关键词: 缺陷检测, 图像处理, 磁片, 傅里叶变换

Abstract: Defects may appear on the surface of the magnet during cutting into smaller slice. These defects will seriously affect the performance and service life of magnetic products. So automatic surface cutting defect detection becomes an important task for magnet producing. A Fourier image reconstruction based magnet surface image process method is proposed, to the question that defect of magnet surface with dark color and low contrast can not be extracted via the classical defect detection algorithm. Fourier transform is used to get the spectrum image of the magnet image, and in the spectrum image, the defect will be shown as a bright line. Hough transform is used to detect the angle of bright line, then the frequency component of this line is removed, and revise Fourier transform is applied to get the background gray image. In the end, the defect region can be obtained by evaluating the gray-level differences between original image and reconstructed image. Experiments show that the method proposed can detect surface cutting defect of magnet accurately and efficiently.

Key words: defect detection, image process, magnet, Fourier transform