Pattern coding strategies for deflectometric measurement systems

Höfer, Sebastian; Roschani, Masoud; Werling, Stefan

doi:10.1117/12.2022133

Cited by 5 publications

(7 citation statements)

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“…Most frequently (but not necessarily) the reference structure is a periodical pattern, and in order to find a unique mapping between the reference and the sensor coordinates one has to use a tandem of encoding and decoding (e.g., as in Section 2.2). There is no shortage of summaries on absolute position coding (Salvi et al, 2004;Höfer et al, 2013a;Gupta and Nakhate, 2018;Zhang, 2018); we mention some possible procedures in Section 4.1.…”

Section: Surface Reconstructionmentioning

confidence: 99%

“…As a direct consequence of this very well-predictable level of statistical noise, one may accurately state the uncertainty limits of phase-measurement methods (Surrel, 1997a;Horneber et al, 2002;Fischer et al, 2011;Faber, 2012;Fischer et al, 2012;Höfer et al, 2013a) and easily devise optimal encoding strategies at least in terms of reference fringe periods.…”

Section: Other Sources Of Measurement Errorsmentioning

confidence: 99%

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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: Surface Reconstructionmentioning

confidence: 99%

Section: Other Sources Of Measurement Errorsmentioning

confidence: 99%

Deflectometry for specular surfaces: an overview

et al. 2023

Self Cite

View full text Add to dashboard Cite

show abstract

“…2.2). There is no shortage of summaries on absolute position coding [273][274][275][276][277]; we mention some possible procedures in Sec. 4.1.…”

Section: Surface Reconstructionmentioning

confidence: 99%

“…As a direct consequence of this very well-predictable level of statistical noise, one may accurately state the uncertainty limits of phase-measurement methods [3,210,274,[355][356][357] and easily devise optimal encoding strategies at least in terms of reference fringe periods.…”

Section: Other Sources Of Measurement Errorsmentioning

confidence: 99%

“…The measurement noise in the derivatives is a serious problem for surface reconstruction [245,274,279,284,308,335,356,[362][363][364][365][366][367][368][369][370] due to the low sensitivity of measured slopes to absolute surface height [45]. Today, only scanning techniques allow uncertainties commensurate with the tolerances of demanding optical surfaces (e.g., synchrotron mirrors) [41,[371][372][373].…”

Section: Examples Of Practically Achieved Uncertaintiesmentioning

confidence: 99%

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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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