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铝合金锻件超声信号的自适应小波压缩方法

DOI: 10.3969/j.issn.1000-1298.2008.2.080238, PP. 159-162

Keywords: 铝合金,超声信号,压缩,自适应算法,小波

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Abstract:

针对铝合金锻件超声信号中含有晶粒散射引起的相干噪声,建立了相应的缺陷回波检测数学模型,提出了基于新的阈值函数Stein无偏估计自适应压缩方法。对离散小波变换各尺度上的小波系数用新的阈值函数进行估值后,进行了小波阈值最小均方误差意义上的迭代,并用小波系数估值进行离散小波反变换,以得到信号的估值,通过反复迭代,得到缺陷回波的最优压缩模型。对含缺陷铝合金锻件的超声信号处理实验的结果表明,与常用的固定阈值方法相比,在相同压缩比下,自适应压缩方法能更好地去除散射噪声及识别缺陷回波信号。

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