US 5,329,379 A · System and method of measuring fidelity of decompressed video signals and images

Abstract

A method of quantitatively measuring fidelity of a reproduced image reconstructed from a compressed data representation of an original image is disclosed. The method comprises, responsive to user selection, for establishing a global assessment mode or a local assessment mode. In the global assessment mode changes in luminance of the reproduced image from the original image and changes in color in first and second color difference values of the reproduced image from the original image are used score fidelity. Changes in luminance are measured using a dynamic range, nonlinear transform equation. In the local assessment mode, and responsive to user selection, the reproduced image and the original image are segmented and corresponding pairs of segments from the reproduced image and the original image are identified. Scoring of fidelity of the reproduced image to the original image is done by comparing corresponding pairs of segments in color, luminance, shape, displacement and texture.

Claims20

Dependent claims

A method of quantitatively measuring fidelity of a reproduced image to an original image, the method comprising the steps of:

capturing and digitizing the original image;
compressing the original image into a compressed data representation;
decompressing the compressed data representation to produce the reproduced image;
responsive to user selection, establishing a global assessment mode or a local assessment mode;
in the global assessment mode, determining luminance fidelity of the reproduced image to the original image and determining color fidelity over first and second color difference values of the reproduced image to the original image;
in the local assessment mode and responsive to user selection, segmenting the reproduced image and the original image and establishing corresponding pairs of segments having one segment each from the reproduced image and the original image;
and
in the local assessment mode, scoring fidelity of segments of the reproduced image by comparing corresponding pairs of segments from the reproduced image and original image in color, luminance, shape and displacement.

5 more elements

Apparatus for quantitatively measuring fidelity of a reproduced image with an original image, comprising:

means for capturing and digitizing the original image;
means for compressing the original image into a compressed data representation;
means for decompressing the compressed data representation to produce the reproduced image;
means for determining luminance fidelity of the reproduced image to the original image and for determining color fidelity from changes in first and second color difference values in the reproduced image from the original image;
means responsive to user selection for segmenting the reproduced image and the original image and establishing corresponding pairs of segments having one segment each from the reproduced image and the original image;
and
means for scoring fidelity of the reproduced image to the original image by comparing corresponding pairs of segments in color, luminance, shape and displacement of a segment from the reproduced image compared to a corresponding segment in the original image to score the segments in the reproduced image.

4 more elements

Dependencies are inferred from the claim text.

System and method of measuring fidelity of decompressed video signals and images

Life of this patent

System and method of measuring fidelity of decompressed video signals and images

Life of this patent

Abstract

Claims20