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7th World Congress in Industrial Process Tomography, WCIPT7

作者： vengrinovich, v. Zolotarev, S. Institute of Applied Physics NAS of Belarus Akademicheskaya 16 str Minsk220072 Belarus

ISBN: (纸本)9780853163237

In many applications, like medical and industrial imaging, for various reasons set of projection images is usually incomplete, and the viewing angle of the reconstructed object is not comprehensive. In these cases classical imaging algorithms are useless and the so-called iterative methods for image reconstruction are applied, while the final image is achieved by the method of successive approximations with certain restrictions (a priori information), imposed on the image under reconstruction. The use of a priori functional significantly reduces the amount of the necessary original projecting information. For this kind of tasks iterative regularization algorithms in many cases provide significantly better results than classical algorithms based on the methods of integral transformations. The article describes the basic principles and recent advances in the development of Bayesian iterative method (BIM) and its applications in various fields, mainly in tomography and restoration of functions from incomplete and noisy data. © 2014 International Society for Industrial Process Tomography.

关键词： image reconstruction

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Inversion of strongly scattered data: shape and permittivity recovery

Inversion of strongly scattered data: shape and permittivity...

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conference on image reconstruction from incomplete data v

作者： Shahid, U. Fiddy, M. A. Testorf, M. E. Univ N Carolina Ctr Optoelect & Opt Commun Charlotte NC 28223 USA Dartmouth Coll Thayer Sch Engn Hanover NH 03755 USA

ISBN: (纸本)9780819472960

Reconstructing an object from scattered field data has always been very challenging, especially when dealing with strong scatterers. Several techniques have been proposed to address this problem but either they fail to provide a good estimate of the object or they are computationally very expensive. We have proposed a straightforward non-linear signal processing method in which we first process the scattered field data to generate a minimum phase function in the object domain. This is accomplished by adding a reference wave whose amplitude and phase satisfy certain conditions. Minimum-phase functions are causal transforms and their phase is continuous in the interval -pi and +pi, i.e. it is always unwrapped. Following this step, we compute the Fourier transform of the logarithm of this minimum phase function, referred to as its cepstrum. In this domain one can filter cepstral frequencies arising from the object from those of the scattered field. Cepstral data arc meaningless for non-minimum phase functions because of phase wraps. We apply low pass filters in the cepstral domain to isolate information about the object and then perform an inverse transform and exponentiation. We have applied this technique to measured data provided by Institut Fresnel (Marseille, France) and investigated in a systematic way the dependence of the approach on the properties of the reference wave and filter. We show that while being a robust method, one can identify optimal parameters for the reference wave that result in a good reconstruction of a penetrable, strongly scattering permittivity distribution.

关键词： inverse scattering minimum phase condition homomorphic filtering imaging

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Processing synthetic aperture sonar data from novel hydrophone arrays

Processing synthetic aperture sonar data from novel hydropho...

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conference on image reconstruction from incomplete data

作者： Millane, RP Gough, PT Univ Canterbury Dept Elect & Elect Engn Christchurch 1 New Zealand

ISBN: (纸本)0819437689

In synthetic aperture sonar, the highest platform speed is limited as a result of the low speed of sound in water and the requirement for adequate sampling in the along-track direction. This can result in slow seafloor mapping, The highest allowable platform speed can be increased by using a linear array of hydrophones. The signal-to-noise can also be improved by using multiple sets of hydrophone arrays. Maximum-likelihood estimation of images using data from sets of hydrophone arrays that each undersample the underlying signal to different degrees is described, Simulations for synthetic aperture sonar imaging show that this improves the images obtained over those from a single array.

关键词： synthetic aperture sonar aliasing maximum-likelihood

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Sampling, radiometry, and image reconstruction for polar and geostationary meteorological remote sensing systems

Sampling, radiometry, and image reconstruction for polar and...

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2nd conference on image reconstruction from incomplete data

作者： Abrams, MC Cain, SC ITT Industries Inc. (United States) Indiana Univ.-Purdue Univ./Fort Wayne (United States)

ISBN: (纸本)0819445592

In this paper, a Bayesian-based image reconstruction scheme is utilized for estimating a high resolution temperature map of the top of the earth's atmosphere using the GOES-8 (Geostationary Operational Environmental Satellite) imager infrared channels. By simultaneously interpolating the image while estimating temperature, the proposed algorithm achieves a more accurate estimate of the sub-pixel temperatures than could be obtained by performing these operations independently of one another. The proposed algorithm differs from other Bayesian-based image interpolation schemes in that it estimates brightness temperature as opposed to image intensity and incorporates a detailed optical model of the GOES multi-channel imaging system. The temperature estimation scheme is compared to deconvolution via pseudo-inverse filtering using two metrics. One metric is the mean squared temperature error. This metric describes the radiometric accuracy of the image estimate. The second metric is the recovered Modulation Transfer Function (MTF) of the image estimate. This method has traditionally been used to evaluate the quality of image recovery techniques. It will be shown in this paper that there is an inconsistency between these two metrics in that an image with high spatial frequency content can be reconstructed with poor radiometric, accuracy. The ramifications of this are discussed in order to evaluate the two metrics for use in quantifying the performance of image reconstruction algorithms.

关键词： Imaging systems image restoration reconstruction algorithms Sensors image resolution Modulation transfer functions Radiometry data modeling Satellite imaging Satellites

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JSR-NET: A DEEP NETWORK FOR JOINT SPATIAL-RADON DOMAIN CT reconstruction from incomplete data 44

JSR-NET: A DEEP NETWORK FOR JOINT SPATIAL-RADON DOMAIN CT RE...

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44th IEEE International conference on Acoustics, Speech and Signal Processing (ICASSP)

作者： Zhang, Haimiao Dong, Bin Liu, Baodong Peking Univ Beijing Peoples R China Chinese Acad Sci Beijing Peoples R China Univ Chinese Acad Sci Beijing Peoples R China

ISBN: (纸本)9781479981311

CT image reconstruction from incomplete data, such as sparse views and limited angle reconstruction, is an important and challenging problem in medical imaging. This work proposes a new deep convolutional neural network (CNN), called JSR-Net, that jointly reconstructs CT images and their associated Radon domain projections. JSR-Net combines the traditional model based approach with deep architecture design of deep learning. A hybrid loss function is adopted to improve the performance of the JSR-Net making it more effective in protecting important image structures. Numerical experiments demonstrate that JSR-Net outperforms some latest model based reconstruction methods, as well as a recently proposed deep model.

关键词： Joint spatial-Radon domain reconstruction Sparse-view CT Limited angle CT Convolutional neural networks Deep learning

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Unified imaging theory for X-ray and acoustic computerized tomography

Unified imaging theory for X-ray and acoustic computerized t...

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conference on image reconstruction from incomplete data III

作者： Liu, PY Wang, G Boyer, A Stanford Univ Dept Radiat Oncol Stanford CA 94305 USA

ISBN: (纸本)0819455008

X-ray computerized tomography (CT) and acoustic CT are two main medical imaging modalities based on two intrinsically different physical phenomena. X-ray CT is based on xray's attenuation when x-ray passes through medium. It has been well known that the Radon transform is the imaging theory for x-ray CT. Photoacoustic CT is a type of acoustic CT, which is based on differentiating electromagnetic energy absorption among media. In 1998 a new 3D reconstruction concept, the P-transform, was proposed to serve the imaging theory for photoacoustic CT. In this paper it was rigorously proved that both x-ray CT and photoacoustic CT are governed by a unified imaging theory. 3D data acquisition can be completed in 2pi stereoangle. This new imaging theory realized, in part, the dream of all physicists, including Albert Einstein, who have long believed that our world is ultimately governed by few simple rules.

关键词： image reconstruction P-transform Radon transform

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Quantitative 3D data extraction using contiguous volumes

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IEEE TRANSACTIONS ON NUCLEAR SCIENCE 1997年第4期44卷 1571-1577页

作者： Dykstra, CJ Harrop, R Celler, AM Atkins, MS SIMON FRASER UNIV SCH COMP SCI BURNABY BC V5A 1S6 CANADA

A new image analysis method, called contiguous volume analysis, has been developed to automatically extract 3D information from emission images. The method considers volumes of activity and displays data about them in a format which allows quantitative image comparison. This method of numerical analysis enables us to show, for example, whether or not information has been gained, lost or changed through the use of different filters and different attenuation and scatter correction, and reconstruction algorithms. Since the analysis method is consistent with a visual inspection of the data, intuitive insights into the meaning of the data are possible, allowing a better understanding of the effects of the different image processing techniques on the images. The method can be used to find patterns of activity in sets of images, and may be used to quantify noise, allowing an objective determination of which volumes in an image are meaningful.

关键词： data mining image analysis Information analysis Displays Numerical analysis Information filtering Information filters Attenuation Scattering reconstruction algorithms

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Determining wind fields in atmospheric mountain waves using sailplane flight data

Determining wind fields in atmospheric mountain waves using ...

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conference on image reconstruction from incomplete data vII

作者： Zhang, Ni Millane, Rick P. Enevoldson, Einar Murray, James E. Univ Canterbury Dept Elect & Comp Engn Computat Imaging Grp Christchurch 1 New Zealand NASA Dryden Flight Res Ctr Edwardsville IL 93523 USA

ISBN: (纸本)9780819492173

The problem of estimating wind velocities from limited flight data recordings is considered, with application to sailplane flights in high-altitude atmospheric mountain waves. Sailplane flight recorders routinely measure only GPS position and the problem is highly underdetermined. The nature of this problem is studied and a maximum a posteriori estimator is developed using prior information on the wind velocity and the sailplane airspeed and heading. The method is tested by simulation and by application to sailplane flight data.

关键词： Maximum a posteriori wind velocity aircraft sailplane mountain wave atmospheric wave

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TOMOGRAPHIC image reconstruction from incomplete INFORMATION BY CONvEX PROJECTIONS AND DIRECT FOURIER INvERSION: SUGGESTED APPLICATIONS TO SPOTLIGHT-MODE SYNTHETIC APERTURE RADAR (SAR) IMAGING.

TOMOGRAPHIC IMAGE RECONSTRUCTION FROM INCOMPLETE INFORMATION...

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Proceedings of the 1984 conference on Information Sciences and Systems.

作者： Sezan, M.Ibrahim Stark, Henry Rensselaer Polytechnic Inst Troy NY USA Rensselaer Polytechnic Inst Troy NY USA

Spotlight-mode synthetic aperture radar (SAR) imaging has a close resemblance to tomographic image reconstruction from incomplete view data. A new algorithm (PRDF), designed for reconstructing tomographic imagery from incomplete view data, is described. The results of applying the PRDF algorithm to reconstruct a human thorax cross-section from simulated X-ray projection data are furnished. An algorithm which is basically a special case of PRDF is suggested for spotlight-mode SAR imaging.

关键词： image PROCESSING

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Oblique surface reconstruction to approximate cone-beam helical data in multi-slice CT

Oblique surface reconstruction to approximate cone-beam heli...

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conference on image reconstruction from incomplete data

作者： Chen, LG Heuscher, DJ Liang, Y Purdue Univ Sch Hlth Sci W Lafayette IN 47907 USA

ISBN: (纸本)0819437689

Multi-slice helical beam scanning involves cone-beam geometry. The primary advantages for use of divergent cone-beams include reduced data acquisition, improved image resolution and optimized photon utilization. Due to the complexity of 3-dimensional cone-beam reconstruction, approximate algorithms have been sought to handle the cone-beam reconstruction. This paper presents a new approximate algorithm termed as oblique surface reconstruction (OSR). Theoretical considerations as well as the reconstruction of simulated phantom data in comparison to the current standard 180 degrees LI are presented. OSR is shown to be effective and practical to generate images with diagnostic quality.

关键词： spiral CT multi-slice CT cone-beam reconstruction oblique surface reconstruction

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