Head-top detecting method, head-top detecting system and a head-top detecting program for a human face

• US 20050147304A1
• Filed: 12/03/2004
• Published: 07/07/2005
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Nagahashi, Toshinori, Hyuga, Takashi
• Granted Patent: US 7,460,705 B2
• Time in Patent Office: Days
• US Class Current: 382/190
• CPC Class Codes: G06V 40/10 Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
• CPC Class Codes: G06V 40/161 Detection; Localisation; Normalisation

Abstract

A head-top detecting method is provided for detecting a head-top of a human face from an image with the human face included therein. After detecting a human face and setting a head-top detecting window at an upper part of the image, an image feature quantity within the head-top detecting window is calculated in a vertical direction and a location in which the image feature quantity changes with a threshold value or more is identified as the head-top of the human face. Thereby the head-top of a human face can be detected accurately and quickly.

Claims

1. A head-top detecting method for detecting a head-top of a human face from an image with the human face included therein, the method comprising:

detecting a face image of an area excluding the head-top of the human face;

setting a head-top detecting window with a size including the head-top of the human face at an upper part of the detected face image;

calculating an image feature quantity within the head-top detecting window in a vertical direction and identifying a location in which the image feature quantity changes with at least a threshold value as the head-top of the human face.

2. A head-top detecting method according to claim 1 wherein the image feature quantity further comprises luminance.

3. A head-top detecting method according to claim 1 wherein the image feature quantity further comprises hue angle.

4. A head-top detecting method according to claim 1 wherein the image feature quantity further comprises an average value in a horizontal direction within the head-top detecting window.

5. A head-top detecting method according to claim 1 wherein the image feature quantity switches automatically in accordance with an image using at least one of luminance and hue angle.

6. A head-top detecting method according to claim 1 wherein the head-top detecting window has a rectangular shape, and a width and a height of the head-top detecting window are wider than a width of the human face.

7. A head-top detecting system for detecting a head-top of a human face from an image with the human face included therein comprising:

an image scanning part for scanning the image with the human face included therein;

a face detecting part for detecting a face image excluding the head-top of the human face from the image scanned in the image scanning part and for setting a face detecting frame in the detected area;

a head-top detecting window setting part for setting a head-top detecting window with a size including the head-top of the human face at an upper part of the face detecting frame;

an image feature quantity calculating part for calculating an image feature quantity in a vertical direction within the head-top detecting window; and

a head-top detecting part for identifying a location in which the image feature quantity calculated in the image feature quantity calculating part changes with at least a threshold value is identified as the head-top of the human face.

8. A head-top detecting system according to claim 7 wherein the image feature quantity calculating part comprises:

a luminance calculating part for calculating a luminance of each pixel;

a hue angle calculating part for calculating a hue angle of each pixel; and

an image feature quantity selecting part for selecting at least one of the luminance calculating part and the hue angle calculating part as the image feature quantity.

9. A head-top detecting system according to claim 7 wherein the head-top detecting part comprises at least one of:

a threshold value setting part for setting a threshold value of the image feature quantity; and

an average value calculating part for calculating an average of the image feature quantity in a horizontal direction within the head-top detecting window.

10. A head-top detecting program for detecting a head-top of a human face from an image with the human face included therein making a computer realize the parts of claim 7.

11. A head-top detecting program according to claim 10 wherein the image feature quantity calculating part fulfills the functions of:

a luminance calculating function for calculating a luminance of each pixel;

a hue angle calculating function for calculating a hue angle of each pixel; and

an image feature quantity selecting function for selecting one of the luminance calculating function and the hue angle calculating function as the image feature quantity.

12. A head-top detecting program according to claim 10 wherein the head-top detecting part comprises at least one of:

a threshold value setting part for setting a threshold value of the image feature quantity; and

an average value calculating part for calculating an average of the image feature quantity in a horizontal direction within the head-top detecting window.