节点文献
声透镜波束形成和水声图像处理技术研究
The Study of Acoustical Lens Beam-forming and Acoustical Image Processing
【作者】 刘东宇;
【作者基本信息】 哈尔滨工程大学 , 电子与通信工程, 2009, 硕士
【摘要】 高分辨率成像声纳被广泛应用于海洋环境监测与资源开发中。论文对高分辨率成像声纳的两个关键技术:波束形成技术和水声图像处理技术进行了研究。论文首先研究了可用于高分辨率声成像的声透镜波束形成技术。利用混合模型计算了透镜声场,通过仿真计算分析了透镜几何参数、材料参数和环境温度对波束形成性能影响的规律;通过试验验证了仿真模型的正确性。其次,论文研究了基于序列声图像的水下目标定位方法。结合图像特点重点研究了图像预处理方法和后续降噪方法,经过预处理、图像累加、后续降噪实现了轨迹合成与目标定位。论文最后研究了水声图像分割技术。针对两类不同的声图像——前视声纳图像和侧扫声纳图像,分别讨论了适用的处理方法。重点研究了侧扫声纳的目标亮区和影区的分割方法。
【Abstract】 High-resolution imaging sonar is widely applied to ocean monitoring and exploiting. In this thesis, two key-techniques of high-resolution imaging sonar are studied: beam-forming and acoustical image processing.Firstly, acoustical lens beam-forming applicable for high-resolution imaging is studied. The acoustical field is calculated from hybrid model. Then, it is simulated that how the beam-forming performance changed by the geometrical and material parameters of the lens and the temperature. The model is verified by experimentation.Secondly, an underwater-object localization method based on sequencal acoustical images is studied. Preprocessing and post de-noising are discussed with consideration of image characteristics. Tracing and objects localizationing are implemented via the procedure of: preprocessing, images accumulation, post de-noising.At last, acoustical image segmentation is studied. The methods which can be applied to images of forward looking sonar and side-scan sonar, are discussed respectively. The emphasis of this part is the method for segmenting bright-area and shadow-area in the side-scan sonar images.
【Key words】 image sonar; acoustical lens; acoustical image processing; image segmentation;