Singular value decomposition combined with wavelet transform for LCD defect detection

Singular value decomposition is used to obtain the mean value of the first and second singular value ratios of normal and defect LCD images. Then the third and fourth singular values matched with the standard deviation of the first two singular value ratios are used to divide the defect images into two categories: coarse and fine. Finally, 2D discrete wavelet coefficient filtering combined with region growing is adopted to extract defect regions.