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Image Reconstruction

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https://www.readbyqxmd.com/read/28339656/development-of-a-real-time-wave-field-reconstruction-tem-system-i-incorporation-of-an-auto-focus-tracking-system
#1
Takahiro Tamura, Yoshihide Kimura, Yoshizo Takai
We have developed a real-time wave field reconstruction transmission electron microscope system that enables auto focus tracking at a video rate. In the developed system, a high-speed image calculation technique using a graphical processing unit was incorporated along with two techniques facilitating high-speed focus control using high-voltage modulation and weighted image integration using exposure time control. By utilizing these techniques, the sample drift induced in the Z-axis direction can be measured and automatically corrected for every 1/30 of a second...
February 18, 2017: Microscopy
https://www.readbyqxmd.com/read/28339612/orthodontically-induced-cervical-root-resorption-in-humans-is-associated-with-the-amount-of-tooth-movement
#2
Alexander Dudic, Catherine Giannopoulou, Paolo Meda, Xavier Montet, Stavros Kiliaridis
Introduction: The aim of this study was to investigate the variation in the amount of the orthodontically induced cervical root resorption and the association with several factors, such as the amount of tooth displacement, location of tooth in the maxilla or mandible, and presence of an interference that may influence the amount of root resorption. Subjects and methods: This study included 30 subjects (20 females, 10 males) with an age range of 11.3 to 43.0 years...
January 25, 2017: European Journal of Orthodontics
https://www.readbyqxmd.com/read/28339423/spherically-symmetric-volume-elements-as-basis-functions-for-image-reconstructions-in-computed-laminography
#3
Patrick Trampert, Jonas Vogelgesang, Christian Schorr, Michael Maisl, Sviatoslav Bogachev, Nico Marniok, Alfred Louis, Tim Dahmen, Philipp Slusallek
BACKGROUND: Laminography is a tomographic technique that allows three-dimensional imaging of flat and elongated objects that stretch beyond the extent of a reconstruction volume. Laminography images can be reconstructed using iterative algorithms based on the Kaczmarz method. OBJECTIVE: This study aims to develop and demonstrate a new reconstruction algorithm that may provide superior image reconstruction quality for this challenged imaging application. METHODS: The images are initially represented using the coefficients over basis functions, which are typically piecewise constant functions (voxels)...
March 21, 2017: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/28335497/ginsenoside-ppd-s-antitumor-effect-via-down-regulation-of-mtor-revealed-by-super-resolution-imaging
#4
Bo Teng, Junguang Jiang, Lijing Zhao, Jing Gao, Junyu Chen, Zhe Liu, Hongda Wang, Binfeng Lu
Derived from Panax ginseng, the natural product 20(S)-Protopanaxadiol (PPD) has been reported for its cytotoxicity against several cancer cell lines. The molecular mechanism is, however, not well understood. Here we show that PPD significantly inhibits proliferation, induces apoptosis and causes G2/M cell cycle arrest in human laryngeal carcinoma cells (Hep-2 cells). PPD also decreases the levels of proteins related to cell proliferation. Moreover, PPD-induced apoptosis is characterized by a dose-dependent down-regulation of Bcl-2 expression and up-regulation of Bax, and is accompanied by the activation of Caspase-3 as well...
March 19, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28335487/electromagnetic-vortex-based-radar-imaging-using-a-single-receiving-antenna-theory-and-experimental-results
#5
Tiezhu Yuan, Hongqiang Wang, Yongqiang Cheng, Yuliang Qin
Radar imaging based on electromagnetic vortex can achieve azimuth resolution without relative motion. The present paper investigates this imaging technique with the use of a single receiving antenna through theoretical analysis and experimental results. Compared with the use of multiple receiving antennas, the echoes from a single receiver cannot be used directly for image reconstruction using Fourier method. The reason is revealed by using the point spread function. An additional phase is compensated for each mode before imaging process based on the array parameters and the elevation of the targets...
March 19, 2017: Sensors
https://www.readbyqxmd.com/read/28335482/improved-wallis-dodging-algorithm-for-large-scale-super-resolution-reconstruction-remote-sensing-images
#6
Chong Fan, Xushuai Chen, Lei Zhong, Min Zhou, Yun Shi, Yulin Duan
A sub-block algorithm is usually applied in the super-resolution (SR) reconstruction of images because of limitations in computer memory. However, the sub-block SR images can hardly achieve a seamless image mosaicking because of the uneven distribution of brightness and contrast among these sub-blocks. An effectively improved weighted Wallis dodging algorithm is proposed, aiming at the characteristic that SR reconstructed images are gray images with the same size and overlapping region. This algorithm can achieve consistency of image brightness and contrast...
March 18, 2017: Sensors
https://www.readbyqxmd.com/read/28334208/morphologically-constrained-spectral-unmixing-by-dictionary-learning-for-multiplex-fluorescence-microscopy
#7
Murad Megjhani, Pedro Correa de Sampaio, Julienne Leigh Carstens, Raghu Kalluri, Badrinath Roysam
Motivation: Current spectral unmixing methods for multiplex fluorescence microscopy have a limited ability to cope with high spectral overlap as they only analyze spectral information over individual pixels. Here, we present adaptive Morphologically Constrained Spectral Unmixing (MCSU) algorithms that overcome this limitation by exploiting morphological differences between sub-cellular structures, and their local spatial context. Results: The proposed method was effective at improving spectral unmixing performance by exploiting: (i) a set of dictionary-based models for object morphologies learned from the image data; and (ii) models of spatial context learned from the image data using a total variation algorithm...
March 2, 2017: Bioinformatics
https://www.readbyqxmd.com/read/28334006/assessing-various-infrared-ir-microscopic-imaging-techniques-for-post-mortem-interval-evaluation-of-human-skeletal-remains
#8
Claudia Woess, Seraphin Hubert Unterberger, Clemens Roider, Monika Ritsch-Marte, Nadin Pemberger, Jan Cemper-Kiesslich, Petra Hatzer-Grubwieser, Walther Parson, Johannes Dominikus Pallua
Due to the influence of many environmental processes, a precise determination of the post-mortem interval (PMI) of skeletal remains is known to be very complicated. Although methods for the investigation of the PMI exist, there still remains much room for improvement. In this study the applicability of infrared (IR) microscopic imaging techniques such as reflection-, ATR- and Raman- microscopic imaging for the estimation of the PMI of human skeletal remains was tested. PMI specific features were identified and visualized by overlaying IR imaging data with morphological tissue structures obtained using light microscopy to differentiate between forensic and archaeological bone samples...
2017: PloS One
https://www.readbyqxmd.com/read/28333776/transcanal-endoscopic-ear-surgery-for-middle-ear-cholesteatoma
#9
Eran Glikson, Ruth Yousovich, Jobran Mansour, Michael Wolf, Lela Migirov, Yisgav Shapira
OBJECTIVE: To evaluate the clinical parameters, outcomes, and complications of transcanal endoscopic ear surgeries for middle ear cholesteatoma. STUDY DESIGN: Retrospective study. SETTING: Tertiary university-affiliated medical center. PATIENTS: Adult patients (age >18) who underwent transcanal endoscopic ear surgeries for cholesteatoma, between March 2009 and March 2015. INTERVENTION: Transcanal endoscopic surgery was indicated when the cholesteatoma did not extend posterior to the anterior limb of the lateral semicircular canal...
March 22, 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28333629/curl-constrained-gradient-estimation-for-image-recovery-from-highly-incomplete-spectral-data
#10
Chiara Ravazzi, Giulio Coluccia, Enrico Magli
In this paper, we introduce new gradient-based methods for image recovery from a small collection of spectral coefficients of the Fourier transform, which is of particular interest for several scanning technologies, such as magnetic resonance imaging. Since gradients of a medical image are much more sparse or compressible than the corresponding image, classical `1- minimization methods have been used to recover these relative differences. The image values can then be obtained by integration algorithms imposing boundary constraints...
March 21, 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
https://www.readbyqxmd.com/read/28333628/rate-distortion-optimized-graph-based-representation-for-multiview-with-complex-camera-configurations
#11
Xin Su, Thomas Maugey, Christine Guillemot
Graph-Based Representation (GBR) has recently been proposed for describing color and geometry of multiview video content. The graph vertices represent the color information, while the edges represent the geometry information, i.e. the disparity, by connecting corresponding pixels in two camera views. In this paper, we generalize the GBR to multiview images with complex camera configurations. Compared with the existing GBR, the proposed representation can handle not only horizontal displacements of the cameras but also forward/backward translations, rotations, etc...
March 21, 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
https://www.readbyqxmd.com/read/28333622/constrained-inversion-and-spectral-unmixing-in-multispectral-optoacoustic-tomography
#12
Lu Ding, Xose Luis Dean Ben, Neal C Burton, Robert W Sobol, Vasilis Ntziachristos, Daniel Razansky
Accurate extraction of physical and biochemical parameters from optoacoustic images is often impeded due to the use of unrigorous inversion schemes, incomplete tomographic detection coverage or other experimental factors that cannot be readily accounted for during the image acquisition and reconstruction process. For instance, inaccurate assumptions in the physical forward model may lead to negative optical absorption values in the reconstructed images. Any artifacts present in the single wavelength optoacoustic images can be significantly aggravated when performing a two-step reconstruction consisting in acoustic inversion and spectral unmixing aimed at rendering the distributions of spectrally-distinct absorbers...
March 22, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28333621/reconstructing-evolving-tree-structures-in-time-lapse-sequences-by-enforcing-time-consistency
#13
Przemyslaw Glowacki, Miguel Amavel Pinheiro, Agata Mosinska, Engin Turetken, Daniel Lebrecht, Anthony Holtmaat, Raphael Sznitman, Jan Kybic, Pascal Fua
We propose a novel approach to reconstructing curvilinear tree structures evolving over time, such as road networks in 2D aerial images or neural structures in 3D microscopy stacks acquired in vivo. To enforce temporal consistency, we simultaneously process all images in a sequence, as opposed to reconstructing structures of interest in each image independently. We formulate the problem as a Quadratic Mixed Integer Program and demonstrate the additional robustness that comes from using all available visual clues at once, instead of working frame by frame...
March 10, 2017: IEEE Transactions on Pattern Analysis and Machine Intelligence
https://www.readbyqxmd.com/read/28333040/rigid-motion-correction-of-dual-opposed-planar-projections-in-single-photon-imaging
#14
Georgios I Angelis, William Ryder, John Gillam, Frederic Boisson, Andre Kyme, Roger Fulton, Steven Meikle, Peter Kench
Awake and/or freely moving small animal single photon emission imaging allows the continuous study of molecules exhibiting slow kinetics without the need to restrain or anaesthetise the animals. Estimating motion free projections in freely moving small animal planar imaging can be considered as a limited angle tomography problem, except that we wish to estimate the 2D planar projections rather than the 3D volume, where the angular sampling in all three axes depends on the rotational motion of the animal. In this study, we hypothesise that the motion corrected planar projections estimated by reconstructing an estimate of the 3D volume using an iterative motion compensating reconstruction algorithm and integrating it along the projection path, will closely match the true, motion-less, planar distribution regardless of the object motion...
March 23, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28332992/clinical-implementation-of-a-model-based-in%C3%A2-vivo-dose-verification-system-for-stereotactic-body-radiation-therapy-volumetric-modulated-arc-therapy-treatments-using-the-electronic-portal-imaging-device
#15
Peter M McCowan, Ganiyu Asuni, Eric Van Uytven, Timothy VanBeek, Boyd M C McCurdy, Shaun K Loewen, Naseer Ahmed, Bashir Bashir, James B Butler, Amitava Chowdhury, Arbind Dubey, Ahmet Leylek, Maged Nashed
PURPOSE: To report findings from an in vivo dosimetry program implemented for all stereotactic body radiation therapy patients over a 31-month period and discuss the value and challenges of utilizing in vivo electronic portal imaging device (EPID) dosimetry clinically. METHODS AND MATERIALS: From December 2013 to July 2016, 117 stereotactic body radiation therapy-volumetric modulated arc therapy patients (100 lung, 15 spine, and 2 liver) underwent 602 EPID-based in vivo dose verification events...
April 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28332211/a-multi-channel-block-matching-denoising-algorithm-for-spectral-photon-counting-ct-images
#16
Adam P Harrison, Ziyue Xu, David A Bluemke, Amir Pourmorteza, Daniel J Mollura
PURPOSE: We present a denoising algorithm designed for a whole-body prototype photon-counting computed tomography (PCCT) scanner with up to 4 energy thresholds and associated energy-binned images. METHODS: Spectral PCCT images can exhibit low signal to noise ratios (SNRs) due to the limited photon counts in each simultaneously-acquired energy bin. To help address this, our denoising method exploits the correlation and exact alignment between energy bins, adapting the highly-effective block-matching 3D (BM3D) denoising algorithm for PCCT...
March 23, 2017: Medical Physics
https://www.readbyqxmd.com/read/28331886/effects-of-line-fiducial-parameters-and-beamforming-on-ultrasound-calibration
#17
Golafsoun Ameri, John S H Baxter, A Jonathan McLeod, Terry M Peters, Elvis C S Chen
Ultrasound (US)-guided interventions are often enhanced via integration with an augmented reality environment, a necessary component of which is US calibration. Calibration requires the segmentation of fiducials, i.e., a phantom, in US images. Fiducial localization error (FLE) can decrease US calibration accuracy, which fundamentally affects the total accuracy of the interventional guidance system. Here, we investigate the effects of US image reconstruction techniques as well as phantom material and geometry on US calibration...
January 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28331884/accuracy-assessment-and-characterization-of-x-ray-coded-aperture-coherent-scatter-spectral-imaging-for-breast-cancer-classification
#18
Manu N Lakshmanan, Joel A Greenberg, Ehsan Samei, Anuj J Kapadia
Although transmission-based x-ray imaging is the most commonly used imaging approach for breast cancer detection, it exhibits false negative rates higher than 15%. To improve cancer detection accuracy, x-ray coherent scatter computed tomography (CSCT) has been explored to potentially detect cancer with greater consistency. However, the 10-min scan duration of CSCT limits its possible clinical applications. The coded aperture coherent scatter spectral imaging (CACSSI) technique has been shown to reduce scan time through enabling single-angle imaging while providing high detection accuracy...
January 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28331587/a-simple-fast-and-repeatable-survey-method-for-underwater-visual-3d-benthic-mapping-and-monitoring
#19
Oscar Pizarro, Ariell Friedman, Mitch Bryson, Stefan B Williams, Joshua Madin
Visual 3D reconstruction techniques provide rich ecological and habitat structural information from underwater imagery. However, an unaided swimmer or diver struggles to navigate precisely over larger extents with consistent image overlap needed for visual reconstruction. While underwater robots have demonstrated systematic coverage of areas much larger than the footprint of a single image, access to suitable robotic systems is limited and requires specialized operators. Furthermore, robots are poor at navigating hydrodynamic habitats such as shallow coral reefs...
March 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28331158/low-serum-levels-of-epa-are-associated-with-the-size-and-growth-rate-of-abdominal-aortic-aneurysm
#20
Tatsuro Aikawa, Tetsuro Miyazaki, Kazunori Shimada, Yurina Sugita, Megumi Shimizu, Shohei Ouchi, Tomoyasu Kadoguchi, Yasutaka Yokoyama, Tomoyuki Shiozawa, Masaru Hiki, Shuhei Takahashi, Hamad Al Shahi, Shizuyuki Dohi, Atsushi Amano, Hiroyuki Daida
AIM: Omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been reported to reduce the risk of cardiovascular disease. However, whether omega-3 PUFAs are involved in the pathogenesis of abdominal aortic aneurysms (AAA) remains unclear. METHODS: We analyzed 67 consecutive patients admitted for the elective surgical repair of AAA. We investigated the association of serum EPA and DHA levels as well as the EPA/AA ratio with the size of AAA assessed using three-dimensional reconstructed computed tomography images...
March 22, 2017: Journal of Atherosclerosis and Thrombosis
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