We propose a mutual information based prior for incorporating information from co-registered anatomical images into PET image reconstruction. The prior uses mutual information between feature vectors that are extracte...
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ISBN:
(纸本)9781424406715;1424406714
We propose a mutual information based prior for incorporating information from co-registered anatomical images into PET image reconstruction. The prior uses mutual information between feature vectors that are extracted from the anatomical and functional images using a scale space approach. We perform simulations on a realistic 3D phantom generated by replicating a 2-D autoradiographic cross section of a mouse labelled with F18-FDG. A digital photograph of the cryosection of the same slice is used to generate the anatomical image. The images are registered using mutual information based rigid registration. PET data are then simulated from the autoradiography based phantom. We use a preconditioned conjugate gradient algorithm to compute the PET image that maximizes the posterior density. The performance of this method is compared with that using a Gaussian quadratic penalty, which does not use anatomical information. Simulation results indicate that the mutual information based prior can achieve reduced standard deviation at comparable bias compared to the quadratic penalty
We investigate fast iterative image reconstruction methods for fully 3D multispectral optical bioluminescence tomography where inhomogeneous optical properties are modeled using the finite element method (FEM). We com...
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ISBN:
(纸本)9781424406715;1424406714
We investigate fast iterative image reconstruction methods for fully 3D multispectral optical bioluminescence tomography where inhomogeneous optical properties are modeled using the finite element method (FEM). We compare two approaches to incorporating the forward model into the solution of the inverse problem. In the direct calculation approach we compute the full forward model by repeated solution of the PEM problem, once for each potential source location. In the on-the-fly approach, we do not explicitly solve for the full forward model. Instead, the solution to the forward problem is included implicitly in the formulation of the inverse problem, and the FEM is solved once at each iteration for the current image estimate. In both approaches we use reordered Cholesky factorization and substitution (CFS) to solve the FEM problem. We compare the computation cost of these two approaches, concluding that the on-the-fly approach can lead to substantial reductions in cost when combined with a rapidly converging iterative algorithm
One of commonly used criteria for finding an endmember set is to assume that for a given number of endmembers, p, a p-vertex simplex with its vertices specified by p endmembers always yields the maximum volume. Since ...
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One of commonly used criteria for finding an endmember set is to assume that for a given number of endmembers, p, a p-vertex simplex with its vertices specified by p endmembers always yields the maximum volume. Since there are also other criteria which have been widely used for endmember extraction, the issue of interest is "does an endmember set really produce a simplex with maximum volume?" In other words, using the criterion of a simplex with maximum volume is a better and more effective measure than other criteria currently being used by endmember extraction such as orthogonal projection-based pixel purity index (PPI), fully constrained least squares-based spectral unmixing, etc. This paper explores this issue by investigating a number of popular endmember extraction algorithms which are designed by different criteria. An extensive experiment-based study is also conducted for comparative analysis.
Support vector machines are applied to extract marker genes from various microarray data sets: Breast Cancer, Leukemia and Monocyte -^sMacrophage Differentiation to ease classification of related pathologies or charac...
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Support vector machines are applied to extract marker genes from various microarray data sets: Breast Cancer, Leukemia and Monocyte -^sMacrophage Differentiation to ease classification of related pathologies or characterize related gene regulation pathways.
The proliferation of strategic subsurface sanctuaries has increased the need for enhanced remote sensing techniques providing for the accurate detection and identification of deeply buried objects. A new RF Tomographi...
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The proliferation of strategic subsurface sanctuaries has increased the need for enhanced remote sensing techniques providing for the accurate detection and identification of deeply buried objects. A new RF Tomographic Technique is proposed in this concept paper for developing RF CAT Scans of buried objects using spectral, spatial/angular, and polarization diversity. This imaging technique uses an embedded ring of subsurface radiators, delivered by earth-penetrating, non-explosive, electronic "e-bombs", as the source of strong underground radiated transmissions and uses distributed surface-contact sensors to collect the tomographic data for relay to a circling UAV and transmission to a remote control site (using layered sensing). Three-dimensional imaging algorithms are being developed to detect, image, and characterize deeply buried targets. Distributed transmitters and receivers significantly increase unwanted mutual coupling and EM emissions that interfere with signal reception. However, by embedding the transmitters underground, reduced mutual coupling and EM emissions (and improved signal-to-noise ratios) can be achieved. Simple surface SAR experiments over deep mine shafts have been performed to validate the 3D processing algorithms using 2D surface SAR sensor data. WIPL-D models have also been used to simulate the embedded and distributed sensors and to verify the significant enhancement in the received signal-to-noise ratio obtained by burying the radiating ring under the surface sensors.
The new DVB-H standard allows broadcasting of audio/video content to mobile terminals. Such devices underlie severe restrictions concerning processing load and power consumption. The most computational intensive and t...
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The new DVB-H standard allows broadcasting of audio/video content to mobile terminals. Such devices underlie severe restrictions concerning processing load and power consumption. The most computational intensive and therewith most power consuming part of such terminals is the decoding of the H.264/A VC video datastream. We present optimization strategies for software-based H.264/AVC video decoding as well as the architecture of an H.264/AVC decoding companion chip with specialized coprocessors, which targets the above mentioned restrictions.
A novel, computationally efficient and robust scheme for multiple initial point prediction has been proposed in this paper. A combination of spatial and temporal predictors has been used for initial motion vector pred...
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A novel, computationally efficient and robust scheme for multiple initial point prediction has been proposed in this paper. A combination of spatial and temporal predictors has been used for initial motion vector prediction, determination of magnitude and direction of motion and search pattern selection. Initially three predictors from the spatio-temporal neighbouring blocks are selected. If all these predictors point to the same quadrant then a simple search pattern based on the direction and magnitude of the final predicted motion vector is selected. However if the predictors belong to different quadrants then we start the search from multiple initial points to get a clear idea of the location of minimum point. In this case a small rood search pattern has been selected. The predictive search center is closer to the global minimum and thus decreases the effect of monotonic error surface assumption and its impact on the motion field. Its additional advantage is that it moves the search closer to the global minimum hence increases the computation speed. Further computational speed up has been obtained by considering the zero motion threshold for no motion blocks, and, specialized rood search pattern. The image quality measured in terms of PSNR also shows good results.
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