声纳测深数据滤波及实践     

杨久东  马飞虎  孙翠羽  肖巍巍  程广振 《测绘信息与工程》2010,35(1):49-50

介绍了声纳测深的主要误差,分析了测深数据的滤波方法,实现了测深数据的质量控制。  相似文献   

多波束测深表层声速误差的动态影响及改正方法   总被引：1，自引：0，他引：1  

赵君毅  阳凡林  刘智敏  李真  赵相伟 《测绘科学》2010,35(6):23-25

表层声速不准确会对多波束测深波束的归位产生影响,对于平面换能器阵,使波束角产生偏差,从而影响波束最终位置,但Snell常数保持不变;对于曲面换能器阵,虽然波束未束控不产生波束角偏差,但Snell常数发生改变,会使波束在传播过程中出现折射误差,对深水环境测量不利。对于表层声速误差带来的水深误差,外部波束比内部波束受到的影响更严重。当表层声速无法实时准确获取时,根据内外部波束对水深的影响大小识别表层声速误差的存在,通过逐步调整表层声速值,计算波束指向角差值,再重新进行声线跟踪,计算改正后的波束位置,消除其带来的水深的影响,完成表层声速误差的改正。文中用实测数据进行了验证,对多波束测深数据质量的改善有一定的参考意义。  相似文献   

利用经验模态分解的侧扫声纳噪声抑制方法     

李应超  居向明  武同元 《测绘工程》2014,(4):24-27,32

针对海道测量中侧扫声纳声强数据中的噪声问题,分析侧扫声纳海底杂波的统计模型,提出基于ping数据的经验模态分解抑制噪声方法。结果表明,从ping声强数据中减掉周期小于4的模态后,声强数据可较好地服从Gamma分布,并保持声图中的细节信息。  相似文献   

侧扫声纳在琼州海峡跨海通道地壳稳定性调查中的应用   总被引：1，自引：1，他引：0  

李振  彭华  姜景捷  孙尧 《地质力学学报》2018,24(2):244-252

为开展琼州海峡跨海通道地壳稳定性评价,利用Sonar Beam S-150D侧扫声纳系统在琼州海峡海底开展了地形地貌调查,获得了琼州海峡跨海通道工程区的侧扫声纳影像。通过数据分析、图像判读,分析了地质灾害类型及其可能的危害。在琼州海峡海底发现软土、活动沙波、岸坡及活动构造等微地貌单元,跨海通道工程施工、运行阶段都将遭受相关地质灾害的危害。这些资料和分析为跨海通道工程地壳稳定性评价提供了基础资料,为工程规划线路优选、建设实施提供了技术支撑。研究表明侧扫声纳技术可应用于海底地壳稳定性调查与评价工作中。   相似文献   

Small-strain dynamic characterization of clayey soil from the Texcoco Lake,Mexico     

《Soil Dynamics and Earthquake Engineering》2014

The area occupied by the former Texcoco Lake was part of a system of lakes inside the Basin of Mexico. The subsoil there has been studied in the past but there is still a need for more and more thorough investigations into the dynamic properties of its highly compressible clays. This paper describes the results of an experimental laboratory research in which a triaxial cell fitted with bender elements was used to measure shear wave velocities (V_s) in clay specimens from the former Texcoco Lake. Soil specimens were subjected to isotropic loading–unloading cycles and values of V_s were determined during the saturation stage and after each stress increment or decrement. Our results show that irrespective of the testing method, shear waves velocities differ in no more than 7–15%.  相似文献   

Offshore sand sources for beach replenishment: Potential borrows on the continental shelf of the Eastern Gulf of Mexico     

Charles W. Finkl Jr.  Syed M. Khalil  Jeffrey L. Andrews 《Marine Georesources & Geotechnology》2013,31(2):155-173

Erosion of sandy beaches is a worldwide problem that elicits innovative geoengineer‐ing techniques to reduce adverse impacts of shoreline retreat. Beach replenishment has emerged as the “soft”; shore‐stabilization technique of choice for mitigating beach erosion. This method of shore protection involves the addition of sand to the littoral sediment budget for sacrificial purposes. Because inland sand sources are often uneconomical or impractical to use, and known nearshore sources are limited, finding adequate quantities of suitable sand on the inner continental shelf is often vital to beach replenishment projects. The technical studies of survey and materials analysis that identify and delineate usable sand sources are sometimes almost as expensive as small‐project dredging, pumping, and placing the sand on the beach as fill. Inadequate quantity or substandard quality of shelf sand, as well as often‐prohibitive overhead expenses, thus compel shoreline managers to seek suitable sand sources offshore.

In the study area off the central‐west coast of Florida, offshore potential borrow areas (PBAs) were identified on the basis of studies conducted in reconnoitory and detailed phases. Sophisticated state‐of‐the‐art equipment used in this investigation provided more detailed subbottom mapping information than is normally obtained with conventional seismic equipment. An example of sand exploration studies was incorporated in a 215‐km² survey of offshore areas by conducting bathymetric surveys and subbottom seismic profiling, collecting jet probes, grab samples, and vibrocores, and analyzing sediment grading in subsamples from vibrocores. These combined analyses indicated that at least 8.8 ×10⁶ m³ of sand is available in potential borrow areas from 7.0 to 12 km offshore in water depths of 8.0 to 11.5 m. In the PBAs, mean grain size of sand falls into the range 0.13–0.53 mm, sorting averages 0.65–1.31ø, and the overall silt content varies from 3.9–8.5%. High silt contents (13–19%) mapped in some areas make these sedimentary deposits unsuitable as fill for artificial beach renourishment.  相似文献   

Evaluating local population dynamics of the American lobster,Homarus americanus,with trap‐based mark‐recapture methods and seabed mapping     

Michael J. Dunnington  Richard A. Wahle  Michael C. Bell  Nathan R. Geraldi 《新西兰海洋与淡水研究杂志》2013,47(6):1253-1276

Seabed mapping, spatially referenced trapping, and mark‐recapture methods have all been useful tools in ecological studies of lobsters and other benthic animals. Here we integrate the three methods to evaluate local population dynamics and movements of American lobsters, Homarus americanus, in coastal fishing grounds in Maine, United States. The study was conducted on five study areas of different size, and used two different sampling protocols. At one site (1 km² in area) we used a monthly mark‐recapture sampling interval over a 6‐month period, only tagging a subsample of the catch. At four smaller sites (0.3 km²) we used a shorter‐term approach, sampling at 3–4‐day intervals for a 2‐week duration, tagging the entire catch. Tagging data were analysed with a modified Jolly‐Seber model adapted for continuous sampling to estimate population abundance, gains (immigration), and losses (emigration and mortality). Side‐scan sonar surveys of the seabed combined with diver‐based population surveys, stratified by substrate type, provided an independent comparison to mark‐recapture‐based estimates of abundance over the same areas. Spatial referencing of trap catch also allowed us to relate catch rates and lobster movements directly to seabed features. The longer‐term tagging data on the larger study area provided abundance estimates that were more consistent with the diver observations, and estimates of gains and losses statistically more robust, than those derived from the shorter‐term effort on the smaller sites. The flux of lobsters followed the well known seasonal movements on these fishing grounds, with gains and losses from the larger study area ranging over 1000 individuals per day, and an estimated mid‐summer peak density of >65 000 lobsters per km² (individuals >50 mm carapace length). This approach may lend itself to broader application with the American lobster.  相似文献   

基于SVM的海底声纳图像底质识别*     

熊明宽  吴自银  李守军  罗孝文  唐秋华 《海洋通报》2012,31(4):409-414

对海底底质声纳图像分割,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,优化支持向量机(SVM)参数.利用多分类 SVM 对砂、礁石、泥进行训练,有效、快速地分离出了3种底质类型,测试精度高于80%,表明该方法可有效用于海底底质声纳图像的识别和分类.  相似文献   

Curvelet变换域侧扫声纳图像增强算法     

盛惠兴  孟凡玲  李庆武  马国翠  曹晔锋 《海洋测绘》2012,(1):8-10

针对海底侧扫声纳图像对比度低、纹理弱、噪声严重等问题,提出了一种基于第二代Curvelet变换的声纳图像增强算法。首先对原始声纳图像进行多尺度、多方向的Curvelet变换分解,得到低频子带和高频子带;然后引入非线性S型函数对低频系数进行处理,提高图像整体的对比度;采用一种可以避免过度增强的新型非线性函数对各尺度的高频子带系数进行处理,提高图像整体的对比度,增强图像边缘和纹理细节,并通过估计噪声水平设定阈值进行阈值降噪。最后经Curvelet逆变换得到增强图像。实验表明,该方法不仅改善了海底侧扫声纳图像对比度低的问题,而且降低了噪声,突出了声纳图像的边缘和纹理细节。  相似文献   

汕头海域海底光缆路由条件及评价          下载免费PDF全文

张志强  刘强  贺惠忠  魏巍  于刚  蒋俊杰 《海洋测绘》2012,32(6):44-47

根据在东南亚至日本海底光缆汕头段（300m水深以浅）路由勘察中所获得的多波束、侧扫声纳、浅地层剖面、柱状取样等资料,结合勘察区的自然环境特征,对路由区的自然环境条件、海底工程地质条件进行了详细的分析,并对该段路由条件进行了综合评价。研究表明,此段路由在大陆架区域路由条件较好,适合海底光缆的铺设;在大陆架与大陆坡结合带路南条件相对较差,应做好应对措施。  相似文献