Method and system for determining a quality measure for an image using a variable number of multi-level decompositions
First Claim
Patent Images
1. 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) determining a number of levels of decomposition, N, to be applied to the image X and the image Y as a function of one or more of a resolution of the image Y, a viewing distance for the image Y, and an image quality metric (IQM) applied to the image Y;
(b1) applying an N level multiresolution decomposition, comprising levels 1, 2, . . . i, i+1, . . . N, to the image X, producing an approximation subband containing main content of the image X and detail subbands containing edges of the image X;
(c1) applying said N level multiresolution decomposition, comprising levels 1, 2, . . . i, i+1, . . . N, to the image Y, producing an approximation subband containing main content of the image Y and detail subbands containing edges of the image Y;
(d1) applying the 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;
(e1) processing the detail subbands of the image X producing an edge map of the image X, characterizing the edges of the image X;
(f1) processing the detail subbands of the image Y producing an edge map of the image Y, characterizing the edges of image Y;
(g1) 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
(h1) processing the approximation quality measure and the edge quality measure to determine the measure of quality.
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Abstract
Method and system for determining a measure of quality for images are presented. Multi-level decomposition of images in the wavelet domain using a variable number of levels of decomposition and aggregation of selected subbands is performed to obtain an accurate measure of quality. The processing time is reduced in comparison to that required by other methods for generating measures of quality.
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Citations
43 Claims
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1. 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:
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(a1) determining a number of levels of decomposition, N, to be applied to the image X and the image Y as a function of one or more of a resolution of the image Y, a viewing distance for the image Y, and an image quality metric (IQM) applied to the image Y; (b1) applying an N level multiresolution decomposition, comprising levels 1, 2, . . . i, i+1, . . . N, to the image X, producing an approximation subband containing main content of the image X and detail subbands containing edges of the image X; (c1) applying said N level multiresolution decomposition, comprising levels 1, 2, . . . i, i+1, . . . N, to the image Y, producing an approximation subband containing main content of the image Y and detail subbands containing edges of the image Y; (d1) applying the 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; (e1) processing the detail subbands of the image X producing an edge map of the image X, characterizing the edges of the image X; (f1) processing the detail subbands of the image Y producing an edge map of the image Y, characterizing the edges of image Y; (g1) 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 (h1) processing the approximation quality measure and the edge quality measure to determine the measure of quality. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A system 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 system comprising:
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a processor, and a computer readable storage medium having computer readable instructions stored thereon, which, when executed by the processor, form the following; (a22) a number of levels unit determining a number of levels of decomposition, N, to be applied to the image X and the image Y as a function of one or more of a resolution of the image Y, a viewing distance for the image Y, and an image quality metric (IQM) applied to the image Y; (b22) a first decomposition unit applying an N level multiresolution decomposition, comprising levels 1, 2, . . . i, i+1, . . . N, to the image X, producing an approximation subband containing main content of the image X and detail subbands containing edges of the image X; (c22) a second decomposition unit applying said N level multiresolution decomposition, comprising levels 1, 2, . . . i, i+1, . . . N, to the image Y, producing an approximation subband containing main content of the image Y and detail subbands containing edges of the image Y; (d22) an approximation quality measure unit applying the 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; (e22) a first detail subbands unit processing the detail subbands of the image X producing an edge map of the image X characterizing the edges of the image X; (f22) a second detail subbands unit processing the detail subbands of the image Y producing an edge map of the image Y characterizing the edges of image Y; (g22) an edge quality measure unit 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 (h22) a quality measure unit processing the approximation quality measure and the edge quality measure to determine the measure of quality. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A non-transitory computer readable storage medium, having computer readable program code instructions stored thereon, which, when executed by a processor, perform the following:
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(a43) determining a number of levels of decomposition, N, to be applied to the image X and the image Y as a function of one or more of a resolution of the image Y, a viewing distance for the image Y, and an image quality metric (IQM) applied to the image Y; (b43) applying an N level multiresolution decomposition, comprising levels 1, 2, . . . i, i+1, . . . N, to the image X, producing an approximation subband containing main content of the image X and detail subbands containing edges of the image X; (c43) applying said N level multiresolution decomposition, comprising levels 1, 2, . . . i, i-+1, . . . N, to the image Y, producing an approximation subband containing main content of the image Y and detail subbands containing edges of the image Y; (d43) applying the 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; (e43) processing the detail subbands of the image X producing an edge map of the image X, characterizing the edges of the image X; (f43) processing the detail subbands of the image Y producing an edge map of the image Y, characterizing the edges of image Y; (g43) 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 (h43) processing the approximation quality measure and the edge quality measure to determine the measure of quality.
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Specification