帧间角点匹配的积分时间实时测算方法

Real-time calculation method of integral time based on interframe angle point matching

  • 摘要: 在阐述积分时间测算原理基础上,对测算算法的误差源及残差进行了分析,并定量分析了残差对成像质量的影响,利用50组样本数据通过MATLAB仿真验证了采用Harris角点特征检测算法来实现帧间图像像移 \Delta L的亚像元精确计算的有效性,采用角点阈值优化及先验知识剔除误匹配点相结合的策略,有效降低特征角点检测及匹配计算时效,减少了运算数据量,对已匹配角点亚像元定位计算,仿真结果表明 \Delta L计算精度优于0.2个像元可满足测算方法在轨使用需求。最后结合实时测算方法应用特点给出了TDI探测器型高分辨率空间遥感相机成像参数的建议,为测算方法的在轨应用提供设计参考。采用高频面阵CMOS测速相机进行积分时间实时测算的方法能有效解决目标高程数据未知情况下,摄影点斜距无法精确获得的问题,方法具备低成本及星上可行性,同时能够弥补像移失配所导致的像质下降现象,有利于TDI探测器型高分辨率空间遥感相机成像性能的提升。

     

    Abstract: On the basis of the theory of integral time calculation, the error sources of measuring algorithm and residual error were analyzed, and the quantitative analysis and research on the influence of residual error on imaging quality was carried out, the effectiveness of using Harris angle point algorithm to realize sub-pixel location of interframe image motion \Delta L was verified by using 50 groups of sample data through MATLAB. The strategy combining the corner threshold optimization and the prior knowledge elimination of mismatching can effectively reduce the amount of operational data, and carry out the sub-pixel location calculation for the matched angle points. The simulation results show that the calculation accuracy of \Delta L is better than 0.2 pixel, which can meet the demand of on-orbit use of the calculation method. Finally, with the application characteristics of the real-time calculation method, the imaging parameters of TDI detector high resolution remote sensing camera were proposed, which provided design reference for on-orbit use of the calculation method. Using high frequency plane array CMOS cameras to calculate integral time method can effectively solve the target elevation data is unknown cases, photography slant distance cannot be accurately obtained. Calculation method with low cost and feasibility on orbit, can compensate for the image quality degradation caused by image motion mismatch, which is beneficial to the improvement of imaging performance of TDI detector high resolution remote sensing camera.

     

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