The Design Of Feature Extractor For Ultrasonic Testing

With the development of science and technology, as an important branch of nondestructive inspection,ultrasonic inspection has been adopted in the many fields, such as medicine, aerospace, and petroleum. The requirements of equipment in industry are becoming higher increasingly, considering the need of the ultrasonic online automatic inspection in industrial application , the rapid features and extraction method of ultrasonic signals in industrial nondestructive inspection are studied in this paper. Several main features of ultrasonic testing technology have been confirmed through analysis, and corresponding feature extraction circuits have been designed to simulate these features and relevant technical indicators.First, fundamentals of A-type industrial ultrasonic testing technology are introduced. As to the main engineering application of ultrasonic testing, flaw detection and thickness measuring, physical characterization of relevant time signals has been studied, with three features signal of ultrasonic identified, i.e. peak value, energy and echo time.Using A-type ultrasonic detector, overall design of the feature extraction device has been done. As to multiple reflection signals, signal energy feature extraction circuits are designed on the base of analog integrator. With sync signal of ultrasonic detector scanning triggering time as the start point and the peak value of echo signal as the stop point, circuits of time feature extraction, relevant sync control, and peak extraction of differential circuit trigger control are designed with the help of CPLD. Simulation ultrasonic detection signal generators are designed according to the simulation experiment requirements.All the circuits designation have been simulated and verified in experiments through VHDL and the Multisim software.