An inspection method for optical components that can be implemented to conform to performance specification MIL-PRF-13830 in order to grade surface imperfections, in particular scratches and digs. A dark-field microscope obtains a digital image of the component, and this digital image is processed to determine scratch and dig numbers. For scratches, the number is obtained by dividing the total intensity of the scratch by the scratch length. For digs, the number is obtained by determining dig diameter or by dividing the dig's total intensity by its area. According to our extensive testing, this automated digital image processing approach appears to faithfully mimic the subjective impression that a scratch makes on an expert inspector who is applying the visibility test of MIL-PRF-13830.
