基于梯度的虹膜定位方法

为了提高虹膜定位的速度以及虹膜定位的准确性，依据虹膜图像灰度的分布特性及良好的环状性质，检测出瞳孔边缘以减少参与Hough变换的点数，进而定位虹膜内边缘．对于外边缘定位采用基于灰度梯度的微分积分圆形检测算子的方法．实验结果表明，此种方法能够准确地进行虹膜内外边缘定位，避免了含有大量其它区域对定位带来的影响．

Algorithm of iris location based on the gray scale

In order to fasten the speed of iris location and to make the iris location algorithm more accurate, two different kinds of approach to locate the inner and outer brim are put forward. According to the distributive character of the iris gray and the ring character, the pupil brim is detected so that the number of points used to Hough transform is reduced, then the inner brim is located. For the location of the outer brim, we adopt the differential and integral operator grounded on the gray scale to detect the circle. Experiments show that the method has good performance for the iris location, and it avoids the effect which is brought about by the other region besides the iris.