Patent ID: 8515182

Claim:
A method for determining a measure of quality for a distorted image Y, characterizing a similarity between the image Y and an undistorted reference image X, having the same number of rows and columns of pixels as the image Y, the method comprising: (a1) applying an N level multiresolution decomposition, comprising levels 1, 2, . . . i, i+1, . . . N, to the image X, to produce: for each level i, with i ranging from 1 to N−1, intermediate subbands of image X for processing at level i+1; and for the level N, an approximation subband containing main content of the image X and detail subbands containing edges of the image X; (b1) applying said N level multiresolution decomposition, comprising levels 1, 2, . . . i, i+1, . . . N, to the image Y, to produce: for each level i, with i ranging from 1 to N−1, intermediate subbands of image Y for processing at level i+1; and for the level, N, an approximation subband containing main content of the image Y and detail subbands containing edges of the image Y; (c1) applying an image quality metric (IQM) to the approximation subband of the image X and the approximation subband of the image Y to produce an approximation quality measure characterizing similarity between the main content of the image X and the main content of the image Y; (d1) aggregating the intermediate subbands at the level i for the image X, with i ranging from levels 1 to N−1, and the detail subbands of the image X to produce an edge map of the image X characterizing the edges of the image X; (e1) aggregating the intermediate subbands at the level i for the image Y, with i ranging from 1 to N−1, and the detail subbands of the image Y to produce an edge map of the image Y characterizing the edges of image Y; (f1) applying the IQM between the edge map of the image X and the edge map of the image Y to produce an edge quality measure characterizing similarity between the edges of the image X and the edges of the image Y; and (g1) processing the approximation quality measure and the edge quality measure to determine the measure of quality.