Time-to-contact maps for navigation with a low resolution visual prosthesis

The perception of independently moving objects in the scene is an important capability for prosthetic vision, but is impeded by the limited resolution and dynamic range of current and near-term retinal prostheses. We propose a novel, biologically-inspired visual representation for prosthetic vision based on the recovery of time-to-contact (τ) with surfaces in the scene. The representation directly encodes the extent of motion towards the observer, placing greatest emphasis on objects posing an imminent threat of collision. Our results suggest the proposed τ-based representation may facilitate earlier perception of incoming objects, and provide clearer distinction between moving objects and the static structure of the scene compared with intensity and depth-based scene representations.