Inspection of surface defects using optimal FIR filters

A new method of surface inspection for the textured materials is investigated. The linear FIR filters that offer optimal energy separation between the defect and defect-free regions of texture have been utilized. Performance of different feature separation criterion with reference to fabric defects has been evaluated. The issues relating to the design of optimal filters for supervised and unsupervised web inspection are discussed. A general web inspection system based on the optimal filters is proposed. The experiments on this new approach have yielded excellent results. The on-line computational simplicity using the proposed scheme confirms the usefulness of the approach for industrial inspection.