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Suche nach „[Herl] [Gabriel]“ hat 5 Publikationen gefunden
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    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Gabriel Herl, Jochen Hiller, A. Stock, T. Sauer

    Edge preserving compression of CT scans using wavelets

    SHM-NDT 2018 International Symposium on Structural Health Monitoring and Nondestructive Testing 4-5 Oct 2018, Saarbrücken – Germany

    2018

    Abstract anzeigen

    This work addresses the subject of efficient storage of computed tomography (CT) data with an emphasis on the quality of surfaces. Industrial dimensional metrology often requires high measurement accuracy and we show that this is retained using wavelet-based compression methods. The applied techniques include a tensor product wavelet transform and soft wavelet shrinkage. In our tests on real objects, we compared dimensional CT measurements of compressed and uncompressed volumes. We were able to reduce the necessary storage space significantly with a minimal loss of accuracy. For a multi sphere phantom, we decreased the storage space to 4.7% (from 638 MB to 30 MB) with an average deviation below 1 µm from the original volume.

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Gabriel Herl, Jochen Hiller, A. Stock, T. Sauer

    Metal artifact reduction by fusion of CT scans from different positions using the unfiltered backprojection

    iCT 2018 8th Conference on Industrial Computed Tomography (iCT) 2018, 6-9 Feb, Wels, Austria

    2018

    Abstract anzeigen

    Metal objects or metal parts in an object are still a major problem of X-ray computed tomography (CT) because of so called metal artifacts. We propose a new method – a multipositional data fusion – for automatically fusing multiple CT volumes from different positions to reduce these metal artifacts. After scanning a specimen several times at different positions and reconstruction of every scan (e.g. by the filtered backprojection), we also perform an unfiltered backprojection. Based on the assumption that metal artifacts occur the most wherever X-rays are attenuated a lot, the unfiltered backprojection is used to autonomously estimate the likelihood of metal artifacts in every voxel of every scan. The different volumes are registered and then fused by weighted sum preferring the voxels with low values in the unfiltered backprojection results. In our tests on real objects, our method fully automatically created optimized volumes with significantly less metal artifacts. The multipositional data fusion was compared to the commercially multi spectra fusion of Werth Messtechnik GmbH and outperformed it in one of the use cases.

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Gabriel Herl, Jochen Hiller, Simon Rettenberger

    Fusion mehrerer Computertomographie-Aufnahmen zur Verbesserung der Bildqualität

    Forschungsbericht 2016/2017 der Technischen Hochschule Deggendorf

    2017

    DigitalMaschinenbau und Mechatronik

    Vortrag

    Gabriel Herl, Jochen Hiller, Simon Rettenberger, T. Sauer

    Metal artifact reduction by fusion of CT scans from different positions using the unfiltered backprojection

    8th Conference on Industrial Computed Tomography (iCT 2018), Wels, Österreich

    Abstract anzeigen

    Metal objects or metal parts in an object are still a major problem of X-ray computed tomography (CT) because of so called metal artifacts. We propose a new method – a multipositional data fusion – for automatically fusing multiple CT volumes from different positions to reduce these metal artifacts. After scanning a specimen several times at different positions and reconstruction of every scan (e.g. by the filtered backprojection), we also perform an unfiltered backprojection. Based on the assumption that metal artifacts occur the most wherever X-rays are attenuated a lot, the unfiltered backprojection is used to autonomously estimate the likelihood of metal artifacts in every voxel of every scan. The different volumes are registered and then fused by weighted sum preferring the voxels with low values in the unfiltered backprojection results. In our tests on real objects, our method fully automatically created optimized volumes with significantly less metal artifacts. The multipositional data fusion was compared to the commercially multi spectra fusion of Werth Messtechnik GmbH and outperformed it in one of the use cases.

    DigitalMaschinenbau und Mechatronik

    Vortrag

    Gabriel Herl, Jochen Hiller, A. Stock, T. Sauer

    Edge preserving compression of CT scans using wavelets

    International Symposium on Structural Health Monitoring and Nondestructive Testing, Saarbrücken

    Abstract anzeigen

    This work addresses the subject of efficient storage of computed tomography (CT) data with an emphasis on the quality of surfaces. Industrial dimensional metrology often requires high measurement accuracy and we show that this is retained using wavelet-based compression methods. The applied techniques include a tensor product wavelet transform and soft wavelet shrinkage. In our tests on real objects, we compared dimensional CT measurements of compressed and uncompressed volumes. We were able to reduce the necessary storage space significantly with a minimal loss of accuracy. For a multi sphere phantom, we decreased the storage space to 4.7% (from 638 MB to 30 MB) with an average deviation below 1 µm from the original volume.