A 375 /spl times/ 365 high-speed 3-D range-finding image sensor using row-parallel search architecture and multisampling technique

Abstract

A high-speed three-dimensional (3-D) image sensor for a 1000 range maps/s 3-D measurement system based on a light-section method is presented. It employs a row-parallel search architecture to achieve a high-speed frame access rate for the detection of activated pixels on the focal plane. The row-parallel search operation is carried out using chained search circuits embedded in a pixel. Moreover, we propose a row-parallel address acquisition technique using a bit-streamed column address flow. Row-parallel processors receive the bit-streamed column address and calculate the center position of activated pixels. The pipelined operations enable a multisampling technique that improves the resolution of pixel detection. A 375 /spl times/ 365 3-D image sensor using the present architecture has been designed in a one-poly five-metal 0.18-/spl mu/m standard CMOS process and successfully tested. It attains a frame access rate of 394.5 kHz with four samplings, which corresponds to 1052 range maps/s. The multisampling operation improves the sub-pixel resolution to around 0.2 pixels and achieves a range accuracy of less than 1.10 mm at a target distance of 600 mm.