载机飞行参数对倾斜成像重叠率影响及补偿

针对飞机姿态角、速度、高度对重叠率影响进行分析并给出了补偿方法。以图像目标直接地理定位方法为基础,给出了大倾斜成像重叠率的基于坐标变换分析方法;对飞行参数单变量影响给出了几何分析方法及计算公式,两种方法结果是一致的。对于载机姿态角综合作用影响,利用基于坐标变换的方法给出了载机姿态角波动在1°范围内,分析了图像目标区域与预期区域偏离的结果,同时提出了使用相机位角和俯角对飞机姿态角影响进行补偿的方法,并给出了基于坐标变换方法的相机位角和俯角补偿量计算公式;基于几何分析结果,提出了通过调整拍照周期对载机速度和载机高度波动影响进行补偿方法,并给出拍照周期的计算公式。仿真结果和实际飞行数据表明,使用相机位角和俯角进行载机姿态补偿,同时调整拍照周期,可以很好抑制航拍过程中飞机参数波动对重叠率影响,在小视场角0.88°时,在平坦地区重叠率均值与预期值偏差为1%。

Effect and compensation of overlap influenced by flight parameter of oblique aerial camera

This study analyzes The effects of aircraft’s attitude, speed, and height on the overlap of an obliqueaerial camera was analyzed in this study, and acorresponding compensation method was developed. The calculation of oblique imaging overlap using coordinate transformation was introduced based on ageo-location algorithm and the Gauss-Kruger projection. In the case of single parameter variations, different formulas were provided by the geometric method, and the results were consistent between coordinate transformation and geometric methods. In the case where the three parameters varys imultaneously, the geometric method did not work adequately, and the coordinate transformation method should be used. In the case where the varied angle value of the aircraft attitude was below 1°, the deviating value between real covered area and expected area was attained by thecoordinate transformation method. The usage of camera’s azimuth and pitch angles to compensate the effect of aircraft attitude on overlap was introduced. For the variation of aircraft speed and height, changing the imaging period according to the aircraft real time values was suggested, and a new formula regarding imaging period was provided.The validity of the compensation algorithm was verified by simulation and real flight. The result shows that when the camera’s field of view is below 0.88°,the deviation between mean and expected values of real overlap is approximately 1%, if the target area is flat.