Enhanced mixed-signal processor for motion sensing

This work describes the application of a novel, mixed-signal processing strategy to a high resolution, optically based motion sensor. The objectives are to integrate several subsystems into a single device to yield a lower cost, higher performance sensor, and to demonstrate the potential merits of moving the analogue/digital processing boundary in certain cases. Laser light, when reflected from an optically rough surface, gives rise to a speckle pattern. After imaging and suitable processing of the speckle, its motion, with respect to the imaging sensor, can be extracted and, from this, the motion of the illuminated surface can be inferred. Through oversampling in time (by taking measurements at a higher rate than required) and/or space (by increasing the imager size), the resolution of the final reading can be arbitrarily high, offering a scalable result depending on application criteria such as speed and cost