A fast and low power CMOS sensor for optical tracking

A new CMOS optical sensor for active optical tracking is presented. The tracking function is carried out pointing the target with a collimated light beam and estimating the position of the back-reflected beam portion impinging on the device. The core of the device, fabricated in standard 0.8 μm CMOS technology, is an array of 20 × 20 pixels where mixed analogue-digital image pre-processing, at pixel and array level, is performed. Image contour is extracted by means of distributed peak-detection, implemented at pixel level, followed by a digital extraction of the beam centroid position executed at row and column level. The image position can be estimated in 120 μs with an accuracy of 0.9 μm. The chip exhibits a worst case power consumption of 15mW @ 5V and 3000 frames/s.