Insitute of Computer Graphics and Algorithms, Vienna University of Technology

Projection-Based Metal-Artifact Reduction for Industrial 3D X-ray Computed TomographyArtem Amirkhanov 1,2Michael Reiter 2Johann Kastner 2Christoph Heinzl 2M. Eduard Grller 11 Institute of Computer Graphicsand AlgorithmsVienna University of Technology2 Upper Austrian University of Applied SciencesWels Campus, Austria

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Artem Amirkhanov1Scanning Geometry1Artem Amirkhanov2Scanning Geometry

X-ray sourceSpecimenDetectorRotary plateProjections3D VolumeReconstruction2

Multi-Material Components (MMCs)Artem Amirkhanov3

Most industrial parts are MMCsMaterials:AirPlasticMetal

Metal ArtifactsArtem Amirkhanov4Appear in MMCsMetal artifactsDark-band artifactsStreak-noise artifactsCaused by beam hardeningBad forMaterial characterization Measurements

Dark-band artifactsStreak-noise artifacts4Our ContributionsArtem Amirkhanov5Adaptation of a projection-based metal artifacts reduction (MAR) workflow for 3DXCTIntegrated visual analysis tool

MAR WorkflowIntegrated VA ToolMain IdeaArtem Amirkhanov6Artifacts source: projectionsWe remove metal from projectionsWe then reconstruct the 3D volume with reduced artifactsWe insert the metal back into this volume Streak-noise artifactsInitial DataInitial Reconstruction3D VolumeMetal3D VolumeWithout MetalProjectionsMetal InterpolatedProjectionMAR Volume3D VolumeOutputReconstructionMaterial SeparationForward ProjectionInterpolationFusionWorkflowMAR without Metal3D VolumeReconstructionProjectionsProjections3D VolumeInputMAR WorkflowArtem Amirkhanov77Attenuation coefficient thresholdingArtem Amirkhanov8Material Separation

8Initial DataInitial Reconstruction3D VolumeMetal3D VolumeWithout MetalProjectionsMetal InterpolatedProjectionMAR Volume3D VolumeInputOutputReconstructionMaterial SeparationForward ProjectionInterpolationFusionWorkflowMAR without Metal3D VolumeReconstructionProjectionsProjections3D VolumeMAR WorkflowArtem Amirkhanov99Artem AmirkhanovForward ProjectionWorks as follows:Project every metal voxel on every projection

X-ray sourceSpecimenProjectionRotary plate10Artem Amirkhanov11Forward ProjectionProjectionMetal voxel projectionVoxel centerLength of projected voxel diagonalCovered pixelsPartially covered pixelsWe overestimate partially covered pixels11Artem Amirkhanov12Initial DataInitial Reconstruction3D VolumeMetal3D VolumeWithout MetalProjectionsMetal InterpolatedProjectionMAR Volume3D VolumeInputOutputReconstructionMaterial SeparationForward ProjectionInterpolationFusionWorkflowMAR without Metal3D VolumeReconstructionProjectionsProjections3D VolumeMAR Workflow123D VolumeMetalForward ProjectionInitial DataInitial Reconstruction3D VolumeMetal InterpolatedProjectionMAR Volume3D VolumeInputReconstructionMaterial SeparationInterpolationFusionWorkflowMAR without Metal3D VolumeReconstructionProjections3D VolumeArtem Amirkhanov13Without MetalProjectionsMAR WorkflowProjectionsOutput13Artem Amirkhanov14InterpolationRow-wise linear interpolation along the X axis14Artem Amirkhanov15InterpolationRow-wise linear interpolation along the X axis15Artem Amirkhanov16InterpolationRow-wise linear interpolation along the X axis16Artem Amirkhanov17InterpolationRow-wise linear interpolation along the X axisStart of the gapEnd of the gap17Artem Amirkhanov18InterpolationRow-wise linear interpolation along the X axisStart of the gapEnd of the gap18Initial DataInitial Reconstruction3D VolumeMetal3D VolumeWithout MetalProjectionsMetal InterpolatedProjectionMAR Volume3D VolumeInputOutputReconstructionMaterial SeparationForward ProjectionInterpolationFusionWorkflowMAR without Metal3D VolumeReconstructionProjectionsProjections3D VolumeMAR WorkflowArtem Amirkhanov1919Artem Amirkhanov20Initial DataInitial Reconstruction3D VolumeMetal3D VolumeWithout MetalProjectionsMetal InterpolatedProjectionMAR Volume3D VolumeInputOutputReconstructionMaterial SeparationForward ProjectionInterpolationFusionWorkflowMAR without Metal3D VolumeReconstructionProjections3D VolumeMAR Workflow20Artem Amirkhanov21FusionInterpolation on the metal boundaries for smooth appearance

21Artem Amirkhanov22Integrated Visual Analysis ToolSteps of the workflow are integratedVisual threshold estimationSegmentation previewResult previewVisual result exploration

22Artem Amirkhanov23Results (1)

23Artem Amirkhanov24Results (1)

24Artem Amirkhanov25Results (2)

25Artem Amirkhanov26Results (2)

26Artem Amirkhanov27Results (3)

27Artem Amirkhanov28Results (3)

28Artem Amirkhanov29Limitations

Interpolation introduces blurring in the result Limiting factor: metal projected area29Artem Amirkhanov30LimitationsInterpolation introduces blurring in the result Limiting factor: metal projected area

30Artem Amirkhanov31ConclusionsMAR for 3D industrial MMCsSignificant artifact reductionWorks for various datasetsIntegrated visual analysis toolAssisting user in threshold estimationExploring the resultGPU implementation (CUDA)ReconstructionForward-projectionInterpolation31Artem Amirkhanov32ConclusionsThank you!

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Contact: artem@cg.tuwien.ac.at

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