根据空间推扫式遥感相机CCD的拼接结构,提出了利用CCD重叠区域的图像指导自动调焦的方法.首先,介绍了空间推扫式遥感相机的CCD拼接结构;根据推扫式成像的特点,利用具有并行处理数据能力的现场可编程门阵列(FPGA)同时接收多个CCD重叠成像区域的图像数据,并计算图像质量评价值.然后,选取图像质量评价值最大的3个重叠区域作为表决调焦方向的依据.最后,通过实验分析说明了本方法的可行性.试验中,相机的推扫频率为10 kHz时,调焦一步的时间为0.2s,表明本文的调焦方法具有较好的实时性.提出的方法为空间推扫式遥感相机的在轨自动调焦提供了可行依据.%According to the stitching structure of CCDs in an Aerial Push-broom Remote-sensing Camera (APRC), an auto-focus method by using the image from the CCD overlapped sections was proposed. Firstly, the structure of CCD in the APRC was introduced. Based on the pushing-broom imaging characteristics, a Field Programming Gate Array (FPGA) which can process data in parallel model was used to receive the image data from multi-CCD overlapped sections and calculate the evaluation values of image quality at the same time. Then, three kinds of the CCD overlapped sections with the biggest evaluation values of image quality were selected as the gist for determining the focus direction. Finally, the feasibility of the method proposed was validated by an experiment. In the experiment, when the push-broom frequency is 10 kHz, the time for one focus step is 0. 2 s, which illuminates that the proposed focusing method has good real-time ability, and it can offer a feasible gist for the on-track focus in the APRC.
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