A Biomimetic Frame-Free Event-Driven Image Sensor

Conventional image sensors acquire the visual information time-quantized at a predetermined frame rate. Each frame carries the information from all pixels, regardless of whether or not this information has changed since the last frame had been acquired. If future artificial vision systems are to succeed in demanding applications such as autonomous robot navigation, high-speed motor control and visual feedback loops, they must exploit the power of the biological, asynchronous, frame-free approach to vision and leave behind the unnatural limitation of frames: These vision systems must be driven and controlled by events happening within the scene in view, and not by artificially created timing and control signals that have no relation whatsoever to the source of the visual information: the world. Translating the frameless paradigm of biological vision to artificial imaging systems implies that control over visual information acquisition is no longer being imposed externally to an array of pixels but the decision making is transferred to the single pixel that handles its own information individually. The notion of a frame has then completely disappeared and is replaced by a spatio-temporal volume of luminance-driven, asynchronous events. ATIS is the first optical sensor to combine several functionalities of the biological ‘where’- and ‘what’-systems of the human visual system. Following its biological role model, this sensor processes the visual information in a massively parallel fashion using energy-efficient, asynchronous event-driven methods.