Analysis of MTF in TDI-CCD subpixel dynamic super-resolution imaging by beam splitter

The subpixel dynamic imaging technique of a beam splitter is one of the most effective super-resolution imaging methods. Aiming to create a linear time delay integration charge coupled device (TDI-CCD) subpixel imaging system based on the optical assembly method, its modulation transfer function (MTF) is analyzed based on the spatial over-sampling theory. Firstly, Fourier transformation of the sampling point is used to describe the frequency domain characteristics of TDI-CCD, which transform a unit cell of the spatial sampling lattice into a bandwidth cell in the spatial-frequency domain. Considering the effects of velocity mismatch and misalignment, the best subpixel staggering position of the linear TDI-CCD pair is given. Moreover, according to the analysis of the MTF of super-resolution reconstruction results from multiple subpixel images with random spatial offsets, the condition of sampling in the limitation of the enhancement of MTF is obtained. The numerical simulation and real experimental analysis reveal results that are consistent with the theoretical model.