Systems and methods for liveness analysis

摘要

In a system for determining liveness of an image presented for authentication, a reference signal is rendered on a display, and a reflection of the rendered signal from a target is analyzed to determine liveness thereof. The analysis includes spatially and/or temporally band pass filtering the reflected signal, and determining RGB values for each frame in the reflected signal and/or each pixel in one or more frames of the reflected signal. Frame level and/or pixel-by-pixel correlations between the determined RGB values and the rendered signal are computed, and a determination of whether an image presented is live or fake is made using either or both correlations.

主权项

1. A computer-implemented method comprising:
rendering on a display device a time-varying multi-color signal comprising a plurality of different color signals that are separated in phase from each other; during the rendering, capturing a plurality of images of a target that is illuminated by the rendered multi-color signal, the plurality of images representing a plurality of frames; tagging the frames with respective color values of the multi-color rendered signal at the time respective images corresponding to the frames were captured; applying a band pass filter temporally to the images to generate a plurality of filtered images; extracting a filtered response signal from the filtered images; generating a frame-level temporal correlation measure based on, at least, a frame-level temporal correlation between respective tagged color values and respective dominant color values of the filtered response signal; calculating across the plurality of frames, for each pixel location, a pixel-level temporal correlation score from temporal correlation between respective color values of pixels at that pixel location in respective frames and respective color values of the multi-color rendered signal at the time respective images corresponding to the frames were captured; generating a pixel-level temporal correlation measure based on, at least, the plurality of the pixel-level temporal correlation scores; and accepting or rejecting the target based on, at least, the frame-level and pixel-level temporal correlation measures.