声呐合成孔径干涉测量的研究现状与进展     

蒋廷臣  王秀萍  王晓松  焦明连  董春来 《测绘科学》2016,41(11):1-4,30

针对合成孔径声呐是一种新型高分辨水下成像声呐,尤其是其干涉测量是一种高精度测量海底地形的先进技术,具有很大的应用前景,但是目前尚还没有得到广泛应用的问题,详细分析了声呐合成孔径干涉测量近期的研究现状与研究进展情况。该文在声呐合成孔径干涉测量原理的基础上,比较了与合成孔径雷达干涉的不同,重点阐述了相关理论和设备的研究现状和进展,同时分析了现在声呐合成孔径干涉测量所存在的主要问题,最后介绍了目前声呐合成孔径干涉测量的研究展望。  相似文献   

多波束声呐和侧扫声呐数据融合方法研究综述          下载免费PDF全文

房旭东  钟贵才 《海岸工程》2016,35(4):63-68

多波束声呐系统与侧扫声呐系统均为海底面探测的重要工具,二者均采用声学方法,在工作原理上存在异同。本文简要介绍了二者的研究进展,分别对其数据处理进行了比对分析,认为多波束声呐处理方法侧重于数据的测量精度,而侧扫声呐则主要侧重于图像处理;归纳了当前二者主要的数据匹配融合方法,包括同名特征融合、基于SURF算法的匹配融合以及特征点融合,从数据采集原理上对数据融合方法进行了深入分析,发现在探头定位、单ping数据点分布以及ping之间的数据定位上存在一定的困难,即使经过一定的处理,二者采集的也非简单的平面图像,故二者的数据融合尚存在一定的难度。  相似文献   

Spatio-temporal characteristics of small-scale wave–current ripples on the Ameland ebb-tidal delta     

Laura Brakenhoff  Maarten Kleinhans  Gerben Ruessink  Maarten van der Vegt 《地球表面变化过程与地形》2020,45(5):1248-1261

Ebb-tidal deltas are highly dynamic environments affected by both waves and currents that approach the coast under various angles. Among other bedforms of various scales, these hydrodynamics create small-scale bedforms (ripples), which increase the bed roughness and will therefore affect hydrodynamics and sediment transport. In morphodynamic models, sediment transport predictions depend on the roughness height, but the accuracy of these predictors has not been tested for field conditions with strongly mixed (wave–current dominated) forcing. In this study, small-scale bedforms were observed in the field with a 3D Profiling Sonar at five locations on the Ameland ebb-tidal delta, the Netherlands. Hydrodynamic conditions ranged from wave dominated to current dominated, but were mixed most of the time. Small-scale ripples were found on all studied parts of the delta, superimposed on megaripples. Even though a large range of hydrodynamic conditions was encountered, the spatio-temporal variations in small-scale ripple dimensions were relatively small (height 0.015 m, length 0.11 m). Also, the ripples were always highly three-dimensional. These small dimensions are probably caused by the fact that the bed consists of relatively fine sediment. Five bedform height predictors were tested, but they all overestimated the ripple heights, partly because they were not created for small grain sizes. Furthermore, the predictors all have a strong dependence on wave- and current-related velocities, whereas the ripple heights measured here were only related to the near-bed orbital velocity. Therefore, ripple heights and lengths in wave–current-dominated, fine-grained coastal areas ( mm) may be best estimated by constant values rather than values dependent on the hydrodynamics. In the case of the Ameland ebb-tidal delta, these values were found to be m and m. ©2019 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.  相似文献   

Mapping benthic habitat in regions of gradational substrata: An automated approach utilising geophysical,geological, and biological relationships     

Craig J. Brown  Jenny S. Collier 《Estuarine, Coastal and Shelf Science》2008

The relationship between acoustic backscatter, sediment characteristics and benthic habitat is examined using high-resolution sidescan sonar data collected at the Loch Linnhe artificial reef site on the west coast of Scotland. The site is typical for the continental shelf of NW Europe, with a mix of seabed environments from muddy to coarse, stony substrata on a 10–100 m length scale. A sidescan sonar mosaic was produced and classified according to derived backscatter parameters (mean, median and standard deviation of the backscatter values) using an unsupervised classification procedure. The accuracy of the final classified map was assessed by comparison with a ground-truthing survey in which the biological habitat was derived from underwater video footage. The sidescan correctly predicted seabed surface characteristics of observed biological habitat with 78% accuracy. A second, and more challenging test of the acoustic data to correctly predict biological habitat was made by comparing it with data from 21 grab sampling stations. These stations were divided into three groups using multivariate statistical techniques based on their backscatter properties. Benthic assemblage structure was found to be significantly distinct between the high and low, and the medium and low backscatter stations. There was a low to moderate but significant correlation between the multivariate patterns of acoustic backscatter, benthic assemblage structure, and particle size distribution. The work shows that even in areas with subtle and gradational changes in substratum, the sidescan was able to predict biological community with an acceptable accuracy.  相似文献   

Megaplume bubble process visualization by 3D multibeam sonar mapping     

《Marine and Petroleum Geology》2015

MultiBeam echosounder data were collected during a surface-ship survey of the 22/4b well site in the North Sea in September 2011 using a Teledyne-Reson 7125. Modern multibeam echosounders are instrumental in providing detection and accurate localization of weak to strong bubble plumes. Two survey profiles effectively insonified the bubble plumes rising from the main crater at the well site, providing snapshot data of bubble plume processes. Additionally, three profiles insonified bubble plumes rising from, in, and to the south of a secondary crater, 1.2 km southeast of the main crater. Data processing included a simple algorithm that muted mislocated echoes from incomplete sidelobe suppression. The data processing produced a Cartesian volume of echo intensity from the water column and seabed.Plume geometry was analyzed to investigate a number of important large-scale plume processes, including plume bubble detrainment due to currents and stratification, downwelling flows, sea surface interaction, plume heterogeneity, and other fluid transport processes. The data showed strong upwelling flows, with bubble vertical motions generally much faster than currents. One important finding was that megaplumes create intrusions above the general thermocline, in part because their extensive upwelling flow lifts the thermocline locally. As a result, the intrusion layer deposits dissolved gases in the upper wave-mixed layer of the water column where it is not isolated from the atmosphere, unlike dissolved gases in the lower water column.The analysis shows that high fidelity multibeam echosounder data can provide a wealth of remote sensing information on bubble plume characteristics and processes, with important applications, including blowout monitoring and response, better understanding of megaplumes such as used in lake destratification, and improved characterization of natural seep emission processes.  相似文献   

基于声纳图像纹理特征的海底底质分类方法研究     

赵永祯  唐劲松  钟何平 《海洋测绘》2015,35(3):60-63

一般不同底质的海底声纳图的纹理特征不同。重点分析了不同底质声纳图像纹理特征的差异,为底质分类的实现提供了基础。并提取了海底声纳图像的灰度共生矩阵,将灰度共生矩阵的统计特征作为特征向量。最后应用自组织迭代(ISODATA)分类算法依据对特征向量进行分类,从而实现了海底底质的划分。  相似文献   

海底冷泉在旁扫声纳图像上的识别   总被引：2，自引：0，他引：2  

栾锡武  刘鸿  岳保静  A Obzhirov 《现代地质》2010,24(3)

海底冷泉是指来自海底沉积地层(或更深)的气体以喷涌或渗漏的方式注入海洋中的一种海洋地质现象,它普遍发育于主动大陆边缘和被动大陆边缘。海底冷泉研究在天然气水合物、全球气候变化、极端生物群落等研究方面都具有重要意义。利用实测的海上资料,通过分析水体声学剖面上的冷泉气柱、旁扫声纳图像上的亮斑异常以及柱状沉积物样品中天然气水合物等的对应关系,指出旁扫声纳图像上出现的亮斑异常是海底冷泉喷逸的指示。海底冷泉逸出的大量气泡遮蔽海底,从而形成一个强波阻抗界面,这个强波阻抗界面在旁扫声纳图像上形成亮斑异常。通过亮斑异常,可以判定海底冷泉的存在。旁扫声纳可以成为海底冷泉探测的有力方法。  相似文献   

海底三维声学图像实时处理系统设计     

李志华  李秋峦 《海洋工程》2014,32(4):124-130

结合多核CPU硬件PC平台,设计了一种海底三维声学图像实时处理系统,主要包括声学前端信号处理子系统、数据传输控制子系统和PC客户端图像处理系统三个部分。声学前端信号处理子系统统根据接收到的多路声学换能器信号,通过两级FPGA信号处理,采集多通道水声信号,进行实时电子聚焦波束形成。为了解决海量声学数据快速传输问题,数据传输控制子系统未采用传统用户空间TCP/IP传输机制,而是直接通过嵌入式PowerPC处理器在Linux内核态采用DMA通道进行声学数据转发,减少系统调用和数据拷贝开销,有效提高网络传输效率。针对海量声学数据实时处理需求,PC客户端图像处理系统通过对复杂、耗时的单帧重建和数据拼接算法模块根据声学数据点的角度范围进行等分分割,对每个子范围声纳数据采用多线程并行处理,均衡多个CPU核之间负载,实现高性能三维声学图像实时处理。通过室内水池和湖试实验,结果表明该系统能够实时高效地进行三维声学图像采集、传输与处理。  相似文献   

声波探测技术在海底输油管道检测中的应用          下载免费PDF全文

张永明  石晓伟  毕建强  孙圣堂  吕志伟 《海洋测绘》2014,(1):65-67

介绍了多波束测深系统、侧扫声纳和浅地层剖面等声波探测技术的基本原理及在海底管道检测中常用设备与参数选择。结合工程实例给出了各种检测方法在海底输油管道检测中应用效果。介绍了海底管道检测流程,分析了各种检测方法的优缺点和不足之处。结果表明,海底管道检测时应充分利用各种方法的互补性,提高检测效率和准确性。  相似文献   

基于遗传小波神经网络的海底声学底质识别分类   总被引：4，自引：3，他引：1  

熊明宽  吴自银  李守军  尚继宏 《海洋学报》2014,36(5):90-97

分割海底声纳探测图像,提取单元特征向量进行主成份分析,选取均值、标准差、对比度、相关系数、能量及同质性作为训练特征向量,构建小波神经网络。利用遗传算法优化小波神经网络的初始权值及小波参数,对砂、礁石、泥3种底质类型分别进行训练,并得到3种底质的测试精度都在90%以上,优于单独利用小波神经网络进行训练时的测试精度,克服了小波神经网络训练时易陷入局部极小的固有缺陷,表明基于遗传算法的小波神经网络可有效用于海底底质声纳图像的识别和分类。  相似文献