The document summarizes dimensional measurement methodologies and their applications. It categorizes common methods as either tactile or non-tactile, and describes examples of each including coordinate measuring machines, interferometry, laser scanning, and photogrammetry. Applications discussed include reverse engineering, quality assurance, medical, automotive, and user interfaces. The market for 3D metrology is projected to reach $10.9 billion by 2022. The document also discusses trends in the field and a vision for the future including more compact, mobile, and cloud-based solutions enabled by advances in components, processing, and artificial intelligence.

1. The Evolution of
Optical Depth Sensing:
“From Exotic to Ubiquitous”
Erik Klaas

2. ▪ Why is metrology important?
▪ Categorization of common methodologies for dimensional measurements
▪ Examples and Applications of Image based Dimensional Measurement
▪ Reverse Engineering
▪ Maintenance
▪ Quality Assurance
▪ Patient Positioning
▪ Dental
▪ Automotive
▪ User Interface
▪ Market segmentation, size, challenges and opportunities
▪ What does 8tree do?
▪ A view into the future…
Agenda

3. ▪ Metrology helps to tell what is “right” from what is “wrong” (with not much room for discussion)
▪ Most often there is a “Ground Truth”
▪ The relevance really started with the concept of interchangeable parts back 100 years ago
▪ With his assembly line and interchangeable parts Henry Ford was able to drop production time for a Model
T from 12 hours to just 93 minutes
▪ Before that, not every bolt would fit every nut, they were custom
fitted
▪ In order to make identical parts checking the parts and so metrology
gained a lot of importance
Why is metrology important?
Because Engineers don´t really like „Fake News“ ☺
https://www.thoughtco.com/henry-ford-and-the-assembly-line-1779201

4. ▪ In todays world we only realize the revolutionary concept of interchangeable parts, when parts don’t fit
▪ But generally we assume that we can put a nut of the same size on any bolt no matter whether its made in
the US, Europe or India.
▪ This is the base for todays mass production and worldwide distributed sourcing of components
▪ Some historical gaging tools:
Why is metrology important?

5. The Hubble Fiasco
▪ The mirror was polished precisely into the wrong shape
▪ At the perimeter it was too flat by about 2.2 micrometers due to
a misalignment of a lens
▪ After launch in 1990 it could
be fixed 3 years later,
saving the US$4.7 billion
investment
What happens when you ignore metrology?
https://en.wikipedia.org/wiki/Hubble_Space_Telescope

6. ▪ Production volume becomes larger, allowable time for inspection shorter
▪ None tactile methods are usually faster
▪ Tolerances become tighter
▪ Customer asking for 100% inspection rather than sample inspection
▪ More complex features should be checked rather than
simple measures
▪ For industry 4.0 data input is expected
-> all good reasons to move from tactile to optical metrology
Why should measurements be non-tactile?

7. One possible Categorization of common methodologies for dimensional measurements
Surface Measurement
Tacticle Non Tactile
Non Destructive Destructive Reflective Transmissive
Computer
Tomography
Optical Other
RadarSonar
SlicingCMM
Articulated
Arm
Uni Utah; Guido Gerig; Lesson: CS 6320, 3D Computer Vision Spring 2012

8. CMMs – Coordinate Measuring Machines and traditional hand tools
Tactile Methods
http://metalworkingnews.info/wp-
content/uploads/2014/11/Prod-Rev-ZEISS-CONTURA.jpg
https://faro.blob.core.windows.net/sitefinity/product-overview-
galleries/faroarm_beauty_1.jpg

9. Method Time of Flight (ToF) Interferometry Triangulation
1D Laser Distance
Measurement
Michelson Interferometer Point Triangulation
2D PMD-sensors White-Light-Interferometer Laser Line Triangulation
2 1/2D Structured Light Techniques
Photogrammmetry
3D Computer Tomografy (CT)
Non Tactile Methods and Measurement Principles – Some Examples

10. Comparison of various methods for 3D-shape measurement
• Conflict: large working distance and
high resolution (and vice versa)
• The 3 methods nicely work together to
cover a broad range of working
distances and uncertainties
www.iap.uni-jena.de

11. Time of Flight – Measuring the time for a light pulse to return
Single Pulse Time of Flight advantages:
• Large working distance, up to 40 km
• Uncertainty down to cm’s
• High speed, up to 100 kHz so suitable for scanning
application

12. Time of Flight – Measuring Phase Difference Output and Input
Phase Difference Time of Flight advantages:
• Middle range working distance
• Without reflector up to 100m
• Uncertainty down to mm’s
• Suitable for low-cost manufacturing

13. Interferometrie
https://qph.ec.quoracdn.net/main-qimg-4afc2005e60a6b5ecbb06fe9f8d71e8d-c
http://www.chemgapedia.de/vsengine/media/vsc/de/ph/14/ep/einf
uehrung/wellenoptik/bilder/sk20_2.jpg
Michelson-Interferometer

14. Computer Tomography (CT) – Application in Medical and Industrial Fields

15. ▪ Most often used method for depth sensing today
▪ Reason: Lots of options possible by varying the following
parameters:
▪ Base distance (b)
▪ Angles alpha and beta control working distance and sensitivity
▪ Different projections of points, lines, fringe patterns control speed versus
amount of points
▪ Different cameras and lenses
▪ Different light sources from UV over white light to IR
Triangulation
http://computingengineering.asmedigitalcollection.asme.org/data/journals/jcisb6/930083/
jcise_014_03_035001_f001.png

16. Triangulation: Laser Line
Uni Utah; Guido Gerig; Lesson: CS 6320, 3D Computer Vision Spring 2012 http://www.automotivemanufacturingsolutions.com/
wp-content/uploads/2016/12/LMI-Fig2.png

17. Triangulation: Shadow Line
Uni Utah; Guido Gerig; Lesson: CS 6320, 3D Computer Vision Spring 2012

18. Triangulation: Shadow Line
Measurement Uncertainty:
1cm on 2m (0,5% Error)
Uni Utah; Guido Gerig; Lesson: CS 6320, 3D Computer Vision Spring 2012

19. Triangulation: Structured Light
http://3dscanningservices.net/wp-content/uploads/2016/07/
Pic2.DecBlog1.WhiteLightScannerDiagram.png

20. Triangulation: Structured Light
• Very common method: Combination of Graycode and Phaseshift
• First binary black/white pattern doubles frequency with every new image,
then 4 sinusoidal images phase-shifted by 90°

21. Triangulation: Stereo Camera Setup
http://robot.neu.edu/rover/wp-content/uploads/sites/3/2013/01/wpid-20130128_220744.jpg http://carnegierobotics.com/multisense-s7/

22. Laser ToF Interferometry Laser Line Structured Light
Advantages High resolution with
high modulation
frequency
Very high resolution
possible up to small
fractions of light wave
length
Simple and easy to
implement
Very flexible technology,
allows adjustment of
sensitivity and field of
view
Disadvantages Fast electronics
necessary because of
high speed of light
Sensitive to small
vibrations, difficult to
measure larger
dimensions
Requires movement of
object or sensor to
swipe line over object
Limited by shadow
effect, doesn´t work on
transparent or shiny
objects
Comparison of different methods

23. Application: Reverse Engineering with structured light system
Duwe-3d AG; Anwenderbericht: Designmodell vollendet

24. Application: Maintenance on a milling machine with Interferometry
http://www.renishaw.de/media/img/gen/83dff5898c364bdd89085869ab482285.jpg
http://www.wzl.rwth-aachen.de/de/f765080f396ef05fc125778f00383cc6/bilderpool-029-2.jpg

25. Application: Quality assurance with structured light and comparison to CAD model
Bilder: GOM Inspect Webseite

26. Application: Patient Positioning and gating for Cancer treatment
http://www.raeng.org.uk/grants-and-prizes/prizes-and-medals/awards/the-macrobert-award/2017-finalist-vision-rt

27. Dental: Scanning in-vivo and on imprints
http://www.biodentalclinic.com.mx/tecnologia.php http://go.lmi3d.com/medical-applications-in-3d-scanning

28. Automotive: Stereo Vision for Safety and Self Driving
http://autonomos-labs.com/research/

29. User Interface: Kinect v1 and v2 – probably the most popular depth sensors
(24 million sold as of February 12, 2013)
https://www.dfki.de/web/research/publications/renameFileForDownload?filename=wasenmuller2016comparison.pdf&file_id=uploads_2964
Kinect v1 : based on triangulation
Kinect v2 : based on time of flight

30. Retail: Bodyscanning and Facescanning
http://www.thinkscan.co.uk/blog-news/biomedical-industry.htmlhttp://www.vfxscan.co.uk/ten24/wp-content/uploads/2012/12/Full-Body-scan-
Zbrush2.jpg

31. Market 2015 by technology, category and price range

32. ▪ The 3D metrology market is expected to reach USD 10.90 Billion by 2022 from USD 7.80 Billion today
▪ CAGR of 7.0% between 2016 and 2022
▪ This includes CMMs as still the biggest share but optical methods growing quicker
▪ The major players in the 3D metrology market include
▪ Hexagon AB(Sweden),
▪ Carl Zeiss AG (Germany)
▪ Faro Technologies, Inc. (U.S.)
▪ Mitutoyo Corporation (Japan),
▪ Nikon Corporation (Japan)
▪ GE Measurement and Control Solutions Inc. (U.S.)
▪ GOM MBH (Germany)
Market size and development
https://www.linkedin.com/pulse/3d-metrology-market-worth-1090-billion-usd-2022-prashau-kumar
▪ Perceptron Inc. (U.S.)
▪ Renishaw PLC (U.K.)
▪ Zygo Corporation (U.S.)
▪ Advantest Corporation (Japan)
▪ Wenzel Prazision GmbH (Germany)
▪ 3D Digital Corp (U.S.)
▪ Creaform Inc.(Canada)

33. www.8-tree.com
What does 8tree do? dentCHECK application, product and workflow

34. dentCHECK - Application

35. dentCHECK - Application
▪ Common Features of 8tree products
▪ Extremely easy to use, built for shop floor operators
▪ Handheld, battery powered surface inspection tools
▪ Application specific 3d scanners
▪ No monitor or keyboard necessary, but AR display of the
results
▪ No compromise in precision, 50 µm (0.002”) for dent
depth
▪ 1-click report generation

36. ▪ Higher image frequency and matching bandwidth on camera-computer interface
▪ Less power consumption from cameras, projectors, computers
▪ Increased processing power
▪ Support of GPU computing
▪ More compact components
▪ -> shrink form factor to cell
phone size ☺
What 8tree would like to see from the vision supply-chain to enable our
future roadmap
www.8-tree.com

37. ▪ We are pretty sure optical dimensional sensors of all kinds will be “Ubiquitous” soon
▪ We see trends towards
▪ Mobile and battery powered devices
▪ Smart phones will eventually replace dedicated devices with cameras becoming higher resolution, 3d sensors built in, projectors built in
and more processing power available
▪ More data will be moved to cloud storage and processing immediately after acquisition
▪ Therefore more bandwidth will be required on Wireless systems
▪ Big data and Artificial intelligence will be “Ubiquitous” as well
▪ Integration of image based systems into other upcoming systems like drones, robots, big data systems
▪ An examples from “our” aerospace and maintenance industry shows what engineers dream of for the next
years
A view into the future…

38. Airbus „Hangar of the Future“ Project

39. 8tree GmbH
Oberlohnstraße 3
78467 Konstanz
Telefon: +49 1516 1022 488
Web: www.8-tree.com
Email: erik@8-tree.com