Visual Optimality And Stability Analysis Of 3DCT Scan Positions Artem Amirkhanov 1,2 Michael Reiter 2 Christoph Heinzl 2 M. Eduard Gröller 1 1 Institute of Computer Graphics and Algorithms Vienna University of Technology 2 Upper Austrian University of Applied Sciences Wels Campus, Austria

Artem Amirkhanov 1 Scanning Geometry X-ray source Specimen Detector Rotary plate

Placement is crucial for Measurements accuracy Iso-surface quality Requires knowledge, intuitive Good placement is hard to find For a complex specimen For measurement features Doing several scans is expensive Artem Amirkhanov 2 Specimen Placement

CAD model is available Quality control – from manufacturer Reverse engineering – preliminary scan Use a CAD model to estimate a good placement Visual analysis tool is required for Simulation-based preview Optimal placement estimation Tool Artem Amirkhanov 3 Motivation Optimal Placement

Artem Amirkhanov 4 Why Placement is Important? Beam-hardening artifacts Cupping artifacts Streaks Bad planar faces artifacts Blurring

Artem Amirkhanov 5 Good/Bad Placement Example Bad: Good:

Shortest penetration lengths Method: ray casting Smallest bad planar faces area Method: Radon-space analysis Stable within a certain range of reliability Method: stability widget Artem Amirkhanov 6 Criteria and Methods

Artem Amirkhanov 7 Workflow Ray casting Radon-space analysis Simulation Stability analysis Data exploration and analysis Visual analysis Optimal placement CAD model Parameter spaces

Artem Amirkhanov 8 Simulation Set of candidate placements Placement is defined by the orientation Orientation is defined by two Euler angles α and β α β

Artem Amirkhanov 9 Ray Casting Simulation Reflects the scanning setup Set of projections for every placement Parameters Maximum penetration length Average penetration length

Artem Amirkhanov 10 Radon-Space Analysis Supporting planes → points in Radon space Finding bad points in Radon space Parameter Bad faces area percentage

Artem Amirkhanov 11 Parameters Representation Best Worst Parameter value:

Artem Amirkhanov 12 Stability Widget Better SameWorse Parameter value:

Penetration-length histograms Visualizing ray subsets. Color coding bad faces. Artem Amirkhanov 13 Data Visualization and Exploration

Artem Amirkhanov 14 Evaluation Using Dimensional Measurements Two test-part specimens Measurement features Radius Distance CALYPSO used to estimate measurement quality

Complex real world specimen Best and worst placements Variance comparison of the iso-surfaces with the CAD model Artem Amirkhanov 15 Evaluation Using Variance Comparison

Artem Amirkhanov 16 Evaluation Bad PlacementGood Placement Position deviation spectrum in [mm]

Artem Amirkhanov 17 Limitations and Future Work Orientation only Detect orientation and position in sequence Still requires user interaction Combining parameters

Artem Amirkhanov 18 Conclusions Thank you! VS Contact: