基于图像处理的光学谐振腔自准直研究方法

针对我国氧碘化学激光器输出能量不断提高的情况下，主要限制光束质量的因素之一是出光过程中的光腔失调，提出了一种基于图像处理的光学谐振腔自准直研究方法。该研究方法利用氦氖穿腔光通过凹腔镜中心孔，并在凸腔镜后方放置工业相机，在屏幕上方形成一个干涉同心圆环。通过借助OpenCV库中二值化、霍夫圆检测等图像处理的方法，获得干涉同心圆环的圆心坐标，再通过以圆心为中心将图像分成上下左右四个部分，通过判断这四部分亮点像素的数量差值来预估干涉同心圆环的偏移状态，进而获得空腔条件下光学谐振腔发生变化的理论判据。实验结果表明，该方法可以获得相当精准的光学谐振腔失调判据，其失调判据选取左右亮点像素差值30 000，上下亮点像素差值45 000，为今后失调判据与步进电机自动调腔的结合做好充足的准备。

Optical cavity self-collimation research method based on image processing

Aiming at the fact that with the increasing output energy of oxygen-iodine chemical lasers in China, one of the main factors limiting the quality of the beam is the misalignment of the optical cavity during the light emission process, a method for self-collimation of optical resonators based on image processing was proposed. This research method uses helium-neon light to pass through the central hole of the concave cavity mirror, and an industrial camera is placed behind the convex cavity mirror to form an interference concentric ring above the screen. Through the image processing methods such as binarization and Hoff circle detection in the OpenCV library, the center coordinates of the interference concentric ring are obtained, and the image is divided into four parts: upper, lower, left, and right. The difference of the number of bright pixels between these four parts is used to estimate the offset state of the interference concentric ring, and then the theoretical criterion for the change of the optical resonator under the cavity condition is obtained. The experimental results show that this method can obtain quite accurate optical resonance cavity misalignment criterion. The misalignment criterion is selected from the difference between the left and right bright pixels of 30 000, and the difference between the upper and lower bright pixels of 45 000.