A proposal of a new Hartmann or corneal topographer sampling screen geometry

Daniel Malacara-Doblado
Centro de Investigaciones en Optica, A. C.
Loma del Bosque 115. Col. Lomas del Campestre. 37150 Leon, Gto, México
Dedicated to Prof (Dr) Daniel Malacara-Hernández

Hartmann, Hartmann-Shack and many corneal topographers or telescope evaluators measure the shape of human eye corneas or telescope mirrors by finding the slope of the optical surface (or wavefront) at many points over the aperture of a beam of light going out of an optical system. They use an array of sampling points (holes or point light sources). The wavefront or shape of the optical surface under measurement is calculated with an interpolation performing a least squares fitting of the measured data with a set of orthogonal polynomials, typically Zernike polynomials. A problem that remains is that if the wavefront or surface deformations are small and with high slopes, that is, with large transverse aberrations, the Zernike polynomials filter out these small irregularities, smoothing the results more than desired. In this paper, we revise the most common geometry of the sampling arrays and propose a new geometrical configuration with some advantages, and of course, some small disadvantages that have to be taken into account. © Anita Publications. All rights reserved.
Doi: 10.54955.AJP.33.12.2024.817-823
Keywords: Hartmann, Hartmann-Shack, Topographer, Deflectometry, Zernike polynomials.

Peer Review Information
Method: Single- anonymous; Screened for Plagiarism? Yes
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