CMOS IMAGE SENSOR FOR DEPTH MEASUREMENT USING TRIANGULATION WITH POINT SCAN

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.

主权项

1. A method comprising:
performing a one-dimensional (1D) point scan of a three-dimensional (3D) object along a scanning line using a light source, wherein the point scan projects a sequence of light spots on a surface of the 3D object; selecting a row of pixels in an image sensor, wherein the image sensor has a plurality of pixels arranged in a two-dimensional (2D) array forming an image plane, and wherein the row of pixels forms an epipolar line of the scanning line on the image plane; detecting each light spot using a corresponding pixel in the row of pixels; generating a pixel-specific output in response to a pixel-specific detection of a corresponding light spot in the sequence of light spots; and determining a distance to the corresponding light spot on the surface of the 3D object based at least on the pixel-specific output and on a scan angle used by the light source for projecting the corresponding light spot.