Region Tracking Research Articles

A new adaptive Cartesian-grid CIP method for computation of violent free-surface flows

A new adaptive Cartesian-grid for the CIP (constrained interpolation profile) method is proposed and applied to two-dimensional numerical simulations of violent free-surface flows. The CCUP (CIP combined and unified procedure) method is employed and combined with this adaptive Cartesian-grid for robust and efficient computation. This adaptive grid is capable of tracking regions where flows vary violently, and a much finer grid is then concentrated automatically on these regions to adapt to the violent changing of the flow. Unlike the abacus-like Soroban grid which is an adaptive meshless grid with complicated algorithms and inefficiency of evaluation of frequently computed spatial derivatives, the present approach not only simplifies computational algorithm but also enhances efficiency of frequently-computed spatial derivatives. It is also different from most of the remeshing schemes that no additional CPU-time for the value-mapping from the old grid to the new grid is taken in this adaptive grid system provided that the advection velocity is interpolated, since the value-mapping process is accomplished simultaneously within the advection process. To validate the accuracy and efficiency of this newly-proposed CFD model, several two-dimensional benchmark problems are performed, and the results are compared with experimental measurements and other published numerical results. Numerical simulations show that the proposed numerical model is robust, accurate, and efficient for strongly nonlinear free-surface flows.

깊이 영상 기반 손 영역 추적 및 손 끝점 검출

본 논문에서는 깊이 영상만을 이용하여 손 영역 추적 및 손 끝점 검출 방법을 제안한다. 조명 조건의 영향을 제거하고 빠르고 안정적인 정보 획득을 위해 깊이 정보만을 이용하는 추적 방법을 제안하고, 영역 확장 방법을 통해 추적 과정 중에 발생할 수 있는 오류에 대한 판단 방법과 다양한 제스처 인식에 응용이 가능한 손 끝점 검출 방법을 제안한다. 먼저 추적점을 찾기 위해 중심점 전이 과정을 통해 최근접점을 찾고 그 점으로부터 영역 확장을 통해 손 영역과 경계선을 검출한다. 그리고 영역 확장을 통해 획득한 무효경계선의 비율을 이용하여 추적영역에 대한 신뢰도를 계산함으로써 정상 추적 여부를 판단한다. 정상적인 추적인 경우, 검출된 손 영역으로부터 윤곽선을 추출하고 곡률 및 RANSAC, 컨벡스 헐(Convex-Hull)을 이용하여 손 끝점을 검출한다. 마지막으로 성능 검증을 위해 다양한 상황에 따른 정량적, 정성적 분석을 통해 제안하는 추적 및 손 끝점 검출 알고리즘의 효율성을 입증한다. This paper proposes a method of tracking the hand region and detecting the fingertip using only depth images. In order to eliminate the influence of lighting conditions and obtain information quickly and stably, this paper proposes a tracking method that relies only on depth information, as well as a method of using region growing to identify errors that can occur during the tracking process and a method of detecting the fingertip that can be applied for the recognition of various gestures. First, the closest point of approach is identified through the process of transferring the center point in order to locate the tracking point, and the region is grown from that point to detect the hand region and boundary line. Next, the ratio of the invalid boundary, obtained by means of region growing, is used to calculate the validity of the tracking region and thereby judge whether the tracking is normal. If tracking is normal, the contour line is extracted from the detected hand region and the curvature and RANSAC and Convex-Hull are used to detect the fingertip. Lastly, quantitative and qualitative analyses are performed to verify the performance in various situations and prove the efficiency of the proposed algorithm for tracking and detecting the fingertip.

Sea Surface Salinity Observations from Space with the SMOS Satellite: A New Means to Monitor the Marine Branch of the Water Cycle

While it is well known that the ocean is one of the most important component of the climate system, with a heat capacity 1,100 times greater than the atmosphere, the ocean is also the primary reservoir for freshwater transport to the atmosphere and largest component of the global water cycle. Two new satellite sensors, the ESA Soil Moisture and Ocean Salinity (SMOS) and the NASA Aquarius SAC-D missions, are now providing the first space-borne measurements of the sea surface salinity (SSS). In this paper, we present examples demonstrating how SMOS-derived SSS data are being used to better characterize key land–ocean and atmosphere–ocean interaction processes that occur within the marine hydrological cycle. In particular, SMOS with its ocean mapping capability provides observations across the world’s largest tropical ocean fresh pool regions, and we discuss from intraseasonal to interannual precipitation impacts as well as large-scale river runoff from the Amazon–Orinoco and Congo rivers and its offshore advection. Synergistic multi-satellite analyses of these new surface salinity data sets combined with sea surface temperature, dynamical height and currents from altimetry, surface wind, ocean color, rainfall estimates, and in situ observations are shown to yield new freshwater budget insight. Finally, SSS observations from the SMOS and Aquarius/SAC-D sensors are combined to examine the response of the upper ocean to tropical cyclone passage including the potential role that a freshwater-induced upper ocean barrier layer may play in modulating surface cooling and enthalpy flux in tropical cyclone track regions.

Measurement of Muon Antineutrino Quasielastic Scattering on a Hydrocarbon Target atEν∼3.5 GeV

We have isolated muon anti-neutrino charged-current quasi-elastic interactions occurring in the segmented scintillator tracking region of the MINERvA detector running in the NuMI neutrino beam at Fermilab. We measure the flux-averaged differential cross-section, d{\sigma}/dQ^2, and compare to several theoretical models of quasi-elastic scattering. Good agreement is obtained with a model where the nucleon axial mass, M_A, is set to 0.99 GeV/c^2 but the nucleon vector form factors are modified to account for the observed enhancement, relative to the free nucleon case, of the cross-section for the exchange of transversely polarized photons in electron-nucleus scattering. Our data at higher Q^2 favor this interpretation over an alternative in which the axial mass is increased.

Side-Reading Effects in High-Track-Density Tape Recording

Aggressive track-density scaling in linear magnetic tape recording has been identified as a key means of sustaining capacity scaling. As the reader width decreases, the relative signal contribution of the written track region outside the lateral extent of the reader increases. We model, analyze and quantify side-reading effects of shielded magneto-resistive read heads reading narrow tracks on perpendicular-oriented tape media. We compare results from extended analytical models with experimental data. An understanding of these effects will be important in designing track misregistration budgets and SNR margins for future operating points of parallel-channel tape recording systems.

빌보드 스윕 스테레오 시차정합 알고리즘을 이용한 차량 검출 및 추적

In this paper, we propose a highly precise vehicle detection method with low false alarm using billboard sweep stereo matching and multi-stage hypothesis generation. First, we capture stereo images from cameras established in front of the vehicle and obtain the disparity map in which the regions of ground plane or background are removed using billboard sweep stereo matching algorithm. And then, we perform the vehicle detection and tracking on the labeled disparity map. The vehicle detection and tracking consists of three steps. In the learning step, the SVM(support vector machine) classifier is obtained using the features extracted from the gabor filter. The second step is the vehicle detection which performs the sobel edge detection in the image of the left camera and extracts candidates of the vehicle using edge image and billboard sweep stereo disparity map. The final step is the vehicle tracking using template matching in the next frame. Removal process of the tracking regions improves the system performance in the candidate region of the vehicle on the succeeding frames.

Sea‐state‐dependent wind work on the oceanic general circulation

AbstractWe examine sea‐state‐dependent wind work on the oceanic general circulation, using a wave hindcast dataset, QuikSCAT winds, and geostrophic and total ocean surface currents from (1) AVISO and (2) ECCO2 model products. For wind work on surface geostrophic currents estimated from AVISO or ECCO2, sea‐state‐dependent wind stress increases an average of 24% (0.17TW) or 23% (0.15TW), compared with estimates that exclude sea state effects. For wind work on the total surface currents, the sea‐state‐dependent wind stress increases the wind work by about 24% (0.4TW). In terms of spatial distribution, the increase in wind power input occurs mainly in high‐wind tropical regions and the mid‐latitude storm track regions, like the Antarctic Circumpolar Current region, where the relatively rough ocean surface is characterized by young waves and high winds. By comparison, in some regions with relatively low winds and mature ocean waves, there is a slight reduction in estimated wind power input.

Features of charge pairs recombination in the track regions of organic solid scintillators. Part II

Features of charge pairs recombination in the track regions of organic solid scintillators. Part II

Defect formation and accumulation in CeO2 irradiated with swift heavy ions

We have investigated microstructure evolution in CeO2 irradiated with 210MeV Xe ions by using transmission electron microscopy to gain the fundamental knowledge on radiation damage induced by fission fragments in nuclear fuel and transmutation target. Analysis on the accumulation of ion tracks has revealed an influence region to recover pre-existing core damage regions of ion tracks to be 8.4nm in radius. Cross section observations showed that high-density electronic excitation induces both ion tracks and dislocation loops. At high fluences of 1.5×1019 and 1×1020ionsm−2, depth-dependent microstructure was developed with radiation-induced defects of ion tracks, dislocation loops (dot-contrast) and line dislocations. Formation of sub-divided small grains was found at shallow depth at a fluence of 1×1020ionsm−2. The microstructure evolution was discussed in terms of the accumulation of interstitials due to significant overlap of high density electronic excitation.

A Formulation of Unified Three-Dimensional Wave Activity Flux of Inertia–Gravity Waves and Rossby Waves

Abstract A companion paper formulates the three-dimensional wave activity flux (3D-flux-M) whose divergence corresponds to the wave forcing on the primitive equations. However, unlike the two-dimensional wave activity flux, 3D-flux-M does not accurately describe the magnitude and direction of wave propagation. In this study, the authors formulate a modification of 3D-flux-M (3D-flux-W) to describe this propagation using small-amplitude theory for a slowly varying time-mean flow. A unified dispersion relation for inertia–gravity waves and Rossby waves is also derived and used to relate 3D-flux-W to the group velocity. It is shown that 3D-flux-W and the modified wave activity density agree with those for inertia–gravity waves under the constant Coriolis parameter assumption and those for Rossby waves under the small Rossby number assumption. To compare 3D-flux-M with 3D-flux-W, an analysis of the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis (ERA-Interim) data is performed focusing on wave disturbances in the storm tracks during April. While the divergence of 3D-flux-M is in good agreement with the meridional component of the 3D residual mean flow associated with disturbances, the 3D-flux-W divergence shows slight differences in the upstream and downstream regions of the storm tracks. Further, the 3D-flux-W magnitude and direction are in good agreement with those derived by R. A. Plumb, who describes Rossby wave propagation. However, 3D-flux-M is different from Plumb’s flux in the vicinity of the storm tracks. These results suggest that different fluxes (both 3D-flux-W and 3D-flux-M) are needed to describe wave propagation and wave–mean flow interaction in the 3D formulation.

Model-based 3D tracking of an articulated hand from single depth images

This paper presents a novel solution to the problem of tracking the 3D position, orientation and full articulation of a human hand from single depth images. We choose the model-based approach and treat the tracking task as an optimization problem. A new objective function based on depth information is presented to quantify the discrepancy between the appearance of hypothesized instances of a hand model and actual hand observations. Sequential Particle Swarm Optimization method is proposed to minimize the objective function for sequential optimization. An semi-automatic hand location method is adopted to predict hand region for sequential tracking. A GPU-based implementation of the proposed method is well designed to address the computational intensity. Extensive experimental results demonstrate qualitatively and quantitatively that tracking of an articulated hand can be achieved in real-time.

Development of Mosaic Algorithm for Mosaic-video Creation using Modified Strip Search Algorithm

Creating Mosaic-video is still a relatively new pursuit. It is also useful inside virtual reality environments, computer game settings, movie special effects and region of interest tracking. Immersive teleconferencing is another application that is being developed using mosaic-video. Many mosaic-video creation techniques are proposed by the researchers but most of them are based on the multiple cameras. We developed it with the use of single moving camera by incorporating simple and efficient steps. Initially a strip search algorithm is modified for mosaic creation with high sensitivity and linearity followed by video background extraction and then mosaic-video frames are created with merging the required dynamic motions from all the frames to mosaic backgrounds. This method handles major problem of non-redundant information retrieval and visualization along large view with respective to the video of tracking camera.

Impacts of global warming on Northern Hemisphere winter storm tracks in the CMIP5 model suite

AbstractA key question in assessing how global warming may affect climate is how it may impact day‐to‐day weather. To help answer this question, we evaluate the frequency and intensity of northern hemisphere storm tracks in the National Center for Climate Prediction reanalysis I dataset, and the historical, RCP4.5, and RCP8.5 climate scenarios featured in the CMIP5 simulations. We found that a warmer climate resulted in a general decrease in storm frequency in midlatitudes, especially in RCP8.5. In contrast, frequency trends in the reanalysis data reflected an increase in the North Pacific consistent with a shift towards a positive Pacific Decadal Oscillation and more frequent El Niño events post mid‐1970s. An examination of frequency and intensity trends in the active storm track regions of the North Pacific and North Atlantic showed that a significant decrease in storm track frequency was evident for RCP8.5. In contrast, intensity trends were dichotomous, with RCP8.5 exhibiting an increase in intensity in the North Atlantic active storm track region and a decrease in intensity in the North Pacific active storm track region. Poleward of these regions, a significant decrease in storm intensity in the North Atlantic and a significant increase in intensity in the North Pacific in RCP8.5 occurred. We also examined the intensity distribution of storms in the active storm track regions of the North Atlantic and North Pacific and determined that the models produced weaker storms with reduced variability relative to reanalysis data regardless of external climate forcing.

English

The identity and multiplication of bacteria and fungi (yeasts and mould) as they pass along the alimentary tract of the earthworm Libyodrilus violaceus have been studied. The bacteria isolated included Acinetobacter sp., Alcaligans faecalis, Bacillus brevis, Bacillus ceveus, Bacillus lalerosporus, Bacillus lichenoform, Bacillus maceraus, Bacillus sp., Corynebacterium sp., Enterobacter cloacae, Erwinia salicie, Flavobacterium aquartile, Flavobacterium sp., Klebsiella sp., Micrococcus inteus, Micrococcus kristinae, Micrococcus varians, Proteus myxofasciens, Proteus rennevi, Proteus vulgaris and Pseudomonas sp. Whereas P. vulgaris is a normal harmless inhabitant of the human intestine where it assist with digestion, it sometimes becomes pathogenic causing urinary tract infection. For now there is no information on if it undergoes similar change in the earthworms and if such a potential risk is transmissible to man. The fungi isolated included the following yeasts: Saccharomycos cerevisiae, Rhodoturula graminis, Saccharomycos sp., Candida valida, Geotrichium niger; and the following moulds: Aspergillus niger, Aspergillus fumigatus, Fusarium sp., Rhizopus sp. It is noteworthy that none of the fungi has the ability to digest melobiose, a disaccharide formed by an alpha linkage between galactose and glucose. Microbial counts increases along the alimentary track from eosophagus to rectum. Most of the microbes flourish best in an alimentary track region than in others. Thus, they tend to colonize different regions and thus minimize competition. Key words: Eudrilidae, earthworm microbiology, agricultural microbiology, earthworm zoonosis, earthworm-microbe mutualism, soil microbiology.

Kinetic Monte Carlo simulations of excitation density dependent scintillation in CsI and CsI(Tl)

AbstractNonlinear quenching of electron–hole pairs in the denser regions of ionization tracks created by γ‐ray and high‐energy electrons is a likely cause of the light yield non‐proportionality of many inorganic scintillators. Therefore, kinetic Monte Carlo (KMC) simulations were carried out to investigate the scintillation properties of pure and thallium‐doped CsI as a function of electron–hole pair density. The availability of recent experimental data on the excitation density dependence of the light yield of CsI following ultraviolet excitation allowed for an improved parameterization of the interactions between self‐trapped excitons (STE) in the KMC model via dipole–dipole Förster transfer. The KMC simulations reveal that nonlinear quenching occurs very rapidly (within a few picoseconds) in the early stages of the scintillation process. In addition, the simulations predict that the concentration of thallium activators can affect the extent of nonlinear quenching as it has a direct influence on the STE density through STE dissociation and electron scavenging. This improved model will enable more realistic simulations of the non‐proportional γ‐ray and electron response of inorganic scintillators.

Hybrid region and interest points-based active contour for object tracking

In this paper, we propose a hybrid object tracking approach based on region intensities and the motion vector of the interest points of the target object. After the heterogeneous region is identified (i.e foreground or background), the information extracted from the region intensities is computed through a pre-processing selection technique using local and global statistics. The motion vector of the interest points is obtained by computing the mean displacement of these points between consecutive frames. Therefore, for each received frame, the displacement vector is applied to the initial active contour that will be evolved using the region information. The main advantages of our approach which combines the information gathered from region intensities and motion of the interest points are first, a priori knowledge of the heterogeneous region is not required and second, the initial active contour in each frame is adjusted much closer to the true boundary of the object of interest. Experiments with synthetic and real-world images validate the efficiency of the proposed hybrid approach.

Right ventricle anatomy can predict new onset ventricular tachycardia in patients with repaired tetralogy of Fallot

Results Nine patients had ventricular tachyarrhythmia (6%) during follow-up. Patients who developed ventricular tachyarrhythmia were older (42.5 [34.9-50.2] vs. 29 [21-40] years; p=0.01), had a later repair (12.8 [6.2-13.9] vs. 4.4 [2-8] years; p=0.02), larger akinetic right ventricular outflow track (RVOT) region (Figure ) (length 55 [34-60] vs. 30 [20-40] mm; p=0.002) and a lower RV ejection fraction (42 [40-52] vs. 53 [51-55] %; p=0.01), compared to the other patients. On univariate Cox analysis, RVOT akinetic region length and RV ejection fraction were predictive of ventricular tachyarrhythmia. On stepwise Cox regression analysis, the RVOT akinetic region length was the only remaining predictor (Hazard ratio 1.05, 95% Confidence Interval 1.01-1.08 per mm; p=0.004). The survival ROC curve analysis indicated a cut-off value of 30mm as a predictor of VA during 6 year follow-up with an AUC of 0.77, sensitivity of 83% and specificity of 61%. RVOT akinetic area length >30mm predicted reduced VA-free survival (Logrank p=0.002).

Probabilistic Tracking of Affine-Invariant Anisotropic Regions

Despite a wide range of feature detectors developed in the computer vision community over the years, direct application of these techniques to surgical navigation has shown significant difficulties due to the paucity of reliable salient features coupled with free--form tissue deformation and changing visual appearance of surgical scenes. The aim of this paper is to propose a novel probabilistic framework to track affine-invariant anisotropic regions under contrastingly different visual appearances during Minimally Invasive Surgery (MIS). The theoretical background of the affine-invariant anisotropic feature detector is presented and a real-time implementation exploiting the computational power of the GPU is proposed. An Extended Kalman Filter (EKF) parameterization scheme is used to adaptively adjust the optimal templates of the detected regions, enabling accurate identification and matching of the tracked features. For effective tracking verification, spatial context and region similarity have also been incorporated. They are used to boost the prediction of the EKF and recover potential tracking failure due to drift or false positives. The proposed framework is compared to the existing methods and their respective performance is evaluated with in vivo video sequences recorded from robotic-assisted MIS procedures, as well as real-world scenes.

Increase in fish abundance during two typhoons in the South China Sea

A fish monitoring program was conducted in the northern region of the South China Sea from March 2009 to December 2010. During this period, two typhoons, GONI and Koppu, hit this region consecutively in August and September 2009. The fish and satellite data were analyzed to understand the influence of the typhoons on fish activities. The results showed that the fish species number (FSN) increased by approximately 14.29% and 14.81% after the two typhoons, GONI and Koppu, respectively. The five increased fish species included three estuarine species and two shallow sea species. However, one shallow sea species was also absent. In the nearshore (near the Pearl River Estuary) and offshore (along the typhoon’s track) regions after GONI, the FSN increased by approximately 24% (nearshore) and 52.63% (offshore), with estuarine species accounting for 42.86% (nearshore) and 33.33% (offshore) of the fish species; after Koppu, the FSN increased by approximately 15.38% (nearshore) and 163.64% (offshore), with estuarine species accounting for 60% (nearshore) and 26.32% (offshore) of the fish species. In the increased records, small and medium-sized fish species were dominant nearshore, and small fish species were dominant offshore. The FSN increased to a maximum value between the 5th and the 10th days after the typhoon nearshore and between the 3rd and 8th days after the typhoon offshore. The results indicated that river discharge, triggered by the typhoon’s nearshore rainfall, as well as offshore upwelling nutrients, also triggered by the typhoons, and may have played important roles in the variability of fish species. This research found that the increase in the FSN was associated with the typhoons in the northern South China Sea.

Spatial effects in the 800 keV 3He implantation in W followed by isochronal annealing at 900 K

The effect of fluence on the depth distribution of vacancy clusters in the track region of room temperature 800keV 3He atom implanted tungsten further annealed up to 900K has been investigated using an Object Kinetic Monte Carlo (OKMC) approach. The results show that the width and the position of the maximum size of the depth distribution strongly depend on the implantation fluence. For the high implantation fluence, the vacancy clusters are the largest in the first 100nm close to the surface, whereas, for the low implantation fluence, the distribution is more uniform in size between 100 and 300nm from the surface. The vacancy clusters are always smaller very close to the surface, and this whatever the fluence. The trends observed are in good agreement with the experimental Positron Annihilation Spectroscopy (PAS) results.