1. Field of the Invention
The present invention relates to a face detecting system and method using a symmetric axis, and more particularly, to a face detecting system and method using a symmetric axis in which a certain-sized front face is allowed to be extracted from various image planes by using symmetric information.
2. Description of the Related Art
Recently, an appliance field of an image processing system for detecting and recognizing a face from an image inputted through various cameras (a personal computer (PC) camera, a portable phone camera, a charge coupled device (CCD) camera and the like) is expanded to a home robot, a game instrument, a portable phone, a PDA and the like. In such various devices, a need for a method for effectively detecting the face is increased.
A face detecting method is very important even as a previous step of a field of face identification, face expression recognition and the like. The face detecting method should satisfy the following several conditions so as to be applied to a real environment.
First, it should not have a particular limitation to illumination.
Second, it should not have a specific limitation to background.
Third, it should be indifferent to a user's age, hairstyle, makeup or the like.
Fourth, it should be indifferent to user's various poses and face expressions.
Fifth, it should be indifferent to a user's motion.
Sixth, a real-time process should be possible.
Several conventional face detecting methods, that is, a method for tracking the face by obtaining a differential image for a consecutive image, a method for detecting and analyzing an edge of a main facial part, a method for utilizing optical flow, a method for extracting a facial outline, a method for obtaining a face region by using a color model, and the like has a drawback in that the face region cannot be extracted even though all of the above-mentioned conditions are all satisfied.
In other words, the method of using the differential image has a drawback in that the background is complex or it is difficult to be applied to a complex background or a dynamic background, the method of detecting and analyzing the edge of the main facial part has a drawback in that it is difficult to be applied according to the user's hairstyle, the method of using the optical flow and the method of extracting the facial outline have a drawback in that they are improper to a real-time process since much computation time is required. Further, the method for dividing the face region by using the color model has a drawback in that it is sensitive to the illumination or the background due to its dependence only on color.
A conventional face detecting technique detects the face irrespective of a facial symmetric type when the face is extracted. Accordingly, it has a disadvantage in that a ratio of face detection is remarkably deteriorated depending on an external environment change of the background and a change of the user's pose, face expression and hairstyle.