Post-Corrections of Image Distortions in a Scanning Grating-Based Spectral Line Imager

In this letter, a post-correction algorithm, which is capable of compensating typical image distortions in a scanning grating-based spectral line imager, is presented in detail. A prototype spectral line imager with a single-pixel detector is built for demonstration purposes. A double-layered vibratory grating scanner and a galvano-scanning mirror are utilized in the imager for fast spatial scanning and slow spectral scanning, respectively. There are three major imager distortions exist in the prototype system, which are spatial smile distortion, spectral keystone distortion, and nonuniform sampled spatial positions due to resonant spatial scanning. They are then corrected using a post-correction algorithm, which is based on reverse ray-tracing and Delaunay Triangulation mapping. The scanning grating-based spectral imager with the post-correction algorithm has the potential to achieve low-cost, small form-factor, and high-speed operation.