2019 年 7 巻 3 号 p. 118-125
A variety of systems have been developed that use information on pupil diameter variation. These systems typically require a general-purpose PC or a portable terminal. In addition, a near-infrared camera and an illumination system are required to obtain pupil diameter information. However, a near-infrared camera and an appropriate illumination source are usually not installed in conventional PCs or mobile devices. If the pupil diameter can be measured using a visible-light camera equipped with a general-purpose PC or portable terminal, the aforementioned systems could become more widely used. However, it is difficult to discriminate between the iris and pupil regions in an image captured using a visible-light camera because the colors of the iris and the pupil are similar in individuals of Asian ancestry. In this study, we determine effective color components for the detection and diameter measurement of the pupil under visible light conditions based on eye images obtained using a visible-light camera. The experimental results revealed that the effective color components for the detection and diameter measurement of the pupil are the R, Y, and K color components for brown eyes and the R and C color components for hazel eyes. The suitable color components differ depending on the color of the iris.
