15 March 2016 Investigation of algorithm discretization error in a zonal wavefront estimation process
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Abstract
Wavefront estimation from measured slope value is an integral part in Shack Hartmann type zonal wavefront sensors that are widely used to analyze the optical aberrations in numerous application areas. Using a specific estimation algorithm, these measured slopes are converted into wavefront phase values. Hence, accuracy in wavefront estimation lies in proper interpretation of these measured slope values using an appropriate estimation algorithm. One of the important sources of error in a basic wavefront estimation process is the algorithm discretization error that primarily depends on the estimation scheme adopted. Basically, this type of error is a result of the finite sampling of the slope geometry. Algorithm discretization error plays an important role and is needed to be considered while choosing a particular estimation geometry as it determines how well the estimation process reconstructs a phase profile. In this paper, we investigate the algorithm discretization error in a recently proposed improved zonal phase-gradient algorithm18 which is a modified form of the popular Southwell geometry. The error is calculated theoretically to ascertain the causes of error and also find ways to reduce it. Both the estimation algorithms are modeled using Taylor series expansion to show the order of discretization error and eventually make a comparison of the improved geometry with the standard Southwell geometry.
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Biswajit Pathak, Bosanta R. Boruah, "Investigation of algorithm discretization error in a zonal wavefront estimation process", Proc. SPIE 9739, Free-Space Laser Communication and Atmospheric Propagation XXVIII, 973916 (15 March 2016); doi: 10.1117/12.2213966; https://doi.org/10.1117/12.2213966
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