红外望远镜变步长自动对焦设计

在远距离目标检测和跟踪的过程中,成像清晰起着至关重要的作用.红外望远镜系统的成像距离远、景深短、失焦引起图像模糊.由于大气折射,望远镜所成的像处于不断变化之中,造成传统对焦算法对焦成功率、效率偏低.为了提高自动对焦的成功率和速度,采用了一种具备变步长的爬山法,利用多次求图像清晰度取其中位数的方法保证清晰度评价的准确性,...

Variable Step Autofocus Design for Infrared Telescopes

In long-range target detection and tracking,image clarity plays a critical role.An infrared telescope system has a long imaging distance and a short depth of field,and the image blur caused by defocusing tends to be more severe in this system.In addition,because of the atmospheric refraction,the image derived from the telescope constantly changes.This results in a low focusing success rate and low efficiency in traditional focusing algorithms.To improve both the success rate and speed of autofocus,a mountain climbing algorithmic method with a variable step size was proposed in this study.Image clarity was obtained several times,and its median was calculated to ensure image clarity accuracy.Using the mountain climbing algorithm with momentum and acceleration reduces focusing instability as well as the number of steps required for the coarse focusing process.The algorithm was applied in an actual medium-wave infrared telescope system.Experimental results revealed that the focusing steps required by the algorithm for the coarse focusing stage were reduced by 12.8%,in comparison with the traditional mountain climbing method,meeting the requirements of an infrared telescope system.