Research On Signal Acquisition And Processing System Of Multi-array Ultrasonic Endoscope

Medical ultrasonic endoscope is an important way to detect lesions in the digestive tract and other parts of the human body.Ultrasonic transducers are used to transmit and receive ultrasonic waves to image human organs,which has the advantages of no damage and no ionizing radiation.Ultrasonic transducers are used to transmit and receive ultrasonic waves to image human organs,which has the advantages of no damage and no ionizing radiation.According to the number of ultrasonic transducer elements,the medical ultrasonic endoscope system can be divided into single-element ultrasonic endoscope system and multi-array ultrasonic endoscope system.Multi-array ultrasonic endoscope system avoids mechanical noise produced by motor rotation and has the advantages of high imaging resolution and high signal-to-noise ratio compared with single-element ultrasonic endoscope,which has become a research focus in recent years.At present,the main difficulty of the research of multi-array ultrasonic endoscope is that with the increase of the number of ultrasonic transducer elements and the requirements for higher system performance,the imaging signal acquisition and processing process of the ultrasound endoscopic imaging system is more complicated and hardware design is more difficult.At the same time,current synthetic aperture ultrasound imaging algorithms still have large sidelobe noise,so new imaging algorithms need to be designed to improve the spatial resolution and signal-to-noise ratio of ultrasonic images.To solve the above problems,a signal acquisition and processing system of multiarray ultrasonic endoscope is designed in this paper,which mainly includes the signal transmission subsystem and the receiving processing subsystem.This system completes the functions of ultrasonic delayed transmission,echo signal conversion and processing.The echo data is transmitted to the host computer by USB3.0.Besides,an ultrasound imaging algorithm based on coded excitation and coherence coefficient is proposed to improve the spatial resolution and signal-to-noise ratio of the medical ultrasonic image.The main work of this paper is listed below:1.A multi-array ultrasound endoscopic imaging system scheme is developed:FPGA is used as the main control chip for signal transmission and reception processing;AD9272 chip is used for echo signal processing;USB3.0 is used to upload data to the host computer and GPU is used for parallel processing of echo signal data.2.Complete the design of multi-array ultrasound endoscopic signal transmission subsystem: FPGA is used as the core chip,the control signal realizes delayed emission,high voltage pulse excitation and other functions.3.The ultrasonic echo signal receiving and processing circuit is designed.The integrated analog front AD9272 is used as the core to complete the functions of analog signal amplification,bandpass filtering and analog-to-digital conversion.The echo data is uploaded by USB3.0.4.The multi-array ultrasound endoscopic signal acquisition and processing experimental system is built,and the experimental verification of the signal transmission system and the receiving processing system is completed,which proved the feasibility of this system.5.An ultrasound endoscopic imaging algorithm based on coding excitation and coherence factor is proposed.The feasibility of the algorithm to improve the spatial resolution and signal-to-noise ratio of ultrasonic imaging is verified by simulation experiments.