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The original slides of my ISMAR 2014 presentation were we presented our paper: Comprehensive Workspace Calibration for Visuo-Haptic Augmented Reality, Authors: Ulrich Eck, Frieder Pankratz, Christian Sandor, Gudrun Klinker, Hamid Laga
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University ofSouth Australia
Comprehensive Workspace Calibration for Visuo-Haptic Augmented RealityUlrich Eck1, Frieder Pankratz2, Christian Sandor3, Gudrun Klinker2, Hamid Laga1 1 PBRC, University of South Australia, Australia 2 FAR, Technische Universität München, Germany3 IMD Lab, Nara Institute of Science and Technology, Japan !10/09/2014, IEEE International Symposium on Mixed and Augmented Reality, Munich
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University ofSouth Australia
Visuo-Haptic Augmented Reality (VHAR)
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[Sandor C., TEDx Adelaide, 2010]
University ofSouth Australia
Contributions
3
Previous work: position calibration only Improved: with orientation calibration
Novel algorithm for orientation calibration: >40% improvement
Position calibration: ~20% improvement
Time-delay compensation between sensors: faster and better calibration procedure
University ofSouth Australia 4
Related Work
[Sandor, C. et al., IEICE 2007][Vallino, J. et al., ICMCS 1998]
Early examples of visuo-haptic co-location
University ofSouth Australia
PHANToM Haptic Device: Joint Angles
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University ofSouth Australia
PHANToM Haptic Device: Gimbal Angles
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University ofSouth Australia
PHANToM Haptic Device: Sensor Errors
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University ofSouth Australia 8
Related Work
[Harders, M. et al., TVCG 2009][Ikits, M. et al., EG 2003]
Compensation of sensor errors
University ofSouth Australia
Missing: Orientation Calibration
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Position calibration only With orientation calibration
Orientation Error in Degrees
University ofSouth Australia
Haptic Device Calibration
External tracker provides reference pose
Forward kinematics model calculates stylus pose from sensor measurements
Sensor errors are modelled as linear or quadratic function
Sensor errors are compensated by minimizing the distance to the reference
Complete coverage of sensor ranges required
Accurate pose correspondences required for good calibration results
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External Tracker (ET)
ETorigin
HIPpose
HIPtarget
Haptic Device (HD)
Camera (C)
Ctarget
HDorigin
University ofSouth Australia
Challenge: Unsynchronized Sensor Input
Unknown delay between haptic device and external tracker
Received measurements do not match during movement
Related work
tedious point and hold process for sampling corresponding measurements
Our solution
determine time-delay between sensors first and compensate it in software to allow users to move freely during the calibration process
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University ofSouth Australia
Calibration Procedure
Tooltip (Tuceryan et al., 1995)
Absolute Orientation (Horn, 1987)
Time-Delay Estimation (Huber et al., 2012)
Joint-Angles (Harders et al., 2009)
Reference Orientation
Gimbal-Angle Errors
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External Tracker (ET)
ETorigin
HIPpose
HIPtarget
Haptic Device (HD)
Camera (C)
Ctarget
HDorigin
University ofSouth Australia
Calibration Procedure
Tooltip (Tuceryan et al., 1995)
Absolute Orientation (Horn, 1987)
Time-Delay Estimation (Huber et al., 2012)
Joint-Angles (Harders et al., 2009)
Reference Orientation
Gimbal-Angle Errors
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External Tracker (ET)
ETorigin
HIPpose
HIPtarget
Haptic Device (HD)
Camera (C)
Ctarget
HDorigin
University ofSouth Australia
Time-Delay Estimation
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External Tracker (ET)
ETorigin
HIP
Haptic Device (HD)
HDorigin
University ofSouth Australia 15
Time-delay estimation
[Huber, M et al., ISMAR 2009]
University ofSouth Australia 16
Time-aware dataflow network execution model
[Puskta, D et al., ISMAR 2007]
University ofSouth Australia
Calibration Procedure
Tooltip (Tuceryan et al., 1995)
Absolute Orientation (Horn, 1987)
Time-Delay Estimation (Huber et al., 2012)
Joint-Angles (Harders et al., 2009)
Reference Orientation
Gimbal-Angle Errors
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External Tracker (ET)
ETorigin
HIPpose
HIPtarget
Haptic Device (HD)
Camera (C)
Ctarget
HDorigin
University ofSouth Australia
Orientation Reference Estimation
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External Tracker (ET)
ETorigin
HIP
Haptic Device (HD)
HDorigin
University ofSouth Australia 19
Reference Orientation
x
y
z
xy
z
HIPpose
HIPtarget
REFzaxis
x
y
z
xy
z
HIPorigin
REFzaxis
University ofSouth Australia
Reference OrientationTracked markers travel on circular paths around the z-axis
Transform marker positions with inverse forward kinematic pose using only the first 5 angles
Fit circles to trajectories to find centers and fit a line through the centres and the HIP position
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University ofSouth Australia
Calibration Procedure
Tooltip (Tuceryan et al., 1995)
Absolute Orientation (Horn, 1987)
Time-Delay Estimation (Huber et al., 2012)
Joint-Angles (Harders et al., 2009)
Reference Orientation
Gimbal-Angle Errors
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External Tracker (ET)
ETorigin
HIPpose
HIPtarget
Haptic Device (HD)
Camera (C)
Ctarget
HDorigin
University ofSouth Australia
Gimbal-Angle Error Compensation
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External Tracker (ET)
ETorigin
HIP
Haptic Device (HD)
HDorigin
University ofSouth Australia
Gimbal-Angle Calibration
Use reference z-axis to determine the errors of the first two gimbal sensors
Model errors as linear or quadratic function
Minimize error using Levenberg-Marquardt optimization
Exploit mechanical limits of the last gimbal sensor by finding the gaps in the circular paths to compensate the offset
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University ofSouth Australia
Evaluation
Numerical Evaluation of calibration results:
Two VHAR workspace setups:
Low-fidelity (LF): PHANToM Omni, OptiTrack
High-fidelity (HF): PHANToM Premium, ART-Tracking
Visual Evaluation:
Unwrapped spherical heatmap of recuded errors
Visual overlays on haptic stylus in calibrated system
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University ofSouth Australia
Numerical Evaluation
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Reduced position errors by ~ 20%
Reduced orientation errors by > 40%
No Calib Harders Our Work No Calib Harders Our Work
No Calib Harders O u r Wo r k No Calib Harders O u r Wo r k
University ofSouth Australia
Improved Orientation Accuracy
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Reduction of Orientation Errors in Degrees
ISMAR 2014 Live DemoYou can: - perform a calibration - paint on a fish We’re in Room 00.07.014
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University ofSouth Australia
SummaryContributions:
Novel algorithm for orientation calibration (>40% improvement)
Improved position calibration (~20% improvement)
Compensated time-delay for faster and better calibration
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x
y
z
xy
z
HIPpose
HIPtarget
REFzaxis
x
y
z
xy
z
HIPorigin
REFzaxis
Questions ?Thank You!!
University ofSouth Australia
ReferencesHarders, M. & Szekely, G., 2009. Calibration, Registration, and Synchronization for High Precision Augmented Reality Haptics. IEEE Transactions on Visualization and Computer Graphics, 15(1), pp.138–149. Fu, M.J. et al., 2011. Effect of Visuo-Haptic Co-location on 3D Fitts' Task Performance. In Proceedings of the International Conference on Intelligent Robots and Systems (IROS), 2011 IEEE/RSJ. San Francisco, CA, USA: IEEE, pp. 3460–3467. Rhienmora, P. et al., 2010. Augmented Reality Haptics System for Dental Surgical Skills Training. In Proceedings of the 17th ACM Symposium on Virtual Reality Software and Technology. Hong Kong: ACM, pp. 97–98. Ikits, M., Hansen, C.D. & Johnson, C.R., 2003. A Comprehensive Calibration and Registration Procedure for the Visual Haptic Workbench. In the workshop. New York, NY, USA: ACM, pp. 247–254. Vallino, J. & Brown, C., 1999. Haptics in Augmented Reality. In Proceedings of the IEEE International Conference on Multimedia Computing and Systems. pp. 195–200. Horn, B.K.P., 1987. Closed-form Solution of Absolute Orientation using Unit Quaternions. Journal of the Optical Society of America, 4(4), pp.629–642. Tuceryan, M., Greer, D.S. & Whitaker, R.T., 1995. Calibration Requirements and Procedures for a Monitor-Based Augmented Reality System. Visualization and …, 1(3), pp.255–273. Pustka, D. et al., 2006. Spatial Relationship Patterns: Elements of Reusable Tracking and Calibration Systems. In Proceedings of the International Symposium for Mixed and Augmented Reality. Santa Barbara, CA, USA, pp. 88–97. Sandor, C. & Uchiyama, S., 2007. Exploring Visuo-Haptic Mixed Reality, IEICE. Huber, M., Michael, S. & Klinker, G., 2012. Temporal Calibration in Multisensor Tracking Setups. 9. Workshop der GI-Fachgruppe Virtuelle und Erweiterte Realität (VR-AR 2012), pp.201–212.
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