exterior edges meaning in English

外部边缘

Firstly , in iris localization of the iris image preprocessing stage , the localization of the interior edge of the iris is more important than the localization of the exterior edge
首先,在虹膜图像预处理的虹膜定位算法中。本文给出了一种改进的虹膜定位算法。
In order to the accuracy of locating iris exterior edge and the speed of iris localization , we will propose an improved algorithm basing on histogram equalization and coarse - to - fine localization . in the aspect of obtaining characteristics and matching , we utilized wavelet transform to detect the signal mutations , and then we matched the signal base on the comparability of the mutations so as to obtain the result of matching
然后,针对定位算法中,存在着定位速度慢、外边缘定位不准的问题,提出一种改进算法:通过分析图像灰度特点,设定阈值,将图像二值化后,提取边缘;再利用增加步骤、减少搜索次数来提高定位速度。