应用于眼底成像的可见光瞳孔定位与对准方法

Visible light pupil localization and alignment method for fundus imaging

为了降低眼底成像过程对操作人员水平的依赖,提出了一种采用可见光瞳孔成像的人眼瞳孔自动快速定位与对准方法。采用可见光摄像模组和三维电动位移台,在实验室眼底成像系统上搭建瞳孔对准装置。用霍夫梯度法提取图像的有效区域,得到眼底成像系统的中心。利用最大类间方差法和图像直方图特征得到了瞳孔区域后,利用最小圆拟合方法确定瞳孔中心。通过反馈控制电动位移台的移动,实现眼底成像系统中心与瞳孔中心对准。实验结果表明:人眼瞳孔的平均识别速度为0.11 s,瞳孔中心的识别平均准确率达98.7%,中心偏差的平均欧氏距离为4.3个像素。上述结果满足眼底成像系统的实时性和准确性要求,为眼底成像系统提供了一种高效的自动瞳孔对准解决方案。

To mitigate reliance on operators during fundus imaging,an automated rapid localization and alignment method for the human pupil using visible light pupil imaging was proposed.Initially,the pupil alignment device was constructed on a laboratory fundus imaging system using a visible light camera module and a three-dimensional electric displacement stage.Subsequently,the effective area of the image was extracted using the Hough gradient method to determine the center of the fundus imaging system.The pupil region was identified through the maximum inter-class variance method and image histogram feature,while the center of the pupil was ascertained via the minimum circle fitting method.Ultimately,the electric displacement stage's movement is regulated through feedback mechanisms,ensuring that the center of the fundus imaging system aligns precisely with the pupil's center.The experimental results show that the average recognition speed of human pupil is 0.11 s,the average recognition accuracy of the pupil center is 98.7%,and the average Euclidean distance of the center deviation is 4.3 pixels.It can satisfy the system requirements of the real-time and accuracy,and provides an efficient automatic pupil alignment solution for fundus imaging system.