Surface shape evaluation with a corneal topographer based on a conical null-screen with a novel radial point distribution

Campos‐García, Manuel; Cossio-Guerrero, Cesar; Moreno‐Oliva, Víctor Iván; Huerta-Carranza, Oliver

doi:10.1364/ao.54.005411

Cited by 32 publications

(7 citation statements)

References 29 publications

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“…Later, these works have paved the way for quantitative evaluations (Rayces, 1964;Salas-Peimbert et al, 2005). There exists considerable freedom to choose the shapes of static reference patterns, sometimes designed as "null screens" (Carmona-Paredes and Díaz-Uribe, 2007): in addition to generic planes (Díaz-Uribe, 2000), also cylinders (Díaz-Uribe and Campos-García, 2000;Campos-García et al, 2004), cones (Campos-García et al, 2015b;Campos-García et al, 2022), boxes (Campos-García et al, 2011), rings (Quach et al, 2022a) and custom geometries (Pérard, 2001) have been used. One may assemble points or lines into 1D or 2D arrays; otherwise, one may use rectangular, Gaussian or sinusoidal intensity profiles.…”

Section: Historical Overviewmentioning

confidence: 99%

Deflectometry for specular surfaces: an overview

et al. 2023

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Deflectometry as a technique to assess reflective surfaces has now existed for some 40 years. Its different aspects and variations have been studied in multiple theses and research articles; reviews are available for certain subtopics. Still a field of active development with many unsolved problems, deflectometry now encompasses a large variety of application domains, hardware setup types, and processing workflows for different purposes, and spans a range from qualitative defect inspection of large vehicles to precision measurements of microscopic optics. Over these years, many exciting developments have accumulated in the underlying theory, in the systems design, and in the implementation specifics. This diversity of topics is difficult to grasp for experts and non-experts alike and may present an obstacle to a wider acceptance of deflectometry as a useful tool for research and industrial applications. This paper presents an attempt to summarize the status of deflectometry and to map relations between its notable branches. Its aim is to provide a communication basis for experienced practitioners and also to offer a convenient entry point for those interested in learning about the method. The list of references introduces some prominent trends and established research groups in order to facilitate further self-directed exploration.

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Section: Historical Overviewmentioning

confidence: 99%

Deflectometry for specular surfaces: an overview

et al. 2023

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“…Later, these works have paved the way for quantitative evaluations [149,150]. There exists a considerable freedom to choose the shapes of static reference patterns [151]: in addition to generic planes [152], also cylinders [153,154], cones [155,156], boxes [157], and custom geometries [158] have been used. One may assemble points or lines into 1D or 2D arrays; otherwise, one may use rectangular, Gaussian or sinusoidal intensity profiles.…”

Section: Historical Overviewmentioning

confidence: 99%

Deflectometry for specular surfaces: an overview

Burke¹,

Pak²,

Höfer³

et al. 2022

Preprint

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Deflectometry as a technical approach to assessing reflective surfaces has now existed for almost 40 years. Different aspects and variations of the method have been studied in multiple theses and research articles, and reviews are also becoming available for certain subtopics. Still a field of active development with many unsolved problems, deflectometry now encompasses a large variety of application domains, hardware setup types, and processing workflows designed for different purposes, and spans a range from qualitative defect inspection of large vehicles to precision measurements of microscopic optics. Over these years, many exciting developments have accumulated in the underlying theory, in the systems design, and in the implementation specifics. This diversity of topics is difficult to grasp for experts and nonexperts alike and may present an obstacle to a wider acceptance of deflectometry as a useful tool in other research fields and in the industry.This paper presents an attempt to summarize the status of deflectometry, and to map relations between its notable "spin-off" branches. The intention of the paper is to provide a common communication basis for practitioners and at the same time to offer a convenient entry point for those interested in learning and using the method. The list of references is extensive but definitely not exhaustive, introducing some prominent trends and established research groups in order to facilitate further selfdirected exploration by the reader.

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“…The National Autonomous University of Mexico has a history of developing corneal topography equipment using the nullscreen method [5][6][7] . This method consists of a set of dots placed in a structure in such a way that, given thier reflection on a test surface, the image obtained consists of a perfect array of the spots.…”

Section: Introductionmentioning

confidence: 99%

Development of a long cone corneal topographer to evaluate corneas without symmetry of revolution

Montes-Valles,

Rojas Liévanos,

Campos García

et al. 2024

Optical Fabrication and Testing VIII

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In this project we propose a new corneal topographer that improves the accuracy of measurement from previous versions, by gathering all those details that made them to have great accuracy. The corneal topographer uses the null-screen method which is based on the idea that a reflected image in a surface contains information about the form of the reflective surface. The topographer uses a long cone, and it is aimed to evaluate corneas removing the symmetry of revolution of the algorithms. At first, the corneal topographer is utilized in a spheric reference surface, where the results obtained show that the radio of the reconstructed surface varies 0.11 % from the radio of the tested surface. This project is still in process since the evaluation algorithms must be adapted to evaluate corneas without symmetry of revolution.

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Surface shape evaluation with a corneal topographer based on a conical null-screen with a novel radial point distribution

Cited by 32 publications

References 29 publications

Deflectometry for specular surfaces: an overview

Deflectometry for specular surfaces: an overview

Deflectometry for specular surfaces: an overview

Development of a long cone corneal topographer to evaluate corneas without symmetry of revolution

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