【摘要】 能量是信号分析的一个重要物理量,它随时间和频率的分布反映了信号的特征。利用建立在小波变换基础上的时间 能密度分析方法分析信号在不同频带内的能量随时间的分布情况,从而提取信号特征。除掉输入信号的影响,便可得到声波在混凝土内部传播过程中各频谱上的能量变化情况,再利用模式识别方法可检测出混凝土内部缺陷。更多还原

【Abstract】 Energy is an important physical variable in signal analysis. The distribution of energy density with the variation in time and frequency can reveal the characteristics of signals. The time-frequency density method based on wavelet analysis was used to analyze the signal energy at different frequencies and time periods. By eliminating the effect of input signal, the energy change of waves at different frequencies during their propagation in concrete was obtained. The inner defects of concrete could be detected out by using pattern recognition method.更多还原