Acoustic Inspection Of Wall Hollowings Based On Embedded SPCE061A Single-chip Microcomputer

At present, there are many NDT methods for inspection of wall, such as ultrasonic testing, infrared thermography and impact acoustics. Because of wall non-uniformity, the method of ultrasonic testing has some limitations. The method of infrared thermography is prone to be influenced by many factors, for example, environmental condition, wall material and so on. The extent of influence cannot be ensured, thus it increases the difficulty of measurable inspection. Traditional impact acoustic inspection method is based on the feeling of impact sound by man's hearing. This method depends on operator's experiences, therefore subjective judgment is not accurate and it can't produce measurable results.This paper designs an acoustic non-destructive inspection system based on embedded Sunplus SPCE61A single-chip microcomputer. The system employs the method of impact acoustics to inspect wall hollowings measurably by analyzing the spectrum of impacting signals. The new system realizes the spectrum analyses and ANN classification of impact sound in Sunplus SPCE61A to inspect the hollowings inside the wall. Experimental results on physical walls demonstrate the effectiveness of the present system, which has the potential of being developed into a portable, convenient, accurate and low-cost inspection tool.The paper is organized as follows:Chapter 1 is the preface which introduces the background and necessity of research, and thereafter describes the history and the trends of NDT technique. Along with the request of wall hollowings inspection, the purpose of this paper is proposed.Chapter 2 is to establish the theoretical model of impact acoustics spectrum analysis system. It provides theoretical basis of the inspection system of wall hollowings and testifies that the distribution of energy at low frequency can tell different structures of wall. Chapter 3 introduces the basic principles and applications of ANN and discusses how to apply BP network to inspect the wall hollowings in accordance with features of impact acoustics.Chapter 4 details the research designs, including hardware and software, especially introduces how to realize spectrum analysis and ANN calculation in Sunplus SPCE61A.Chapter 5 is to make comparisons among the three different methods of wall hollowings inspecting, and then provide the experiments results.Chapter 6 summarizes the paper's working and proposes elementary assumption on improving the stability and inspection precision of the system.