Dr. Xuan Liu Profile

Dr. Xuan Liu

at Bruker microCT

SPIE Involvement:

Author

Publications (12)

Proceedings Article | 25 September 2017 Presentation + Paper

A comparison study: image-based vs signal-based retrospective gating on microCT

Xuan Liu, Phil Salmon, Kjell Laperre, Alexander Sasov

Proceedings Volume 10391, 1039103 (2017) https://doi.org/10.1117/12.2275609

KEYWORDS: Video, Electrocardiography, Cardiac imaging, X-ray imaging, X-rays, Scanners, Heart, Data acquisition, Image processing, Aluminum

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Proceedings Article | 11 September 2014 Paper

Practical pseudo-3D registration for large tomographic images

Xuan Liu, Kjell Laperre, Alexander Sasov

Proceedings Volume 9212, 921208 (2014) https://doi.org/10.1117/12.2061618

KEYWORDS: Image registration, 3D image processing, Tomography, Foam, Metals, Image compression, Teeth, Image processing, 3D acquisition, Visualization

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Image registration is a powerful tool in various tomographic applications. Our main focus is on microCT applications in which samples/animals can be scanned multiple times under different conditions or at different time points. For this purpose, a registration tool capable of handling fairly large volumes has been developed, using a novel pseudo-3D method to achieve fast and interactive registration with simultaneous 3D visualization. To reduce computation complexity in 3D registration, we decompose it into several 2D registrations, which are applied to the orthogonal views (transaxial, sagittal and coronal) sequentially and iteratively. After registration in each view, the next view is retrieved with the new transformation matrix for registration. This reduces the computation complexity significantly. For rigid transform, we only need to search for 3 parameters (2 shifts, 1 rotation) in each of the 3 orthogonal views instead of 6 (3 shifts, 3 rotations) for full 3D volume. In addition, the amount of voxels involved is also significantly reduced. For the proposed pseudo-3D method, image-based registration is employed, with Sum of Square Difference (SSD) as the similarity measure. The searching engine is Powell's conjugate direction method. In this paper, only rigid transform is used. However, it can be extended to affine transform by adding scaling and possibly shearing to the transform model. We have noticed that more information can be used in the 2D registration if Maximum Intensity Projections (MIP) or Parallel Projections (PP) is used instead of the orthogonal views. Also, other similarity measures, such as covariance or mutual information, can be easily incorporated. The initial evaluation on microCT data shows very promising results. Two application examples are shown: dental samples before and after treatment and structural changes in materials before and after compression. Evaluation on registration accuracy between pseudo-3D method and true 3D method has been performed.

Proceedings Article | 17 October 2012 Paper

Calibration of a combined laboratory microCT/microXRF system

Xuan Liu, Peter Bruyndonckx, Alexander Sasov

Proceedings Volume 8506, 850615 (2012) https://doi.org/10.1117/12.929594

KEYWORDS: Calibration, Sensors, Imaging systems, Image registration, Scanners, X-rays, Collimators, X-ray computed tomography, Computed tomography, Copper

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Proceedings Article | 17 October 2012 Paper

First small-animal in-vivo phase-contrast micro-CT scanner

B. Pauwels, P. Bruyndonckx, X. Liu, A. Tapfer, A. Velroyen, A. Yaroshenko, M. Bech, F. Pfeiffer, A. Sasov

Proceedings Volume 8506, 85060J (2012) https://doi.org/10.1117/12.929567

KEYWORDS: Scanners, X-rays, Absorption, Visibility, Interferometers, Cameras, In vivo imaging, X-ray imaging, Sensors, X-ray sources

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Proceedings Article | 3 September 2010 Paper

Key components for artifact-free micro-CT and nano-CT instruments

Alexander Sasov, Bart Pauwels, Xuan Liu, Peter Bruyndonckx

Proceedings Volume 7804, 78040U (2010) https://doi.org/10.1117/12.860380

KEYWORDS: X-rays, Cameras, Charge-coupled devices, Scintillators, Scanners, Sensors, Fiber optics, X-ray sources, CCD cameras, X-ray detectors

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Proceedings Article | 2 September 2010 Paper

Progress in development of a laboratory microXRF-microCT system

Peter Bruyndonckx, Alexander Sasov, Xuan Liu, Johan Van Geert

Proceedings Volume 7804, 78041A (2010) https://doi.org/10.1117/12.860384

KEYWORDS: X-rays, Charge-coupled devices, Luminescence, X-ray fluorescence spectroscopy, Prototyping, Chemical elements, X-ray detectors, Spatial resolution, X-ray imaging, Iron

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Proceedings Article | 2 September 2010 Paper

Reconstruction algorithms for laboratory microCT/microXRF system

Xuan Liu, Peter Bruyndonckx, Alexander Sasov

Proceedings Volume 7804, 780419 (2010) https://doi.org/10.1117/12.860541

KEYWORDS: Signal attenuation, Expectation maximization algorithms, X-rays, Reconstruction algorithms, Imaging systems, Sensors, X-ray sources, Algorithm development, X-ray fluorescence spectroscopy, Denoising

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Proceedings Article | 2 September 2010 Paper

X-ray nanotomography in a SEM

Bart Pauwels, Xuan Liu, Alexander Sasov

Proceedings Volume 7804, 78040S (2010) https://doi.org/10.1117/12.860201

KEYWORDS: X-rays, Cameras, Scanning electron microscopy, Electron beams, X-ray imaging, Bismuth, Metals, CCD cameras, Objectives, Quantum efficiency

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Proceedings Article | 18 September 2008 Paper

Adaptive acquisition geometry for micro-CT with large format detectors

Alexander Sasov, Faisal Nadeem, Xuan Liu, Koen Verelst

Proceedings Volume 7078, 70781Q (2008) https://doi.org/10.1117/12.793203

KEYWORDS: Sensors, Cameras, Phase contrast, Scanners, X-rays, X-ray detectors, X-ray sources, Absorption, Scattering, Charge-coupled devices

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Proceedings Article | 17 September 2008 Paper

Compensation of mechanical inaccuracies in micro-CT and nano-CT

Alexander Sasov, Xuan Liu, Phil Salmon

Proceedings Volume 7078, 70781C (2008) https://doi.org/10.1117/12.793212

KEYWORDS: Scanners, X-ray sources, X-rays, Cameras, Metals, Scanning electron microscopy, Spatial resolution, Image resolution, Temperature metrology, Image quality

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