Automatic Synthetic Aperture Radar based oil spill detection and performance estimation via a semi-automatic operational service benchmark

Today the health of ocean is in danger as it was never before mainly due to man-made pollutions. Operational activities show regular occurrence of accidental and deliberate oil spill in European waters. Since the areas covered by oil spills are usually large, satellite remote sensing particularly Synthetic Aperture Radar represents an effective option for operational oil spill detection. This paper describes the development of a fully automated approach for oil spill detection from SAR. Total of 41 feature parameters extracted from each segmented dark spot for oil spill and ‘look-alike’ classification and ranked according to their importance. The classification algorithm is based on a two-stage processing that combines classification tree analysis and fuzzy logic. An initial evaluation of this methodology on a large dataset has been carried out and degree of agreement between results from proposed algorithm and human analyst was estimated between 85% and 93% respectively for ENVISAT and RADARSAT.     

测定天文大气折射和建立电磁波折射延迟实测模型(Ⅲ)-专用测量仪器

针对用天文大气折射测定值,建立随观测站和随方位而异的电磁波折射延迟改正模型的高精度要求,提出了新的仪器误差理论,其主要内容是允许仪器误差存在,并看成是不断变化的,采用相应的测量方法作实时的测定和修正,同时消除仪器的各种变形和误差的影响,排除观测数据中的各种系统误差来源,并达到提高单次测定精度目的;文中还针对不同纬度的观测站、多方位、从天顶直到低空的观测需要,给出了仪器总体结构的安排,和采用视频CCD作为接收器的终端设计方案,也给出了各种仪器误差的测定方法和测量装置的设计要求。     

基于H.264编码标准的远程视频采集系统的设计与实现

通过对如何构建远程视频采集(监控)系统的关键技术进行了较深入的研究,解决了非宽带环境下视频数据连续性和视频数据丢包等问题,视频编解码使用H.264压缩卡完成。     

高速公路视频监控系统

结合上界高速公路视频监控系统的开发, 探讨了视频监控系统开发中的两项关键技术--视频切换与视频采集的原理与具体实现.     

基于DSP的纸币号码识别系统

给出并实现了一种基于DSP的纸币号码识别系统。该系统通过视频解码器SAA7113将纸币号码图像转换成数字图像，并通过复杂可编程逻辑器件CPLD对SAA7113输出的数字图像进行开窗处理，以减小DSP的图像数据处理量和存储量。该系统的特点是在采用TI公司较廉价的54x系列DSP条件下，可以实现每秒25幅号码图像的视频采集速度，为实现具有纸币号码自动识别记录功能的点钞机奠定了基础。此外，系统还提供了与PC机通信的异步串行接口。     

基于WebGIS的视频星车流量分析与路况查询系统

车流量作为衡量路况信息的重要因素,需要一个低成本且高效的可视化监控系统。本文对视频监控中的车流量信息进行了提取分析,采用背景差分的方法对视频中有关的车辆因子进行提取,包括车流量信息提取、车辆类型提取、车速提取,并将分析得到的数据通过Web GIS发布到网络上支持在线预览,结合GIS和视频监控的特点,解决了传统视频监控系统空间位置感较差的问题。     

单幅图像地理信息提取方法

针对单幅图像难以提取地理信息的问题,该文提出了一种基于场景结构或单一坐标值约束的地理信息提取方法。面向地形起伏不大或结构化场景,基于几何关系约束,该文设计了单幅图像地理信息提取的总体框架。分别针对结构化和非结构化场景,采用场景结构约束、图像EXIF信息等,实现了摄像机内参及部分外参的求解。基于该信息,通过单一坐标值约束,构建了单幅图像地理信息的提取方法。最后,在平面或垂面约束下,对室内外地理场景进行了二、三维地理信息提取实验。结果表明,该方法能够将单幅图像中的特征点、线或面转换为地理空间数据。     

结合运动平滑约束与灰度特征的卫星视频点目标跟踪

针对卫星视频条件下的点目标跟踪问题,提出了一种运动平滑约束的贝叶斯分类目标跟踪方法(BMoST)。本方法引入朴素贝叶斯分类器的思想,不依赖目标的任何先验概率,在运动平滑性约束下,利用灰度相似性特征来表达描述目标的似然度,并根据独立假设的贝叶斯定理,建立简化的分类器条件概率修正模型,通过该模型估计目标的后验概率,从而实现目标跟踪。同时,采用卡尔曼滤波辅助、优化跟踪处理,提高算法的稳健性。试验数据采用SkySat和吉林一号拍摄的视频各两段,对6个点目标进行跟踪试验。结果表明,本文提出的方法针对卫星视频的点目标跟踪效果良好,精度达到90%左右,且跟踪轨迹平滑,满足卫星视频后续高级处理和应用需要。     

Supporting local health decision making with spatial video: Dengue,Chikungunya and Zika risks in a data poor,informal community in Nicaragua

One challenge facing spatial scientists trying to support public health outreach and intervention in challenging environments is the lack of fine scale spatial data. These data are required to gain a better understanding of both physical and social systems; why disease occurs where it does, and how to disrupt it. While data options exist, including high resolution aerial imagery, remotely sensed data, and even online mapping products like Google Street View, these all come with limitations. One option that has previously been utilized to assess cholera risk is spatial video. Here it is used to map potential mosquito breeding sites in an endemic Dengue and Chikungunya, and emerging Zika impacted community. We show how this method can provide mapping support in the hands of non-specialist public health workers who, working in collaboration with out-of-area geographic information systems (GIS) teams, can identify where to target limited intervention resources. We use a case study of an impoverished informal style Nicaraguan community suffering from a high disease burden to show spatial variation in potential mosquito breeding habitats. A field team collected street-by-street spatial video data to produce fine scale risk maps of standing water and trash locations, which, when interpreted with the associated spatial video imagery, were used to suggest where intervention strategies should be targeted. We also discuss how these same data layers can be used to address other health concerns traditionally found in informal settlements.     

海岸带实时实地视频观测ARGUS技术

区别于传统的定时定点野外测量方法,近年来各种遥感监测技术被应用于海岸带的实地观测领域。其中基于岸线的近岸实时实地视频观测技术(ARGUS系统)可获取大范围、长时间内的海岸带动力环境要素实测资料(诸如波浪、水流、岸线、地貌特征等),在海岸工程研究领域被广泛应用。通过对ARGUS系统的回顾,叙述了该技术的发展概况、视频数据类型和特点、图像分析方法和实际应用举例,同时简介了我国第一套ARGUS系统的构建。此外,也简要介绍了X波段雷达影像系统和红外线摄像系统在海岸工程研究中的应用。期望进一步推动上述近岸视频观测技术在我国海岸工程研究中的应用,为海岸带的综合管理利用和合理开发规划提供相应的科学支撑,同时促进各相关学科间(如海岸工程、测绘、图像分析等)的交叉合作。