Research On Detection And Processing Of Ultrasonic Signal Based On Wavelet Transform

As the development of sensor, electronic, automation and computer technology, modern detection technology has been in the times of information processing which main rely on computer and microprocessor. Being the main embranchment of the modern detection technology, the ultrasonic detection also tends toward the direction of digitalization, automaton, intellectualization and image. The technology of signal processing which has become an important part of information processing is signification to the ultrasonic detection. In the ultrasonic detection, the first purpose of signal processing is to enhance and improve the signal; and then pick up the information which is difficult to find previously. The second purpose is to analyze the ultrasonic signal by the orientation and property. For the two purposes, wavelet analysis technology is used for de-noising research and detective in echo location which is in ultrasonic echo signal.1. For the aspect of signal de-noising, there is discussing the property of wavelet transform and analyzing three difference ways to signal de-noising. And then, according to the correlativity of scale wavelet parameters and the aggregation between the wavelet parameters, the properties are matched by the hidden Markov models. At last, the signal de-noising is realized by Bayesian hidden Markov tree estimation and correction factor.2. For the aspect of ultrasonic echo location, we analyze the transmit property of the ultrasonic echo at first; and then, according to the property of ultrasonic signal and the deficiency of character location which is only using wavelet transform, the method which is combining Hilbert transform and wavelet transform is used for the ultrasonic echo location. Furthermore, the approximate linear phase-frequency property of bi-orthogonal spline wavelet is applied to accurately fast locating the ultrasonic echo.For the detection and processing of ultrasonic echo signal, the method proposed by this paper is able to improve the whole precision on a certain technical condition.