Abstract: A method and apparatus for scanning a surface of an optical disk which has signal recording pits or bumps covered with a transparent layer, with a flying spot to detect surface defects of the optical disk surface. The optical disk is rotated at a constant speed of rotation and scanned along a scanning line parallel to but spaced at least 10 mm from a line radial to the center of rotation of the optical disk. A light-detecting unit receives diffused light reflected by the disk surface to provide an output corresponding to the intensity of the diffused light and converts it into an electric output which is used to evaluate the surface of the optical disk.

Abstract: An apparatus for inspecting the surface of web material moving lengthwise at a constant speed by scanning the surface in the direction of the width of the surface with a light beam. The scanned beam modulated by the surface is received and converted into an electric signal which is divided into division signals representing divisions of the width of the web. A first memory capability is provided for storing division signals added together by division every N transverse scans. The added division signals are transferred to a second memory capability by division, for evaluating the surface defect distribution of the scanned surface division by division.