Research And Realization Of Ultrasonic Arrary Imaging Algorithm

Ultrasonic phased array imaging technology has the characteristics of flexible beam control,large measurement range and intuitive results,which is widely used in the field of industrial nondestructive testing.This paper aims to study the ultrasonic phased array sound field and beam forming algorithm,on the basis of this,a 64 channel ultrasonic phased array detection system is developed.The main work of this paper is as follows:1.The basic principle and scanning mode of ultrasonic phased array is studied.The acoustic field calculation method of a single rectangular transducer and a linear transducer array is studied,and the effect of time delay on the beam is analyzed.2.The ultrasonic beam forming algorithms are studied.These algorithms can achieve high precision delay,which include the algorithm based on the fractional time delay filter and the algorithm based on phase rotation.3.The ultrasonic coding excitation technique is studied,the performance index and the commonly used binary coding sequences are analyzed,as well as the modulation mode of the coding sequence is proposed.4.The ultrasonic detection algorithm based on frequency domain channel estimation is proposed.By making a comparison with the theory of multipath channel in wireless communication,based on traditional ultrasonic excitation,the Zadoff-Chu encoding sequence with cyclic prefix to achieve pulse compression the ideal through frequency domain is processed.5.A 64 channel ultrasonic phased array detection imaging system is developed,which is based on the modular design ideas.The system includes signal transmitting board,signal receiving and processing board,system control board and so on.On the basis of the hardware platform,the FPGA design of the module of ultrasonic transmit beam forming,multi channel high speed LVDS signal receiving,dynamic focusing and receiving beam forming as well as bus transmission are completed.