Real-Time Phase-Stamp Range Finder Using Correlation Image Sensor

This paper proposes the phase-stamp range finder (PSRF) for real-time three-dimensional (3-D) imaging. The PSRF consists of a time-domain correlation image sensor (CIS) proposed by us, a scanning sheet of light (SOL), and three-phase reference signals supplied to the CIS. After the SOL was scanned over the object during a frame period, the CIS records the phase stamp of the reference signals at the moment when the SOL reflected on the object arrived at each pixel. The range image is then reconstructed at the frame rate by converting the phase stamp image from the CIS pixel-wise to the projection angle of the SOL and then applying triangulation. An experimental system is constructed with a 200 x 200-pixel CIS camera and a light-sectioning laser projection system. Experimental results confirm that the constructed system outputs range images at 12.5 frames/s, achieves measurement accuracy of less than 1 mm in standard deviation for imaging distance of 300-500 mm, and is robust to time-varying, spatially nonuniform ambient illumination and fine surface texture of objects.