基于功率谱的星载相机在轨自检焦系统

摘要

Due to rocket launchers, shock, vibration, and space environmental impact, cause the space camera to produce beyond the depth of focus range. So, it is very important to test the focus of high-resolution, large-caliber, long focal length space camera in real-time. In view of the past focus-testing model of space camera can not do it in real-time, the paper has introduced the theory of invariance of power spectrum, and brought forward auto-focusing model based on image processing, then Realized this method on DSP hardware platform. The space Camera's Auto-Focusing system can focused operation in real-time, by the calculation of the image power spectrum.When the image focus is correct, it is the peak value of the power spectrum curve (EFV=17.1). It reached the expected ideal system design requirements.%星载相机搭载火箭升空后，由于各种环境因素的影响，会产生超出焦深范围的离焦，因而，对高分辨、大口径、长焦距星载相机实时进行精密检焦是十分重要的。笔者首先针对以往星载相机被动检焦的缺点，利用功率谱不变性，提出基于图像处理的星载相机自检焦设计，其次，在 DSP 硬件平台上实现了自动检焦过程。通过整个系统的测试和运行，系统稳定，系统能够对图像功率谱进行计算，并根据计算结果实时进行自检焦操作，当图像对焦正确时，对应功率谱曲线的峰值点（EFV=17.1）。自检焦系统达到了预期理想的系统设计要求。