基于动态轮廓模型的虹膜定位.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。-Iris contour model based on dynamic positioning. In the digital image in the position of the iris iris recognition and effective positioning is the key issue. Using a model based on active contour method of positioning the iris position, the first gray projection method used to detect a point within the pupil as a pupil of the pseudo-center of a circle, the center of a circle can be as long as it falls within the pupil. And then the pseudo-center of a circle centered around the angle of its N-point interval to take the snake as the initial reference point, in accordance with operating mechanism evolving snake, until the iris until the inner boundary. Finally, the calculation of the evolution of the snake-shaped after the heart and snake on the control point with the centroid distance, whichever is the average radius of the pupil as a dynamic contour model of the centroid as the center of the pupil can accurately locate out of the iris inner boundary position. Experiments show that, com