Effect of pupil dilation on off-angle iris recognition
Effect of pupil dilation on off-angle iris recognition
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DOI：
10.1117/1.jei.28.3.033022
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发表时间：
2019-06
影响因子：
1.1
通讯作者：
M. Karakaya;E. Celik
中科院分区：
文献类型：
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作者：
M. Karakaya;E. Celik
抽象的。由于远距离虹膜识别系统的设置限制较少，因此可能会捕获具有注视角度、瞳孔扩张、反射和遮挡的非理想虹膜图像。研究了瞳孔扩张和注视角度对虹膜识别的综合影响。我们首先强调对使用光线追踪算法的生物识别眼睛模型生成的合成图像的影响。然后，我们量化了瞳孔扩张和注视角度对不同扩张水平下的真实正面和斜角图像的影响。我们的实验表明，所比较的虹膜图像之间的扩张水平和注视角度的较大差异会增加汉明距离。即使线性橡胶片归一化有助于最大限度地减少正面图像中的扩张效应，但在斜角虹膜图像中也无法完全消除扩张效应，因为不仅存在瞳孔扩张和三维虹膜纹理，而且还存在角膜屈光畸变和角膜缘遮挡。我们还观察到，注视角度是较陡峭的斜角图像中性能下降的主要原因，其中膨胀的效果有限。此外，由于斜角和扩张虹膜图像中的虹膜区域小于正面和收缩虹膜图像中的虹膜区域，因此它们的类间汉明距离分布向类内分布移动，这可能会增加错误匹配率。
Abstract. Due to the less constrained setup in standoff iris recognition systems, it is likely to capture nonideal iris images with gaze angle, pupil dilation, reflections, and occlusions. The combined effect of pupil dilation and gaze angle on iris recognition is examined. We first highlight the effects on synthetic images generated with a biometric eye model using a ray-tracing algorithm. Then, we quantify the effects of pupil dilation and gaze angle on the real frontal and off-angle images at different dilation levels. Our experiments reveal that the larger differences in dilation levels and gaze angles between the compared iris images increase the Hamming distance. Even if the linear rubber-sheet normalization helps to minimize the dilation effect in frontal images, it cannot fully eliminate it in off-angle iris images because of not only the pupil dilation and three-dimensional iris texture but also the corneal refraction distortion and limbus occlusion. We also observe that the gaze angle is the main reason for the performance degradation in steeper off-angle images, where the effect of the dilation is limited. In addition, since the iris region in off-angle and dilated iris images is smaller than that in frontal and constricted iris images, their interclass Hamming distance distribution is shifted toward the intraclass distribution, which may increase the false match rate.