Development Of High Performance Ultrasonic Imaging System Based On Virtual Instrument Architecture

The ultrasonic nondestructive testing technology(UNDT),which possesses some advantages of being harmless to the human body,tremendous acoustic information about the internal structure of the object to be examined and flexible integration with information science technology easily,has become the effective means of monitoring the quality of parts and materials.It also has been widely used in many fields and has a significant impact on the development of national defense industry and national economy.However,ultrasound imaging,regarded as the most important technical means of quantitative ultrasonic nondestructive testing,indicates the internal defects of the tested objects by means of image technology,decreases the difficulty of the operation and reduces the influence of human factors on the test results.Meanwhile,it accelerates the development of nondestructive testing(NDT)to nondestructive evaluation(NDE).Therefore,the UNDT has become one of the most popular research topics in the field of NDT,and has been widely valued by academia and engineering circles which has developed a number of ultrasonic imaging methods.However,with the rapid development of modern industry,higher requirements,such as,the stability,resolution,real-time and application adaptability,are proposed in terms of ultrasonic imaging technology.Due to complicated ultrasonic imaging procedure,such as ultrasonic emission,conditioning,receiving,analysis,mechanical or electronic scanning and coupling,a variety of functions and complex testing samples,the traditional instrument system structure could not meet the need of high performance ultrasound imaging system.According to the background above,this dissertation which is funded by National Natural Science Foundation of China(No.51675480)proposes research on high performance ultrasonic imaging system based on virtual instrumental system.Given the structural features and advantages of virtual instrumentation,this paper investigates the motion tracking and control of multi-axis mechanical scanning and the theory and technology of ultrasonic imaging detection and focuses on real-time high-resolution imaging and the results friendly representation and other key issues based on the detection principles of ultrasonic imaging.Furthermore,in order to carry out relevant experimental research to verify the effectiveness of this technology and system,a set of high-performance ultrasonic imaging detection system is developed by using virtual instrument architecture and combining ultrasonic non-destructive testing and electromechanical technology,The specific research contents are presented as below:In chapter one,the significance of UNDT technology is discussed by introducing the importance of UNDT in modern industry and summarizing the research status and future trend of UNDT.The research contents are specified by pointing out the main problems existed in ultrasonic imaging technology,which defines the orientation of the subsequent research.In chapter two,the essential theoretical basis for research on ultrasonic imaging technology is established by analyzing the propagation mechanism of ultrasonic wave and the sound field distribution of ultrasonic transducer and introducing the principle of ultrasonic C-scan imaging.Meanwhile,on the basis of specifying the function target of ultrasonic imaging system,the design of the overall framework for high performance ultrasonic imaging system based on virtual instrument is completed with PXI bus and the function modules are illustrated.In chapter three,the track and control of space motion are achieved by the multi-axis motion control card based on PXI bus which supports the research of ultrasonic imaging technology on the basis of completing the design of the multi axis ultrasonic scanning device.Furthermore,according to ultrasonic C-scan plan,a variety of scanning path theory models are established and the scanning efficiency of each path is analyzed.In addition,the influence of scanning steps on the imaging accuracy is discussed,which manifests the guiding principles for the planning of ultrasonic C-scan path and the selection of relevant parameters.In chapter four,research on ultrasonic C-Scan imaging and the result processing is carried out.The two-dimensional characterization of ultrasonic C-scan images is achieved by using bilinear interpolation method and RGB color-mapping method,and the synthetic aperture imaging based on phase migration is utilized to improve lateral resolution of ultrasonic imaging after de-noising the echo signal.Besides,as for the limitation of the traditional algorithm to extract the edge of the defect image,an edge extraction technique for ultrasonic C-scan defect imaging based on Snake model is proposed to characterize the defect precisely.In chapter five,based on the research and development achievements above,a set of high-performance ultrasound imaging system is devised by applying the virtual instrument architecture and modular design idea,PXI bus as the information transmission bridge,integrating UNDT and mechatronics technology,completing ultrasonic detection board and software development and the integration of the system.Moreover,the relevant experimental researches are carried out on this platform to verify the effectiveness and feasibility of the technology and system proposed in the dissertation.In chapter six,the research contents of this paper are summarized,and the further research works are also forecasted.