The document discusses targetless registration accuracy validation methods. It presents a reproducible method for validating targetless registration using spherical targets and laser distance measurements between targets. The goal is to encourage accuracy checks for every targetless registration to identify any errors. Equipment used includes a Faro X330 laser scanner, Faro spherical targets, and a Leica DISTO laser distance meter. Targets were placed and scanned, and measurements were taken between targets using the DISTO and averaged to validate registration accuracy.

1. Targetless Registration: By the numbers
David J. Dustin, Eric J. Dustin

2. Targetless Registration: By the Numbers
•Present a method for validating targetless registration accuracy
•One that can be reproduced by anyone
•Initiate a discussion on other techniques for ensuring the accuracy of targetless registration.
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3. Targetless Registration: By the Numbers
•A single scan is going to be very accurate (+/- 2mm)
•Greatest potential for error occurs in registration of multiple scans.
•Want to encourage some type of accuracy check in every scanning “opportunity”
•Error isn’t a bad thing as long as you know what it is. Everything has error
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4. Targetless Registration: By the Numbers
•Love targeted registration
•Hate targeted registration
•Love targetless registration
•Hate targetless registration
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5. Targetless Registration: By the Numbers
•Have had projects that should have worked targetless and did not
•Long sections of flat roads (did not)
•Hilly section of road (did.. Sort of)
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6. Targetless Registration: By the Numbers
•Equipment Used for test:
•Faro X330, specially outfitted Dustin Forensics version
•Faro 145mm spherical targets
•Faro checkerboard targets
•Leica DISTO E7500i Laser Distance Meter
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7. Targetless Registration: By the Numbers
•Faro X330, specially outfitted Dustin Forensics version (kidding)
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8. Targetless Registration: By the Numbers
•Faro 145mm spherical targets mounted to tripods (about 12 used for the test)
•Faro checkerboard targets printed via laser printer, affixed to flat surfaces via adhesive tape
•Note: checkerboard targets were not used for registration
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9. Targetless Registration: By the Numbers
•Leica DISTO E7500i Laser Distance Meter
•Mounted to various tripods for stability
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10. Targetless Registration: By the Numbers
•Method
•Place targets
•Scan area with targets in position
•Perform hand measurements with tape (discontinued due to wind and inaccuracies)
•Perform measurements with Disto
•3 measurements per target pair, average results
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11. Targetless Registration: By the Numbers
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12. Targetless Registration: By the Numbers
•Questions?
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