Abstract: A method of and an apparatus for inspecting a traveling sheet material, in which the ability to detect a defect is made as close to the identifying ability of man's visual inspection as possible, the detected defect is converted into an electrical signal and separated into four factors of width, quantity, depth or density, and length to make the sorting process most economical, the factors are discriminated to be of high, medium or low class, respectively, and the discriminated defect factors are synthetically judged through a decision circuit according to a defect pattern.

Abstract: A system for determining a transversal position of any defect in a traveling sheet material having a defect detector and at least one scanning detector, in which the transversal position of the defect in the sheet material is determined by the coincidence between a defect signal from the defect detector and an output signal from the scanning detector.