Title :
A time-frequency method for ultrasonic flaw inspection based on HHT
Author :
Kong, Tao ; Xu, Chunguang ; Zhou, Shiyuan
Author_Institution :
Key Lab. of Fundamental Sci. for Adv. Machining, Beijing Inst. of Technol., Beijing, China
Abstract :
A time-frequency analysis method based on Hilbert-Huang transform (HHT) was employed to character ultrasonic flaw echo signals. In this method, time and frequency characteristics of ultrasonic transducers used in inspection were considered to eliminate noises and identify the flaws. First, the flaw echo signals were decomposed into a series of mono-components called intrinsic mode functions (IMF) using the theories of EMD. Secondly, the best IMF was identified and represented in time-frequency domain using Hilbert transform, time and frequency characteristics were used to determine the flaw. Finally, the addition of the best IMF and the hypo-best IMF comes close to approximating the original flaw signal. The results of experiments with three transducers validate the effectiveness of the method in ultrasonic echo signal analysis.
Keywords :
Hilbert transforms; acoustic signal processing; deconvolution; echo; time-frequency analysis; ultrasonic materials testing; ultrasonic transducer arrays; EMD theory; HHT based ultrasonic flaw inspection; Hilbert-Huang transform; flaw echo signal decomposition; hypobest IMF; intrinsic mode functions; time-frequency analysis method; ultrasonic echo signal analysis; ultrasonic flaw echo signals; ultrasonic transducer frequency characteristics; ultrasonic transducer time characteristics; Acoustics; Bandwidth; Fault diagnosis; Inspection; Time frequency analysis; Transducers; Transforms; HHT; flaw inspection; time-frequency analysis; ultrasonic transducer;
Conference_Titel :
Image and Signal Processing (CISP), 2010 3rd International Congress on
Conference_Location :
Yantai
Print_ISBN :
978-1-4244-6513-2
DOI :
10.1109/CISP.2010.5647817
