The rainfall process in autumn of Chengdu region has significant regional characteristics. Since GPS detection technology has characteristics such as all-weather, high accuracy, high spatial and temporal resolution an...
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ISBN:
(纸本)9780819485762
The rainfall process in autumn of Chengdu region has significant regional characteristics. Since GPS detection technology has characteristics such as all-weather, high accuracy, high spatial and temporal resolution and low cost, its tracking and monitoring technique on water vapor has achieved rapid developments in recent years. In this paper, it makes use of GPS-PWV data from 6 foundation GPS observation stations of GPS observation network in Chengdu region from September 2007 to November 2007 and from September 2008 to November 2008 these two falls which have 30min intervals. Fast Fourier transform was used to obtain the variation principle that in autumn the rainfalls change in the time period and there also has one quarter season within the fall, which is around 22 days or so. After the analysis, it finds that PWV drastically decreases at late October which is closely correlated to the local climate changing cycle. After we conduct composite analysis on diurnal cycle by integrating PWV with other meteorological elements we can find: There is a negative correlation between PWV and temperature;there is more obvious positive correlation between humidity and PWV. GPS precipitable water vapor may increase or maintain the characteristics within high value area from midnight to early morning which can bitterly correspond with the actual rainfall process of this region.
Coherent targetanalysis (CTA) method derived for the (Interferometric SAR) InSAR data processing has developed as one of the critical techniques in the field of surveying subtle land deformation. This paper discusses...
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ISBN:
(纸本)9780819469519
Coherent targetanalysis (CTA) method derived for the (Interferometric SAR) InSAR data processing has developed as one of the critical techniques in the field of surveying subtle land deformation. This paper discusses the principles and characteristics of CTA procedure, which can remove the errors caused by temporal and spatial decorrelation and atmospheric effects. The paper presents the validation of characteristics of CTA applied in city subsidence in Shanghai test site, where has been affected by subsidence for more than eighty years. The 32 scenes from the ERS-1/2 satellites covering the test area between 1992 and 2000 were chosen and processed. Based on the theory of CTA, we can get the map of land subsidence of Shanghai. Quality assessment between the velocity fields derived of CTA and that of leveling data observed on benchmarks within the same periods is then discussed. The comparison with ground leveling data shows the derived result from CTA approach is consistent with leveling data. The further investigation of CTA approach in Shanghai will be continued to improve the accuracy and robustness.
The increasing demand for the protection of persons and facilities requires the application of sophisticated technologies for surveillance and object tracking. For this purpose appropriate sensors are used like imagin...
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ISBN:
(纸本)9780819466914
The increasing demand for the protection of persons and facilities requires the application of sophisticated technologies for surveillance and object tracking. For this purpose appropriate sensors are used like imaging IR sensors suitable for day/night operation and laser radar supplying 3D information of the scenario. In this context there is a requirement of automatic and semi-automatic methods supporting the human observer in his decision-making process. A prevalent task is automatic tracking of striking objects like vehicles or individual persons in an image sequence during a time slice. Classical methods are based on template matching implying certain shortcomings concerning homogeneous background or passing objects occluding the target object. The authors propose a new concept for generating templates for IR target signatures based on the interpretation of laser range data in order to optimize the tracking process. The testbed is realized by a helicopter equipped with a multisensor suite (laser radar, imaging IR, GPS, IMU). Results are demonstrated by the analysis of an exemplary data set. A vehicle situated in a complex scenario is acquired by a forward moving sensor platform and is tracked robustly by the proposed method.
automaticrecognition of human activities is important for the development of next generation video-surveillance systems. In this paper we address the specific problem of automatically detecting violent interpersonal ...
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automaticrecognition of human activities is important for the development of next generation video-surveillance systems. In this paper we address the specific problem of automatically detecting violent interpersonal acts in monocular colour video streams. Unlikely previous approaches, only little knowledge is assumed about the acquisition setup and about the content of the acquired scenes. So the proposed approach is suitable in a wide range of practical cases. Reliability and general-purpose applicability is achieved by analysing low-level features (like the spatial-temporal behaviour of coloured stains), and by measuring some warping and motion parameters. In this way it is not necessary to extract accurate target silhouettes, that is a critical task because of occlusions and overcrowding that are typical during interpersonal contacts. A suitable index called maximum warping energy (MWE) has been defined to describe the localized spatial-temporal complexity of colour conformations. Our experiments show that aggressive activities give significantly higher MWE values if compared with safe actions like: walking, running, embracing or handshaking. So it is possible to distinguish violent acts from normal behaviours even in presence of many people and crowded environments. Homography is used to improve robustness by verifying the real targets nearness. False interactions because of perspective-induced occlusions are discarded.
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