A method is described for reconstructing images fromincompletedata sets if subsets of the data are obtained with different data acquisition systems. The proposed method is able to incorporate prior information about...
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ISBN:
(纸本)0819463957
A method is described for reconstructing images fromincompletedata sets if subsets of the data are obtained with different data acquisition systems. The proposed method is able to incorporate prior information about the object into the reconstruction process. The general scheme is applied to construct improved images from multiple low resolution frames of the same scene, where each frame is obtained with an imaging system characterized by a different response function. The working principle is demonstrated with synthetic data for a set of generic imaging systems. Additional attention is given to the potential of the inherent superresolution capabilities of this method in the context of compressed image representations.
Many imaging systems involve a loss of information that requires the incorporation of prior knowledge in the restoration/reconstruction process. We focus on the typical case of 30 reconstructionfrom an incomplete set...
Many imaging systems involve a loss of information that requires the incorporation of prior knowledge in the restoration/reconstruction process. We focus on the typical case of 30 reconstructionfrom an incomplete set of projections. An approach based an constrained optimization is introduced This approach provides a powerful mathematical framework for selecting a specific solution from the set of feasible solutions;this is done by minimizing some criteria depending on prior densitometric information that can be interpreted through a generalized support constraint. We propose a global optimization scheme using a deterministic relaxation algorithm based on Bregman's algorithm associated with half-quadratic minimization techniques. When used for 30 vascular reconstructionfrom 2D digital subtracted angiography (DSA) data, such an approach enables the reconstruction of a well-contrasted 30 vascular network in comparison with results obtained using standard algorithms. (C) 1997 SPIE and IS&T.
In real-world image processing applications, the data is high dimensional but the amount of high-quality data needed to train the model is very limited. In this paper, we demonstrate applicability of a recently presen...
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ISBN:
(纸本)9780992862671
In real-world image processing applications, the data is high dimensional but the amount of high-quality data needed to train the model is very limited. In this paper, we demonstrate applicability of a recently presented method for dictionary learning fromincompletedata, the so-called Iterative Thresholding and K residual Means for Masked data, to deal with high-dimensional data in an efficient way. In particular, the proposed algorithm incorporates a corruption model directly at the dictionary learning stage, also enabling reconstruction of the low-rank component again from corrupted signals. These modifications circumvent some difficulties associated with the efficient dictionary learning procedure in the presence of limited or incompletedata. We choose an image inpainting problem as a guiding example, and further propose a procedure for automatic detection and reconstruction of the low-rank component fromincompletedata and adaptive parameter selection for the sparse imagereconstruction. We benchmark the efficacy and efficiency of our algorithm in terms of computing time and accuracy on colour, 3D medical, and hyperspectral images by comparing it to its dictionary learning counterparts.
Symmetry provides a source of redundancy which can be exploited in imagereconstruction. In particular, internal symmetries in molecules can help to compensate for the loss of Fourier phase information in macromolecul...
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ISBN:
(纸本)9780819482969
Symmetry provides a source of redundancy which can be exploited in imagereconstruction. In particular, internal symmetries in molecules can help to compensate for the loss of Fourier phase information in macromolecular x-ray crystallography. Symmetry projections are incorporated into iterative projection algorithms for reconstruction of macromolecular electron densities from x-ray diffraction amplitudes from crystals. The effects of interpolation are studied and the algorithms are applied to reconstruction of an icosahedral virus.
Diffraction tomography (DT) is an established imaging technique for use with diffracting wavefields, which represents a generalized form of x-ray tomography. In this work, we revisit the three-dimensional reconstructi...
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ISBN:
(纸本)0819463957
Diffraction tomography (DT) is an established imaging technique for use with diffracting wavefields, which represents a generalized form of x-ray tomography. In this work, we revisit the three-dimensional reconstruction problem of DT for variable density acoustic media. Novel reconstruction algorithms are developed for reconstructing separate images that depict a weakly scattering object's compressibility and density variations. If tomographic measurement data are acquired at four distinct temporal frequencies, we demonstrate that the effects of object dispersion can be accounted for completely by use of analytic reconstruction formulas. Computer-simulation studies are conducted to demonstrate the developed imagereconstruction methods.
In order to improve the quality and solve the problem of low speed of imagereconstruction in the traditional optical computerized tomography (OCT) when the data acquired is incomplete projection, the multiple constra...
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ISBN:
(纸本)9780819470072
In order to improve the quality and solve the problem of low speed of imagereconstruction in the traditional optical computerized tomography (OCT) when the data acquired is incomplete projection, the multiple constrained of genetic algorithm based on algebraic iterative was proposed. Generally speaking, under the condition of multiple-objective optimization, the common extreme point for all the objective functions doesn't exist. So we can achieve the preferable compromise in the contradictions of multiple objectives. In this article, there are three constrained conditions. The first one is the maximum entropy criterion which is used mostly to solve the problem of OCT imagereconstruction when the data acquired is incomplete projection recently. The second one is the minimum criteria of peak value which is introduced to suppress noise effectively and ensure the gliding property of the imagereconstruction, because of the first one leading to noise amplification during the iterative process. The last constrained condition is the minimum criteria of the difference between the projection again of imagereconstruction and the original projection. The concept of penalize-function is introduced into the genetic algorithm, which would transform the constrained optimization problem to unconstrained. It is clearly demonstrated from the experiment results that the algorithm reconstruction technique can efficiently improve the quality of images reconstruction of the incomplete projection data.
A statistical model for the object and the complete image formation process in cryo electron microscopy of viruses is presented. Using this model, maximum likelihood reconstructions of the 3D structure of viruses are ...
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ISBN:
(纸本)0819437689
A statistical model for the object and the complete image formation process in cryo electron microscopy of viruses is presented. Using this model, maximum likelihood reconstructions of the 3D structure of viruses are computed using the expectation maximization algorithm and an example based on Cowpea mosaic virus is provided.
In this paper, we describe a practical implementation of an imagereconstruction method designed to generate a map of the brightness distribution fromdata consisting of squared visibilities and complex closure amplit...
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ISBN:
(纸本)9780819482969
In this paper, we describe a practical implementation of an imagereconstruction method designed to generate a map of the brightness distribution fromdata consisting of squared visibilities and complex closure amplitudes resulting from observations of an astronomical target with a broadband, multichannel, spatial optical interferometer. Given the data, the method estimates the true brightness distribution with a model sampled on a rectangular grid of discrete positions on the sky with the assumption that the model intensities in the region not defined by the discrete positions being described by bilinear interpolation of the discrete intensities. The developed imagereconstruction method has been applied to real observational data obtained from existing optical interferometer facilities.
Measuring a series of far-field intensity patterns from an object, taken after a, transverse translation of the object with respect to a known illumination pattern, has been shown to make the problem of image reconstr...
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ISBN:
(纸本)9780819472960
Measuring a series of far-field intensity patterns from an object, taken after a, transverse translation of the object with respect to a known illumination pattern, has been shown to make the problem of imagereconstruction by phase retrieval much more robust. However, previously reported reconstruction algorithms [Phys. Rev. Lett. 93, 023903 (2004)] rely oil an accurate knowledge of the translations and illumination pattern for a successful reconstruction. We developed a nonlinear optimization algorithm that allows optimization over the translations and illumination pattern, dramatically improving the reconstructions if the system parameters are inaccurately known [Opt. Express 16, 7264 (2008)]. In this paper we compare reconstructions obtained with these algorithms under realistic experimental scenarios.
A statistical estimation problem for determining 3-D reconstructions from a single 2-D projection image of each of multiple objects when the objects are heterogeneous is described. The method is based on a Gaussian mi...
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ISBN:
(纸本)9780819482969
A statistical estimation problem for determining 3-D reconstructions from a single 2-D projection image of each of multiple objects when the objects are heterogeneous is described. The method is based on a Gaussian mixture description of the heterogeneity and is motivated by cryo electron microscopy of biological objects.
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