基于Skyline视频监控系统研究

视频监控系统能够实时获取监控范围的影像,发现被监控目标的即时状态。2维GIS与视频监控的集成逐步走向成熟,但在可视化效果方面远不如3维GIS。因此,结合Skyline软件中的Video On Terrain技术提出了一种3维地面影像视频监控新方案,并设计了地面影像视频监控系统的软硬件框架,分析了音视频编码传输原理和视频控制机制,总结归纳了地面影像视频监控系统的关键技术要求,最后实现了3维地面影像视频监控原型系统。     

应急管理部多层级视频会议系统跨网段转发技术

介绍应急管理部视频会议系统接入地震系统的基本情况,结合地震应急视频会议系统应用现状,分析多层级跨网视频会议系统的架构特点,着重分析跨网段"背靠背"转发优化技术方案在视频会议系统融合中的实现与应用,以期为类似的应用场景提供参考。     

MCU在地震应急视频会议系统中的应用

介绍了北京市地震局应急指挥中心MCU高清视频会议系统的设计与实现,分析了MCU在地震应急视频会议系统中的优势,并阐述了MCU不同组会模式在地震应急指挥和日常会议中的应用。通过多点台站、区地震局和三方级联模式在地震演练和日常会议中的应用案例表明,MCU的建设在提高应急联动协调能力和满足日常会议需求方面起着重要作用,未来使用云视频、MCU资源池等技术更有助于资源的合理利用。     

基于Pfafstetter规则的流域编码算法并行化方法

流域编码是以子流域划分进行流域相关研究的重要内容。Pfafstetter 流域编码以编码唯一、顾及流域拓扑关系及编码效率高等优点而被广泛采用。本文在流域相关研究的分析范围不断增大、数据精度越来越高的需求背景下,以Pfafstetter 编码为基础,对流域编码并行化方法进行研究。首先,分析了Pfafstetter 编码不全面和码位不一致的问题,改进了Pfafstetter 编码规则;然后,从数据并行的角度,讨论了并行计算环境下的数据划分及并行化策略,进而设计了流域编码并行算法;最后,利用长江中上游流域SRTM数据,在集群系统上对流域编码并行算法的正确性和并行性能进行了测试。实验结果表明,本文设计实现的流域编码并行算法可获取与实际较为一致的计算结果,且提高了编码计算效率,可为基于子流域划分的流域分析并行化提供参考。     

改进SPIHT算法及硬件高速实现

基于小波变换的SPIHT图像压缩方案是一种实用高性能图象压缩编码算法,但原始SPIHT算法链表式编码限制了其在高速处理中的应用。本文提出了一种改进的SPIHT压缩编码算法,在确保恢复图像质量与原始算法基本相当的基础上,改进算法可以采用并行流水结构实现,有利于高速处理中的应用,可以对高达40×8Mbit／s的原始图像实时压缩和去压缩。     

Quantification of Spatial and Thematic Uncertainty in the Application of Underwater Video for Benthic Habitat Mapping

This study presents an analysis of the application of underwater video data collected for training and validating benthic habitat distribution models. Specifically, we quantify the two major sources of error pertaining to collection of this type of reference data. A theoretical spatial error budget is developed for a positioning system used to co-register video frames to their corresponding locations at the seafloor. Second, we compare interpretation variability among trained operators assessing the same video frames between times over three hierarchical levels of a benthic classification scheme. Propagated error in the positioning system described was found to be highly correlated with depth of operation and varies from 1.5m near the surface to 5.7m in 100m of water. In order of decreasing classification hierarchy, mean overall observer agreement was found to be 98% (range 6%), 82% (range 12%) and 75% (range 17%) for the 2, 4, and 6 class levels of the scheme, respectively. Patterns in between-observer variation are related to the level of detail imposed by each hierarchical level of the classification scheme, the feature of interest, and to the amount of observer experience.     

HiPAP100水下定位系统在海底摄像中的应用

分析了HiPAP100高精度声学定位系统及其水下定位原理,阐述了影响水声传播的因素及HiPAP100的解决办法,介绍了水下定位系统在我国海洋区域地质调查海底摄像测站作业中的应用,分析比较海底摄像常规定位与HiPAP100超短基线的定位精度,说明水下定位在海底摄像等水下拖曳和定点作业中的必要性和重要性。     

Crime in Urban Post-Disaster Environments: A Methodological Framework from New Orleans

This paper considers the interrelationship between residential occupancy status, blight, and crime. An analytical frame is provided for a fine-scale analysis that is sufficiently flexible to capture both spatial and temporal dynamism in field-collected data. Unlike other works linking crime to evidence of disorder within neighborhoods, this paper considers this relationship in terms of neighborhoods affected by an external event (natural disaster), which results in more dynamic spatial and temporal patterns as the neighborhood is in a state of flux. As a result, new means of data collection and analysis are required, as any fine-scale relationship is longitudinal as well as cross sectional. The focus here is on the interrelationship of post-disaster residential occupancy, building conditions, and crime incidence for the Holy Cross neighborhood of New Orleans as it recovers from Hurricane Katrina. Results suggest that crime is inversely related to the amount of activity on a recovering street.     

基于改进SIFT算法的视频图像序列自动拼接

本文提出了一种自适应帧采样和限定特征提取区域的拼接方法,根据帧间重叠率和帧间隔建立线性模型,并把各帧图像对准到其前后的关键帧上。在特征点提取方面,提出了一种改进的SIFT算法进行特征点提取,并采用随机采用一致性(RANSAC)方法来更新匹配点,在图像融合中采用线性加权渐入渐出的自然融合算法。实验结果表明:该方法对一般场景能稳定的抽取到关键帧,并进行拼接,取得了较好的拼接效果。     

System structure and calibration models of intelligent photogrammetron

This paper describes the structure, geometric model and geometric calibration of Photogrammetron I—the first type of photogrammetron which is designed to be a coherent stereo photogrammetric system in which two cameras are mounted on a physical base but driven by an intelligent agent architecture. The system calibration is divided into two parts: the in-lab calibration determines the fixed parameters in advance of system operation, and the in-situ calibration keeps tracking the free parameters in real-time during the system operation. In a video surveillance set-up, prepared control points are tracked in stereo image sequences, so that the free parameters of the system can be continuously updated through iterative bundle adjustment and Kalman filtering.