animal motion perception. In particular, the spatial excitation properties of sinusoidal gratings are important since these basis signals are typically utilized as visual stimuli in biology. It is demonstrated that one cannot uniquely estimate the weights of more than three contributing EMDs with a single frequency sinusoidal grating as the visual stimulus. However, a higher spatial excitation order can be obtained with multi-frequency sinusoidal grating stimuli. Two approaches to the design of stimuli with a given spatial excitation order are presented. Several numerical examples are provided to examine the performance of the proposed stimuli design methods.