Orthorectification of Planetary Linear Pushbroom Images Based on an Improved Back-Projection Algorithm

The digital orthophoto map of planetary bodies plays a significant role in landing site selection, traverse path planning, and scientific research. However, existing orthorectification methods in the planetary mapping community exhibit low-computational efficiency for linear pushbroom images. To solve this problem, this letter presents a novel orthorectification method based on an improved back-projection algorithm. The back-projection algorithm is based on the geometric constraints of the central perspective plane (CPP) and is further improved to process linear pushbroom images with distortions. Specifically, we segment the linear array in the focal plane into multiple line segments and find the exact CPP using simple analytical geometric calculations. The proposed method was fully tested and evaluated with well-known planetary mapping software packages, namely, the integrated system for imagers and spectrometers (ISIS). The experimental results demonstrated that compared with ISIS, the proposed orthorectification method can increase the computational efficiency by more than fivefold and deliver consistent geometric accuracy. The proposed orthorectification method greatly enhances geometric processing capabilities for massive planetary remote sensing images.