基于频域纹理消除的结构性纹理缺陷检测方法

Structural texture defects detection method based on frequency domain texture elimination

针对金属加工表面等结构纹理表面图像缺陷检测问题,结构纹理的存在会对缺陷(比如划痕)检测带来干扰,该文开展在频率域中消除背景纹理的方法来进行缺陷检测的研究。首先基于傅里叶变换的图像复原技术,空间域图像中的结构性纹理对应傅里叶域中高能频率分量,使用最小二乘法直线拟合操作去除,并将这些能量设置为零,经傅里叶逆变换为空间域图像。在复原的图像中,原始图像中的结构纹理区域将变为近似的均匀灰度级,但其中缺陷部分将被保留下来。再使用统计过程控制来设置阈值的方法就能从复原图像中分离出缺陷。最后在一系列的结构性纹理图像上的实验证实了所提方法可行且有效。

The existence of structural texture can interfere with the defects(such as scratches) detection for the surface texture images defects detection of machined surface. The method of eliminating background texture in frequency domain was studied for the defects detection. Firstly, based on the image restoration technology of Fourier transform, the structural texture in spatial domain image corresponded to the high energy frequency component in Fourier domain, which was removed by the least square method linear fitting, and these energies were set to zero finally transformed into the spatial domain image. In the restored image, the structural texture region in original image became an approximate uniform gray level, in which the defective region was preserved. And then the statistical process control was used to set threshold to separate the defects from the restored image. Finally, experiments on a series of structural texture images show that the proposed method is feasible and effective.