【摘要】 为了提高获取角膜地形图的测量精度,将相位测量偏折术和传统Placido盘法相结合,研究了一种新型的人眼角膜地形图获取方法。将人眼顶点处的法线与相机光轴共线,且与显示器的法线平行。显示器上显示的二维正交条纹图经人眼反射后,被相机接收。利用相位提取算法和迭代算法得到显示器和人眼角膜的坐标,再根据两者的几何关系,进而得到人眼角膜地形图。数值模拟表明模型眼的曲率半径和屈光度的测量精度理论上可达±14.7μm和±0.07D。最后实验上对曲率半径与人眼接近的球面元件进行了测量验证,结果表明,本方法具有测量精度高、装置简单、成本低等优点。更多还原

【Abstract】 In order to improve the accuracy,a new method is proposed to obtain the corneal topography based on phase measurement deflectometry and the traditional placido disk system. The proposed method utilizes a geometry configuration where the normal at the apex of the human eye is collinear with the optical axis of the camera and parallel with the normal of the screen. Two-dimensional orthogonal fringe pattern displayed on the screen is reflected off the human eye,and the deformed fringe image is recorded by camera. Then the coordinates of the screen and human cornea are calculated by phase extraction algorithm and iterative algorithm,respectively. According to the geometric relationship between them,the corneal topography can be obtained. The numerical simulation demonstrates that the measurement accuracy of the radius of curvature and diopter of the model eye can theoretically reach ±14.7 μm and ±0.07 D,respectively. Finally,experiments are conducted to measure a spherical element with a radius of curvature close to that of the human eye. The results show that this method has the advantages of highaccuracy,simple deviceand low cost.更多还原