共查询到19条相似文献,搜索用时 125 毫秒
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针对重力式码头沉箱安装接缝难以检测的问题,分别采用水下机器人、多波束扫测、三维声呐扫描技术进行检测。检测数据表明:水下机器人对沉箱接缝的检测效果直观、准确度较高;多波束测深系统对沉箱接缝具有一定的识别能力,但对于缝宽较小及距离较远的接缝分辨率较差;三维声呐探测扫测精度高,但扫测范围小且效率低。从测试原理上分析各种方法测试优缺点产生的原因并根据检测需求自主设计了三维声呐测量支架,实现对沉箱接缝任意深度量测,并结合工程实例取得良好的测试效果,为沉箱接缝检测方法的选取提供借鉴。 相似文献
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防波堤工程水下块石安装的效率及安全是工程中至关重要的部分,而传统的安装方法和检测手段存在严重不足。三维实时声呐成像系统有效克服了传统方法的弊端,具有实时、高效、清晰、保证人员安全的优势。并且能够在水下能见度极低、海况条件差等复杂条件下正常工作。以以色列阿什杜德港防波堤工程为例,总结利用水下三维声呐成像系统安装人工护坡块石所采取的技术与控制措施,具有较高的适用和推广价值。 相似文献
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声纳目标特征级融合的主要任务是实现信息压缩、目标身份确定(分类) ,以利于实时处理、决策分析。基于数学模型的各种算法,由于情况复杂,往往很难建立。而人工神经网络通过样本的学习,具有存储记忆、在相似输入下能恢复记忆等特性,从而避免了烦琐而复杂的建模。在神经网络声纳目标识别前的噪声预处理方法中,选用了功率谱特征提取、双谱特征提取算法;在研究了提取的特征后,选取反向传播神经网络(BP)模型;在此基础上构造了BP神经网络,并对网络进行训练与测试,给出识别实验结果。仿真模拟分析证明,基于神经网络的声纳特征级信息的融合,对目标分类有一定效果,为进一步实现声纳信息融合奠定了基础 相似文献
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In underwater target detection, the bottom reverberation has some of the same properties as the target echo, which has a great impact on the performance. It is essential to study the difference between target echo and reverberation. In this paper, based on the unique advantage of human listening ability on objects distinction, the Gammatone filter is taken as the auditory model. In addition, time-frequency perception features and auditory spectral features are extracted for active sonar target echo and bottom reverberation separation. The features of the experimental data have good concentration characteristics in the same class and have a large amount of differences between different classes, which shows that this method can effectively distinguish between the target echo and reverberation. 相似文献
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水下三维声纳目标在线运动监测与识别 总被引:1,自引:0,他引:1
随着声学探测在海洋资源开发中的广泛应用,水声成像技术已成为水下目标监测的重要手段,文章提出了一种基于三维声纳技术的在线运动目标识别方法。通过对三维声学图像进行网格搜索和三角面片连接,进行单帧三维声学图像的多层实时重建,实现单帧图像内目标的重建、聚类与标示。结合GPS定位仪和姿态仪信息,修正位移和姿态变化引起的运动误差,利用反向投影和最近点搜索方法查找相邻图像帧之间两两匹配的控制点对,进行相邻图像帧的快速配准。根据配准矩阵将相邻图像帧的的各个目标转换到同一全局坐标系中,提取有效的声学目标特征变化相对值,并评估特征权重,实现相邻图像帧之间运动目标的在线检测与识别。通过室内水池和湖试实验,结果表明该方法能有效地实现三维声学图像在线运动目标实时识别。 相似文献
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In underwater target detection, the bottom reverberation has some of the same properties as the target echo, which has a great impact on the performance. It is essential to study the difference between target echo and reverberation. In this paper based on the unique advantage of human listening ability on objects distinction, the Gammatone filter is taken as the auditory model. In addition, time-frequency perception features and auditory spectra features are extracted for active sonar target echo and bottom reverberation separation. The features of the experimental data have good concentration characteristics in the same class and have a large amount of differences between different classes, which shows that this method can effectively distinguish between the target echo and reverberation. 相似文献
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The effective method of the recognition of underwater complex objects in sonar image is to segment sonar image into target, shadow and sea-bottom reverberation regions and then extract the edge of the object. Because of the time-varying and space-varying characters of underwater acoustics environment, the sonar images have poor quality and serious speckle noise, so traditional image segmentation is unable to achieve precise segmentation. In the paper, the image segmentation process based on MRF (Markov random field) model is studied, and a practical method of estimating model parameters is proposed. Through analyzing the impact of chosen model parameters, a sonar imagery segmentation algorithm based on fixed parameters' MRF model is proposed. Both of the segmentation effect and the low computing load are gained. By applying the algorithm to the synthesized texture image and actual side-scan sonar image, the algorithm can be achieved with precise segmentation result. 相似文献
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YAO Bin LI Hai-sen ZHOU Tian SUN SHENG-he 《船舶与海洋工程学报》2006,5(4):42-47
The effective method of the recognition of underwater complex objects in sonar image is to segment sonar image into target, shadow and sea-bottom reverberation regions and then extract the edge of the object. Because of the time-varying and space-varying characters of underwater acoustics environment, the sonar images have poor quality and serious speckle noise, so traditional image segmentation is unable to achieve precise segmentation. In the paper, the image segmentation process based on MRF (Markov random field) model is studied, and a practical method of estimating model parameters is proposed. Through analyzing the impact of chosen model parameters, a sonar imagery segmentation algorithm based on fixed parameters' MRF model is proposed. Both of the segmentation effect and the low computing load are gained. By applying the algorithm to the synthesized texture image and actual side-scan sonar image, the algorithm can be achieved with precise segmentation result. 相似文献