Principles of Computerized Tomographic Imaging

Kak, Avinash C.; Slaney, Malcolm; Wang, Ge

doi:10.1118/1.1455742

Cited by 1,445 publications

(2,099 citation statements)

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“…2). This type of projection is described in detail for tomography applications by Kak et al [7] and for radioscopy by Mery et al [6] One implication is the possibility to adjust the required magnification M. It is given by M = b/a (a is the distance between source and sample and b between source and detector). Useful M's can be as high as 10 for our configuration.…”

Section: Real-time X-ray Radioscopymentioning

confidence: 99%

Real‐time X‐ray Radioscopy on Metallic Foams Using a Compact Micro‐Focus Source

García‐Moreno

Fromme²,

Banhart

2004

Adv Eng Mater

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A measurement apparatus for observing the foaming of metals is described. It consists of a microfocus X‐ray source, a small heater and a panel detector. The foaming of samples can be recorded in real‐time with frequencies up to 9 Hz and resolutions down to 5 μm due to the small spot size. Magnifications up to 10x are obtained by simply changing the distance between source, sample and detector. Foaming of Al alloys and sandwiches was investigated applying different final foaming temperatures, heating rates and blowing agent pre‐treatments. An image analysis program was developed to automatically recognise the foam expansion.

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Section: Real-time X-ray Radioscopymentioning

confidence: 99%

Real‐time X‐ray Radioscopy on Metallic Foams Using a Compact Micro‐Focus Source

García‐Moreno

Fromme²,

Banhart

2004

Adv Eng Mater

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“…The ramp filter design uses a method reported in [33] and [34], aiming to suppress the dc shift and inter-period interference artifacts. This is achieved by calculating an impulse response approximation of the ramp filter and matching the sampling interval to the bandwidths of the filter and the projection data, which are also zero-padded before the FFT is applied.…”

Section: Computer Implementation Of the Standard Fbp Algorithmmentioning

confidence: 99%

Tiled-Block Image Reconstruction by Wavelet- Based, Parallel-Filtered Back-Projection

Escobedo

Ozanyan

2016

IEEE Sensors J.

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Abstract-We demonstrate an algorithm, relevant to tomography sensor systems, to obtain images from the parallel reconstruction of essentially localized elements at different scales. This is achieved by combining methodology to reconstruct images from limited and/or truncated data, with the time-frequency capabilities of the Wavelet Transform. Multi-scale, as well as time-frequency, localization properties of the separable twodimensional wavelet transform are exploited as an approach for faster reconstruction. The speed up is realized not only by reducing the computation load on a single processor, but also by achieving the parallel reconstruction of several tiled blocks. With tiled-block image reconstruction by wavelet-based, parallel filtered back-projection we measure more than 36 times gain in speed, compared to standard filtered back-projection.Index Terms-image reconstruction, computed tomography, data processing algorithms, parallel processing, wavelet transform. I. INTRODUCTIONCROSS many applications, it is common to identify the need of information about an object, without altering its physical structure. Fortunately, there are numerous methods allowing radiation, either emitted or transmitted, to be employed to obtain cross-sectional images characterizing the inner structure of an object. The mathematical foundation behind such an approach was developed by Johann Radon in 1917 [1] and several decades later, in 1972, experimentally implemented by Hounsfield [2] resulting in the demonstration of the first Computed Tomography (CT) scanner.The main motivation for this work was the existing body of knowledge and achievements on the reconstruction of reduced-area full-resolution images, originally encouraged by the radiation dose exposure reduction in medical imaging and where the Wavelet Transform (WT), along its different representations, proved to be an effective tool given its timefrequency localization capabilities [4], [5]. Such research has been commonly named as Wavelet-based local reconstruction, and has been reported to be useful in other application areas such as Nano and Micro Tomography [6], [7]; Terahertz Tomography [8], and Dental Radiology [9].Of special interest is the 2D fast wavelet transform (2D FWT), employed in [5] and [10]. In addition to achieving local Manuscript received October 15, 2015. Jorge Guevara Escobedo (jorge.guevaraescobedo@manchester.ac.uk) and Krikor B. Ozanyan (k.ozanyan@manchester.ac.uk) are with the School of Electrical and Electronic Engineering, The University of Manchester, M13 9PL, Manchester, UK. JGE wishes to acknowledge the financial support of Consejo Nacional de Ciencia y Tecnología (CONACyT), Mexico, for a doctoral studentship.reconstruction, it allows projection data to be processed in a multi-resolution scheme. Such a feature proves to be of great benefit, when realizing its similarities with the parallel algorithm proposed in [11]. In that algorithm, a frequential decomposition of projection data is performed with the aim to back-project every componen...

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“…[22] It provides a 3D image with a grayscale colormap that is proportional to the local X-ray attenuation coefficient. The voxel size was chosen equal to 5.06 mm although better resolutions are achievable to visualize fatigue cracks with synchrotron microtomography.…”

Section: In Situ Testing Proceduresmentioning

confidence: 99%

3D X‐ray Microtomography Volume Correlation to Study Fatigue Crack Growth

et al. 2010

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International audienceGlobal digital volume correlation is used to analyze a series of computed tomography images of a nodular graphite cast iron specimen subjected in situ to a fatigue test. From the obtained displacement field, a specific procedure is implemented to extract stress intensity factors all along the crack front. The proposed methodology allows one to measure key parameters in fatigue crack propagation directly from 3D images

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Principles of Computerized Tomographic Imaging

Cited by 1,445 publications

References 0 publications

Real‐time X‐ray Radioscopy on Metallic Foams Using a Compact Micro‐Focus Source

Real‐time X‐ray Radioscopy on Metallic Foams Using a Compact Micro‐Focus Source

Tiled-Block Image Reconstruction by Wavelet- Based, Parallel-Filtered Back-Projection

3D X‐ray Microtomography Volume Correlation to Study Fatigue Crack Growth

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