A Rapid Iris Location Method Based on the Structure of Human Eyes
Weiqi Yuan, Zhonghua Lin, Xu Lu · 2005
Iris location is an important part of iris recognition. Speed of location and robustness of arithmetic of location are factors which we must pay attention to especially. In this paper we analyse eye images that we have based on structure characteristics of eyes, we put forward a rapid iris location arithmetic. Firstly, we get an approximative center by gray projection, we get two points that locate at left and right boundary by threshold value respectively, and we get a point that locates at the lower boundary by direction edge detection operators, then we can ensure the boundary of pupil and probable center. Secondly, we get exact pupil boundary and center by Hough transform that is processed at a small scope surrounding the probable center. Thirdly, we search two points that locate at left and right boundaries between iris and sclera along horizontal direction by using the exact center and direction edge detection operators. Then we ensure the horizontal coordinate of the center of iris based on the above two point accurately. Finally, we search two points that locate at upper and lower boundaries between iris and sclera beginning at the horizontal coordinate of the center of iris along the directions that making plus and minus thirty angles between horizontal direction respectively by using direction edge detection operators, so we ensure the coordinate of the center of iris and the boundary between iris and sclera. The experiments indicate that this method reaches about zero point two second at speed and percentage of ninety nine point forty five at precision. This method is faster than existing methods at speed.