Towards photosensor movement-adaptive image analysis in an electronic retinal prosthesis

By way of extracellular, stimulating electrodes, electronic vision prosthesis aims to render discrete light spots - so-called phosphenes - in the visual field, thereby providing a phosphene image serving as a rudimentary remediation of profound blindness. It is proposed that a digital camera, or some other photosensitive array, captures frames, the frames be analyzed, and phosphenes be actuated accordingly. We present a numerical experiment wherein we observed the phosphene image in response to a set of stimuli for various image analysis schemes. We used the mutual-information function to quantify the efficacy of analysis schemes; the function penalizes a scheme for introducing redundancy to the phosphene image, while accounting for the probability of each stimulus. We demonstrate an effective scheme involving Laplacian of Gaussian (/spl nabla/2G) kernels geometrically transformed in accordance with phosphene layout. Further, we propose adapting the kernels comprising a scheme in accordance with photosensor movement.