Design Of Sonar Imaging System Based On LabVIEW

Sonar imaging system is widely used in exploring, mapping, transporting,rescuing and many other fields due to its low environmental constraints andhigh-level imaging quality. The key factors to the image resolution of an imagingsystem are the precision and stability of echo signal measurement. Compared withthe traditional developing platform, LabVIEW can accomplish echo signalacquisition with high velocity, stability and accuracy. Therefore, in this dissertation,a multi-channel sonar imaging system is designed based on LabVIEW.Firstly, the feasibility of designing a multi-channel sonar imaging systems isdiscussed, combined with LabVIEW programming environment and PXIe-6358data acquisition card, including the introduction of basic principle, the propositionof design requirements and the system parameter analysis. Then the overall designscheme of hardware and software for the sonar imaging system is proposed toprovide theoretical support and basis.Subsequently, hardware circuit for sonar imaging system is designed,consisting of a transmitter and a receiver. The transmitter which launches specificsonar signals is composed of a power amplification circuit and a transceiverconversion circuit while the receiver which acquires and amplifies the echo signal ismade up of echo amplifying circuit.The emphases of the design in this dissertation is the software programmingfor the sonar imaging system, including data processing, image processing andinterface design. Data processing module, which realises echo signal acquisition,condition and gain control, is composed of a Kaiser-windowed band-pass filter, aHilbert envelope detection, a variable sampling data compression and a two-stagetime-gaining compensation. Image processing module is composed of imagepre-processing and image post-processing. Pre-processing, including dynamic rangetransformation and edge enhancement based on one-dimensional echo signal,improves the quality of two dimensional sonar image indirectly. Andpost-processing, including denoising and histogram enhancement, improves thequality of two dimensional sonar image directly. The interface for the sonar imagingsystem is designed utilizing the concept of virtual instruments in LabVIEWprogramming environment. Thus, not only the complexity of the hardware circuit has been reduced, but the development cycle has also been shortened. Thescalability and flexibility of the system interface has been increased as well.Besides, this dissertation also accomplishes the pool test of the sonar imagingsystem. The results show that various system parameters meet the designrequirements while the image quality and system instantaneity are guaranteed.