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Projection-Based Metal-Artifact Reduction for Industrial 3D X-ray Computed Tomography. Artem Amirkhanov 1,2 Michael Reiter 2 Johann Kastner 2 Christoph Heinzl 2 M. Eduard Gröller 1. 1 Institute of Computer Graphics and Algorithms Vienna University of Technology.
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Projection-Based Metal-Artifact Reduction for Industrial 3D X-ray Computed Tomography Artem Amirkhanov 1,2 Michael Reiter 2 Johann Kastner 2 Christoph Heinzl 2 M. Eduard Gröller 1 1 Institute of Computer Graphicsand Algorithms Vienna University of Technology 2 Upper Austrian University of Applied Sciences Wels Campus, Austria
Scanning Geometry Artem Amirkhanov
Scanning Geometry Detector Specimen X-ray source Rotary plate Reconstruction Projections 3D Volume Artem Amirkhanov
Multi-Material Components (MMCs) • Most industrial parts are MMCs • Materials: • Air • Plastic • Metal Artem Amirkhanov
Metal Artifacts • Appear in MMCs • Metal artifacts • Dark-band artifacts • Streak-noise artifacts • Caused by beam hardening • Bad for • Material characterization • Measurements Dark-band artifacts Streak-noise artifacts Artem Amirkhanov
Our Contributions • Adaptation of a projection-based metal artifacts reduction(MAR) workflow for 3DXCT • Integrated visual analysis tool Integrated VA Tool MAR Workflow Artem Amirkhanov
Main Idea • Artifacts source: projections • We remove metal from projections • We then reconstruct the 3D volume with reduced artifacts • We insert the metal back into this volume Streak-noise artifacts Artem Amirkhanov
MAR Workflow Input Initial Data Projections Reconstruction 3D Volume Projections Initial Reconstruction 3D Volume Material Separation Metal 3D Volume Forward Projection Workflow Without Metal Projections Interpolation Metal Interpolated Projection Reconstruction MAR without Metal 3D Volume Fusion Output MAR Volume 3D Volume Artem Amirkhanov
Attenuation coefficient thresholding Material Separation 8 Artem Amirkhanov
MAR Workflow Input Initial Data Projections Reconstruction 3D Volume Projections Initial Reconstruction 3D Volume Material Separation Metal 3D Volume Forward Projection Workflow Without Metal Projections Interpolation Metal Interpolated Projection Reconstruction MAR without Metal 3D Volume Fusion Output MAR Volume 3D Volume Artem Amirkhanov
Forward Projection Projection • Works as follows: • Project every metal voxel on every projection Specimen X-ray source Rotary plate Artem Amirkhanov
Forward Projection • Partially covered pixels • We overestimate partially covered pixels Voxel center Covered pixels Projection Metal voxel projection Length of projected voxel diagonal 11 Artem Amirkhanov
MAR Workflow Input Initial Data Projections Reconstruction 3D Volume Projections Initial Reconstruction 3D Volume Material Separation Metal 3D Volume Forward Projection Workflow Without Metal Projections Interpolation Metal Interpolated Projection Reconstruction MAR without Metal 3D Volume Fusion Output MAR Volume 3D Volume Artem Amirkhanov
MAR Workflow Input Initial Data Projections Reconstruction 3D Volume Projections Initial Reconstruction 3D Volume Material Separation Metal 3D Volume Forward Projection Workflow Without Metal Projections Interpolation Metal Interpolated Projection Reconstruction MAR without Metal 3D Volume Fusion Output MAR Volume 3D Volume Artem Amirkhanov
Interpolation • Row-wise linear interpolation along the X axis 14 Artem Amirkhanov
Interpolation • Row-wise linear interpolation along the X axis 15 Artem Amirkhanov
Interpolation • Row-wise linear interpolation along the X axis 16 Artem Amirkhanov
Interpolation • Row-wise linear interpolation along the X axis End of the gap Start of the gap 17 Artem Amirkhanov
Interpolation • Row-wise linear interpolation along the X axis End of the gap Start of the gap 18 Artem Amirkhanov
MAR Workflow Input Initial Data Projections Reconstruction Projections 3D Volume Initial Reconstruction 3D Volume Material Separation Metal 3D Volume Forward Projection Workflow Without Metal Projections Interpolation Metal Interpolated Projection Reconstruction MAR without Metal 3D Volume Fusion Output MAR Volume 3D Volume Artem Amirkhanov
MAR Workflow Input Initial Data Projections Reconstruction 3D Volume Initial Reconstruction 3D Volume Material Separation Metal 3D Volume Forward Projection Workflow Without Metal Projections Interpolation Metal Interpolated Projection Reconstruction MAR without Metal 3D Volume Fusion Output MAR Volume 3D Volume Artem Amirkhanov
Fusion Interpolation on the metal boundaries for smooth appearance 21 Artem Amirkhanov
Integrated Visual Analysis Tool • Steps of the workflow are integrated • Visual threshold estimation • Segmentation preview • Result preview • Visual result exploration 22 Artem Amirkhanov
Results (1) 23 Artem Amirkhanov
Results (1) 24 Artem Amirkhanov
Results (2) 25 Artem Amirkhanov
Results (2) 26 Artem Amirkhanov
Results (3) 27 Artem Amirkhanov
Results (3) 28 Artem Amirkhanov
Limitations • Interpolation introduces blurring in the result • Limiting factor:metal projected area Artem Amirkhanov
Limitations • Interpolation introduces blurring in the result • Limiting factor:metal projected area Artem Amirkhanov
Conclusions • MAR for 3D industrial MMCs • Significant artifact reduction • Works for various datasets • Integrated visual analysis tool • Assisting user in threshold estimation • Exploring the result • GPU implementation (CUDA) • Reconstruction • Forward-projection • Interpolation Artem Amirkhanov
Conclusions Thank you! VS Contact: artem@cg.tuwien.ac.at Artem Amirkhanov