疲劳断口分析的Fourier变换方法

FOURIER TRANSFORM METHOD FOR ANALYSIS OF FATIGUE FRACTOGRAPHS

对疲劳断口图像进行恰当的图像变换处理，可以从其丰富而复杂的图像信息中提取重要的有用特征，实现疲劳断口的定量分析。本文应用二维离散Fourier变换对疲劳断口表面图像进行分析处理后，再通过二次特征提取将二维图像分析转化为对两个一维特征波形的分析，从而有利于获得更为明确的有关疲劳断口的纹理特征和疲劳条纹的方向特征。研究结果表明，利用二维离散Fourier变换在空频域上对疲劳断口图像进行分析，可以获得在单纯空间域上所无法得到的疲劳断口图像的特征表征，这为进一步开展疲劳断口的定量分析研究提供了一条有效的新途径。

The quantitative analysis for fatigue fractography can be realized through the suitable image transform of fatigue fractographs, from which some useful characteristics can be obtained. Two-dimensional discrete Fourier transform is used in the process of fatigue fractograph, and the important characteristics to describe the texture and direction features on a fatigue fracture surface are abstracted from the Fourier power spectrum. A two-dimensional image analysis problem can be simplified as a one-dimensional characteristic curve analysis. The results show that some important characteristics on a fatigue fracture surface can be obtained in space frequency domain by means of two-dimensional discrete Fourier transform, which are impossibly acquired in space domain of fractograph. The method presented in this paper is identified to be a new way to carry out quantitative analysis of fatigue fractography.