Development of three-phase lock-in camera for AM-PM demodulation imaging

This paper proposes a new structure of the correlation image sensor whose pixel consists of a triplet of common-source MOS transistors with individual capacitive loads. It can accept two independent reference signals simultaneously, thus can generate two correlation integrals at a time for an incident light. The correlation results being stored as charges on the capacitors are read out via conventional scanning channels. We also describe a quadrature detection principle for simultaneous detection of amplitude and phase of modulated light. We apply this sensor to the involuntary eye-movement vision system with single and double circular scans. By this, we show that the novel, single-frame, gradient vector imager and the curvature tensor imager can be realized.