| 航天TDI推扫式光学遥感器机动成像质量 |
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| 引用本文： | 汪巧萍,齐文雯,谭伟.航天TDI推扫式光学遥感器机动成像质量[J].红外与激光工程,2022,51(10):20220094-1-20220094-8. |
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| 作者姓名： | 汪巧萍 齐文雯 谭伟 |
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| 作者单位： | 北京空间机电研究所，北京 100094 |
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| 基金项目： | 国家自然科学基金（42050202） |
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| 摘 要： | 从分辨率和辐亮度两个角度出发，对TDI推扫相机机动成像模式下的成像质量进行了分析。首先，提出了视轴追迹法分析计算TDI和线阵两个方向的分辨率，通过构建侧摆和星下点之间的坐标转换矩阵，得到不同机动角度下TDI和线阵方向的单位矢量，随后计算出这两个方向的单位矢量沿着视轴方向在地面的投影矢量，结合相机的参数和轨道高度、地球半径等计算出地面像元分辨率。同时根据卫星在地面的投影速率得到不同视场的积分时间，并分析以中心视场为积分时间基准下，边缘视场在不同TDI级数下的MTF退化情况。以某遥感型号为例进行了具体的分析计算，并根据MTF的退化情况对侧摆角度提出了要求，计算结果表明，边缘谱段在大侧摆下TDI级数为60时，MTF已下降为0，在轨使用时要慎重选用级数。然后，结合理论计算和在轨图像分析了了不同侧摆角度下大气对图像对比度的影响，通过分析表明侧摆会改变大气传输路径，从而影响目标的对比度，分析结果可以为后期的图像校正提供参考。
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| 关 键 词： | 航天光学遥感 机动成像质量 视场边缘MTF 视轴追迹 大气对比度 |
| 收稿时间： | 2022-02-10 |
Maneuvering imaging quality of space TDI push scan optical remote sensor |
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| Affiliation: | Beijing Institute of Space Mechanics & Electricity, Beijing 100094, China |
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| Abstract: | The imaging quality of TDI push broom camera in maneuvering imaging mode is analyzed from the perspectives of resolution and radiance. Firstly, the Los tracking method is proposed to analyze and calculate the resolution of TDI and linear array directions. By constructing the coordinate conversion matrix between sidesway and satellite points, the unit vectors of TDI and linear array in different maneuver angles are obtained. Then, the projection vectors of the unit vectors in two directions on the ground are calculated along the Los direction, the ground pixel resolution is calculated, combined with the parameters of the camera, the orbital height and the earth radius. At the same time, the integration time of different fields of view are obtained according to the projection rate of the satellite on the ground, and the MTF degradation of edge fields of view under different TDI stages is analyzed with the reference integration time of central field of view. Taking a remote sensing model as an example, the specific analysis and calculation are carried out, and the requirements for the yaw angle are put forward according to the degradation of MTF. The calculated results show that the MTF of the edge spectrum section has decreased to 0 when the TDI series is 60 under the large side sway, so the TDI stage should be selected carefully in orbit. Then, combined with the theoretical calculation and on orbit image, the influence of the atmosphere on the image contrast under different side or yaw angles is analyzed. The analysis shows that the yaw will change the atmospheric transmission path, thus affecting the target contrast. The analysis results can provide a reference for the later image correction. |
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