Identifying Fabric Structures with Fast Fourier Transform Techniques
Identifying Fabric Structures with Fast Fourier Transform Techniques
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DOI：
10.1177/004051759606600803
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发表时间：
1996-08
影响因子：
2.3
通讯作者：
Bugao Xu
中科院分区：
文献类型：
--
作者：
Bugao Xu
快速傅里叶变换（FFT）在图像处理和模式识别中起着非常重要的作用。由于机织织物由规则的重复单元组成，FFT对于分析织物中重复单元的周期性、方向性和间距特别有用。本文描述了在图像处理中应用FFT技术来识别织物花纹、织物支数、纱线偏度和其他机织物结构特征的程序。使用彩色扫描仪对织物图像（空间域中的二维函数）进行数字化，并使用定制软件包对图像进行FFT处理。功率谱图像是从图像的FFT中导出的，并被认为是频域中的二维函数。功率谱图像中的峰代表周期元素的频率项，从中可以识别基本的编织图案（例如，平纹，斜纹，缎纹等）。由功率谱导出的径向函数和角函数用于测量周期元素的粗度和方向性。通过选取某一方向的功率峰重构图像，提取经纱或纬纱元素，方便织物计数和偏度测量。傅里叶滤波，即频域的图像滤波，用于抑制噪声和选择具有一定频率范围的特征。使用FFT技术测试具有不同织型和纱线支数的织物。
The Fast Fourier Transform (FFT) plays a very important role in image processing and pattern recognition. Since a woven fabric consists of regular repeating units, the FFT is particularly useful for analyzing periodicity, directionality, and spacing of re peating units in the fabric. This paper describes procedures for applying FFT techniques in image processing to identify weave pattern, fabric count, yarn skewness, and other structural characteristics of woven fabrics. A color scanner is used to digitize fabric images (two-dimensional functions in a spatial domain), and a customized software package is used to apply the FFT to the images. A power spectrum image is derived from the FFT of an image, and considered a two-dimensional function in a frequency domain. Peaks in the power spectrum image stand for frequency terms of periodic elements, from which basic weave patterns (e.g., plain, twill, satin, etc.) can be rec ognized. A radial function and an angular function, derived from the power spectrum, are used to measure the coarseness and directionality of the periodic elements. By selecting power peaks in a certain direction to reconstruct the image, warp or weft elements can be extracted to facilitate fabric count and skewness measurements. Fourier filtering, that is, image filtering in the frequency domain, is used to suppress noise and to select features that have a certain range of frequencies. Fabrics with various weave patterns and yarn counts are tested using the FFT techniques.