Alibaba Group Holding Limited
SYNCHRONIZING AN ILLUMINATION SEQUENCE OF ILLUMINATION SOURCES WITH IMAGE CAPTURE IN ROLLING SHUTTER MODE

Abstract:

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for a biometric authentication system. In one aspect, a method includes receiving, at one or more processing devices, data corresponding to a first set of pixels of an image sensor. The first set of pixels are exposed under illumination by a first source. Data corresponding to a second set of pixels of the image sensor is received, at the one or more processing devices. The second set of pixels are exposed under illumination by a second source that is spatially separated from the first source. A three-dimensional image is generated using the data corresponding to the first set of pixels as a first image of a pair of photometric stereo images, and the data corresponding to the second set of pixels as a second image of the pair of photometric stereo images.