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91.
介绍了8mm高分辨机载SAR雷达的组成、主要技术参数、工作原理及其研制情况,最后给出了该雷达飞行成像试验的结果。 相似文献
92.
To progressively provide the competitive rate-distortion performance for aerial imagery,a quantized block compressive sensing(QBCS) framework is presented,which incorporates two measurement-side control parameters:measurement subrate(S) and quantization depth(D).By learning how different parameter combinations may affect the quality-bitrate characteristics of aerial images,two parameter allocation models are derived between a bitrate budget and its appropriate parameters.Based on the corresponding allocation models,a model-guided image coding method is proposed to pre-determine the appropriate(S,D) combination for acquiring an aerial image via QBCS.The data-driven experimental results show that the proposed method can achieve near-optimal quality-bitrate performance under the QBCS framework. 相似文献
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Sepideh Maaref 《Journal of Dispersion Science and Technology》2018,39(5):721-733
Water-in-oil emulsion usually forms during waterflooding in some heavy oil reservoirs. The composition and salinity of the injected water critically affect the w/o emulsion droplet size distribution, which control the emulsion stability and emulsion flow in porous media. The aim of the present work is to assess the effect of different sea water salinities on w/o emulsion stability through microscopic imaging. Therefore, w/o emulsions were prepared with different sea water samples, which were synthesized to resemble Persian Gulf, Mediterranean, Red Sea, and North Sea water samples. The results showed that log-normal distribution function predicts very well the experimental data to track the emulsion droplet size distribution, and then it was used for the emulsion stability analysis. It was found that among the four emulsion samples, North Sea emulsion with the lowest NaCl and TDS concentration of 24.12?g/L and 34.44?g/L remained stable up to almost 24 hours, while Red sea emulsion with the highest NaCl and TDS concentration of 32.39?g/L and 41?g/L became unstable after 6-hour period. This indicated that as the brine concentration increases, the w/o emulsion droplets would be larger due to the higher rate of aggregation and coalescence, and the emulsion stability decreases. 相似文献
97.
设计了一种基于三角法线扫描的无人机载激光雷达三维成像系统。系统以520 nm线激光为光源照射目标,利用无人机扫描获取目标的三维数据。文章设计了无人机载激光线扫描系统的硬件系统,构建了线激光水下折射三维坐标解算模型,提出了水上、水面与水下激光条纹提取的图像处理方法,并利用研制的雷达系统进行了近海浅水区域无人机扫描实验。实验结果表明,系统利用IMU及GPS能够有效提升三维图像的准确性,快速获取目标区域水上及水下目标的三维数据,平均距离分辨率达到3 cm,具有速度快、精度高、成本低的优势,在近岸浅海区域的大范围高速三维成像领域具有广阔的应用前景。 相似文献
98.
为进一步提升数字城市平台建设质效,增强城市规划、管理的指向性,政府主管部门以及相关技术团队投入大量资源,引进、优化数码航空摄影技术,通过必要的技术创新,为数字城市平台建设提供数据支持。文章以数码航空摄影测量的应用作为出发点,系统探讨POS技术辅助下,数码航空摄影测量在数字城市平台建设中应用的基本方式与主要方法。 相似文献
99.
Mohd Abuzar Sayeed Rajesh Kumar Vishal Sharma 《International Journal of Communication Systems》2020,33(1)
The recent developments in collaborative search, acquisition, and tracking have hoisted the geographical barrier. The network between unmanned aerial vehicles (UAVs) and wireless sensor networks (WSNs) is one such collaboration, which comprises battery‐powered static sensor nodes that act as sources and sinks and UAVs that act as relays. This collaborative network presents with opportunities and advantages, but at the same time, configuration of such networks is an arduous task. The WSN nodes are characterized by constant depleting power. Their network itself requires constant management and reconfiguration. These requisites can be slaked through the formation of an efficient data dissemination algorithm, which acclimates according to the network state. Considering this, a data dissemination approach is presented in this paper, which constructs a virtual topology predicated on the charge of WSN nodes utilizing software‐defined networks (SDNs) through UAVs. The topology is constantly monitored and reconfigured when required. The aerial nodes are equipped with multiple‐input multiple‐output (MIMO) antennas in order to facilitate simultaneous communication with the ground nodes, the base station, and the SDN controller. An efficient sleep timer and backoff counter strategies are also utilized by the proposed approach. The SDN controller facilitates the topology formation and maintenance of a sleep timer and a backoff counter. The proposed model is compared with clustered hierarchical layouts and hexagonal cell layouts through the network simulations. The results suggest significant improvements in the proposed model for various metrics, such as lifetime, delay, latency, delivery ratio, and throughput in comparison with the existing solutions. 相似文献
100.
Reza Tarighi Kamran Farajzadeh Hooman Hematkhah 《International Journal of Communication Systems》2020,33(7)
Since unmanned aerial vehicles (UAVs) have been introduced as mobile nodes for data gathering, wireless sensor networks (WSNs) have progressed considerably. The resulting WSN‐UAV systems are employed for emergency applications and also for remote monitoring purposes. WSN‐UAV systems yield an optimum data gathering method using the WSN. In the proposed method, the nodes' data are transferred using a remotely operated vehicle (drone) rather than the conventional data transferring methods like the direct and hop‐to‐hop data transmission approaches. Then, the gathered data are delivered in the pre‐determined destination point. WSN‐UAV systems, in fact, are a special case of the systems with the mobile sink in which the sink path is previously specified and controlled. In this paper, the effects of clustering parameters on the WSNs are studied; then, the network's lifetime is prolonged by applying some parameters. In addition, the network's performance is enhanced to some extent by assigning some changes in the media access control (MAC) layer. Also, the effect of drone's path pattern on the lifetime of the network is studied. 相似文献