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Jia Xu, Zuzhen Huang, Liang Yan, Xu Zhou, Furu Zhang, Teng Long
For modern synthetic aperture radar (SAR), it has much more urgent demands on ground moving target indication (GMTI), which includes not only the point moving targets like cars, truck or tanks but also the distributed moving targets like river or ocean surfaces. Among the existing GMTI methods, displaced phase center antenna (DPCA) can effectively cancel the strong ground clutter and has been widely used. However, its detection performance is closely related to the target's signal-to-clutter ratio (SCR) as well as radial velocity, and it cannot effectively detect the weak large-sized river surfaces in strong ground clutter due to their low SCR caused by specular scattering...
October 12, 2016: Sensors
You Li, Dongwoon Hyun, Lotfi Abou-Elkacem, Juergen Willmann, Jeremy Dahl
Power Doppler (PD) imaging is a widely used technique for flow detection. Despite the wide use of Doppler ultrasound, limitations exist in the ability of Doppler ultrasound to assess slow flow in small-diameter vasculature, such as the maternal spiral arteries and fetal villous arteries of the placenta and focal liver lesions. The sensitivity of PD in small vessel detection is limited by the low signal produced by slow flow and the noise associated with small vessels. The noise sources include electronic noise, stationary or slowly moving tissue clutter, reverberation clutter, and off-axis scattering from tissue, among others...
October 10, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Myoung-Gyun Suh, Qi-Fan Yang, Ki Youl Yang, Xu Yi, Kerry J Vahala
Rapid characterization of optical and vibrational spectra with high resolution can identify species in cluttered environments and is important for assays and early alerts. Dual-comb spectroscopy has emerged as a powerful approach to acquire nearly instantaneous Raman and optical spectra with unprecedented resolution. Spectra are generated directly in the electrical domain and avoid bulky mechanical spectrometers. We demonstrate a miniature soliton-based dual-comb system that can potentially transfer the approach to a chip platform...
October 13, 2016: Science
Daniel Kaiser, Nikolaas N Oosterhof, Marius V Peelen
: The human visual system can only represent a small subset of the many objects present in cluttered scenes at any given time, such that objects compete for representation. Despite these processing limitations, the detection of object categories in cluttered natural scenes is remarkably rapid. How does the brain efficiently select goal-relevant objects from cluttered scenes? In the present study, we used multivariate decoding of magneto-encephalography (MEG) data to track the neural representation of within-scene objects as a function of top-down attentional set...
October 12, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Mark A Bee, Jakob Christensen-Dalsgaard
Acoustic signaling plays key roles in mediating many of the reproductive and social behaviors of anurans (frogs and toads). Moreover, acoustic signaling often occurs at night, in structurally complex habitats, such as densely vegetated ponds, and in dense breeding choruses characterized by high levels of background noise and acoustic clutter. Fundamental to anuran behavior is the ability of the auditory system to determine accurately the location from where sounds originate in space (sound source localization) and to assign specific sounds in the complex acoustic milieu of a chorus to their correct sources (sound source segregation)...
October 12, 2016: Biological Cybernetics
Yasuharu Ohno, Tamotsu Fujimoto, Yukari Shibata
Introduction Superb microvascular imaging is a new ultrasound image processing technique that uses advanced clutter suppression to extract flow signals from vessels and which helps us visualize very small vascular structures that were not previously visible without the use of a contrast agent. We herein analyzed the usefulness of superb microvascular imaging in the diagnosis of hepato-gastrointestinal disorders in pediatric patients. Materials and Methods Fifty-six pediatric patients who underwent a total of 81 superb microvascular imaging examinations with an Aplio 300 ultrasound system (Toshiba Medical Systems, Tokyo, Japan) were enrolled in this study...
October 3, 2016: European Journal of Pediatric Surgery
Bo Zheng, Xiao-Dong Wang, Jing-Tao Huang, Jian Wang, Yang Jiang
Most existing clutter metrics are proposed based on fixed structural features and experienced weight measures. In this paper, we identify the clutter as selective visual attention effects and propose a type of clutter metric. First, adaptive structural features are extracted from the blocks with an edge-structure similarity to the target. Next, the confusing blocks are selected by the similarity threshold based on the attention guidance map. The clutter is estimated by quantifying the effects of confusing blocks on target acquisition performance...
September 20, 2016: Applied Optics
Jesse V Gavette, Matthias Stoop, Nicholas V Hud, Ramanarayanan Krishnamurthy
The RNA world hypothesis posits that DNA and proteins were later inventions of early life, or the chemistry that gave rise to life. Most scenarios put forth for the emergence of DNA assume a clean separation of RNA and DNA polymer, and a smooth transition between RNA and DNA. However, based on the reality of "clutter" and lack of sophisticated separation/discrimination mechanisms in a protobiological (and/or prebiological) world, heterogeneous RNA-DNA backbone containing chimeric sequences could have been common-and have not been fully considered in models transitioning from an RNA world to an RNA-DNA world...
October 10, 2016: Angewandte Chemie
Zhenwei Chen, Lei Zhang, Guo Zhang
Co-registration is one of the most important steps in interferometric synthetic aperture radar (InSAR) data processing. The standard offset-measurement method based on cross-correlating uniformly distributed patches takes no account of specific geometric transformation between images or characteristics of ground scatterers. Hence, it is inefficient and difficult to obtain satisfying co-registration results for image pairs with relatively big distortion or large incoherent areas. Given this, an improved co-registration strategy is proposed in this paper which takes both the geometric features and image content into consideration...
2016: Sensors
Tianjiang Hu, Boxin Zhao, Dengqing Tang, Daibing Zhang, Weiwei Kong, Lincheng Shen
This article concentrates on open-source implementation on flying object detection in cluttered scenes. It is of significance for ground stereo-aided autonomous landing of unmanned aerial vehicles. The ground stereo vision guidance system is presented with details on system architecture and workflow. The Chan-Vese detection algorithm is further considered and implemented in the robot operating systems (ROS) environment. A data-driven interactive scheme is developed to collect datasets for parameter tuning and performance evaluating...
2016: Robotics and Biomimetics
Yafen Liang, Bret Alvis, Mark J Rice, Andrew D Shaw, Lori A Deitte, Susan Eagle
No abstract text is available yet for this article.
October 2016: Anesthesia and Analgesia
Feng Xiao, Innes C Cuthill
Remaining undetected is often key to survival, and camouflage is a widespread solution. However, extrinsic to the animal itself, the complexity of the background may be important. This has been shown in laboratory experiments using artificially patterned prey and backgrounds, but the mechanism remains obscure (not least because 'complexity' is a multifaceted concept). In this study, we determined the best predictors of detection by wild birds and human participants searching for the same cryptic targets on trees in the field...
September 14, 2016: Proceedings. Biological Sciences
Hyung Il Koo
Camera-based text processing has attracted considerable attention and numerous methods have been proposed. However, most of these methods have focused on the scene text detection problem and relatively little work has been performed on camera-captured document images. In this paper, we present a text-line detection algorithm for camera-captured document images, which is an essential step towards document understanding. In particular, our method is developed by incorporating state estimation (an extension of scale selection) into a connected component (CC)-based framework...
September 8, 2016: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Adrian Chee, Billy Yiu, Alfred Yu
Eigen-filters with attenuation response adapted to clutter statistics in color flow imaging (CFI) have shown improved flow detection sensitivity in the presence of tissue motion. Nevertheless, its practical adoption in clinical use is not straightforward due to the high computational cost for solving eigen-decompositions. Here, we provide a pedagogical description of how a real-time computing framework for eigen-based clutter filtering can be developed through a single-instruction, multiple data (SIMD) computing approach that can be implemented on a graphical processing unit (GPU)...
September 7, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Anne Saris, Hendrik Hansen, Stein Fekkes, Maartje Nillesen, Marcel Rutten, Chris de Korte
Conventional color Doppler imaging is limited, since it only provides velocity estimates along the ultrasound beam direction for a restricted field of view at a limited frame rate. High frame rate speckle tracking, using plane wave transmits, has shown potential for 2D blood velocity estimation. However, due to the lack of focusing in transmit, image quality gets reduced, which hampers speckle tracking. Although ultrafast imaging facilitates improved clutter filtering, it still remains a major challenge in blood velocity estimation...
September 7, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Michael S Langer, Haomin Zheng, Shayan Rezvankhah
Objects such as trees, shrubs, and tall grass consist of thousands of small surfaces that are distributed over a three-dimensional (3D) volume. To perceive the depth of surfaces within 3D clutter, a visual system can use binocular stereo and motion parallax. However, such parallax cues are less reliable in 3D clutter because surfaces tend to be partly occluded. Occlusions provide depth information, but it is unknown whether visual systems use occlusion cues to aid depth perception in 3D clutter, as previous studies have addressed occlusions for simple scene geometries only...
September 1, 2016: Journal of Vision
Pengfei Song, Armando Manduca, Joshua Trzasko, Shigao Chen
Robust clutter filtering is essential for ultrasound small vessel imaging. Eigen-based clutter filtering techniques have recently shown great improvement in clutter rejection over conventional clutter filters in small animals. However, for in vivo human imaging, eigen-based clutter filtering can be challenging due to the complex spatially-varying tissue and noise characteristics. To address this challenge, we present a novel block-wise adaptive singular value decomposition (SVD) based clutter filtering technique...
September 2, 2016: IEEE Transactions on Medical Imaging
Lijun Huo, Dabiao Zhou, Dejiang Wang, Rang Liu, Bin He
Focal-plane arrays (FPAs) are often interfered by heavy fixed-pattern noise, which severely degrades the detection rate and increases the false alarms in airborne point target detection systems. Thus, high-precision nonuniformity correction is an essential preprocessing step. In this paper, a new nonuniformity correction method is proposed based on a staircase scene. This correction method can compensate for the nonlinear response of the detector and calibrate the entire optical system with computational efficiency and implementation simplicity...
September 1, 2016: Applied Optics
Donatien Sabushimike, Seung You Na, Jin Young Kim, Ngoc Nam Bui, Kyung Sik Seo, Gil Gyeom Kim
The detection of a moving target using an IR-UWB Radar involves the core task of separating the waves reflected by the static background and by the moving target. This paper investigates the capacity of the low-rank and sparse matrix decomposition approach to separate the background and the foreground in the trend of UWB Radar-based moving target detection. Robust PCA models are criticized for being batched-data-oriented, which makes them inconvenient in realistic environments where frames need to be processed as they are recorded in real time...
2016: Sensors
Matthew Ritchie, Matthew Ash, Qingchao Chen, Kevin Chetty
The ability to detect the presence as well as classify the activities of individuals behind visually obscuring structures is of significant benefit to police, security and emergency services in many situations. This paper presents the analysis from a series of experimental results generated using a through-the-wall (TTW) Frequency Modulated Continuous Wave (FMCW) C-Band radar system named Soprano. The objective of this analysis was to classify whether an individual was carrying an item in both hands or not using micro-Doppler information from a FMCW sensor...
2016: Sensors
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