Face detection device

• US 20060177110A1
• Filed: 01/18/2006
• Published: 08/10/2006
• Est. Priority Date: 01/20/2005
• Status: Active Grant

• Current Assignee: Algogene Financial Technology Company Limited
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Imagawa, Kazuyuki, Ishii, Yasunori, Iwasa, Katsuhiro, Fukumiya, Eiji
• Granted Patent: US 7,783,084 B2
• Time in Patent Office: Days
• US Class Current: 382/118
• CPC Class Codes: G06V 40/161 Detection; Localisation; Normalisation

Abstract

A face detection device comprises: a judgment area determining operable to judgment areas in an inputted image; and a face judgment unit operable to judge existence of a face image greater than a first predetermined size in the judgment areas. According to face directions, the judgment area determining unit determines a ratio of the inputted image to the judgment areas. The characteristics of face images can be effectively utilized.

Claims

1. A face image detection device, comprising:

a judgment area determining unit operable to determine, in an inputted image, a first judgment area for judging existence of a face image in a front view direction and a second judgment area for judging existence of a face image, the face image to be judged in the second judgment area facing one of predetermined directions different from the front view direction; and

a face judgment unit operable to judge existence of a face image in the first judgment area, the face image having a size greater than a first predetermined size, and to judge existence of a face image in the second judgment area, the face image having a size greater than a second predetermined size, as defined correspondingly to the second judgment area,

wherein said judgment area determining unit determines a ratio of the first judgment area to the inputted image and a ratio of the second judgment area to the inputted image, according to respective directions of the front view direction and the predetermined directions.

2. A face detection device as claimed in claim 1, wherein the first judgment area is the smallest in a group of the first judgment area and the second judgment area.

3. A face detection device as claimed in claim 1, wherein said judgment area determining unit determines, according to the front view direction, a first rotation range of the first judgment area with respect to the inputted image, and rotates the first judgment area within the determined first rotation range, and

wherein said judgment area determining unit determines, according to each of the predetermined directions, a second rotation range for the second judgment area with respect to the inputted image, and rotates the corresponding one of the second judgment area within the determined second rotation range.

4. A face detection device as claimed in claim 3, wherein the determined first rotation range is the smallest range in a group of the first said judgment area and the second rotation areas.

5. A face detection device as claimed in claim 1, wherein said judgment area determining unit determines an aspect ratio of the first judgment area according to the front view direction, and

wherein said judgment area determining unit determines an aspect ratio the second judgment area according to each of the predetermined directions.

6. A face detection device as claimed in claim 5, wherein the determined aspect ratio of the first judgment area is a smallest length-to-width aspect ratio in a group of the first judgment area and the second judgment area.

7. A face detection device as claimed in claim 2, wherein the predetermined directions includes at least one of a left view direction and a right view direction.

8. A face detection device as claimed in claim 2, wherein the front view direction is a direction toward which a face looks when both of two eyes on the face are included in the inputted image, and

wherein each of the predetermined directions is a direction toward which a face looks when at least one of two eyes on the face is not included in the inputted image.

9. A face detection device as claimed in claim 1, wherein said judgment area determining unit determines the first judgment area and the second judgment area such that the first judgment area and the second judgment area can be raster-scanned to entirely cover the inputted image.

10. A face detection device as claimed in claim 2, wherein said judgment area determining unit determines each of the sizes of the first judgment area and the second judgment area based on a size range of a face image to be extracted.

11. A face detection device as claimed in claim 4, wherein said judgment area determining unit determines, according to an rotation range of a face image to be extracted, the first rotation range of the first judgment area with respect to the inputted image and the second rotation range for the second judgment area with respect to the inputted image.

12. A face detection device as claimed in claim 6, wherein said judgment area determining unit determines each of aspect ratios of the first judgment area and the second judgment area, based on range of aspect ratios of rectangles enclosing face parts in a face image to be extracted.

13. A face detection device as claimed in claim 6, wherein said judgment area determining unit scales at least a part of the inputted image based on a size range of a face image to be extracted.

14. A face detection device as claimed in claim 4, wherein said judgment area determining unit turns at least a part of the inputted image based on an rotation range of a face image to be extracted.

15. A face detection device as claimed in claim 6, wherein said judgment area determining unit changes the aspect ratio of the inputted image based on an aspect ratio range of a face image to be extracted.

16. A face detection device as claimed in claim 10, wherein said judgment area determining unit selects a partial area of the inputted image as an area to be searched, and determines the partial area to cover all of the area to be searched.

17. A face detection device as claimed in claim 7, wherein said face judgment unit utilizes a value obtained based on first and second pre-taught parameters and images within the first judgment area and the second judgment area, thereby judging if a face image of size greater than the predetermined size exists in either one of the first judgment area and the second judgment area,

wherein the first pre-taught parameter has been obtained pre-teaching face images in the front view direction, thereby defining statistical distributions of the face images in the front view direction, and

wherein each of the second pre-taught parameters has been obtained pre-teaching face images in each of the predetermined directions, thereby defining statistical distributions of the face images in each of the predetermined directions.

18. A face detection device as claimed in claim 16, further comprising:

a person image selecting unit operable to select the inputted image when said face judgment unit judges that the inputted image is a person image; and

a person image displaying unit operable to display the inputted image selected by said person image selecting unit.

19. A face detection device as claimed in claim 16, further comprising:

a person image selecting unit operable to select an image within the partial area when said face judgment unit judges that the image within the partial area is a person image; and

a person image displaying unit operable to display the image within the partial area selected by said person image selecting unit.

20. A face detection device as claimed in claim 18, wherein the inputted image is one of images photographed by an amateur.

21. A face detection device as claimed in claim 18, wherein said person image displaying unit cuts an image within an area that said face judgment unit judges to include one or more face images, thereby displaying the cut image.

22. A face detection device as claimed in claim 18, wherein said person image displaying unit attaches a frame enclosing an image within an area that said face judgment unit judges to include one or more face images, thereby displaying the framed image.

23. A mobile information terminal comprising:

a face detection device,

wherein said face detection device comprises;

a judgment area determining unit operable to determine, in an inputted image, a first judgment area for judging existence of a face image in a front view direction and a second judgment area for judging existence of a face image, the face image to be judged in the second judgment area facing one of predetermined directions different from the front view direction; and

a face judgment unit operable to judge existence of a face image in the first judgment area, the face image having a size greater than a first predetermined size, and to judge existence of a face image in the second judgment area, the face image having a size greater than a second predetermined size, as defined correspondingly to the second judgment area,

wherein said judgment area determining unit determines a ratio of the first judgment area to the inputted image and a ratio of the second judgment area to the inputted image, according to respective directions of the front view direction and the predetermined directions.

24. A semiconductor integrated circuit comprising:

a judgment area determining unit operable to determine, in an inputted image, a first judgment area for judging existence of a face image in a front view direction and a second judgment area for judging existence of a face image, the face image to be judged in the second judgment area facing one of predetermined directions different from the front view direction; and

a face judgment unit operable to judge existence of a face image in the first judgment area, the face image having a size greater than a first predetermined size, and to judge existence of a face image in the second judgment area, the face image having a size greater than a second predetermined size, as defined correspondingly to the second judgment area,

wherein said judgment area determining unit determines a ratio of the first judgment area to the inputted image and a ratio of the second judgment area to the inputted image, according to respective directions of the front view direction and the predetermined directions.

25. A semiconductor integrated circuit as claimed in claim 24, wherein said judgment area determining unit determines, according to the front view direction, a first rotation range of the first judgment area with respect to the inputted image, and rotates the first judgment area within the determined first rotation range, and

wherein said judgment area determining unit determines, according to each of the predetermined directions, a second rotation range for the second judgment area with respect to the inputted image, and rotates the corresponding one of the second judgment area within the determined second rotation range.

26. A semiconductor integrated circuit as claimed in claim 24, wherein said judgment area determining unit determines an aspect ratio of the first judgment area according to the front view direction, and

wherein said judgment area determining unit determines an aspect ratio the second judgment area according to each of the predetermined directions.