【摘要】：水下聲學成像是進行水下探測的重要方法之一,相比于光學成像等其他方式的成像,具有成像距離遠、環(huán)境適應(yīng)性好等優(yōu)點。以往的水下成像中一般使用較為成熟延時疊加等成像算法,并采用大規(guī)模的分立元器件和較多的傳感器陣元,這樣的設(shè)計方式系統(tǒng)運算量大,硬件系統(tǒng)復雜不便于移植和修改,傳感器基陣較大。文中探索了應(yīng)用于稀疏基陣水下正視成像的壓縮感知方法,根據(jù)數(shù)字化的思想利用FPGA作為硬件系統(tǒng)的主控芯片,設(shè)計了水下成像系統(tǒng)。文中選取線性調(diào)頻信號作為發(fā)射信號,分析了水下成像場景的稀疏性,根據(jù)發(fā)射信號和目標作用產(chǎn)生的回波信號的特點設(shè)計了字典對回波信號進行了稀疏表示。利用自適應(yīng)的塊貝葉斯恢復方法對回波信號中的場景系數(shù)進行恢復,相比于傳統(tǒng)的成像算法對回波信號的數(shù)據(jù)量需求較少,可以在不同的信噪比下得出較好的結(jié)果。本文設(shè)計并實現(xiàn)了一種基于FPGA和USB的水下成像硬件控制采集系統(tǒng)。利用FPGA作為電路的主控芯片,使用Verilog HDL和原理圖相結(jié)合的編程方式,完成了 AD采樣控制、SRAM存儲、USB通信控制、數(shù)據(jù)解碼等功能,通過Modelsim對所設(shè)計的程序進行了仿真測試。電路和上位機間使用USB通信方式,通過對芯片cyc68013中的51單片機核進行C語言編程控制實現(xiàn)。仿真結(jié)果表明在文中所設(shè)計的字典下用自適應(yīng)的塊貝葉斯的方法能夠得到水下目標的幾何結(jié)構(gòu),FPGA和USB編程各模塊仿真測試符合要求,硬件系統(tǒng)能在FPGA控制下有效工作并和上位機進行通信。
[Abstract]:Underwater acoustic imaging is one of the important methods for underwater detection. Compared with other imaging methods such as optical imaging, underwater acoustic imaging has the advantages of long imaging distance and good environmental adaptability. In the past underwater imaging generally used more mature imaging algorithms such as delay superposition, and used large scale discrete components and more sensor array elements. This design method has a large amount of calculation and complex hardware system is not easy to transplant and modify. The sensor array is large. In this paper, the compression sensing method applied to sparse array underwater emmetropia imaging is explored. According to the idea of digitization, the underwater imaging system is designed using FPGA as the main control chip of the hardware system. In this paper, the linear frequency modulation (LFM) signal is selected as the transmitting signal, and the sparsity of underwater imaging scene is analyzed. According to the characteristics of the transmitted signal and the echo signal generated by the target action, a dictionary is designed to represent the echo signal sparsely. The adaptive block Bayesian restoration method is used to recover the scene coefficients of echo signal. Compared with the traditional imaging algorithm, the data volume of echo signal is less, and better results can be obtained under different SNR. In this paper, a hardware control acquisition system for underwater imaging based on FPGA and USB is designed and implemented. By using FPGA as the main control chip of the circuit and the programming method of combining Verilog HDL with schematic diagram, the functions of AD sampling control, FPGA storage, communication control and data decoding are completed. The designed program is simulated and tested by Modelsim. The communication mode of USB is used between the circuit and the host computer. The 51 MCU core of the chip cyc68013 is controlled by C language programming. The simulation results show that the geometric structure of underwater target can be obtained by using the adaptive block Bayes method in the dictionary designed in this paper. The simulation tests of the modules of FPGA and USB programming meet the requirements. The hardware system can work effectively under the control of FPGA and communicate with the host computer.
【學位授予單位】：南京信息工程大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TP391.41;TB56

【參考文獻】

中國期刊全文數(shù)據(jù)庫 前10條

1 李鵬;鄭太成;徐麗華;陳金立;;稀疏基陣水下聲成像的壓縮感知方法[J];儀器儀表學報;2016年08期

2 花少炎;丁明躍;尉遲明;;基于壓縮感知的超聲衍射層析成像研究[J];生物醫(yī)學工程學雜志;2015年05期

3 劉曉東;王磊;楊娟;鄧鍇;;我國海洋聲學探測技術(shù)競爭力分析[J];海洋技術(shù)學報;2015年03期

4 潘浩;孫超;卓頡;劉雄厚;;基于稀疏陣列技術(shù)的MIMO聲吶低運算量二維成像[J];西北工業(yè)大學學報;2014年04期

5 呂q，

本文編號：2222335