Optimal Demodulation Algorithm of Spatially Modulated Full-Polarization Imaging System

Spatially modulated full-polarization imaging systems can obtain full Stokes parameter information by single imaging, with strong characteristics of real-time execution and stability. Since all the polarization information is modulated into an interferogram, demodulation becomes an essential step. As the resolution of the obtained image continuously increases, the data to be calculated also increase. Therefore, a higher speed for the demodulation process is requisite. This article proposes a local filtering method and bypasses the frequency centralization method in the frequency domain to improve the speed of demodulation. The demodulation time of an interferogram of size 1024×1024 pixels was reduced from 3.027 473 s to 0.134 637 s, increasing the speed of demodulation by 97.72%. Meanwhile, the demodulation time of an interferogram of size 6144×6144 pixels was reduced from 444.329 92 s to 4.637 069 s, increasing the speed of demodulation by 98.75%.