针对已有显微自动对焦方法存在的不足,提出了一种通过倾斜安装摄像头所采集图像的清晰聚焦带偏离视场中心的距离和方向来探测样本离焦量及离焦方向的方法,并搭建了一套显微自动对焦系统对该方法进行可行性验证。结果表明:该方法可以通过检测样本单帧倾斜面图像聚焦带偏离视场中心的水平偏移量,并根据标定好的离焦量-聚焦带偏移量曲线,快速获取离焦量及离焦方向,配以电机驱动可实现自动对焦。该方法的光学结构简单,可直接在常规三目显微成像系统中使用,因此可应用于各领域在线、在位大视场高分辨检测所需要的自动对焦过程。

To overcome the disadvantages of the existing microscopy autofocus technology, this study proposes a method for detecting the defocusing distance and orientation of a sample according to the distance and direction from the center of the field of view (FOV) of the focusing band in a tilt plane image, which is acquired using a tilt camera. The feasibility of this method is verified by constructing an experimental microscope autofocus system. Results show that this system can quickly obtain a defocusing distance and orientation by detecting the amount of horizontal shift from the center of FOV of the focusing band in a single-frame tilt plane image, which can be determined according to a calibration curve between the defocusing distance and focusing band's horizontal-shift value. Autofocus can then be achieved in applications using motor drive. The optical structure presented herein is simple and cost-effective. It can be directly used in a conventional, trinocular microscope-imaging system and can thus be applied to the autofocus process required in online, in situ, large FOV, and high-resolution detection in various fields.