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Compressed sensing

Azar Tolouee, Javad Alirezaie, Paul Babyn
In this work, a robust nonrigid motion compensation approach, is applied to the compressed sensing reconstruction of dynamic cardiac cine MRI sequences. Respiratory and cardiac motion separation coupled with a registration algorithm is used to provide accurate reconstruction of dynamic cardiac images. The proposed scheme employs a variable splitting based optimization strategy to enable joint motion estimation along with reconstruction. We define the recovery as an energy minimization scheme utilizing an objective function that combines data consistency, spatial smoothness, and motion penalties...
November 14, 2017: Magnetic Resonance Imaging
Catarina Brás-Pereira, Eduardo Moreno
Maintenance of tissue organization is crucial to ensure normal organ function and organism viability. Tissues are loaded with the ability to sense the available space, measuring cell density and adapting their behaviour accordingly. To keep homeostasis, compression pressure generated by local cell density increment triggers cell elimination. During mechanical cell competition, winner cells compress the neighbouring cells, promoting tissue crowding, which leads to cell elimination. Thus, the hypersensitivity to crowding may confer a loser status, whereas resistance to mechanical-induced elimination may favour a winner status...
November 15, 2017: Current Opinion in Cell Biology
Hiroyuki Shinohara, Takeyuki Hashimoto, Nobuyuki Takeyama, Eriko Tanaka, Takaki Hayashi, Touji Hashimoto
We performed numerical and visual evaluation of compressed sensing MRI (CS-MRI) using 3D Cartesian sampling by numerical simulation. Three brain anatomical ROIs (white matter, gray matter, cerebrospinal fluid) of a T1-weighted image (T1WI), a T2-weighted image (T2WI) and a proton density-weighted image (PDWI) were used for numerical evaluation. Sampling ratio of the Cartesian grid was 30%. Reconstruction was performed by the projection onto convex sets (POCS) method with soft thresholding, subject to data fidelity constraints...
2017: Japanese Journal of Medical Physics
Bin Liang, Yongbao Li, Wei Ran, Bin Guo, Xuang Xu, Bo Liu, Jiafeng Li, Qiuwen Wu, Fugen Zhou
With robot-controlled linac positioning, the robotic radiotherapy system such as CyberKnife significantly increases the freedom in radiation beam placement, but also imposes more challenges on treatment plan optimization. The resampling mechanism in vendor supplied treatment planning system (MultiPlan) could not fully explore the increased beam direction search space. Besides, a sparse treatment plan (using fewer beams) is desired to improve the treatment efficiency. This study proposes a singular value decomposition linear programming (SVDLP) optimization technique for circular collimator based robotic radiotherapy...
November 17, 2017: Physics in Medicine and Biology
Toby Sanders, Ilke Arslan
Electron tomography has become an essential tool for three-dimensional (3D) characterization of nanomaterials. In recent years, advances have been made in specimen preparation and mounting, acquisition geometries, and reconstruction algorithms. All of these components work together to optimize the resolution and clarity of an electron tomogram. However, one important component of the data-processing has received less attention: the 2D tilt series alignment. This is challenging for a number of reasons, namely because the nature of the data sets and the need to be coherently aligned over the full range of angles...
November 16, 2017: Microscopy and Microanalysis
Ipshita Bhattacharya, Jonathan J Humston, Christopher M Cheatum, Mathews Jacob
We introduce a computationally efficient structured low-rank algorithm for the reconstruction of two-dimensional infrared (2D IR) spectroscopic data from few measurements. The signal is modeled as a combination of exponential lineshapes that are annihilated by appropriately chosen filters. The annihilation relations result in a low-rank constraint on a Toeplitz matrix constructed from signal samples, which is exploited to recover the unknown signal samples. Quantitative and qualitative studies on simulated and experimental data demonstrate that the algorithm outperforms the discrete compressed sensing algorithm, both in uniform and non-uniform sampling settings...
November 15, 2017: Optics Letters
Jing Ma, Bing Yan
This paper tries to prepare soft ionogels through the carboxyl ion liquid (IM(+)Br(-)) as double chemical linker connecting both Bio-MOF-1 (Zn8(ad)4(BPDC)6O·2Me2NH2, BPDC=biphenyl-4,4'-dicarboxylate, Ad = adeninate) and lanthanide complexes. Among anionic Bio-MOF-1 interacts with IM(+)Br(-) through cation exchange (IM(+)) to form BMOF-IM and lanthanide ions are further introduced through the coordination to the carboxylic group of IM(+) together with Phen (1,10-phenanthroline) as assistant ligand for Ln(3+) (Ln = Eu, Tb or Eu/Tb)...
November 7, 2017: Journal of Colloid and Interface Science
Claudio de'Sperati, Gabriel Baud Bovy
When watching videos, our sense of reality is continuously challenged. How much can a fundamental dimension of experience such as visual flow be modified before breaking the perception of real time? Here we found a remarkable indifference to speed manipulations applied to a popular video content, a soccer match. In a condition that mimicked real-life TV watching, none of 100 naïve observers spontaneously noticed speed alterations up/down to 12%, even when asked to report motion anomalies, and showed very low sensitivity to video speed changes (Just Noticeable Difference, JND = 18%)...
November 13, 2017: Scientific Reports
Guoqiang Han, Bo Lin, Yuling Lin
Atomic Force Microscopy (AFM) is one of the most popular and advanced tools for ultra high-resolution imaging and nanomanipulation of nano-scale matter. But AFM imaging typically takes a long time. High-speed and high-precision AFM measurement has attracted wide attention in recent several years. In traditional AFM, simple reduction in the number of measurement points may lose essential sample topography information. To resolve such problems, an AFM image reconstruction method based on Compressed Sensing (CS) theory is applied to reduce image acquisition time without cutting down the image quality...
November 10, 2017: Micron: the International Research and Review Journal for Microscopy
Teresa Correia, Gastão Cruz, Torben Schneider, René M Botnar, Claudia Prieto
PURPOSE: To develop an accelerated and nonrigid motion compensated technique for efficient isotropic 3D whole-heart coronary magnetic resonance angiography (CMRA) with Cartesian acquisition. METHODS: Highly efficient whole-heart 3D CMRA was achieved by combining image reconstruction from undersampled data using compressed sensing (CS) with a nonrigid motion compensation framework. Undersampled acquisition was performed using a variable-density Cartesian trajectory with radial order (VD-CAPR)...
November 13, 2017: Medical Physics
Karel Žídek, Ondřej Denk, Jiří Hlubuček
We propose and demonstrate a spectrally-resolved photoluminescence imaging setup based on the so-called single pixel camera - a technique of compressive sensing, which enables imaging by using a single-pixel photodetector. The method relies on encoding an image by a series of random patterns. In our approach, the image encoding was maintained via laser speckle patterns generated by an excitation laser beam scattered on a diffusor. By using a spectrometer as the single-pixel detector we attained a realization of a spectrally-resolved photoluminescence camera with unmatched simplicity...
November 10, 2017: Scientific Reports
Po-Chieh Chiang, Kevin Tanady, Ling-Ting Huang, Ling Chao
Being able to directly obtain micron-sized cell blebs, giant plasma membrane vesicles (GPMVs), with native membrane proteins and deposit them on a planar support to form supported plasma membranes could allow the membrane proteins to be studied by various surface analytical tools in native-like bilayer environments. However, GPMVs do not easily rupture on conventional supports because of their high protein and cholesterol contents. Here, we demonstrate the possibility of using compression generated by the air-water interface to efficiently rupture GPMVs to form micron-sized supported membranes with native plasma membrane proteins...
November 9, 2017: Scientific Reports
Lixiang Li, Dafei Xu, Haipeng Peng, Jürgen Kurths, Yixian Yang
It is generally known that the states of network nodes are stable and have strong correlations in a linear network system. We find that without the control input, the method of compressed sensing can not succeed in reconstructing complex networks in which the states of nodes are generated through the linear network system. However, noise can drive the dynamics between nodes to break the stability of the system state. Therefore, a new method integrating QR decomposition and compressed sensing is proposed to solve the reconstruction problem of complex networks under the assistance of the input noise...
November 8, 2017: Scientific Reports
Haifeng Zheng, Jiayin Li, Xinxin Feng, Wenzhong Guo, Zhonghui Chen, Neal Xiong
Compressive sensing (CS) provides an energy-efficient paradigm for data gathering in wireless sensor networks (WSNs). However, the existing work on spatial-temporal data gathering using compressive sensing only considers either multi-hop relaying based or multiple random walks based approaches. In this paper, we exploit the mobility pattern for spatial-temporal data collection and propose a novel mobile data gathering scheme by employing the Metropolis-Hastings algorithm with delayed acceptance, an improved random walk algorithm for a mobile collector to collect data from a sensing field...
November 8, 2017: Sensors
Kerstin Hammernik, Teresa Klatzer, Erich Kobler, Michael P Recht, Daniel K Sodickson, Thomas Pock, Florian Knoll
PURPOSE: To allow fast and high-quality reconstruction of clinical accelerated multi-coil MR data by learning a variational network that combines the mathematical structure of variational models with deep learning. THEORY AND METHODS: Generalized compressed sensing reconstruction formulated as a variational model is embedded in an unrolled gradient descent scheme. All parameters of this formulation, including the prior model defined by filter kernels and activation functions as well as the data term weights, are learned during an offline training procedure...
November 8, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Philip R Szeszko, Ek Tsoon Tan, Aziz M Uluğ, Peter B Kingsley, Juan A Gallego, Kathryn Rhindress, Anil K Malhotra, Delbert G Robinson, Luca Marinelli
BACKGROUND: Standard diffusion tensor imaging measures (e.g., fractional anisotropy; FA) are difficult to interpret in brain regions with crossing white-matter (WM) fibers. Diffusion spectrum imaging (DSI) can be used to resolve fiber crossing, but has been difficult to implement in studies of patients with psychosis given long scan times. METHODS: We used four fold accelerated compressed sensing to accelerate DSI acquisition to investigate the superior longitudinal fasciculus (SLF) in 27 (20M/7F) patients with recent onset psychosis and 23 (11M/12F) healthy volunteers...
October 28, 2017: Progress in Neuro-psychopharmacology & Biological Psychiatry
Ilhwan You, Doo-Yeol Yoo, Sooho Kim, Min-Jae Kim, Goangseup Zi
This study examined the electrical and self-sensing capacities of ultra-high-performance fiber-reinforced concrete (UHPFRC) with and without carbon nanotubes (CNTs). For this, the effects of steel fiber content, orientation, and pore water content on the electrical and piezoresistive properties of UHPFRC without CNTs were first evaluated. Then, the effect of CNT content on the self-sensing capacities of UHPFRC under compression and flexure was investigated. Test results indicated that higher steel fiber content, better fiber orientation, and higher amount of pore water led to higher electrical conductivity of UHPFRC...
October 29, 2017: Sensors
Min Sun, Jing Liu
As a first-order method, the augmented Lagrangian method (ALM) is a benchmark solver for linearly constrained convex programming, and in practice some semi-definite proximal terms are often added to its primal variable's subproblem to make it more implementable. In this paper, we propose an accelerated PALM with indefinite proximal regularization (PALM-IPR) for convex programming with linear constraints, which generalizes the proximal terms from semi-definite to indefinite. Under mild assumptions, we establish the worst-case [Formula: see text] convergence rate of PALM-IPR in a non-ergodic sense...
2017: Journal of Inequalities and Applications
Seung Hyun Lee, Young Han Lee, Jin-Suck Suh
PURPOSE: To compare image quality between compressed sensing (CS)-3D-fast spin-echo (FSE) and conventional 3D-FSE sequences for knee magnetic resonance imaging (MRI). METHODS: Knee MRI of 43 patients (male:female, 14:29; mean age, 53years) were acquired using conventional and CS-3D-FSE with an acceleration factor of 1.5. Overall image quality was assessed by correlation coefficient, root-mean-square error (RMSE), and structural similarity (SSIM) index. Regional image quality was evaluated using signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs)...
November 2, 2017: Magnetic Resonance Imaging
Mahan Rahimi, Andrew P Blaber, Carlo Menon
Notwithstanding the extensive use of conventional compression devices in managing venous disorders, these modalities have shortages that diminish their treatment efficacy and lessen patient adherence to therapy. The purpose of this study was to develop an improved compression system that eliminates the flaws of the existing devices. A motorized bandage was designed that takes advantage of continuous feedback from force-sensing resistors to apply reproducible, controlled pressure on the lower extremities. The performance of the device in enhancing venous return was explored in a pilot test on 11 healthy participants, wherein graded lower body negative pressure was employed as a surrogate of passive standing...
December 2017: Medical Engineering & Physics
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