超声合成孔径聚焦成像技术实验教学研究

发布时间：2018-03-31 05:08

本文选题：水浸超声　切入点：合成孔径聚焦成像技术　出处：《北京交通大学》2017年硕士论文

【摘要】：合成孔径聚焦成像技术作为超声探伤的处理方法,通过将小孔径合成大孔径成像,提高扫描图像的空间分辨率,在工程领域具有广泛的应用。本文主要通过研究合成孔径聚焦成像算法并通过实验验证算法的可行性,将合成孔径聚焦成像技术应用于大学物理实验教学中,并实现实验方案的设计。本文主要做了以下几个方面的研究工作:首先,通过了解合成孔径聚焦成像技术的发展背景,对合成孔径聚焦成像算法进行了研究,提出了超声波在两种介质中传播时合成孔径长度以及延迟时间的计算方法,在原有SAFT延时取整算法、SAFT引入小数延时系数算法以及SAFT相关性算法的基础上进行了算法研究。然后,基于以上的理论研究,进行了水浸超声金属丝扫描实验、水浸超声铝试块扫描实验,分别对应于超声波在一种介质中传播和在两种介质中传播时的合成孔径聚焦成像算法。通过实验验证了所研究的合成孔径聚焦成像算法的可行性。最后,以以上研究为基础,将合成孔径聚焦成像技术与大学物理实验进行结合,设计符合学生发展的教学实验。首先设计水浸超声扫描回波观察实验,使学生熟悉实验仪器,熟练操作JDUT-1B型超声波扫描成像软件,通过手动扫描熟悉超声波的探伤规律,能够正确分辨回波信号的波形图中的各部分的回波信号。然后,设计水浸超声金属丝扫描实验和水浸超声铝试块扫描实验,通过自动扫描得到超声B扫描图像,学生可以直观地看到扫描结果,并对其进行合成孔径聚焦成像处理。使学生通过实验,加深对合成孔径聚焦成像技术的认识,达到实验教学的目的。
[Abstract]:As a processing method of ultrasonic flaw detection, synthetic aperture focused imaging (SAR) can improve the spatial resolution of scanning image by imaging small aperture and large aperture. In this paper, the synthetic aperture focusing imaging algorithm is studied and the feasibility of the algorithm is verified by experiments, and the synthetic aperture focusing imaging technology is applied to the teaching of college physics experiment. The main work of this paper is as follows: firstly, by understanding the development background of synthetic aperture focusing imaging technology, the synthetic aperture focusing imaging algorithm is studied. This paper presents a method to calculate the length of synthetic aperture and the time of delay when ultrasonic waves propagate in two kinds of media. The algorithm is studied on the basis of introducing fractional delay coefficient algorithm and SAFT correlation algorithm into the original SAFT delay rounding algorithm. Based on the above theoretical research, the ultrasonic wire scanning experiment and the ultrasonic aluminum sample scanning experiment were carried out. The synthetic aperture focusing imaging algorithms corresponding to ultrasonic wave propagation in one medium and in two media respectively. The feasibility of the proposed synthetic aperture focusing imaging algorithm is verified by experiments. Finally, based on the above research, Combining the technique of synthetic aperture focusing imaging with the experiment of college physics, the teaching experiment is designed to meet the development of the students. First, the experiment of ultrasonic scanning echo observation is designed to familiarize the students with the experimental instruments. Skilled operation of JDUT-1B ultrasonic scanning imaging software, through manual scanning familiar with ultrasonic flaw detection law, can correctly identify the echo signal in each part of the echo signal waveform. Then, The ultrasonic wire scanning experiment and the ultrasonic aluminum sample scanning experiment were designed. The ultrasonic B scan images were obtained by automatic scanning, and the students could see the scan results intuitively. Through experiments, the students can get a deeper understanding of the synthetic aperture focusing imaging technology and achieve the purpose of experimental teaching.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB55-4;G642

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