Device and method for face image extraction, and recording medium having recorded program for the method

• US 20010002932A1
• Filed: 11/30/2000
• Published: 06/07/2001
• Est. Priority Date: 12/01/1999
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Matsuo, Hideaki, Imagawa, Kazuyuki, Takata, Yuji, Baba, Naruatsu, Ejima, Toshiaki
• Granted Patent: US 6,697,503 B2
• Time in Patent Office: Days
• US Class Current: 382/118
• CPC Class Codes: G06V 10/48 by mapping characteristic values of the pattern into a parameter space, e.g. Hough transformation
• CPC Class Codes: G06V 40/162 using pixel segmentation or colour matching

Abstract

In a broadly-applicable face image extraction device and method for defining a face by position and size in target images varied in type for face image extraction at high speed, an edge extraction part 1 extracts an edge part from a target image and generates an edge image. A template storage part 2 previously stores a template composed of a plurality of concentric shapes varied in size. A voting result storage part 3 has voting storage regions for each size of the concentric shapes of the template so as to store the result obtained by voting processing carried out by a voting part 4. The voting part 4 carries out the voting processing utilizing the template at each pixel in the edge image, and stores the result obtained thereby in the corresponding voting storage region. After the voting processing, an analysis part 5 performs cluster evaluation based on the voting results stored in the voting storage regions, and then defines the face in the target image by position and size.

Claims

1. A face image extraction device for defining a face in a target image by position and size for extraction, comprising:

an edge extraction part for extracting an edge part (pixels outlining a person or face) from said target image, and generating an image having only the edge part (hereinafter, edge image);

a template storage part for storing a template composed of a plurality of predetermined concentric shapes equal in shape but varied in size;

a voting result storage part for storing, in a interrelating manner, voting values and coordinates of pixels on said edge image for every size of the concentric shapes of said template;

a voting part for increasing or decreasing said voting values of every pixel, specified by the coordinates, outlining each of said concentric shapes every time a center point of said template moves on the pixels in said edge part; and

an analysis part for defining the face in said target image by position and size based on said voting values stored in said voting result storage part.

2. The face image extraction device according to

claim 1

, wherein said predetermined concentric shape is a circle.

3. The face image extraction device according to

claim 1

, wherein said predetermined concentric shape is an ellipse.

4. The face image extraction device according to

claim 1

, wherein said predetermined concentric shape is a polygon.

5. The face image extraction device according to

claim 1

, wherein said edge extraction part extracts said edge part from said target image by using a filter for a high frequency component.

6. The face image extraction device according to

claim 1

, wherein, when said target image is structured by a plurality of successive images, said edge extraction part extracts said edge part by comparing a current image with another image temporally before, and with after to calculate a difference therebetween, respectively, for every image structuring said target image.

7. The face image extraction device according to

claim 1

, wherein said edge extraction part detects, with respect to pixels extracted in every predetermined box, one pixel located far-left end or far-right end in the box on a scanning line basis, and regards only the pixels detected thereby as said edge part.

8. The face image extraction device according to

claim 1

, wherein said analysis part performs clustering with respect to said voting values stored in each of said voting result storage parts, and narrows down position and size of the face in said target image.

9. The face image extraction device according to

claim 1

, further comprising an image editing part for editing said target image in a predetermined manner by distinguishing a face region defined by position and size in said analysis part from the rest in the target image.

10. The face image extraction device according to

claim 1

, further comprising an image editing part for replacing an image of the face region defined by position and size by said analysis part with another.

11. A face image extraction method for defining a face in a target image by position and size for extraction, comprising:

an extraction step of extracting an edge part (pixels outlining a person or face) from said target image, and generating an image having only the edge part (hereinafter, edge image);

a first storage step of storing a template composed of a plurality of predetermined concentric shapes equal in shape but varied in size;

a second storage step of storing, in a interrelating manner, voting values and coordinates of pixels on said edge image for every size of the concentric shapes of said template;

a voting step of increasing or decreasing said voting values of every pixel, specified by the coordinates, outlining each of said concentric shapes every time a center point of said template moves on the pixels in said edge part; and

an analysis step of defining, after said voting step, the face in said target image by position and size based on said voting values.

12. The face image extraction method according to

claim 11

, wherein said predetermined concentric shape is a circle.

13. The face image extraction method according to

claim 11

, wherein said predetermined concentric shape is an ellipse.

14. The face image extraction method according to

claim 11

, wherein said predetermined concentric shape is a polygon.

15. The face image extraction device according to

claim 11

, wherein, in said extraction step, said edge part is extracted from said target image by using a filter for a high frequency component.

16. The face image extraction method according to

claim 11

, wherein, in said extraction step, when said target image is structured by a plurality of successive images, said edge part is extracted by comparing a current image with another image temporally before, and with after to calculate a difference therebetween, respectively, for every image structuring said target image.

17. The face image extraction method according to

claim 11

, wherein, in said extraction step, with respect to pixels extracted in every predetermined box, one pixel located far-left end or far-right end in the box is detected on a scanning line basis, and only the pixels detected thereby is regarded as said edge part.

18. The face image extraction method according to

claim 11

, wherein, in said analysis step, clustering is performed with respect to said voting values stored in each of said voting result storage parts, and position and size of the face is narrowed down in said target image.

19. A recording medium having recorded a face image extraction method for defining a face in a target image by position and size as a program executable on a computer device, the program at least comprising:

a extraction step of extracting an edge part (pixels outlining a person or face) from said target image, and generating an image having only the edge part (hereinafter, edge image);

a first storage step of storing a template composed of a plurality of predetermined concentric shapes equal in shape but varied in size;

a second storage part of storing, in a interrelating manner, voting values and coordinates of pixels on said edge image for every size of the concentric shapes of said template;

a voting step of increasing or decreasing said voting values of every pixel outlining each of said concentric shapes every time a center point of said template moves on the pixel in said edge part; and

an analysis step of defining, after said voting step, the face in said target image by position and size based on said voting values.