The Digital Image Technology On The Ultrasonic Test Of The Rod Workpiece And Forging

This dissertation relies on the practical scientific research project that is "Type Project & ultrasonic testing system research", combining with the theories such as: image recognition, image processing, image registration, the object of the dissertation that is "The research and application of digital image technology in ultrasonic testing system" is put forward. Then proposed the application of ultrasonic image, based on introduction in the origin of ultrasonic image, the theories of ultrasonic image processing, pattern recognition and forging defects recognition are discussed respectively. The details are studied as follows:The first chapter talks about the background and summarizes the development of digital image technology and ultrasonic test technology. Then, the relative theories are introduced here. Main contents and general structure scheme of this dissertation are also presented.The second chapter introduces the method of ultrasonic imaging and the imaging system. And the theory of actual testing systems is discussed carefully.The third chapter introduces the methods of ultrasonic image processing. Based on the analysis to the actual image, edge-save filter and other methods are used to remove noise. Then, ultrasonic image is divided based on both the test mode and the ultrasonic feature pick-up. At last, the Robert operator and other operators are used to reinforce the flaw edges.The fourth chapter gives the brief expatiation the basis theory of image recognition, the ultrasonic image is segmented based on the comparability and the discontinuity. The characteristics of the flaw, such as the girth, long-pathway etc, are constructed. And they are selected by systematic characteristic. Finally, the method of flaw pattern recognition is implemented with the binary sorter.The fifth chapter summarizes the theory of image registration. Analyzing the results of advantages and limitations of two different image registration methods that are the arithmetic based on character points and the arithmetic based on maximal cross correlation. Then, introduces the process of forging-image testing, designs the arithmetic of module image and defect image. Finally, gives the actual example of the forging-image testing.The sixth chapter summarizes the main fruits and prospects the future of the research.