基于短时傅里叶变换的纺织材料纤维取向度测量方法

摘要

In order to show the fiber orientation distribution of the textile material,based on textile fiber scanning electron microscopy(SEM)images,a method of measuring the degree of orientation of textile fiber by short-time Fourier transform is proposed.The fiber image is regarded as a global non-smooth but local smooth signal.Firstly, by setting and shifting a window for the fiber image to cover the entire time domain,the short time Fourier transform of the fiber image is realized.Then the region of interest in the spectrum is selected.Then the energy of the region of interest in the spectrum along the different directions is calculated and the main direction of the fiber in each sub-block is found.Finally,the main directions of all sub-window are counted to obtain the fiber orientation. Compared with the traditional FFT method,the results of the four samples show that the ratio of fiber along 90° and 180°is reduced by 14.75% and 15.25% respectively,which indicates that the border effect can be effec-tively reduced and the proposed method can characterize the degree of orientation of textile fiber more accurately.%为了更准确地表征纺织材料的纤维取向分布,基于纺织材料纤维扫描电镜(SEM)图像,提出了一种利用短时傅里叶变换的纺织材料纤维取向度测量方法.把纤维图像看作总体非平稳、局部平稳的信号,首先通过对纤维图像加窗并使窗口平移覆盖整个时域,实现纤维图像的短时傅里叶变换;然后选取频谱图中的感兴趣区域;接着统计频谱图中感兴趣区域沿不同方向角的能量并找出每个子块中纤维的主方向;最后对所有子块的主方向进行统计得到纺织材料纤维取向度.对4个样品的测试结果表明:使用本文方法得到的测量结果与传统的FFT方法测量结果相比较,90°方向和180°方向的纤维比例平均分别减少14.75%和15.25%,说明本文方法能有效减少边界效应,更准确地表征纺织材料纤维的取向度.