Optical 3D Measuring

NTB
INTERSTAATLICHE HOCHSCHULE
FÜR TECHNIK BUCHS
Institut für Produktionsmesstechnik,
Werkstoffe und Optik (PWO)
www.ntb.ch/pwo
Optical 3D Measuring
Näher dran
am System
der Technik
Short Overview about different principles
der Zukunft
NTB
INTERSTAATLICHE HOCHSCHULE
FÜR TECHNIK BUCHS
PWO
Why Optical Measurement ?
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Fast
Non contact
Without influence to the surface
Full field measurement possible
Manyfold principles
Manyfold applications
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2
© PWO
PWO
NTB
INTERSTAATLICHE HOCHSCHULE
FÜR TECHNIK BUCHS
Optical Measurement - Principles
The two natures of light
Photon
Time of Flight Triangulation Reflectivity
Wave
Color
Interference
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3
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PWO
NTB
INTERSTAATLICHE HOCHSCHULE
FÜR TECHNIK BUCHS
Time Of Flight
Light Source
10
2 s
Sender
1
0
10
Answer
1.5
Amplitude
A cceleratio n (un scaled)
Detector
Time
t
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2
3
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5
Time (milliseconds)
Time resolution:
Distance resolution:
~ ps
~ mm
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4
© PWO
PWO
NTB
INTERSTAATLICHE HOCHSCHULE
FÜR TECHNIK BUCHS
Triangulation
Illumination
Detector
 Change of distance = lateral shift of position
 Resolution: 100 m … 10 (1) m
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Imaging Optics
Applications:
Measurement of free form surfaces
Reverse engineering
Quality control
Measuring
Object
Camera
Fringe
Projector
Triangulation
Base
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5
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PWO
NTB
INTERSTAATLICHE HOCHSCHULE
FÜR TECHNIK BUCHS
Confocal Microscopy
 Focussing a light spot to surface
 Backscattered intensity through
pinhole
 I~
1
z
4
 Sensitivity ~nm
z
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6
© PWO
PWO
NTB
INTERSTAATLICHE HOCHSCHULE
FÜR TECHNIK BUCHS
Chromatic Confocal Sensor
 Chromatic aberration generates focus
in different positions for different
colors
 Spectrometer resolves distance
White light
source
Pinhole
Beam
splitter
Features
 No moving components
 Fast
 Can be miniaturized
 Measuring range up to several 10 mm
 Resolution down to nm
Detector with
spectrometer
Imaging
lens
Surface
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© PWO
PWO
NTB
INTERSTAATLICHE HOCHSCHULE
FÜR TECHNIK BUCHS
Interferometry
 White Light Interferometry
 Short coherence
 Digital holography
 Reconstruction of complete
White Light
Source
Laser
wavefront
Object wave
Object
Translation
Reference
Mirror
Camera
CCDSensor
Reference
wave
Microscope
Objective
Sample
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8
© PWO
NTB
INTERSTAATLICHE HOCHSCHULE
FÜR TECHNIK BUCHS
PWO
Advantages of Optical 3D Measuring
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Non contact
Very fast
Point measurement
Full field measurement
High sensitivity
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© PWO