METHOD, APPARATUS, COMPUTER PROGRAM, COMPUTER SYSTEM, AND COMPUTER-READABLE STORAGE MEDIUM FOR REPRESENTING AND SEARCHING FOR AN OBJECT IN AN IMAGE

• US 20080050049A1
• Filed: 10/30/2007
• Published: 02/28/2008
• Est. Priority Date: 07/05/1999
• Status: Active Grant

• Current Assignee: Rakuten Group, Inc.
• Original Assignee: Miroslaw Bober
• Inventors: Bober, Miroslaw
• Granted Patent: US 7,492,972 B2
• Time in Patent Office: Days
• US Class Current: 382/305
• CPC Class Codes: G06F 16/5854 using shape and object relationship
• CPC Class Codes: G06V 10/46 Descriptors for shape, contour or point-related descriptors, e.g. scale invariant feature transform [SIFT] or bags of words [BoW]; Salient regional features colour feature extraction G06V10/56
• CPC Class Codes: G06V 10/752 Contour matching

Abstract

A method of representing an object appearing in a still or video image, by processing signals corresponding to the image, comprises deriving a plurality of numerical values associated with features appearing on the outline of an object starting from an arbitrary point on the outline and applying a predetermined ordering to said values to arrive at a representative of the outline.

Claims

1. A method of representing an object appearing in an image or sequence of images, by processing signals corresponding to the image or images, the method comprising deriving a plurality of numerical values associated with features appearing on the outline of an object to represent said outline and deriving a factor indicating the reliability of said representation using a relationship between at least two of said values.

2. A method as claimed in claim 1 wherein the factor is based on the ratio between two of said values.

3. A method as claimed in claim 2 wherein the ratio is of the two greatest values.

4. A method as claimed in claim 1 wherein said values are values of a CSS curvature scale space representation.

5. A method as claimed in claim 4 wherein said values are peak height co-ordinate values.

6. A method as claimed in claim 1 wherein a curvature scale space representation of the outline is obtained by smoothing the outline in a plurality of stages using a smoothing parameter sigma, resulting in a plurality of outline curves, using values for the maxima and minima of the curvature of each outline curve to derive curves characteristic of the original outline, and selecting the co-ordinates of peaks of said characteristic curves as said numerical values.

7. A method as claimed in claim 1 further comprising applying a predetermined ordering to said numerical values to arrive at a representation of the outline.

8. A method as claimed in claim 7 wherein the predetermined ordering is such that the resulting representation is independent of the starting point on the outline.

9. A method as claimed in claim 7 wherein the values are ordered starting from the greatest value.

10. A method as claimed in claim 9 wherein the values are ordered in decreasing size.

11. A method as claimed in claim 7 wherein the values are ordered starting from the smallest value.

12. A method of searching for an object in an image or sequence of images, by processing signals corresponding to images, the method comprising inputting a query in the form of a two-dimensional outline, deriving a descriptor of said outline using a method as claimed in claim 1, obtaining a descriptor of objects in stored images derived using a method as claimed in claim 1 and comparing said query descriptor with each descriptor for a stored object, and selecting and displaying at least one result corresponding to an image containing an object for which the comparison indicates a degree of similarity between the query and said object.

13. A method as claimed in claim 12 wherein a factor is derived for the query outline and for each stored outline using a method as claimed m claim 1, and the comparison is made using the predetermined ordering only or the predetermined ordering and some other ordering depending on said factors.

14. An apparatus adapted to implement a method as claimed in claim 1 or claim 12.

15. A computer-readable storage medium storing computer-executable process steps for implementing a method as claimed in claim 1 or claim 12.

16. A computer system programmed to operate according to a method as claimed in claim 1 or claim 12.