Design Of Phased Array Ultrasonic Endoscope Signal Transmitting System And Research On Parallel Implementation Of Imaging Algorithm

Endoscopic ultrasonography(EUS)combines the endoscopy and ultrasound.While using endoscopy to observe the digestive tract diseases,ultrasound scanning can be performed,and the examination process is nondestructive to the human body.It is one of the most effective methods for the detection of digestive tract diseases.EUS is commonly divided into two types: mechanical ring scanning ultrasonic endoscope and phased array ultrasonic endoscope.Compared with the traditional mechanical ring scanning ultrasonic endoscope,phased array ultrasonic endoscope has obvious advantages.It not only has clearer imaging,stronger anti-interference ability,but also can be used for clinical treatment,such as puncture.At present,the direct factor that restricts the performance of phased array ultrasonic endoscope system is the number of elements of ultrasonic transducer.Although increasing the number of elements can improve the imaging resolution and performance of the system,the corresponding hardware design will become more complex,at the same time,the amount of data to be processed will also increase,and the real-time performance of the system can not be guaranteed.To solve the above problems,a 64-element medical phased array ultrasonic endoscope imaging system is designed in this paper.The system is composed of three subsystems,such as the signal transmitting and gating module,the echo receiving and uploading module and the data parallel processing module.This paper mainly completes the signal transmitting and gating module based on FPGA and the data parallel processing module based on GPU.Finally,the feasibility and high efficiency of the developed modules in phased array ultrasonic endoscope imaging system are verified by related experiments.The main work of this paper is as follows:1.A 64-element phased array ultrasonic endoscope imaging system scheme is worked out.In this system,FPGA,as the control core,is responsible for the signal transmitting and gating & the echo receiving and uploading;GPU,as the processing core,is responsible for the data parallel processing and image display.2.The phased array ultrasonic endoscope transmitting system is designed.The hardware design of the transmitting circuit,the gating circuit and the limiting circuit is completed;the program of the phased array transmitting with FPGA as the controlcore is written.The functions of high voltage pulse excitation,signal delay,element gating,limiting isolation in this subsystem are implemented.3.The echo data parallel processing and image display are completed.With GPU as the processing core,a mixed software architecture based on MATLAB and CUDA is proposed through the parallel processing analysis of the synthetic aperture imaging algorithm.The hardware acceleration of the imaging algorithm is implemented by using the NVIDIA GeForce GT630.4.The 64-element phased array ultrasonic endoscope imaging system is built with each subsystem module.The feasibility and high efficiency of the system are verified by imaging experiments of the iron wires in a water tank and the pigskin tissue.