Moiré pattern movement compensation and quadrature averaging phase retrieval from time series of speckled arbitrary phase shift interferograms for automatic computation of fundus pulsation curve of the human eye

Abstract

the method described here allows for automatic calculation of the fundus pulse from interferometric measurements. a low intensity laser beam is coupled into the eye. Two strong reflections, one of the cornea and one of the retina, interfere on a high-speed complementary metal-oxide-semiconductor camera chip. After eye movement compensation, a speckle-free phase of the interferograms is calculated from a series of interference fringes. Then, the fundus pulsation is calculated from the phase shift between two consecutive interferograms. occurring speckle perturbs the fringe images, and therefore, classical geometrical movement compensation algorithms do not work with sufficient accuracy. The movement compensation algorithm needs to work without prior knowledge of the phase. the proposed algorithms yield the fundus pulse from speckled interferograms, overcoming the above mentioned problems.