【摘要】 从信号处理的角度给出了小波变换的工程理解,即小波变换可以看作从原始信号中不断抽取细节,最终只留下信号主干的过程;接着用小波变换对中碳钢摩擦焊和钛合金扩散焊接头的超声A扫描信号进行了降噪处理.结果表明,在对小波系数的合理解释情况下,小波变换能有效地提高信噪比,并能提供比传统方法更为完整的时域和频域信息.更多还原

【Abstract】 The common perceptions of wavelet transform for engineering are given from the point of view of signal processing. Wavelet transform is a process of keeping extracting details from primitive signal until the main is left. Ultrasonic A-scan signals from friction-welded joints in medium carbon steel and diffusion-bonded joints in titanium were processed by wavelet transform to reduce noises. Results showed that wavelet transform could be used to improve signal-to-noise ratio and to provide more perfect time-domain and frequency-domain information than conventional signal processing methods.更多还原