Biologically-inspired low light integrated vision systems

ABSTRACT: Our objective is to develop a vision system for a micro air vehicle (MAV) or other robotic system that allows it to operate in extremely low light levels. We will develop systems capable of operating in ambient light or with active illumination carried aboard the vehicle, and will explore both silicon-based sensors for the visible/NIR band and hybridized sensors for the SWIR and/or MWIR bands. The image sensors will comprise capacitive transimpedance amplifer driven photodetectors and/or single photon avalanche diode devices, and biologically inspired pooling mechanisms to extract spatiotemporal features from the visual field. We will draw inspiration on integrated sensing and processing methods from the visual systems of nocturnal insects, who navigate in light levels on the order of several photons per photoreceptor per second. We will also explore use of statistics and information theoretic measures to optimally detect visual features, optical flow patterns, and ultimately egomotion and the presence of targets of interest. In Phase I we will conduct a feasibility study in which we explore signal processing techniques and sensor architecture concepts, and select a semiconductor material for making a hybridized infrared sensor. We will build a prototype system in Phase II. BENEFIT: The resulting visual systems will enable air vehicles and robotic platforms in general to operate in extremely low light levels on the order of tens of photons per pixel per second or less. The final system will be light enough for use on micro- or nano-air vehicles. Sample anticipated applications include: 1) Enabling air or ground vehicles to operate stealthily in an indoor environment, including deep inside caves, tunnels, pipes, or other structures. 2) Enabling air vehicles to operate at night, using only starlight or airglow for ambient illumination, including underneath forest canopies or deep in urban canyons. 3) Providing see-and-avoid capabilities to a UA (unmanned aircraft) operating at night. 4) Stealthy operation in pure dark environments, by allowing active illumination with only a minimal amount of illumination provided by the platform. We anticipate the resulting technology to be useful to both the military, especially special forces, and civilian customers.