Design Methodology for Focal Plane Mirrors Based on Inverse Ray Tracing

The increasing demand for high-resolution and wide-swath remote sensing drives continuous growth in detector pixel counts. However, limited by current manufacturing technologies, multi-detector stitching becomes essential for large-swath imaging. Improper focal plane design may cause image gaps, stray light, and optical path obstruction, significantly complicating image correction. This study presents an inverse ray-tracing based optimization method for mirror geometric parameters and spatial configurations, validated using an off-axis TMA system with three stitched detectors. Experimental results demonstrate that the proposed design enables efficient image uniformity correction using simple linear fitting, outperforming conventional lookup table and line-scan methods. This work provides practical guidance for optical stitching mirror design, facilitating wide-swath imaging applications.