【作者】 王波；

【导师】 沈建新；

【作者基本信息】 南京航空航天大学 ， 航空宇航制造工程， 2009， 硕士

【摘要】 视网细胞显微镜系统采用自适应光学技术来调整人眼的波前像差,获取理想的视网膜细胞图像。波前探测作为自适应光学系统的一个重要环节,通过波前探测器实时测量人眼的波前像差,再用波前复原算法计算出波前相位,为波前校正提供准确的信号。本文研究了几种常用波前探测技术,比较了其优缺点,选择了哈特曼-夏克波前传感器作为视网膜细胞显微镜的波前探测部分。研究了哈特曼-夏克传感器的工作原理,详细分析了其探测误差的来源,研究如何通过图像处理技术来提高哈特曼-夏克波前探测器质心探测精度。提出了一种基于数学形态学的阈值选取算法,考虑了光斑点的大致形态,设计了一个形态滤波器,该滤波器具有较高的效率,可以获取与常规阈值方法相比更合适的二值化灰度图的阈值,并对算法进行了仿真实验。同时在质心计算的过程中,改进优化了一种质心探测窗口自动确定方法,运用数学和几何知识首先确定光斑图片的六边形,再确定圆心,通过标准光斑位置的坐标来确定探测窗口。本方法确保了探测窗口确定的准确性和完整性,同时也减小了背景噪声对质心计算的影响,提高了质心探测精度。采用了VC++6.0开发了波前探测软件,并集成到视网膜细胞显微镜控制软件中。更多还原

【Abstract】 Retina-cell microscope adjusts the wave-front aberration of eye by adaptive optics technology and obtains the ideal image of the retina cells. Wave-front exploration, as an important tache of this system, provides the exact signal for wave-front emendation by the wave-front aberration scaled by the detector at the same time and the wave-front phase calculated by Wave-front reconstruction algorithm.This thesis investigates some wave-front exploring technology and each one is compared with others. Hartmann-Shack wave-front sensor is chosen as the exploring part of the system. The thesis focuses on the principle of Hartmann—Shack wave-front sensor, and labors the origin of the exploring aberration, meanwhile studying how to improve the accuracy of centroid detection by image processing. A kind of arithmetic to select the threshold which is based on mathematical morphologies is devised. A Filter is designed by making use of the shape of the facular location and it is so efficient that can get a more appropriate threshold of binarization grayscale than the normal threshold methods. The simulating experiment in allusion to the arithmetic is carried out. A optimizing method to confirm the centroid detecting window has been also proposed, which confirms the hexagon of the centroid detecting window first by mathematics and geometry, and then confirming the centre of the circle. This way makes sure of the accuracy and completeness of detection window and reduces the infection of the setting yawp and improves the accuracy of centroid detection. VC++6.0 software package was used to make the wave-front exploring software which is already installed into the retina-cell microscope system.更多还原