基于偏心光束法的离焦量探测装置及计算方法的改进

引入生物显微镜用于探测病理切片离焦量。针对反射光斑内部纹理缺陷、畸变严重的特殊情况,通过自适应中值滤波、基于Ostu算法的Canny边缘检测(去除非圆弧边缘部分)、畸变校正、最小二乘法拟合非完整圆等算法,直接计算光斑半径大小及离焦方向,建立光斑半径与离焦量的线性关系模型。实验结果表明,与传统的灰度重心法相比,离焦量计算方法抗噪性强、稳定性高,可大幅度地提高线性关系模型的范围及光斑半径、圆心位置的准确度。

Improved auto-focus system and calculation method used for detecting the defocus value of the pathological section

The eccentric light beam method is applied into the auto-focus system of biological microscope to detect the defocusing value of the pathological section.To resolve the problems caused by the semicircular laser spot images with se-rious distortion,using the image processing software programmed by ourselves,combining the adaptive median filter and Ostu algorithm based Canny edge detection algorithm,the laser spot contour is acquired,and finally the least square method is employed to fit contour curve,the model of linear correlation analysis between laser spot radius and defocusing values is established.Experiment results show that,compared to traditional gray-weighted centroid method,the Radius-Detected method proposed has strong noise resistance and high stability,it can not only help expand the linearity range, but also improve the computational accuracy of the position and the radius value of the semicircular laser spots.