大畸变航天遥感相机焦平面弧形拼接

Focal Plane Curve Splicing of Large Distortion Aerospace Remote Sensing Camera

时间延迟积分电荷耦合器件(TDICCD)及多光谱线阵探测器是航天遥感相机常用的成像器件。为了获得高质量的航天遥感图像,要求TDICCD的电荷转移速度与像移速度相等、方向相同。航天遥感相机在轨推扫成像时,畸变会导致像移方向与积分方向不匹配。为了减小电荷转移方向和像移方向之间的失配误差,将探测器拼接成一条弧线以补偿畸变引起的像移。首先建立了时间延迟积分(TDI)方向和像移方向失配的数学模型,分别给出了枕形畸变和桶形畸变弧形拼接的方向。其次,推导了像移方向与TDI方向夹角的计算公式,建立目标函数计算每片探测器的弧形拼接角度。最后,进行了弧形拼接在轨实验,结果表明,相比拼接前,弧形拼接后边缘视场的配准精度由4 pixel提升到1 pixel。

Time delay and integration charge-coupled devices(TDICCD) and multispectral linear array sensor are usually used as the imaging detector in aerospace remote sensing camera. In order to obtain high-quality aerospace remote sensing images, the charge transfer speed of the TDICCD is required to be equal to the image motion velocity and in the same direction. When the aerospace remote camera is in orbit push-broom imaging, the distortion will cause the mismatch between the image motion direction and the integration direction. In order to reduce the mismatch error between the direction of charge transfer and the image motion direction, the detectors are spliced into a curve to compensate for the image movement caused by distortion. First, a mathematical model of mismatch between the time delay and integration(TDI) direction and the image motion direction is established, and the directions of the pincushion distortion and the barrel distortion curve splicing are given respectively. Second, the calculation formula for the angle between the image shift direction and the TDI direction is derived, and the objective function is established to calculate the curve stitching angle of each detector. Finally, an on-orbit curve splicing experiment is carried out. The results show that the registration accuracy of the edge field of view after curve splicing is improved from 4 pixel to 1 pixel compared to before splicing.