Study of Improved Modulus Maximum Algorithm Based on Thresholding Wavelet in Ultrasonic Testing Signal De-Noising for Super Alloy

The ultrasonic testing signal of super alloy is always immingled with the scattering noise. According to the phenomena, this paper presents a kind of signal model of ultrasonic testing for super alloy and a wavelet transform de-noising algorithm based on modulus maximum. The characters of producing mode and wavelet transform of noise and signal are discussed. In the wavelet transformation mold maximum value space, this algorithm identifies signal and the noise through the hypothesis threshold value, and reaches the purpose of de-noising by removing the mold maximum value of the corresponding noise. Examples prove that the model can reflect the character of the ultrasonic signal and noise correctly, and the result of the de-noising for super alloy using this algorithm is satisfactory.