A 0.5-degree error 10mW CMOS image sensor-based gaze estimation processor with logarithmic processing

A CMOS image sensor (CIS)-based gaze estimation processor (GEP) is proposed for the next generation user interface (UI) of the smart glasses. It integrates a functional CMOS image sensor (CIS), a RISC, and an ellipse fitting engine (EFE) on a single chip to reduce the power consumption. The functional CIS includes mixed-signal pre-processing circuits, pupil edge detection circuit (PEDC) and glint corner detection circuit (GCDC). Logarithmic processing elements (LPE) is used for EFE to reduce the power consumption further. As a result, PEDC/GCDC and LPE can reduce overall power by 55.2% and 14.1%, respectively. Implemented in 65nm CMOS technology, the 11.29mm
²
chip consumes 10mW power at 30fps real-time operation, and 0.5° error is achieved in a glass-type wearable system.