Underwater Sparse Array Imaging Beamforming Algorithm And System Implementation

Research and design of portable,high-speed real-time array imaging systems has been the goal of all marine workers and researchers.Array imaging is an imaging modality that utilizes large two-dimensional arrays to acquire three-dimensional ultra-high resolution acoustic images.At present,the research on array imaging system mainly focuses on the design of matrix,beamforming algorithm and related hardware and software design with fast,high resolution and strong robustness as the design goals.Based on the traditional B-mode ultrasound imaging technology combined with synthetic aperture technology,array imaging technology and other related theoretical research and experimental basis,a sparse array based underwater ultrasound imaging software and hardware system was designed and implemented,and a one-time launch was verified.The sparse array imaging method of imaging can be realized by the receiving process,and the correctness of the algorithm is verified by simulation experiments and hardware system experiments.The underwater acoustic transducer,named as an underwater sensor,is designed to have a decisive effect on the imaging quality of the imaging system.The design and layout of the sensor array directly affects the final performance of the imaging system.With the size of the sensor array element as the point of entry to analyze the performance of the sensor array,which has different aperture sensor array elements and different array element spacing,the multi-positive sparse array is designed by multiplicative theorem and its performance is compared with the Mills cross array.The structural advantage of this type of array is used as a front-end imaging array for sparse array imaging.Firstly,the beamforming algorithm in the one-time transmit-receive imaging method is analyzed,and the difference between near-field and far-field beamforming performance is simulated.The single-focus,multi-focus and apodization functions are performed using the Field-II toolbox based on Matlab.The imaging simulation experiment analyzes the imaging results and trends in different imaging modes,and determines and describes the sparse array imaging algorithm that can be imaged by one-time transmit-receive.Secondly,the far-field sound potential function is used to construct the sound field echo at any position in space,and the imaging simulation is carried out by using two preset point targets and four rounds and nine closed frontal sparse arrays.The correctness of the model is verified.On this basis,the dual square structure of 16-Transmitting and 25-receiving elements is used to further enlarge the size of the array to improve the quality of imaging.The results of double frontal sparse array imaging under different array spacings are compared.The results fully verify the imaging model,algorithm and the relevant theory is correct and effective.Finally,an ultra-infrared imaging system with dual frontal arrays of 4 and 9 outputs,including data downlink,uplink and processing systems.In particular,the drive circuit is redesigned to meet the needs of underwater acoustic transducers of different sizes,characteristic impedances,and capacitive resistance.The key parameters of the push-pull AC-AC converter circuit are qualitatively analyzed,and the key parameters of the “symmetric T-structure” filter are quantitatively analyzed and simulated to ensure that the transmitted sinusoidal pulse signal is stable at 100 KHz.