OBJECT OR SHAPE INFORMATION REPRESENTATION METHOD

• US 20130236108A1
• Filed: 11/11/2011
• Published: 09/12/2013
• Est. Priority Date: 11/26/2010
• Status: Active Grant

• Current Assignee: NEC Corporation, Tohoku University National Universities Corporation
• Original Assignee: NEC Corporation, Tohoku University National Universities Corporation
• Inventors: Matsuda, Yuma, Ogawa, Masatsugu, Yano, Masafumi, Kawakami, Susumu
• Granted Patent: US 9,256,802 B2
• Time in Patent Office: Days
• US Class Current: 382/203
• 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 10/471 using approximation functions

Abstract

An information representation method for representing an object or a shape includes: dividing a contour shape of an entirety or a part of the object or the shape into one or a plurality of curves; and representing the contour shape of the object or the shape by parameters including a degree of curvature and a positional relationship of each curve obtained by the dividing. Therefore, there is provided an information representation method for an object or a shape, which is capable of robust object recognition against a change in image by geometric transformations and occlusions.

Claims

1. An information representation method for representing an object or a shape, comprising:

dividing a contour shape of an entirety or a part of the object or the shape into one or a plurality of curves; and

representing the contour shape by parameters including a degree of curvature and a positional relationship of each curve obtained by the dividing.

2. An information representation method for an object or a shape according to claim 1, wherein the degree of curvature of the curve is represented by an area calculated by using a plurality of points on the curve or a plurality of points in positions which are determinable by a shape of the curve.

3. An information representation method for an object or a shape according to claim 1, wherein the degree of curvature of the curve is represented by any two or more of an area calculated by using a plurality of points on the curve or a plurality of points in positions which are determinable by a shape of the curve, an arc length of the curve, and a curvature of the curve.

4. An information representation method for an object or a shape according to claim 1, wherein the degree of curvature of the curve is represented by the following two:

an arc length of the curve and a curvature of the curve.

5. An information representation method for an object or a shape according to claim 1, wherein an arc length of the curve and a curvature of the curve are respectively an affine arc length and an affine curvature.

6. An information representation method for an object or a shape according to claim 1, wherein positions of a plurality of points on the curve or a plurality of points in positions which are determinable by the shape of the curve are invariant positions with respect to an affine geometric transformation.

7. An information representation method for an object or a shape according to claim 1, wherein a division point at which the division is carried out includes an inflection point at which a sign of a curvature on a contour changes.

8. An information representation method for an object or a shape according to claim 1, wherein a method used for the dividing uses a division method on two stages involving:

carrying out global division based on inflection points at which a sign of a curvature on a contour changes; and

further locally dividing a region between the inflection points.

9. An information representation method for an object or a shape according to claim 1, wherein an area defined by the curve is derived by using at least three points out of division points for dividing the curve into a plurality of parts based on an affine arc length of the curve as an index, and end points of the curve.

10. An information representation method for an object or a shape according to claim 1, wherein a positional relationship between the one or the plurality of curves is represented by an invariable with respect to an affine geometric transformation.

11. An information representation method for an object or a shape according to claim 1, wherein a positional relationship of the curve is a positional relationship among the one or the plurality of curves obtained by the dividing or a positional relationship among the one or the plurality of curves obtained by the dividing in a plurality of the contour shapes.

12. An information representation method for an object or a shape according to claim 1, wherein the positional relationship of the curve is represented by one or more indices selected from objective indices including a sequence or coordinates of the each curve.

13. An information representation method for an object or a shape according to claim 1, wherein the each curve obtained by the dividing is represented by parameters including an direction in addition to the degree of curvature and the positional relationship of the curve.

14. An information representation method for an object or a shape according to claim 1, wherein the each curve obtained by the dividing is represented by a plurality of pieces of stratified information.

15. An information representation method for an object or a shape according to claim 1, wherein, when two of the objects or the shapes are matched to each other, the information representation method accompanies a geometric transformation.

16. A system for representing information on an object or a shape, comprising:

dividing means for dividing a contour shape of an entirety or a part of the object or the shape into one or a plurality of curves; and

parameter calculation means for representing the contour shape by parameters including a degree of curvature and a positional relationship of each curve obtained by the division.

17. A computer-readable program recording medium which stores a program for causing a computer to execute the steps of:

dividing a contour shape of an entirety or a part of an object or a shape into one or a plurality of curves; and

representing the contour shape by parameters including a degree of curvature and a positional relationship of each curve obtained by the dividing.

18. A representation method for an object shape comprising:

dividing, by processing image data representing an image including an object, at least a part of a contour line of the object into one or more curves; and

representing each of the one or more curves by a first parameter representing a degree of curvature and a second parameter representing a position.