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Noise reduction

Aoxue Li, Zhiwu Lu, Liwei Wang, Peng Han, Ji-Rong Wen
In this paper, we present a large-scale sparse learning (LSSL) approach to solve the challenging task of semantic segmentation of images with noisy tags. Different from the traditional strongly supervised methods that exploit pixel-level labels for semantic segmentation, we make use of much weaker supervision (i.e., noisy tags of images) and then formulate the task of semantic segmentation as a weakly supervised learning (WSL) problem from the view point of noise reduction of superpixel labels. By learning the data manifolds, we transform the WSL problem into an LSSL problem...
December 2, 2016: IEEE Transactions on Cybernetics
Qiao-Ru Hou, Wei Gao, Yu Min Zhong, Ai Min Sun, Qian Wang, Hai Sheng Qiu, Fang Wang, Jian Ying Li, Liwei Hu
OBJECTIVE: To assess image quality, contrast dose and radiation dose in cardiac CT in children with congenital heart disease using low-concentration iodinated contrast agent and low tube voltage and current in comparison with standard-dose protocol. METHODS: 110 patients with congenital heart disease were randomized to one of the two scan protocols: Group A (n=45) with 120mA tube current and contrast agent of 270mgI/ml in concentration (Visipaque, GE Healthcare), and Group B (n=65) with the conventional 160mA and 370mgI/mL concentration contrast (Iopamiro, Bracco)...
December 7, 2016: British Journal of Radiology
Tali Manber Ball, Sarah E Knapp, Martin P Paulus, Murray B Stein
BACKGROUND: Exposure therapy, a gold-standard treatment for anxiety disorders, is assumed to work via extinction learning, but this has never been tested. Anxious individuals demonstrate extinction learning deficits, likely related to less ventromedial prefrontal cortex (vmPFC) and more amygdala activation, but the relationship between these deficits and exposure outcome is unknown. We tested whether anxious individuals who demonstrate better extinction learning report greater anxiety reduction following brief exposure...
December 6, 2016: Depression and Anxiety
Xikun Hu, Tian Jin
The radar sensor described realizes healthcare monitoring capable of detecting subject chest-wall movement caused by cardiopulmonary activities and wirelessly estimating the respiration and heartbeat rates of the subject without attaching any devices to the body. Conventional single-tone Doppler radar can only capture Doppler signatures because of a lack of bandwidth information with noncontact sensors. In contrast, we take full advantage of impulse radio ultra-wideband (IR-UWB) radar to achieve low power consumption and convenient portability, with a flexible detection range and desirable accuracy...
November 30, 2016: Sensors
Nicola Mammarella, Alberto Di Domenico, Rocco Palumbo, Beth Fairfield
Activation of medial Prefrontal Cortex (mPFC) has been typically found during reality monitoring tasks (i.e., distinguishing between internal self-generated vs external information). No study, however, has yet investigated whether transcranial Random Noise Stimulation (tRNS) over the mPFC leads to a reduction in reality-monitoring misattributions in aging. In particular, stimulating mPFC should increase the number of cognitive operations engaged while encoding and this distinctive information may help older adults to discriminate between internal and external sources better...
November 15, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
Juliane Reinhardt, Robert Hoppe, Georg Hofmann, Christian D Damsgaard, Jens Patommel, Christoph Baumbach, Sina Baier, Amélie Rochet, Jan-Dierk Grunwaldt, Gerald Falkenberg, Christian G Schroer
In recent years, X-ray ptychography has been established as a valuable tool for high-resolution imaging. Nevertheless, the spatial resolution and sensitivity in coherent diffraction imaging are limited by the signal that is detected over noise and over background scattering. Especially, coherent imaging of weakly scattering specimens suffers from incoherent background that is generated by the interaction of the central beam with matter along its propagation path in particular close to and inside of the detector...
November 14, 2016: Ultramicroscopy
Polyane M Queiroz, Gustavo M Santaella, Thais D J da Paz, Deborah Q Freitas
OBJECTIVE: To evaluate the action of a metal artefact reduction tool when artefact-generator metal object is on different positions in the field of view (FOV). METHODS: A cylindrical utility wax phantom with a metal alloy sample inside was made. The phantom was positioned centrally and peripherally in the FOV for image acquisition, with and without the metal artefact reduction tool activation. Standard deviation values (image noise levels) from areas around the metal sample and the control area were obtained...
December 2, 2016: Dento Maxillo Facial Radiology
K O Plaud-Ramos, M S Freeman, W Wei, E Guardincerri, J D Bacon, J Cowan, J M Durham, D Huang, J Gao, M A Hoffbauer, D J Morley, C L Morris, D C Poulson, Zhehui Wang
Consumer imaging sensors (CIS) are examined for real-time charged-particle detection and CR-39 plastic detector replacement. Removing cover glass from CIS is hard if not impossible, in particular for the latest inexpensive webcam models. We show that $10-class CIS are sensitive to MeV and higher energy protons and α-particles by using a (90)Sr β-source with its cover glass in place. Indirect, real-time, high-resolution detection is also feasible when combining CIS with a ZnS:Ag phosphor screen and optics...
November 2016: Review of Scientific Instruments
S R Nagel, L R Benedetti, D K Bradley, T J Hilsabeck, N Izumi, S Khan, G A Kyrala, T Ma, A Pak
The dilation x-ray imager (DIXI) [T. J. Hilsabeck et al., Rev. Sci. Instrum. 81, 10E317 (2010); S. R. Nagel et al., ibid. 83, 10E116 (2012); S. R. Nagel et al., ibid. 85, 11E504 (2014)] is a high-speed x-ray framing camera that uses the pulse-dilation technique to achieve a temporal resolution of less than 10 ps. This is a 10 × improvement over conventional framing cameras currently employed on the National Ignition Facility (NIF) (100 ps resolution), and otherwise only achievable with 1D streaked imaging...
November 2016: Review of Scientific Instruments
S Kobayashi, S Ohshima, H Matsuda, X X Lu, D Kokubu, K Ida, T Kobayashi, M Yoshinuma, S Kado, T Oishi, K Nagasaki, H Okada, T Minami, S Yamamoto, Y Nakamura, A Ishizawa, N Kenmochi, Y Otani, S Konoshima, T Mizuuchi
This paper describes the development study of the beam emission spectroscopy (BES) for the turbulent transport study in Heliotron J. Modification of the sightlines (10 × 4 for edge and 10 × 2 for edge) enables us to obtain 2-dimensional BES imaging. The cooling effect on the reduction in the electrical noise of avalanche photodiode (APD) assembly has been investigated using a refrigerant cooling system. When the temperature of the APD element has set to be -20 °C, the electrical noise can be reduced more than 50%...
November 2016: Review of Scientific Instruments
M F Brandl, M W van Mourik, L Postler, A Nolf, K Lakhmanskiy, R R Paiva, S Möller, N Daniilidis, H Häffner, V Kaushal, T Ruster, C Warschburger, H Kaufmann, U G Poschinger, F Schmidt-Kaler, P Schindler, T Monz, R Blatt
We report on the design of a cryogenic setup for trapped ion quantum computing containing a segmented surface electrode trap. The heat shield of our cryostat is designed to attenuate alternating magnetic field noise, resulting in 120 dB reduction of 50 Hz noise along the magnetic field axis. We combine this efficient magnetic shielding with high optical access required for single ion addressing as well as for efficient state detection by placing two lenses each with numerical aperture 0.23 inside the inner heat shield...
November 2016: Review of Scientific Instruments
Fahimeh Mamashli, Sheraz Khan, Hari Bharadwaj, Konstantinos Michmizos, Santosh Ganesan, Keri-Lee A Garel, Javeria Ali Hashmi, Martha R Herbert, Matti Hämäläinen, Tal Kenet
Autism spectrum disorder (ASD) is associated with difficulty in processing speech in a noisy background, but the neural mechanisms that underlie this deficit have not been mapped. To address this question, we used magnetoencephalography to compare the cortical responses between ASD and typically developing (TD) individuals to a passive mismatch paradigm. We repeated the paradigm twice, once in a quiet background, and once in the presence of background noise. We focused on both the evoked mismatch field (MMF) response in temporal and frontal cortical locations, and functional connectivity with spectral specificity between those locations...
December 2, 2016: Autism Research: Official Journal of the International Society for Autism Research
Christopher M Rank, Thorsten Heußer, Andreas Wetscherek, Martin T Freitag, Oliver Sedlaczek, Heinz-Peter Schlemmer, Marc Kachelrieß
PURPOSE: Positron emission tomography (PET) of the thorax region is impaired by respiratory patient motion. To account for motion, the authors propose a new method for PET/magnetic resonance (MR) respiratory motion compensation (MoCo), which uses highly undersampled MR data with acquisition times as short as 1 min/bed. METHODS: The proposed PET/MR MoCo method (4D jMoCo PET) uses radial MR data to estimate the respiratory patient motion employing MR joint motion estimation and image reconstruction with temporal median filtering...
December 2016: Medical Physics
Justin Solomon, Alexandre Ba, François Bochud, Ehsan Samei
PURPOSE: To use novel voxel-based 3D printed textured phantoms in order to compare low-contrast detectability between two reconstruction algorithms, FBP (filtered-backprojection) and SAFIRE (sinogram affirmed iterative reconstruction) and determine what impact background texture (i.e., anatomical noise) has on estimating the dose reduction potential of SAFIRE. METHODS: Liver volumes were segmented from 23 abdominal CT cases. The volumes were characterized in terms of texture features from gray-level co-occurrence and run-length matrices...
December 2016: Medical Physics
Zhaoyang Tai, Lulu Yan, Yanyan Zhang, Xiaofei Zhang, Wenge Guo, Shougang Zhang, Haifeng Jiang
The reduction of the residual amplitude modulation (RAM) induced by electro-optic modulation is essential for many applications of frequency modulation spectroscopy requiring a lower system noise floor. Here, we demonstrate a simple passive approach employing an electro-optic modulator (EOM) cut at Brewster's angle. The proposed EOM exhibits a RAM of a few parts per million, which is comparable with that achieved by a common EOM under critical active temperature and bias voltage controls. The frequency instability of a 10 cm cavity-stabilized laser induced by the RAM effect of the proposed EOM is below 3×10<sup>-17</sup> for integration times from 1 to 1000 s, and below 4×10<sup>-16</sup> for comprehensive noise contributions for integration times from 1 to 100 s...
December 1, 2016: Optics Letters
Joseph M Lukens, Nicholas A Peters, Raphael C Pooser
Interferometers measure a wide variety of dynamic processes by converting a phase change into an intensity change. Nonlinear interferometers, making use of nonlinear media in lieu of beamsplitters, promise substantial improvement in the quest to reach the ultimate sensitivity limits. Here we demonstrate a new nonlinear interferometer utilizing a single parametric amplifier for mode mixing-conceptually, a nonlinear version of the conventional Michelson interferometer with its arms collapsed together. We observe up to 99...
December 1, 2016: Optics Letters
Ahmed Almaiman, Yinwen Cao, Morteza Ziyadi, Amirhossein Mohajerin-Ariaei, Peicheng Liao, Changjing Bao, Fatemeh Alishahi, Ahmad Fallahpour, Bishara Shamee, Nisar Ahmed, Asher J Willner, Youichi Akasaka, Tadashi Ikeuchi, Shigehiro Takasaka, Ryuichi Sugizaki, Steven Wilkinson, Joseph D Touch, Moshe Tur, Alan E Willner
All-optical phase regeneration of a binary phase-shift keying signal is demonstrated at 10-30 Gb/s without a phase-locked loop in a phase-sensitive amplification-based system using Brillouin amplification of the idler. The system achieves phase noise reduction of up to 56% and up to 11 dB OSNR gain at 10<sup>-5</sup> bit error rate for the 10 Gb/s signal. The system's sensitivity to different parameters and stability is also evaluated.
December 1, 2016: Optics Letters
Thomas W Blythe, Andrew J Sederman, E Hugh Stitt, Andrew P E York, Lynn F Gladden
Many industrial flow processes are sensitive to changes in the rheological behaviour of process fluids, and there therefore exists a need for methods that provide online, or inline, rheological characterisation necessary for process control and optimisation over timescales of minutes or less. Nuclear magnetic resonance (NMR) offers a non-invasive technique for this application, without limitation on optical opacity. We present a Bayesian analysis approach using pulsed field gradient (PFG) NMR to enable estimation of the rheological parameters of Herschel-Bulkley fluids in a pipe flow geometry, characterised by a flow behaviour index n, yield stress τ0, and consistency factor k, by analysis of the signal in q-space...
November 10, 2016: Journal of Magnetic Resonance
Jennifer B Parrish, Jennifer A Teske
OBJECTIVE: Chronic partial sleep deprivation (SD) by environmental noise exposure increases weight gain and feeding in rodents, which contrasts weight loss after acute SD by physical methods. This study tested whether acute environmental noise exposure reduced sleep and its effect on weight gain, food intake, physical activity, and energy expenditure (EE). It was hypothesized that acute exposure would (1) increase weight gain and feeding and (2) reduce sleep, physical activity, and EE (total and individual components); and (3) behavioral changes would persist throughout recovery from SD...
November 29, 2016: Obesity
Sebastian Fischer, David M Grodzki, Markus Domschke, Moritz Albrecht, Boris Bodelle, Katrin Eichler, Renate Hammerstingl, Thomas J Vogl, Stephan Zangos
OBJECTIVE: Purpose of our study was to demonstrate the feasibility and limitations of acoustic noise reduction in a standard clinical MRI protocol for abdominal imaging. METHODS: Acoustic noise and image quality were assessed in 17 patients for a standard liver imaging protocol including TSE and GRE sequences and compared to quiet optimizations as described by Heismann et al. Two blinded readers scored artifacts, the delineation of the abdominal organs and level of diagnostic confidence...
November 28, 2016: La Radiologia Medica
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