说明：  hough变换 该算法首先使用边缘检测算子，如常用的边缘检测算子有 Roberts 算子、Prewitt 算子、Sobel 算子、Laplace 算子以及Canny 算子，提取边缘信息。然后再使用Hough变换找出虹膜的几何信息。
(hough transform algorithm first uses the edge detection operator, such as the commonly used edge detection operators are Roberts operator, Prewitt operator, Sobel operator, Laplace operator and Canny operator to extract edge information. Then use the Hough transform to find the iris geometry.)