In line-of-sight detection or facial expression detection, pupil detection is performed. When this pupil detection is performed at the time of wearing of eyeglasses, a pupil may not be detected. This is caused by a reflection phenomenon, in which ambient light is reflected to lenses of the eyeglasses. The extent of reflection of ambient light to the lenses of the eyeglasses differs depending on the material of the lenses, coating, posture of the face, intensity of the ambient light, wavelength, etc. Thus, it is difficult to estimate a reflection state highly accurately from indirect information other than reflection itself.
To deal with such a problem, a method for detecting reflection of ambient light to lenses of eyeglasses (first ambient light reflection detecting method) is proposed conventionally (for example, refer to Patent Literature 1). In the first ambient light reflection detecting method, reflection of ambient light to lenses of eyeglasses is detected based on a moving direction of an edge of an eye area. In the first ambient light reflection detecting method, since detecting reflection of ambient light to eyeglasses of a driver occurring when a car is moving forward is presupposed, reflection is detected when the edge moves from the top to the bottom of an image.
Also, as a second ambient light reflection detecting method, a method for detecting a high-luminance area of an eye area is proposed (for example, refer to Patent Literature 2). In this method, images are photographed while a light projector irradiating a face is switched, and a high-luminance area that moves in plural obtained images is detected as reflection to lenses of eyeglasses.
USPTO Backgrounds
USPTO Backgrounds