Method and apparatus for representing a group of images

• US 20050013491A1
• Filed: 06/25/2004
• Published: 01/20/2005
• Est. Priority Date: 07/04/2003
• Status: Active Grant

• Current Assignee: Rakuten Group, Inc.
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Cieplinski, Leszek
• Granted Patent: US 7,630,545 B2
• Time in Patent Office: Days
• US Class Current: 382/226
• CPC Class Codes: G06F 16/5838 using colour
• CPC Class Codes: G06F 16/7328 Query by example, e.g. a complete video frame or video sequence graphical querying G06F16/7335
• CPC Class Codes: G06F 16/785 using colour or luminescence
• CPC Class Codes: G06T 7/90 Determination of colour characteristics
• CPC Class Codes: G06V 10/56 relating to colour

Abstract

A method of representing a group of images comprises determining the values of one or more dominant colours for the group of images and deriving a dominant colour representation expressing the group of images in terms of one or more of said dominant colour values.

Claims

1. A method of representing a group of images, the method comprising determining the values of one or more dominant colours for the group of images and deriving a dominant colour representation expressing the group of images in terms of one or more of said dominant colour values.

2. A method as claimed in claim 1, wherein at least some of the images in the group of images are represented by a respective dominant colour representation in terms of one or more dominant colour values for the image, the method comprising combining a plurality of said dominant colour representations or selecting one of the dominant colour representations as representative of the group.

3. A method as claimed in claim 2 where each of the dominant colour representations has one or more components including at least one dominant colour value, and optionally for each dominant colour value, a variance indicating colour distribution variance of the image with respect to the dominant colour value, a weight indicating the influence of the dominant colour in the image, the number of dominant colours in the image, and spatial homogeneity of pixels corresponding to the dominant colors in the image.

4. A method as claimed in claim 3 comprising combining one or more components of the representations based on proximity of dominant colours in colour space.

5. A method as claimed in claim 4 wherein one or more of the dominant colour values, variances and weights are combined.

6. A method as claimed in claim 5 wherein the combining involves calculating a weighted average of the dominant colour values, variances and weights.

7. A method as claimed in claim 4 comprising combining, in a first stage, components for which the distance between the respective dominant colours satisfies a predetermined condition such as being less than a predetermined threshold, and combining other components in a second stage.

8. A method as claimed in claim 1, the method comprising combining a plurality of images in the image/pixel or colour space/histogram domain or selecting one of the group of images as representative of the group, and determining the values of one or more dominant colours in the combined or selected image, to derive a dominant colour representation of the group of images in terms of one or more dominant colour values of the combined or selected image.

9. A method as claimed in claim 8 where the dominant colour representation has one or more components including at least one dominant colour value of the combined or selected image, and optionally for each dominant colour value, a variance indicating colour distribution variance with respect to the dominant colour value, a weight indicating the influence of the dominant colour in the combined or selected image, the number of dominant colours, and spatial homogeneity of pixels corresponding to the dominant colors in the combined or selected image.

10. A method as claimed in claim 8, wherein the step of combining the images involves calculating a sum, average, median or intersection of a plurality of images.

11. A method as claimed in claim 4 involving temporally or spatially subsampling the group of images.

12. A method as claimed in claim 11 wherein images are omitted or included depending on their similarity to other images in the group.

13. A method as claimed in claim 11 wherein the sub-sampling involves the steps of claim 4.

14. A method as claimed in claim 8 wherein the selection of the representative image or dominant colour representation involves a comparison or test involving at least one other image or representation in the group.

15. A method as claimed in claim 14, wherein the image or representation that is closest to all other images or representation in or for the group is selected.

16. A descriptor for a group of images derived by a method according to claim 1.

17. A method of searching for a group of images, the method comprising comparing a query dominant colour descriptor with a plurality of descriptors according to claim 16 using a matching procedure, and selecting one or more group of images for which the matching procedure indicates the closest match or matches.

18. An apparatus adapted to implement a method according to claim 1 or 17.

19. An apparatus as claimed in claim 18 comprising storage means for storing image data and/or descriptor data, processing means, and control means.

20. A computer program and/or a computer-readable storage medium storing a computer program for executing a method according to claim 1.