Motion aligned distance calculations for image comparisons

摘要

Image comparison techniques allow a quick method of recognizing and identifying faces or other objects appearing in images. A series of quick distance calculations can be performed between an unknown input image and a reference image. These calculations may include facial detection, normalization, discrete cosine transform calculations, and threshold comparisons to determine whether an image is recognized. In the case of identification uncertainty, slower but more precise motion aligned distance calculations are initiated. Motion aligned distance calculations involve generating a set of downscaled images, determining motion field and motion field-based distances between an unknown input image and reference image, best scale factors for aligning an unknown input image with reference images, and calculating affine transformation matrices to modify and align an unknown input image with reference images.

主权项

1. A computer-implemented method comprising:
detecting a facial image in an input image, the input image received by a detection module; calculating a distance between the input image and a reference image, the reference image retrieved from a reference image database and the reference image containing a known facial image for aiding recognizing detected facial images; executing, in response to determining the distance calculated is within a predetermined threshold, a motion aligned distance calculation comprising:
identifying a center point for each of the input image and the reference image;splitting the input image and the reference image into blocks based on the center point of the input image and the center point of the reference image, respectively;determining a motion field for aligning the input image with the reference image, the motion field comprising, for a pair of corresponding blocks of the input image and the reference image, at least one vector corresponding to a modification of a portion of the facial image within a first block in the pair of corresponding blocks to shift the portion of the facial image within the first block to align with a corresponding portion of the facial image within a second block in the pair of corresponding blocks; andaligning the input image with the reference image based on the motion field;calculating a motion aligned distance between the input image and the reference image based on the motion field; and providing, in response to the motion aligned distance calculated, a recognition result for the input image.