Improving the performance of fringe projection profilometry by accurate geometric modelling and

113 Pages·2017·2.54 MB·English

by  Zhengrong Huang

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Zhengrong Huang
University of Wollongong, [email protected]
Follow this and additional works at: https://ro.uow.edu.au/theses
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Huang, Zhengrong, Improving the performance of fringe projection profilometry by accurate geometric
modelling and system calibration, Doctor of Philosophy thesis, , University of Wollongong, 2016.
https://ro.uow.edu.au/theses/4594
Research Online is the open access institutional repository for the University of Wollongong. For further information
contact the UOW Library: [email protected]
Improving the Performance of Fringe Projection Profilometry by
Accurate Geometric Modelling and System Calibration
A thesis submittedinfulfilment oftherequirements forthe awardof thedegree
Doctorof Philosophy
from
UniversityofWollongong
By
Zhengrong HUANG
B.E.,EastChina InstituteofTechnology,China, 2006
M.S.,NanChang HangKongUniversity,China,2010
Schoolof Electrical,Computer andTelecommunicationsEngineering
2016
CERTIFICATION
I, Zhengrong Huang, declare that this thesis, submitted in fulfilment of the
requirements for the award of Doctor of Philosophy, in the School of Electrical,
Computer and Telecommunications Engineering, University of Wollongong, is
wholly my own work unless otherwise referenced or acknowledged. The document
hasnot beensubmittedfor qualificationatanyotheracademicinstitution.
ZhengrongHuang
February 25,2016
i
AUTHOR’SPUBLICATIONS
Some of the work in this thesis has been published as academic papers, including the
following:
1. Zhengrong Huang, Jiangtao Xi, YanguangYu, Qinghua Guo and Limei Song
“Improved geometric model for fringe projection profilometery,” Opt. Express,
vol.22,pp.32220-32232,2014.
2. Zhengrong Huang, Jiangtao Xi, Yanguang Yu and Qinghua Guo “Accurate
projector calibration based on new point-to-point mapping relationship between
the cameraandprojectorimages,” Appl.Optics,vol.54,pp.347-356,2015.
ii
TABLEOFCONTENTS
CERTIFICATION.......................................................................................................i
AUTHOR’SPUBLICATIONS..................................................................................ii
LISTOFTABLES......................................................................................................v
LISTOFFIGURES...................................................................................................vi
LISTOFABBREVIATIONS.................................................................................viii
ABSTRACT...............................................................................................................ix
ACKNOWLEDGEMENTS.......................................................................................x
CHAPTER1:INTRODUCTION.............................................................................1
1.1 Background.........................................................................................................1
1.1.1 Applications..........................................................................................1
1.1.2 Typicaltechniques................................................................................2
1.2 Fringeprojectionprofilometry............................................................................4
1.2.1 Fringeprojectionandacquirement........................................................6
1.2.2 Phasemap detection..............................................................................7
1.2.3 Phase-to-heightmapping.......................................................................8
1.2.4 Systemcalibration.................................................................................8
1.3 Aims of thisthesis work....................................................................................11
1.4 Structureof this thesis.......................................................................................12
CHAPTER2:LITERATUREREVIEW...............................................................13
2.1 Fourier transformprofilometry andphaseshiftingprofilometry......................13
2.1.1 Fouriertransform profilometry(FTP).................................................13
2.1.2 Phaseshiftingprofilometry (PSP).......................................................15
2.2 Geometricmodels andPTH mapping...............................................................16
2.2.1 The geometricmodel proposedin[59]...............................................17
2.2.2 Animprovedgeometricmodel............................................................20
2.2.3 Anotherimprovedgeometric model...................................................24
2.2.4 Existingissue......................................................................................27
2.3 Cameracalibration............................................................................................28
2.3.1 Linearapproach...................................................................................31
2.3.2 Non-linearapproach............................................................................32
2.3.3 Outstandingissue................................................................................36
iii
2.4 Projectorcalibration..........................................................................................37
2.4.1 Phase-shiftingmethod.........................................................................37
2.4.2 Calibratedcamerabasedmethod........................................................41
2.4.3 Outstandingissue................................................................................44
2.5 Calulationof thesystematicparameters............................................................44
2.5.1 Model-basedmethod...........................................................................44
2.5.2 Least-squaresmethod..........................................................................47
2.5.3 Outstandingissue................................................................................48
CHAPTER3:CAMERACALIBRATION............................................................49
3.1 Principle of the new sub-pixel point-to-point mapping relationship between the
LCD andCCD............................................................................................................49
3.2 Estimatetheparametersof camera....................................................................54
3.3 Experiments.......................................................................................................56
CHAPTER4:PROJECTORCALIBRATION.....................................................60
4.1 Principle of the new sub-pixel point-to-point mapping relationship between the
CCDandDMD...........................................................................................................60
4.2 Estimateparametersof projector.......................................................................68
4.3 Experiments.......................................................................................................70
CHAPTER5:ANOVEL GEOMETRICMODELAND SYSTEM
CALIBRATION........................................................................................................78
5.1 Anovelgeometric model..................................................................................78
5.2 Systemcalibration.............................................................................................81
5.3 Experiments.......................................................................................................85
CHAPTER6:CONCLUSIONS..............................................................................93
6.1 Conclusions.......................................................................................................93
6.2 Futurework.......................................................................................................94
REFERENCES.........................................................................................................95
iv
LISTOFTABLES
Table4-1 Intrinsic parametersand coefficientsof lensdistortion.............................76
Table4-2 Extrinsicparametersfor thethirdpositionof thecalibrationboard..........76
Table5-1 The parametersof ourproposedphase-to-heightmapping.......................89
v
LISTOFFIGURES
Fig.1-1 Fringeprojectionprofilometry system...........................................................5
Fig.2-1 The geometricmodel in[59]........................................................................18
Fig.2-2 Animprovedgeometricmodel.....................................................................21
Fig.2-3 Anotherimprovedgeometrical model..........................................................24
Fig.2-4 Cameracalibrationsystem...........................................................................28
Fig. 2-5 (a) A chessboard as a calibration board and (b) circles as a calibration
board..................................................................................................................36
Fig.2-6 (a)Vertical fringe patternsand(b)horizontalfringe patterns......................37
Fig.2-7 The phase-shiftingprojectorcalibrationsystem...........................................38
Fig.2-8 Projectedfringe patterns...............................................................................40
Fig.2-9 Projectorcalibrationbasedonthecalibratedcamera method......................42
Fig.2-10 Projectedcircles..........................................................................................43
Fig.3-1 The displayedfringe patternsandphasereference lines..............................51
Fig.3-2 The designedimage withknowncirclecentres andedgepixels..................53
Fig.3-3 The capturedimages withone positionof the LCD.....................................57
Fig. 3-4 (a) The reprojection error based on direct mapping precise point on
the LCD into the CCD of camera and (b) the reprojection error based on
mymethod.........................................................................................................59
Fig. 4-1 Generate six images including figures (a), (b), (c), (d), (e) and (f) are
vertical DMD fringe patterns, and corresponding figures (g), (h), (i), (j),
(k)and(l)arethe horizontalones......................................................................62
Fig.4-2 The projectedgraycodeimage.....................................................................65
Fig.4-3 The equipment inourlab..............................................................................70
Fig. 4-4 Captured six images including figure (a), (b), (c), (d), (e) and (f) are
the vertical fringe patterns and corresponding images including figures
(g),(h),(i), (j),(k)and(l) arethehorizontalones.............................................72
Fig. 4-5 Captured six images including figure (a), (b), (c), (d), (e) and (f) are
the vertical gray code fringe patterns and corresponding images including
figures (g), (h),(i),(j), (k)and(l) arethehorizontalones.................................74
Fig. 4-6 (a) The captured image of the calibration board on the third position
and(b)detectededge pixels of circles..............................................................75
Fig.4-7 Capturedimagesof calibration boardonthree different positions............75
vi
Fig. 4-8 (a) The reprojection error based on method in [69] and (b) the
reprojectionerror basedonproposedmethod...................................................77
Fig.5-1 The proposedgeometricmodel for fringe projectionprofilometry..............79
Fig.5-2 Systemcalibrationequipment inour lab......................................................86
Fig.5-3 The flowchartof 3D shapemeasurement.....................................................87
Fig.5-4 Capturedimagesof thecalibrationboard....................................................88
Fig. 5-5 (a) Reconstruction based on ideal geometric model in [59] (b)
reconstruction based on model in [81] and (c) reconstruction based on
proposedmodel.................................................................................................92
vii
LIST OFABBREVIATIONS
2D two-dimensional
3D three-dimensional
CCD charge-coupleddevice
DMD digitalmicro-mirror device
LCD liquidcrystaldisplay
viii