Portable phosphene image generator simulating cortical visual prosthesis

Electrical stimulation delivered to the visual cortex evokes spot-like visual perceptions of light, called phosphenes. Artificial prosthetic vision is based on the concept that patterns of phosphenes can be used to convey visual information to blind patients. In the previous study, we developed a phosphene simulator which generates phosphene images evoked by cortex stimulation in accordance with the mapping model of the visual field in cerebral cortex in order to visualize the phosphene images. In this study, we further developed the system to include the following features: portability and adaptive image sensing. The simulator consists of an adaptive vision sensor, a laptop computer, and a head-mounted display. Phosphene images were generated in indoor and outdoor situations taking advantages of its compactness and adaptive output to illumination changes. We examined the effect of the number of virtual electrodes for stimulation and that of eccentricity from the center of the visual field.