Design and implementation of real-time 3-D image sensor with 640 × 480 pixel resolution

In this paper, the first real-time range finder with the capability of VGA (640 × 480) resolution based on the light-section method is presented. We propose an adaptive thresholding circuit and column-parallel time-domain approximate analog-to-digital converters to realize high-speed readout for real-time range finding. Sub-pixel position calculation based on intensity profile achieves high-accuracy range finding. A column-parallel position detector suppresses redundant data transmission for a real-time measurement system. A 640 × 480 range finder using these techniques has been developed and successfully tested. The maximum range finding speed is 65.1 range_maps/s. The maximum range error is 0.87 mm and the standard deviation of error is 0.26 mm at 1200-mm distance. We have acquired a two-dimensional image and a high-resolution three-dimensional (3-D) image by the 3-D measurement system using our range finder.