摘要
传统的虹膜定位方法是在人眼图像上把虹膜轮廓当作理想圆来提取。针对虹膜内边界不是理想圆,外边界边缘模糊等问题,提出一种新的虹膜轮廓提取方法。先利用极坐标变换将包含全部虹膜区域的某个范围展开成矩形形状,然后在此矩形区域上根据灰度的阶跃进行虹膜真实内边界的查找,最后在矩形区域上利用直线定位虹膜外边界代替在人眼图像上利用圆定位外边界。该方法不仅解决了内边界不是理想圆造成的瞳孔遗留或纹理损失问题,而且以点、线检测代替圆检测显著降低了虹膜定位时间。通过对CASIA-IrisV3虹膜图像库进行定位测试结果表明,该方法平均定位时间0.172 s,定位准确率99.35%。
The traditional way of iris location is to extract the iris edge considering it as an ideal circle. To solve the problem that the inner edge of iris is actually not an ideal circle and the outer edge is blurred, a new way to extract the iris edge is proposed in this paper. It firstly unfolds some certain area in iris to a rectangle shape using the pole coordinates transformation, then searches the real inner iris edge according to the steps of grayscale in this rectangular area and finally takes advantages of linear location in this rectangular area to locate the outer iris edge instead of location of that in the human eye images. This method not only solves the problem of pupil carry-over or the texture loss caused by that the inner edge is not an ideal circle but also sharply reduces the location time since it constitutes the point and line detection to the circle detection. Testing on the CASIA-IrisV3 database, the results show that the proposed method costs an average time of 0. 172 s and the correct rate is 99.35 %.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2009年第8期2158-2163,共6页
Acta Optica Sinica
基金
国家自然科学基金(60672078
60472088)资助项目
关键词
图像处理
虹膜定位
点线检测
真实内边界
image processing
iris location
point and line detection
real inner edge
