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291.
在含有运动地物的"凝视"卫星视频影像超分辨率重建问题中,针对由于运动估计不准确导致的重建后运动物体存在"格网"和"拖尾"等问题,提出了顾及运动估计误差的运动场景超分辨率重建方法。首先,在MAP模型框架下分析了基于L1范数和L2范数的保真项对于运动估计误差的稳健性,引入稳健的M-估计作为保真项,自适应的减少运动估计误差对重建结果的影响;然后,分析了稳健估计条件下Tikhonov、TV、BTV正则项的重建效果;最后,提出了基于稳健估计的双边滤波超分辨率重建方法,用SkyBox和吉林一号的卫星视频数据验证本文方法。试验证明,本文方法对含有运动目标的卫星视频影像具有较好的重建效果,重建后动态和静态地物细节都得到提升,归一化方差和梯度能量指标都优于其他方法。试验表明了本文方法的可行性。 相似文献
292.
针对低空飞行器(飞艇)为平台获取的高清晰交通视频数据,通过对交通视频序列数据进行运动补偿与配准,提出了一个在复杂变化背景下基于帧差法的运动目标(车辆)快速检测与提取方法。实验结果验证了本方法的准确与可靠性。 相似文献
293.
从物联网的根本目的出发,利用压缩方法和统计过程控制(SPC)技术研究了物联网中节点实时信息的精简和分析技术,并以计算机网络中的节点计算机的监视数据为例进行了实验分析,为物联网中节点数据的精简和分析提供了参考。 相似文献
294.
数字视频加密技术发展现状及展望 总被引:8,自引:0,他引:8
对视频加密所涉及到的基本原理和技术、存在的问题和一些重要的方法、当前研究热点及发展趋势等进行了全面介绍和综述;通过分析视频加密方法的特点,指出针对压缩视频数据信源特征而采用的选择性加密技术是未来的主要研究方向。 相似文献
295.
介绍了利用视频技术检测激光束牛顿环中心的方法,为准直应用提供了参考。实验表明,快速Hough变换可以获取理想的检测结果。 相似文献
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297.
Fine scale disaster response and recovery data suitable for spatial analysis are still relatively rare. This is unfortunate as insight into spatial patterns of recovery could be invaluable in predicting the reestablishment of homes, streets and neighborhoods. The purpose of this paper is to show how fine scale geographic data can be collected in near real-time for the intermediate phase between response and recovery. These data will initially be used to assess the degree of damage (with relation to the Enhanced F scale) while also establishing a baseline for subsequent recovery monitoring. A spatial video system is used to collect data from the post-disaster landscape of Tuscaloosa which was hit by a large tornado in April 2011. This video, once processed, can be viewed within a Geographic Information System which combines street-level images with exact location. These data can be used to support ongoing recovery efforts, while also archiving a dataset suitable for the spatial analysis of the changing post-disaster landscape. 相似文献
298.
《Urban geography》2012,33(10):1467-1484
ABSTRACTIn this paper, we investigate people’s perception of datafication and surveillance in Amsterdam Smart City. Based on a series of focus groups, we show how people understand new forms of hypervisbility, what strategies they use to navigate these experiences, and what the limitations of these strategies are. We show how people tried to discern between public and private sector actors, to differentiate who they trusted by building on the existing social contract. People also trusted the objectivity of data in relation to prior experiences of social contexts and discrimination. Lastly, we show how the experiences of some of the inhabitants in our study who were most vulnerable to hypervisibility highlight the limits to strategies based on the neutrality of data. By asking about perceived surveillance rather than emphasising actual practices of surveilling, we show differentiated contexts and strategies, providing empirical grounds to question the dominant technical framing of smart cities. 相似文献
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Gauging extreme floods on YouTube: application of LSPIV to home movies for the post‐event determination of stream discharges
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Raphaël Le Boursicaud Lionel Pénard Alexandre Hauet Fabien Thollet Jérôme Le Coz 《水文研究》2016,30(1):90-105
Movies taken by witnesses of extreme flood events are increasingly available on video sharing websites. They potentially provide highly valuable information on flow velocities and hydraulic processes that can help improve the post‐flood determination of discharges in streams and flooded areas. We investigated the troubles and potential of applying the now mature large‐scale particle image velocimetry (LSPIV) technique to such flood movies that are recorded under non‐ideal conditions. Processing was performed using user‐friendly, free software only, such as Fudaa‐LSPIV. Typical issues related to the image processing and to the hydrological analysis are illustrated using a selected example of a pulsed flash‐flood flow filmed in a mountainous torrent. Simple corrections for lens distortion (fisheye) and limited incoherent camera movement (shake) were successfully applied, and the related errors were reduced to a few percents. Testing the different image resolution levels offered by YouTube showed that the difference in time‐averaged longitudinal velocity was less than 5% compared with full resolution. A limited number of GRPs, typically 10, is required, but they must be adequately distributed around the area of interest. The indirect determination of the water level is the main source of uncertainty in the results, usually much more than errors because of the longitudinal slope and waviness of the free‐surface of the flow. The image‐based method yielded direct discharge estimates of the base flow between pulses, of the pulse waves, and of the time‐averaged flow over a movie sequence including a series of five pulses. A comparison with traditional indirect determination methods showed that the critical‐depth method may produce significantly biassed results for such a fast, unsteady flow, while the slope‐area method seems to be more robust but would overestimate the time‐averaged flow rate if applied to the high‐water marks of a pulsed flow. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献