Method of and device for inspecting images to detect defects

A method of inspecting unsupervised web materials containing defects, the method comprising:

• designing a plurality of optimal filters for different categories of defects;
• combining the output from each of the optimal filters in a data fusion module to obtain a fused output image;
• and
• segmenting defects in the fused output image.

A method of inspecting defects in textured materials for industrial automation, the method comprising:

• imaging the material under inspection;
• using pre-designed optimal filters to attenuate pixels in acquired images corresponding to defect free region;
• using a nonlinear function to compute energy of each pixel;
• using a smoothing filter to compute energy of every pixel in a local region;
• and
• thresholding the acquired images to segment the defects.

A filter device for detecting fabric detects, the filter being designed to optimize the object function of:

• 15 J 1 ⁢ ( h op ) = μ f d μ f r = h op T ⁢ R ii d ⁢ h op h op T ⁢ R ii r ⁢ h op
• wherein μfd and μfr designate the average local energy estimate for a fabric with defect and without defect, respectively;
• and
• wherein Rii=E{i(x, y)iT(x, y)} is the L×L (L=M×N) correlation matrix and can be constructed from the autocorrelation function of the image i(x, y).