基于SVM算法和GLCM的侧扫声纳影像分类研究     

郭军  马金凤  王爱学 《测绘与空间地理信息》2015,(3):60-63

根据侧扫声纳影像的特征,提出一种基于SVM和GLCM的侧扫声纳影像分类方法,利用灰度共生矩阵提取其纹理特征,采用主成分分析法对纹理特征进行筛选,选择适合侧扫声纳影像的最佳纹理特征,结合侧扫声纳影像的回波强度,应用支持向量机对侧扫声纳影像进行分类。研究结果表明,纹理特征结合回波强度的支持向量机分类精度高于只依靠回波强度的支持向量机分类精度。  相似文献   

Extraction of morphometric bedform characteristics from profiling sonar datasets recorded in shallow coastal waters of China     

黄瀚  汪亚平  高抒  陈坚  杨旸  高建华 《中国海洋工程》2012,26(3):469-482

The morphological characteristics of small-scale bedforms were measured by means of an acoustic profiling sonar on the Dafeng tidal flat,Jiangsu,in 2009,and in the Jiulong Estuary,Xiamen,in 2010,respectively.The "multi-threshold value" method was utilized to reveal the morphological undulations along which bedforms were present.Analyses of the datasets obtained show that:(1) sand ripples can have irregular shapes,and(2) changes in bedform morphology are small within a single tidal cycle but may be significant over several tidal cycles.Fractal and variogram analyses of the seabed roughness revealed the existence of a significant relationship between current speed and the fractal dimension of the seabed roughness.As current speed increases,seabed roughness increases with a trend of smaller-scale bottom structures being replaced by larger-scale structures.Furthermore,the surface of the larger-scale bottom structures can either become smooth due to the absence of smaller-scale features or become rougher due to the presence of superimposed smaller-scale structures.  相似文献   

利用粗集理论的声呐图像边缘锐化     

郭海涛  闫宏生  田坦  王连玉 《海洋技术学报》2005,24(1):118-119

边缘锐化是图像增强的重要内容。声呐图像像素少品质恶劣,边缘锐化是个难题。粗集理论是一种新的处理含糊和不确定性问题的数学工具,它为智能信息处理提供了有效的处理技术。将粗集理论应用于声呐图像的边缘锐化中,给出了实验结果。结果表明这种方法具有可行性。  相似文献   

Characterizing uncertainties for quantifying bathymetry change between time-separated multibeam echo-sounder surveys     

Thierry Schmitt  Neil C. Mitchell  A. Tony S. Ramsay 《Continental Shelf Research》2008

Changes of bathymetry derived from multibeam sonars are useful for quantifying the effects of many sedimentary, tectonic and volcanic processes, but depth changes also require an assessment of their uncertainty. Here, we outline and illustrate a simple technique that aims both to quantify uncertainties and to help reveal the spatial character of errors. An area of immobile seafloor is mapped in each survey, providing a common ‘benchmark’. Each survey dataset over the benchmark is filtered with a simple moving-averaging window and depth differences between the two surveys are collated to derive a difference histogram. The procedure is repeated using different length-scales of filtering. By plotting the variability of the differences versus the length-scale of the filter, the different effects of spatially uncorrelated and correlated noise can be deduced. The former causes variability to decrease systematically as predicted by the Central Limit Theorem, whereas the remaining variability not predicted by the Central Limit Theorem then represents the effect of spatially correlated noise. Calculations made separately for different beams can reveal whether problems are due to heave, roll, etc., which affect inner and outer beams differently. We show how the results can be applied to create a map of uncertainties, which can be used to remove insignificant data from the bathymetric change map. We illustrate the technique by characterizing changes in nearshore bed morphology over one annual cycle using data from a subtidal bay, bedrock headland and a banner sand bank in the Bristol Channel UK.  相似文献   

Further evidence of abrupt Holocene drowning of the Black Sea shelf     

R. D. Ballard  D. F. Coleman  G. D. Rosenberg 《Marine Geology》2000,170(3-4):253-261

A 1999 survey of the Black Sea continental shelf off the north central Turkish seaport of Sinop using a side-scan sonar, small remotely operated vehicles, and a series of dredge lowerings located, inspected and sampled an exposed high-energy paleoshoreline at a depth of 155 m. Radiocarbon dating of mollusk shells collected from this ancient beach revealed that the marine flooding of the Black Sea took place between 7460 and 6820 yr B.P. (all ages are reported in radiocarbon years, not calendar years, without correction for reservoir age or dendro-calibration) changing it from a lacustrine to marine environment. This relic surface remained in contact with the bottom waters of the Black Sea for a long period of time before being draped by a thin layer of sapropel mud. Wood samples recovered from this same location were very well preserved and yielded dates as old as 3580 yr B.P.  相似文献   

基于能量测量的声呐渗流矢量法及其应用     

胡盛斌  杜国平  徐国元  周天忠  钟有信  石重庆 《岩土力学》2020,41(6):2143-2154

为准确测定天然流场和人工流场下的地下水渗漏隐患,从能量测量的角度提出了一种水文地质测井的新方法——声呐渗流矢量法,系统地介绍了该方法的基本理论、原型仪器和测试步骤等内容。以时差法测量原理为基础,融合了矢量声呐技术、航空定向技术、压力传导技术、GPS定位等多种新技术,自主研发了声呐渗流测量仪及其显控软件,能够准确测定渗漏部位、渗漏通道以及流速、流向、流量等量化指标。并以富水地层地下连续墙基坑为工程案例,建立三维可视化渗流场成像系统,揭示三维空间渗流场分布特征,动态指导基坑渗控设计和堵漏处理,通过复测验证堵漏处理效果。结果表明：声呐渗流矢量法能够实现地下工程渗漏缺陷精准定位,在无强噪声干扰的情况下,检测结果完全满足工程渗控需要;提出以渗透流速为主、单孔渗流量和渗透系数为辅的基坑渗漏风险预警分级判定指标;结合地质勘察、监测预警、现场巡查、应急处置等手段,与其他方法相互验证,提前采取处理措施,有效规避渗漏水风险。  相似文献   

海洋调查中水下目标位置的确定   总被引：2，自引：0，他引：2  

隋海琛  刘彦祥  姜晓晖 《海洋测绘》2004,24(3):32-34

介绍了海洋调查中测量设备拖曳体(拖鱼)的三种定位方法：舷挂式、LAYBACK方式和超短基线方式;分析了不同定位方法确定水下目标位置的差异,并进行了精度估计。  相似文献   

台风对北部湾南部海底地形地貌及海底管线的影响   总被引：7，自引：0，他引：7  

董志华  曹立华  薛荣俊 《海洋技术学报》2004,23(2):24-28,34

利用旁侧声纳和多波束在不同时间段内对琼西南近岸海域进行了探测,并对台风前后的旁侧声纳资料进行了对比和分析。研究表明,琼西南近岸海域主要存在沙脊区和沙波区两种地貌类型,其中,沙波波高在1～5.5m,波长3～60m,沙脊波高在6～20m,波长2～4km。在不同年份和台风期间,沙波和沙脊存在明显的活动性,对铺设于此的海底管线构成了严重的影响。台风对小沙波起夷平作用,对较大沙波、沙脊增高加宽,并且可以使海底出现冲刷沟槽和凹坑。  相似文献   

基于模糊聚类的声呐图像多区域分割   总被引：2，自引：0，他引：2  

郭海涛  田坦  张春田 《海洋技术学报》2004,23(3):39-40,45

图像分割是图像识别中的主要问题,同时它又是一个经典难题;声呐图像恶劣的品质使图像的分割变得更为困难。文章将模糊聚类应用于声呐图像的多区域分割,实验证明这种方法简便而有效。  相似文献   

两种多波束反向散射强度数据归一化方法的建立与分析     

杨彬  何林帮 《海洋学报》2018,40(7):143-149

多波束反向散射强度数据应用广泛，但由于受到角度响应的影响，导致生成的多波束声呐图像质量偏低，且现有角度响应改正方法在复杂海底底质环境下适应性较差。为此本文对散射强度进行分析，给出了两种多波束反向散射强度数据归一化方法，分别为基于高斯拟合以及角度响应的散射强度改正方法，前者主要是基于散射强度的变化规律进行改正，而后者则是基于声波的散射机理进行改正。实验结果表明两种方法较传统改正方法精度均有约30%的提升，并且角度响应方法较高斯拟合方法改正精度更高，但计算效率有所下降。以上实验验证了两种方法的有效性，实现了散射强度数据的归一化，提升了多波束声呐图像的质量。  相似文献