【作者】 吴菊；

【导师】 卞红雨；

【作者基本信息】 哈尔滨工程大学 ， 信号与信息处理， 2013， 博士

【摘要】 本文围绕着声透镜成像技术，对透镜声场模型的改进、透镜系统的分析与设计、透镜系统的水池试验及可用于声透镜成像技术的压缩传感理论四个方面展开了研究。详细阐述了混合法透镜声场模型的基本结构及实施方法，并分析了其优点及仍需改进的地方。在此基础上，提出了改进的混合法透镜声场模型，即改进的射线声学-基尔霍数值积分混合模型和改进的射线声学-求和法混合模型。详细介绍了改进的混合法的基本结构及实现方法，并给出了仿真与试验结果，从而验证了改进的混合法透镜声场模型较原混合模型在模拟透镜声场性能上具有更高的准确度。运用改进的混合法透镜声场模型，仿真分析了透镜系统的焦点布放问题，详细研究了透镜系统的各参数对透镜系统波束性能的影响情况。这些参数包括几何参数（界面形状、界面尺寸、透镜个数及镜间距）、材料参数（声速和声衰减系数）、环境温度和工作频率等。根据仿真分析得到的先验知识，进行了四个透镜系统的设计：一、由单个透镜构成的单透镜系统；二、由两个透镜构成的透镜组系统；三、在水平方向和垂直方向上都具有聚焦性能的二维透镜；四、能够抵抗环境温度影响复合透镜系统，并给出了仿真结果及加工成型的透镜实物图。对已设计的透镜系统进行了水池试验，试验共分为两部分，第一部分为透镜系统的波束形成试验，试验内容包括透镜系统焦点位置的确定，波束指向性图的绘制，及聚焦深度的测量，试验结果与仿真结果基本吻合，充分验证了论文提出的改进的混合法用于模拟透镜声场的准确性。第二部分为透镜声纳样机系统的目标成像试验，利用单透镜声纳样机系统和透镜组声纳样机系统分别对圆环和叉形两种目标进行了成像试验，所成的目标图像轮廓清晰，更新速度快，从而充分地说明了透镜声纳用于目标成像的可行性及其良好的性能。阐述了压缩传感理论在声透镜成像技术中的应用前景，详细论述了压缩传感三个方面的基本理论：信号的稀疏表示、测量值的获取和信号的重构，重点研究了匹配追踪系列的信号重构算法，在正则化正交匹配追踪算法的基础上提出了一种渐进式的正则化自适应匹配追踪算法，仿真研究表明，用所提算法重建的图像在峰值信噪比、相对误差、匹配度及运行时间相比于现有相关算法都有提高。深入研究了分块压缩传感理论，在图像自适应分块压缩传感重建模型的基础之上，根据水声图像的特点，提出了一种新的图像自适应分块压缩传感重建算法，所提算法消除了图像中目标区域相邻块之间的块效应，提高了图像的重建质量，方便后续的目标特征提取及识别。更多还原

【Abstract】 The thesis discussed the acoustic lens imaging technology. Four main contents wereincluded in the thesis: improving the model of sound field generated by acoustic lens;analyzing and designing acoustic lens system; testing in a tank; compressive sening theorythan can be applied in acoustic lens imaging technology.The hybrid geometric/wave acoustic model was introduced in detail, and that theadvantages and disadvantages were analyzed. The improved hybrid geometric/wave acousticmodels were proposed. Detailed structure and implementation steps of improved model weregiven. Experimental results were compared to simulation. Therefrom, the improved modelhad more accuracy than the original hybrid model.The performance of an acoustic lens system was analyzed using the improved hybridmodel, such as focal region and parameter’s influnce on beampatterns of acoustic lens. Theparameters of lens system were geometry、material、tempreture、frequency and so on. Basedon the simulation results, four acoustic lens systems were designed: single-element acousticlens system; two-element acoustic lens system; two-demension acoustic lens; compoundacoustic lens system. The simulation and picture of the designed acoustic lens system weregiven.The tank tests were operated for the designed acoustic lens system. The test were dividedinto two parts. One was the beamforming test of the acoustic lens system, the other wasbeamforming and imaging test of the prototype. The former concluded testing the focalposition, drawing the beampatterns, measuring the field of view and practical range. Thecomparison between the simulation and test results verified the good accuracy of theimproved hybrid model in modeling the sound field. The latter concluded testing thebeamwidth of the prototype in the horizontal axis, testing the fied-of-view in the horizontaland vertical axis, testing the pratical range and range resolution and imaging the objects withshape of circle and cross. The images formed by the prototype had clearcutness and rapidupdate rate. Therefor, acoustic lens system were available in underwater acoustic imaging.Compressed sensing theory had potential application in acoustic lens image technology.Three aspects of compressed sensing theory: sparse representation, acquring measured dataand reconstruction of signal were introduced in detail.Orthogonal matching pursuit series theory was researched implemented. A gradual regularized adaptive matching pursuit was presented. Simulation results proved that theproposed algorithm improved peak signal noise ratio、relative error、matching and runtimeof reconstructed image. Block compressed sensing theory was the other research focus.According to the characteristics of underwater acoustic image, a new adaptive blockcompressed sensing reconstructing scheme was proposed. The improving algorithmeliminated blocking effect between neighboring subblocks in target area. The quality ofreconstructed image was increased which was convenient for feature extraction and targetidentification.更多还原