Detection of surface defects on sheet metal parts by using one-shot deflectometry in the infrared range

Sárosi, Zoltán; Knapp, Wolfgang; Kunz, Andreas; Wegener, Konrad

doi:10.3929/ethz-a-006206898

Cited by 5 publications

(2 citation statements)

References 10 publications

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“…Today, different versions of DM are employed in a wide range of applications such as industrial quality control for household items, mobile phones, automotive parts (Lippincott and Stark, 1982;Höfling et al, 2000;Skydan et al, 2007;Armesto et al, 2011;Arnal et al, 2017;Molina et al, 2017;Zhou et al, 2019), reflective sheet, rod, or tape materials (Hung and Shang, 2003;Caulier et al, 2008;Sárosi et al, 2010), Fresnel lenses , solar concentrator mirrors (Arqueros et al, 2003;Fontani et al, 2005;Heimsath et al, 2008;Scott and Burgess, 2010;Wang et al, 2010;Ulmer et al, 2011;Campos-García et al, 2015a;El Ydrissi et al, 2019), and even astronomical and synchrotron mirrors of various sizes (Parks et al, 2011;Schulz et al, 2011;Su et al, 2012a;Su et al, 2012b;Su P. et al, 2013;Hofbauer et al, 2013;Burge et al, 2014;Olesch et al, 2014;Oh et al, 2016;Davies et al, 2017;Wu et al, 2022). We have last summarized the state of the art over a decade ago (Werling et al, 2009;Balzer and Werling, 2010); driven by applications, the discipline has seen many exciting advances since then.…”

Section: Figurementioning

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: Figurementioning

confidence: 99%

Deflectometry for specular surfaces: an overview

et al. 2023

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“…Today, different versions of DM are employed in a wide range of applications, such as industrial quality control for household items, mobile phones, automotive parts [6][7][8][9][10][11][12], reflective sheet, rod, or tape materials [13][14][15], Fresnel lenses [16,17], solar concentrator mirrors [18][19][20][21][22][23][24][25], and even astronomical and synchrotron mirrors of various sizes [26][27][28][29][30][31][32][33][34][35]. We have last summarized the state of the art over a decade ago [36,37]; driven by applications, the discipline has seen many exciting advances since then.…”

Section: Introductionmentioning

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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A Defect Recognition System for Automated Inspection of Non-rigid Surfaces

Enzberg¹,

Al-Hamadi²

2014

2014 22nd International Conference on Pattern Recognition

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The goal of this work is the automated recognition of 3D surface defects for quality inspection in industrial production. For complexly shaped workpieces that are non-rigid and have non-uniform tolerance ranges, it is hard to distinguish acceptable surface deviations from defects.We propose a 3-stage defect recognition system based on 3D measurement of the defective part. First, a variable B-Spline surface model is used to adapt to acceptable tolerance ranges. The remaining model deviations are then used for segmentation of possible defects. Finally, a SVM-based classifier separates true defects from pseudo defects.On a real world data set of a series of measurements for a car front hood, the effectiveness of the approach is proven.

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Detection of surface defects on sheet metal parts by using one-shot deflectometry in the infrared range

Cited by 5 publications

References 10 publications

Deflectometry for specular surfaces: an overview

Deflectometry for specular surfaces: an overview

Deflectometry for specular surfaces: an overview

A Defect Recognition System for Automated Inspection of Non-rigid Surfaces

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