Error analysis and optimization for Risley-prism imaging distortion correction
Feng Huang, He Ren, Ying Shen, Pengfei Wang
Abstract
The reverse ray-tracing method has become a well-known technique to correct the dynamic imaging distortion caused by the Risley-prism imaging system due to its precision and computational efficiency. However, the reverse ray-tracing method is sensitive to equipment error, which seriously degrades the quality of distortion correction when using a prism with a large wedge angle or a camera with a large field of view. We optimize the distortion correction method utilizing reverse ray tracing. In addition, we propose a distortion correction model with error parameters to investigate the influence of prism orientation error, prism tilt error, prism parameter error, and model simplification errors on the correction accuracy. The work on the optimized model clearly indicates the obvious image distortion introduced by different kinds of errors, including model error and systematic error. Furthermore, we propose an error parameter identification method to eliminate the negative results of error on the image correction. The simulation results show that the boresight pointing error and distortion correction error are reduced to about 1% of the initial value after 10 iterations, thus achieving high-precision imaging distortion correction and providing better data support for other subsequent applications.