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Accurate fringe analysis Accurate fringe analysis in a 3D range sensor in a 3D range sensor for the fast measurement for the fast measurement of shapes of shapes G. Sansoni, G. Sansoni, F. Docchio, E. Redaelli F. Docchio, E. Redaelli Laboratory of Optoelectronics Laboratory of Optoelectronics University of Brescia, Italy University of Brescia, Italy

Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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Page 1: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

Accurate fringe analysisAccurate fringe analysis in a 3D range sensor in a 3D range sensor

for the fast measurement for the fast measurement of shapes of shapes

G. Sansoni, G. Sansoni, F. Docchio, E. RedaelliF. Docchio, E. Redaelli

Laboratory of OptoelectronicsLaboratory of Optoelectronics

University of Brescia, ItalyUniversity of Brescia, Italy

Page 2: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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Context of the workContext of the work

National Italian Project: Low-cost 3D imaging and modeling automatic system (LIMA3D)

BRESCIA

MILANO

GENOVA

VERONA

FIRENZE

PALERMO

BRESCIA

Laboratory of Optoelectronics

Design, development and metrological characterization of a low-cost optical digitizer based on the projection of

a single grating of non-coherent light

Field of View (FOV): up to 300X400mm2

Depth range: up to 100mm

Measurement uncertainty: 0.3mm

Page 3: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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What the system is notWhat the system is not

• Optical active triangulation• Time-space coding of the meas. volume

Fringe projectorVideo camera

Assembly system

OPL-3D

Page 4: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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Winged Victory

Sestertius

Ferrari 250 MM

Page 5: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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What the system isWhat the system is

• Use of low-cost projection device

Slide projector Video beam

• Optical active triangulation

• Projection of a single pattern of light

• Time space coding of the scene

Page 6: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

66

ji

Up

FW

FH

Projector

Video cameraS’(iS,jS)

Zg

Xg

YgOg

c c

c

c

O X

Y

Z

p

pX

OZ

Yp

p

Projection Label: LS

d L

S

S(iS, jS, LS)

LS

T

LT

T(iS, jS, LT)

S(XS, YS, ZS)

T(XT,YT, ZT)

Map of labelsj

i

Phase mapping

Camera-projector Calibration

Measurement principleMeasurement principle

Page 7: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

77

Input GC(i,j)

Normalization

Gc(i,j)

-50

0

50

100

150

200

250

100 120 140 160 180 200

Pixel

Inte

nsi

ty

Phase mappingPhase mapping

GC,n(i,j)

Gc,n(i,j)

-150

-100

-50

0

50

100

150

200

100 120 140 160 180 200

Pixel

Inte

nsi

ty

GC,b(i,j)

Binarization Gc,b(i,j)

-150

-100

-50

0

50

100

150

100 120 140 160 180 200

Pixel

Inte

nsity

gf(i,j)gr(i,j)

Edge detector

gr(i,j), gf(i,j)

-150

-100

-50

0

50

100

150

100 120 140 160 180 200

Pixel

Inte

nsity

Rise Fall

gr,f(i,j) gf,f(i,j)

Low-pass filtering

gr,f(i,j), gf,f(i,j)

-300

-200

-100

0

100

200

300

100 120 140 160 180 200

Pixel

Inte

nsi

ty

Rise Fall

gr,n(i,j) gf,n(i,j)

Amplitude normalization

gr,n(i,j), gf,n(i,j)

-1,5

-1

-0,5

0

0,5

1

1,5

100 120 140 160 180 200

Pixel

Inte

nsi

ty

Rise Fall

W(i,j)

%

ATAN2

W(i,j)

-4

-3

-2

-1

0

1

2

3

4

100 120 140 160 180 200

Pixel

Rad

Page 8: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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The phase unwrappingThe phase unwrapping

• Pure spatial approach• Spatio-temporal approach (optional)

Page 9: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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Camera-Projector calibrationCamera-Projector calibration

Page 10: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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Sanyo PROxtraX LCD

Hitachi KP-D50 Color

The prototypeThe prototype

Page 11: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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Experimental results (1)Experimental results (1)

Page 12: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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Exprimental results (2)Exprimental results (2)

Page 13: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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Metrological characterizationMetrological characterization

Page 14: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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Metrological characterizationMetrological characterization

Page 15: Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University

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ConclusionsConclusions

• Low-cost 3D system based on phase measurement

• Characterization of the measurement performance

• Experimentation with high resolution cameras• Experimentation with a 3CCD color camera