Reliable automatic alignment of tomographic projection data by passive auto‐focus

Kingston, Andrew; Sakellariou, Arthur; Varslot, Trond; Myers, Glenn R.; Sheppard, Adrian

doi:10.1118/1.3609096

Cited by 106 publications

(106 citation statements)

References 39 publications

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“…We also used 10 clearfields, 5 darkfields to obtain the linearized attenuation data. To reduce dynamic misalignment (aka drift) of the sample and detector during the experiment, 20 keyfields (equally spaced in the circular source trajectory) are collected, and Andrew Kingston's Auto focus 13 and Myer's Drift correction 14 technique is used.…”

Section: Methodsmentioning

confidence: 99%

Improving spatial-resolution in high cone-angle micro-CT by source deblurring

Kingston

Myers

et al. 2014

SPIE Proceedings

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Micro scale computed tomography (CT) can resolve many features in cellular structures, bone formations, minerals properties and composite materials not seen at lower spatial-resolution. Those features enable us to build a more comprehensive model for the object of interest. CT resolution is limited by a fundamental trade off between source size and signal-to-noise ratio (SNR) for a given acquisition time. There is a limit on the X-ray flux that can be emitted from a certain source size, and fewer photons cause a lower SNR. A large source size creates penumbral blurring in the radiograph, limiting the effective spatial-resolution in the reconstruction.High cone-angle CT improves SNR by increasing the X-ray solid angle that passes through the sample. In the high cone-angle regime current source deblurring methods break down due to incomplete modelling of the physical process. This paper presents high cone-angle source de-blurring models. We implement these models using a novel multi-slice Richardson-Lucy (M-RL) and 3D Conjugate Gradient deconvolution on experimental high cone-angle data to improve the spatial-resolution of the reconstructed volume. In M-RL, we slice the back projection volume into subsets which can be considered to have a relative uniform convolution kernel. We compare these results to those obtained from standard reconstruction techniques and current source deblurring methods (i.e. 2D Richardson-Lucy in the radiograph and the volume respectively).

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Section: Methodsmentioning

confidence: 99%

Improving spatial-resolution in high cone-angle micro-CT by source deblurring

Kingston

Myers

et al. 2014

SPIE Proceedings

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“…One optimal unit (1.0 ou) is defined separately for each parameter, and is the largest amount the parameter can be perturbed such that the deviation from the correct ray path through the tomogram is on the order of one voxel, and were derived for FDK reconstruction by Kingston et al 21 Clearly, this is not a rigorously defined concept, but rather a guide for obtaining a consistent stopping criterion when searching for the optimal set of parameters. In this section, we derive the optimal unit for sample-distance R in K1PI reconstruction, as this parameter plays a role in K1PI, but not for FDK.…”

Section: Iiib Optimal Unitsmentioning

confidence: 99%

“…The same general approach has successfully been used for FDK reconstruction, where an autofocus method was developed to determine the best alignment parameters. 21 In the remainder of this section, we will develop an autofocus method which is suited for use in concert with K1PI reconstruction. We refer to the extended reconstruction method as autofocus-corrected K1PI reconstruction.…”

Section: Autofocus-corrected K1pi Reconstructionmentioning

confidence: 99%

High-resolution helical cone-beam micro-CT with theoretically-exact reconstruction from experimental data

et al. 2011

Self Cite

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“…Many methods have been proposed for CT geometric calibration [1,2,[5][6][7][8][9][10][11] , most of these methods require special manufactured calibration phantom for calculating the geometric parameters [5][6][7][8][9] . Noo et al [5] proposed an analytic method based on identification of ellipse parameters, they use the ellipse parameters as intermediate parameters to calculate the CT geometric parameters.…”

Section: Introductionmentioning

confidence: 99%

A wire scanning based method for geometric calibration of high resolution CT system

Jiang

et al. 2015

SPIE Proceedings

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This paper is about geometric calibration of the high resolution CT (Computed Tomography) system. Geometric calibration refers to the estimation of a set of parameters that describe the geometry of the CT system. Such parameters are so important that a little error of them will degrade the reconstruction images seriously, so more accurate geometric parameters are needed in the higher-resolution CT systems. But conventional calibration methods are not accurate enough for the current high resolution CT system whose resolution can reach sub-micrometer or even tens of nanometers. In this paper, we propose a new calibration method which has higher accuracy and it is based on the optimization theory. The superiority of this method is that we build a new cost function which sets up a relationship between the geometrical parameters and the binary reconstruction image of a thin wire. When the geometrical parameters are accurate, the cost function reaches its maximum value. In the experiment, we scanned a thin wire as the calibration data and a thin bamboo stick as the validation data to verify the correctness of the proposed method. Comparing with the image reconstructed with the geometric parameters calculated by using the conventional calibration method, the image reconstructed with the parameters calculated by our method has less geometric artifacts, so it can verify that our method can get more accurate geometric calibration parameters. Although we calculated only one geometric parameter in this paper, the geometric artifacts are still eliminated significantly. And this method can be easily generalized to all the geometrical parameters calibration in fan-beam or cone-beam CT systems.

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Reliable automatic alignment of tomographic projection data by passive auto‐focus

Cited by 106 publications

References 39 publications

Improving spatial-resolution in high cone-angle micro-CT by source deblurring

Improving spatial-resolution in high cone-angle micro-CT by source deblurring

High-resolution helical cone-beam micro-CT with theoretically-exact reconstruction from experimental data

A wire scanning based method for geometric calibration of high resolution CT system

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