CMOS image sensor for 2D imaging and depth measurement with ambient light rejection

摘要

Using the same image sensor to capture both a two-dimensional (2D) image of a three-dimensional (3D) object and 3D depth measurements for the object. A laser point-scans the surface of the object with light spots, which are detected by a pixel array in the image sensor to generate the 3D depth profile of the object using triangulation. Each row of pixels in the pixel array forms an epipolar line of the corresponding laser scan line. Timestamping provides a correspondence between the pixel location of a captured light spot and the respective scan angle of the laser to remove any ambiguity in triangulation. An Analog-to-Digital Converter (ADC) in the image sensor generates a multi-bit output in the 2D mode and a binary output in the 3D mode to generate timestamps. Strong ambient light is rejected by switching the image sensor to a 3D logarithmic mode from a 3D linear mode.