光学显微镜自动聚焦算法研究

Study on automatic focusing algorithm of optical microscope

聚焦是显微成像系统中的重要环节之一,为解决由目标内容分布及噪声引起聚焦曲线失去理想曲线特性的问题,提出一种新的自动聚焦算法。该算法通过设定阈值剔除大量无用的图像子块,根据图像子块的梯度幅值总和确定最终的聚焦窗口;然后通过计算窗口子块的梯度及方差,并利用像素权重进行加权,将其作为聚焦评价函数。实验结果表明:新算法中聚焦窗口选取方法能选取到内容较丰富的子块作为聚焦窗口,且新算法中聚焦评价函数在抗噪性、灵敏度和稳定性方面具有一定的优势。

Focusing is one of the most important links in the microscopic imaging system, in order to solve the problem that the distribution of target content and noise cause the loss of ideal curve characteristic of the focusing curve, a new automatic focusing algorithm is proposed. In this algorithm, a large number of useless image sub-blocks are eliminated by setting a threshold, and then the final focus window is determined according to the sum of the gradient amplitude of the image subblock. The gradient and variance of the window sub-block are calculated after the focus window is determined, using pixel weight to weight it as a focusing evaluation function. The experimental results show that the focusing window selection method in the new algorithm can be selected as the focusing window with rich content, and the focusing evaluation function in the new algorithm has some advantages in noise resistance, sensitivity and stability.