Wavefront aberration correction using circulation feedback control based on image boundary definition
In wavefront correction the pixels position error will affect wavefront corrector precision. To solve this problem a circulation feedback control method based on image boundary definition was proposed and an experiment is done on wavefront correcting based on liquid crystal spatial light modulator (LC SLM). The measured wavefront aberration is transformed a gray image to search edge pixels and centroid coordinates by boundary detection method of the digital image processing. On this basis the wavefront aberration is corrected by circulation feedback control. The experimental results show that the PV value of the static wavefront aberration is 0.66λ, the RMS is 0.13λ and the Strehl ratio is 0.54 before correcting and the PV is 0.17λ, the RMS is 0.02λ and the Strehl ratio is 0.98 after correcting. The PV value is less than λ/4 and the Strehl ratio is near diffraction limit, which proves that the above method is effective.