To the iris' outer boundary, we use the feature of the iris' structure and mathematical means to verify whether the iris outer boundary points are correct, and calculate the correct ones if necessary.

本方法主要针对定位容易出现错误的外边界，利用虹膜的结构特征和数学手段，对得到的虹膜外边界点进行验证，必要时通过计算得到准确的外边界点。

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Detect iris edge to extract points on the boundaries by pixel gradient.

接着利用梯度和搜索虹膜外边界的边界点。

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Then classify the set of points to remove most fake edge points based on circle shape of iris 'edge.

然后根据虹膜的形状特性和分布特性，对提取出来的边界点集合进行两次分类，删除部分伪边界点。

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Huddled in a damp fire-station a young man connects a laptop, a binocular-style iris scanner and a glowing green machine that records 30 points from a set of fingerprints.

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