Acoustic Imaging Algorithm Implementation Based On Imaging Sonar Platform

With the proposal of China’s strategy of building a maritime power,the development,utilization and protection of marine resources are inseparable from the research and development of marine equipment.Imaging sonar has more and more applications in military and civil fields.Based on the wide application requirements,the theory and implementation of imaging sonar system are studied in this paper.According to the technical requirements of the system,the corresponding research and implementation work are carried out in two aspects: system hardware platform and acoustic imaging algorithm.Firstly,the paper gives the technical index requirements of acoustic imaging sonar system,and theoretically calculates the key technical indexes of the system,such as array element spacing,angular resolution,array length and emission sound source level,which provides theoretical guidance for the design of sonar array,analog receiving circuit and emission circuit of subsequent systems;Secondly,the corresponding design of analog receiving circuit and digital circuit according to the requirements of system technical indicators,including the overall framework of hardware system,analog amplification circuit,automatic gain control circuit,A/D circuit and digital signal processing circuit based on FPGA device;Secondly,in order to meet the real-time imaging function of the system,the acoustic imaging algorithm based on focused beamforming is studied.The key factors affecting the imaging performance,such as near-field focused beamforming technology,array element amplitude weighting and automatic gain control,are analyzed in detail.Then,the effects of these key factors are evaluated by simulation;Finally,based on the FPGA core,the related functions such as automatic gain control circuit,A/D control,SD card reading and writing,serial port communication,network port communication and transmission waveform generation are realized.At the same time,the acoustic imaging algorithm is realized based on FPGA.After completing the system software and hardware design,the laboratory joint commissioning of the whole system is carried out,including hardware circuit,peripheral interface and related imaging algorithms.The joint commissioning results preliminarily verify the feasibility,real-time and stability of the system scheme.