Abstract: A flaw detection system that can detect not only bubbles, stones and knots but also flaws, such as cords and reams, that are subject to less optical changes in transmitted light is provided. A glass plate travelling in a manufacturing line is scanned with a beam spot in the direction orthogonally intersecting the manufacturing line. The light transmitted through the glass plate is received by an optical-fiber array arranged in a direction orthogonally intersecting the line. Optical fibers in the optical-fiber array are connected cyclically to a plurality of photomultipliers, which convert the light received by the optical fibers into electrical signals. Flaw signals are produced by extracting flaw information signals from these electrical signals in an analog processing section, and masking them in a masking section. Positional information indicating flaw patterns and positions is produced from these flaw signals.

Abstract: In a distortion inspection apparatus of a glass plate, a light and dark contrast pattern is sensed by an image sensor through a glass plate. The number of bits corresponding to a light or dark portion is detected from bipolar image data which are divided into a plurality of bits along each of parallel scanning lines assumed upon a surface of the glass plate. Then, a distortion state of the surface of the glass plate is discriminated in accordance with the differences among the thus detected number of bits and a reference value thereof. In such an arrangement, quantitative distortion discrimination can be performed.