Contour extraction apparatus

• US 5,881,170 A
• Filed: 03/22/1996
• Issued: 03/09/1999
• Est. Priority Date: 03/24/1995
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yokoya, Naokazu, Araki, Shoichi
• Primary Examiner(s): Tran, Phuoc
• Application Number:
  US08/620,463
• Time in Patent Office: 1,082 Days
• Field of Search: 382/199, 382/107, 382/236, 382/242, 382/197
• US Class Current: 382/199
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06T 7/149 involving deformable models, e.g. active contour models
• CPC Class Codes: G06T 7/215 Motion-based segmentation
• CPC Class Codes: G06T 7/251 involving models

Abstract

The present invention provides a contour extraction apparatus which has an image storing section 1 for storing an image, a contour model storing section 2 for storing a contour model, a contour model transforming section 3 for transforming and shrinking the contour model according to a prescribed rule, a contour model intersection detecting section 4 for detecting a contact or intersection in the contour model, a contour model dividing section 5 for dividing the contour model into contour models based on the detected contact or intersection, and an extraction completion judging section 7 for judging whether or not extraction of the contour of the object has been completed. According to the contour extraction apparatus, even when there are objects whose contours are to be extracted, the contour of the each object can be extracted correctly by predesignating a region only once, or without predesignating a region at all, despite the presence of excessive noise or a discontinuity in the edge.

Claims

1. A contour extraction apparatus comprising:

an image storing section for storing an image;

a contour model storing section for storing a contour model in the form of an ordered set of directed line segments that encloses at least one object contained in said image, each line segment being an ordered set of two points;

a contour model transforming section for transforming said contour model according to a prescribed rule;

a contour model intersection detecting section for detecting a contact or intersection of line segments in the transformed contour model by determining a point of intersection lying on two of the directed line segments free of following the edge of the contour model; and

a contour model dividing section for dividing said contour model into a plurality of contour models on the basis of the contact or intersection thus detected.

3. A contour extraction apparatus according to claims 1 or 2, wherein said contour model storing section stores a plurality of contour candidate points for forming said contour model and an order in which the contour candidate points are to be connected.

4. A contour extraction apparatus according to claim 3, wherein the plurality of contour candidate points and the order of their connection stored in said contour model storing section are updated into a plurality of contour candidate points and an order of their connection for each of a plurality of different contour models resulting from the division in said contour model dividing section.

5. A contour extraction apparatus according to claim 4, wherein said contour model transforming section transforms and shrinks said contour model by moving or stopping each of the plurality of contour candidate points of the contour model.

6. A contour extraction apparatus according to claim 4, further comprising a contour model creating/deleting section for, when a prescribed criterion is satisfied, adding a new contour candidate point to said contour model and/or deleting at least one contour candidate point on the contour model.

7. A contour extraction apparatus according to claim 4, further comprising a contour model selecting section for, when any of the plurality of different contour models resulting from the division in said contour model dividing section does not satisfy a prescribed criterion, deleting any such contour models from the contour model storing section.

8. A contour extraction apparatus according to claim 4, wherein said image storing section stores in addition to said image at least one different image continuing from the image at a prescribed time interval,

said contour extraction apparatus further comprising a motion detecting section for detecting a motion vector on the basis of the plurality of successive images stored in said image storing section.

9. A contour extraction apparatus according to claim 4, wherein said image storing section stores a plurality of images continuing one after another at a prescribed time interval,

said contour extraction apparatus further comprising a contour-model-discriminating motion detecting section for detecting a motion vector for at least one of said plurality of images within a prescribed range of each of the contour candidate points forming a contour model of at least one object extracted by said contour extraction apparatus.

10. A contour extraction apparatus according to claim 3, wherein said contour model transforming section transforms and shrinks said contour model by moving or stopping each of the plurality of contour candidate points of the contour model.

11. A contour extraction apparatus according to claim 10, further comprising a contour model creating/deleting section for, when a prescribed criterion is satisfied, adding a new contour candidate point to said contour model and/or deleting at least one contour candidate point on the contour model.

12. A contour extraction apparatus according to claim 10, further comprising a contour model selecting section for, when any of the plurality of different contour models resulting from the division in said contour model dividing section does not satisfy a prescribed criterion, deleting any such contour models from the contour model storing section.

13. A contour extraction apparatus according to claim 10, wherein said image storing section stores in addition to said image at least one different image continuing from the image at a prescribed time interval,

said contour extraction apparatus further comprising a motion detecting section for detecting a motion vector on the basis of the plurality of successive images stored in said image storing section.

14. A contour extraction apparatus according to claim 10, wherein said image storing section stores a plurality of images continuing one after another at a prescribed time interval,

said contour extraction apparatus further comprising a contour-model-discriminating motion detecting section for detecting a motion vector for at least one of said plurality of images within a prescribed range of each of the contour candidate points forming a contour model of at least one object extracted by said contour extraction apparatus.

15. A contour extraction apparatus according to claim 3, further comprising a contour model creating/deleting section for, when a prescribed criterion is satisfied, adding a new contour candidate point to said contour model and/or deleting at least one contour candidate point on the contour model.

16. A contour extraction apparatus according to claim 15, further comprising a contour model selecting section for, when any of the plurality of different contour models resulting from the division in said contour model dividing section does not satisfy a prescribed criterion, deleting any such contour models from the contour model storing section.

17. A contour extraction apparatus according to claim 15, wherein said image storing section stores in addition to said image at least one different image continuing from the image at a prescribed time interval,

said contour extraction apparatus further comprising a motion detecting section for detecting a motion vector on the basis of the plurality of successive images stored in said image storing section.

18. A contour extraction apparatus according to claim 15, wherein said image storing section stores a plurality of images continuing one after another at a prescribed time interval,

said contour extraction apparatus further comprising a contour-model-discriminating motion detecting section for detecting a motion vector for at least one of said plurality of images within a prescribed range of each of the contour candidate points forming a contour model of at least one object extracted by said contour extraction apparatus.

19. A contour extraction apparatus according to claim 3, further comprising a contour model selecting section for, when any of the plurality of different contour models resulting from the division in said contour model dividing section does not satisfy a prescribed criterion, deleting any such contour models from the contour model storing section.

20. A contour extraction apparatus according to claim 19, wherein said image storing section stores in addition to said image at least one different image continuing from the image at a prescribed time interval,

said contour extraction apparatus further comprising a motion detecting section for detecting a motion vector on the basis of the plurality of successive images stored in said image storing section.

21. A contour extraction apparatus according to claim 19, wherein said image storing section stores a plurality of images continuing one after another at a prescribed time interval,

said contour extraction apparatus further comprising a contour-model-discriminating motion detecting section for detecting a motion vector for at least one of said plurality of images within a prescribed range of each of the contour candidate points forming a contour model of at least one object extracted by said contour extraction apparatus.

22. A contour extraction apparatus according to claim 3, wherein said image storing section stores in addition to said image at least one different image continuing from the image at a prescribed time interval,

said contour extraction apparatus further comprising a motion detecting section for detecting a motion vector on the basis of the plurality of successive images stored in said image storing section.

23. A contour extraction apparatus according to claim 3, wherein said image storing section stores a plurality of images continuing one after another at a prescribed time interval,

said contour extraction apparatus further comprising a contour-model-discriminating motion detecting section for detecting a motion vector for at least one of said plurality of images within a prescribed range of each of the contour candidate points forming a contour model of at least one object extracted by said contour extraction apparatus.

24. A contour extraction apparatus according to claims 1 or 2, wherein said image storing section stores in addition to said image at least one different image continuing from the image at a prescribed time interval,

said contour extraction apparatus further comprising a motion detecting section for detecting a motion vector on the basis of the plurality of successive images stored in said image storing section.

25. A contour extraction apparatus according to claims 1 or 2, wherein said image storing section stores a plurality of images continuing one after another at a prescribed time interval,

said contour extraction apparatus further comprising a contour-model-discriminating motion detecting section for detecting a motion vector for at least one of said plurality of images within a prescribed range of each of the contour candidate points forming a contour model of at least one object extracted by said contour extraction apparatus.

26. The contour extraction apparatus of claim 1, wherein the contour model dividing section divides said contour model into a plurality of new ordered sets of line segments in which points are reconnected thereby to reform line segments.

2. A contour extraction apparatus comprising:

an image storing section for storing an image;

a contour model storing section for storing a contour model in the form of an ordered set of directed line segments that encloses at least one object contained in said image, each line segment being an ordered set of two points;

a contour model transforming section for transforming said contour model according to a prescribed rule;

a contour model intersection detecting section for detecting a contact of line segments in the transformed contour model by determining a point of contact of two of the directed line segments; and

a contour model dividing section for dividing said contour model into a plurality of contour models on the basis of the contact thus detected.