We investigate the feasibility of the design of a small artificial compound eye that comprises micro-optical, micro-mechanical components and additional electronics for visual processing. The hybrid integration of this "mini-sensor" addresses important issues such as mechanic scale-effect, assembly of small parts and functional testing. The use of retinal scanning for the perception of visual motion is highlighted in the design of a small-sized horizontal array with a scanning retina of 2/spl times/30 photoreceptor elements (R/sub eye/=30 mm). The scanning motion is achieved by actuating the photodiode arrays with a piezoelectric bimorph cantilever beam coupled to a plate spring. The mini-compound eye, equipped with analogue motion detecting circuits, is able to guide the steps of a small mobile platform and perform multi-task visual processing for obstacle avoidance, tracking and pursuit of visual target.

We introduce and implement a way of processing visual motion, which is directly inspired by the functional features of insects' visual systems. Rather than focusing on the computational performances of visual processing, alternative ways of detecting visual cues involving controlled eye movements are investigated. In this case, we show that the combination of retinal/eye movements significantly enhances the visual perception of motion for a sighted observer. The two kinds of eye movements introduced are: 1) pulsed retinal scanning, and 2) visually-guided eye rotations. Pulsed retinal scanning helps the eye to detect visual contrasts with enhanced reliability by increasing the S/N ratio of early visual signals. Rotations of the eye help a moving observer to maintain a continuous visual contact with obstacles while tracking their motion using pulses of retinal scanning. A direct demonstration of the performances has been implemented on a prototype eye, that successfully guides the motion of HECTOR, a small mobile platform, autonomously and in real-time.