在数字图像中虹膜位置的有效定位是虹膜识别的关键问题。用一种基于主动轮廓线模型的方法定位虹膜的位置，先用灰度投影法检测出瞳孔内的一点作为瞳孔的伪圆心，该圆心只要能落在瞳孔内部即可。然后以该伪圆心为中心，在其周围等角度间隔地取N个点作为初始的snake基准点，按照snake 的运行机制不断进化，直到虹膜的内边界为止。最后，计算进化后的snake形心和snake上的控制点与该形心的距离，取其平均值作为瞳孔的半径，动态轮廓模型的形心作为瞳孔的圆心，即可准确定位出虹膜内边界的位置。实验表明，与常见的定位方法相比，文中的方法速度快、精度高，而且，对瞳孔初始的伪圆心要求不高，鲁棒性更强。-Digital image of the iris in the location of the effective positioning of the key issues of iris recognition. With a model based on the active contour method of positioning the location of the iris, the first gray projection method used to detect the pupil as the point of the pseudo-pupil center, the center of a circle as long as it can fall within the pupil. And then to the pseudo-center as the center, in terms of their spacing around the N points to get the snake as the initial reference point, the operating mechanism in accordance with the snake continued to evolve until the border until the inner iris. Finally, after calculating the evolution of snake and snake-shaped heart of the control point on the centroid distance, choose the average as the radius of the pupil, the dynamic contour model of the centroid as the center of pupil can be an accurate positioning within the borders of the iris position. The experimental results show that the position with common methods, the methods o