An effective thin cloud removal procedure for visible remote sensing images     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

Clouds are obstructions for land-surface observation, which result in the regional information being blurred or even lost. Thin clouds are transparent, and images of regions covered by thin clouds contain information about both the atmosphere and the ground. Therefore, thin cloud removal is a challenging task as the ground information is easily affected when the thin cloud removal is performed. An efficient and effective thin cloud removal method is proposed for visible remote sensing images in this paper, with the aim being to remove the thin clouds and also restore the ground information. Since thin cloud is considered as low-frequency information, the proposed method is based on the classic homomorphic filter and is executed in the frequency domain. The optimal cut-off frequency for each channel is determined semi-automatically. In order to preserve the clear pixels and ensure the high fidelity of the result, cloudy pixels are detected and handled separately. As a particular kind of low-frequency information, cloud-free water surfaces are specially treated and corrected. Since only cloudy pixels are involved in the calculation, the method is highly efficient and is suited for large remote sensing scenes. Scenes including different land-cover types were selected to validate the proposed method, and a comparison analysis with other methods was also performed. The experimental results confirm that the proposed method is effective in correcting thin cloud contaminated images while preserving the true spectral information.  相似文献   

移动领域中的GIS技术     

张昊然 《东北测绘》2014,(4):137-138

简要介绍了移动GIS技术的产生背景、系统构成、工作原理、关键技术、实际应用以及发展趋势。  相似文献   

Efficiently implementable algebra for distributed in-network spatial analysis     

Farhana Jabeen  Alvaro A.A. Fernandes 《International journal of geographical information science》2013,27(4):815-844

Existing sensor network query processors (SNQPs) have demonstrated that in-network processing is an effective and efficient means of interacting with wireless sensor networks (WSNs) for data collection tasks. Inspired by these findings, this article investigates the question as to whether spatial analysis over WSNs can be built upon established distributed query processing techniques, but, here, emphasis is on the spatial aspects of sensed data, which are not adequately addressed in the existing SNQPs. By spatial analysis, we mean the ability to detect topological relationships between spatially referenced entities (e.g. whether mist intersects a vineyard or is disjoint from it) and to derive representations grounded on such relationships (e.g. the geometrical extent of that part of a vineyard that is covered by mist). To support the efficient representation, querying and manipulation of spatial data, we use an algebraic approach. We revisit a previously proposed centralized spatial algebra comprising a set of spatial data types and a comprehensive collection of operations. We have redefined and re-conceptualized the algebra for distributed evaluation and shown that it can be efficiently implemented for in-network execution. This article provides rigorous, formal definitions of the spatial data types, points, lines and regions, together with spatial-valued and topological operations over them. The article shows how the algebra can be used to characterize complex and expressive topological relationships between spatial entities and spatial phenomena that, due to their dynamic, evolving nature, cannot be represented a priori.  相似文献   

观测系统逼真度特性分析   总被引：1，自引：0，他引：1  

刘序俨  黄声明  梁全强  季颖锋  王旭 《大地测量与地球动力学》2010,30(Z1)

在对观测系统保真度概念内涵阐述的基础上,对观测系统满足逼真度要求为什么必须为一线性不变系统的原理作了分析,指出观测系统的单位脉冲时间响应函数(权系数)和传递函数与输入的大小及其性质无关,并完全表征了系统的特性,从时域和频域对观测系统的权系数与传递函数的特征进行的分析表明:对于一个物理可实现的观测系统,不可能为一理想线性时不变系统,仅能要求在规定的通频带内和允许的观测精度范围内其传递函数近似为一平坦直线时,其相位滞后近似等于0或与频率成正比,就能满足观测的逼真度。最后对观测系统的格值及其标定进行讨论,以水平摆为例,从其动力学常系数线性微分方程推导出理论格值,以说明一种优良的观测系统,不但要给出格值人工标定的方法,同时也要给出理论格值公式,并要经受住观测数据的可靠性检验。  相似文献   

汶川8级地震后对地震数据远程传输方式的思考     

康宏  王余伟  吴彤 《地震地磁观测与研究》2010,31(4):32-38

2008年5月12日汶川8.0级特大地震,是继1976年唐山大地震后的又一人间悲剧。灾难过后,痛定思痛,如何保证在非常时期将地震数据可靠地传输回台网管理中心,为研究人员提供完整的数据波形,是地震观测技术人员在这次地震后应该慎重思考的问题之一。本文收集比较了中国地震部门常用的4种地震数据传输方式在8.0级特大地震中的表现,供同行参考。  相似文献   

环境监测网络中的ZigBee网关服务器     

杨春勇  牛磊  路杰  李明 《大地测量与地球动力学》2011,31(2):156-159

针对在环境监测网络中使用 PC服务器存在造价高、体积大、不易移动,以及客户端软件安装繁琐等问题,设计并实现了一种基于微处理器STM32F101R8和CGI技术的ZigBee网关服务器。该服务器采用内嵌TCP/IP协议栈的网络接口模块芯片W5100,具有UART/SPI/I\+2C/USB多种硬件接口并在可拆卸U盘中植入系统应用程序;环境监测参数由嵌入式网页发布,用户可通过网页远程控制传感器节点。对系统的实际测试结果表明,该设计具有成本低、可靠性高、操作简单等优点,较PC服务器更能满足环境监测的需要。  相似文献   

全液压深孔钻机适用的钻探参数监测系统     

方俊  鄢泰宁  卢春华  张杰 《煤田地质与勘探》2013,41(1):84-88

针对全液压深孔钻机的特点,研制了一种钻探参数监测系统（简称钻参仪）。该钻参仪采用模块化设计,可实现钻探参数实时监测、存储、回看、工况识别和数据远近程无线传输等功能。现场试验表明,该钻参仪技术先进,性能稳定可靠,可满足施工需要,效果显著。   相似文献   

GSM短信预警的智能家居服务系统设计     

朱恒军  张志华  于泓博  都文和 《东北石油大学学报》2012,36(4):79-84,9

针对家居水表流量和有害气体浓度无法实时监控问题,设计一种监控水表流量和有害气体浓度的实用智能家居服务系统.该系统以ARM9作为主控处理器,采用无线方式读取水表数据,采用CAN总线接收有害气体浓度信息,通过GSM短信模块实现与手机终端的双工通信;可以通过手机短信设置用水量信息,当需要购买水费或有害气体浓度超标时,业主能够得到及时提示,从而实现对水表流量和有害气体浓度的实时监控.  相似文献   

一种气象数据无线传输与综合显示系统     

李杰  陈钟荣  黄鹏良  黄建松 《南京气象学院学报》2012,4(4):371-375

为提高气象数据传输的灵活性,采用一种安装方便、性价比较高的无线模块来传输数据.常见气象仪器有一套独立的数据接收显示软件,但无法综合显示.开发一款软件,将VPF-730实时天气现象仪、WEATHERPAK-2000自动气象站数据和串口摄像头图像进行综合对比显示,并提供数据存储及历史数据查询基本功能.经实验验证,该系统运行稳定,数据显示效果较好.  相似文献   

掌上型导游器的实现   总被引：1，自引：0，他引：1  

董军  林翔 《测绘信息与工程》2003,28(4):34-36

介绍了基于地理信息系统、全球定位系统和无线上网技术的移动定位信息浏览器——掌上型自主导游器，给出了在Palm OS上的总体结构和软件设计方案，描述了特定的地理信息系统及其人机界面。  相似文献