A Novel Range Finding System Using Correlation Image Sensor

Abstract

This paper proposes a 3-D measurement principle for the correlation image sensor (CIS) which generates temporal correlation between incident light intensity and an external reference signal at each pixel. Another key of our system besides the CIS is amplitude modulation of the scanning sheet beam, the phase of which relative to a reference signal is varied according to the angle of the sheet beam. After a scan within a frame, the phase is demodulated with a quadrature pair of reference signals and output by the CIS to compute the individual angle of the sheet beam on each pixel. By virtue of the lock-in detection principle, effects of background illumination and/or surface reflectance nonuniformity of the object are thoroughly removed. We impleinented this system using our CMOS 64×64-pixel CIS, and successfully reconstructed a depth map under its frame rate (30Hz).