METHOD FOR INSPECTING TRANSPARENT BODY, AND APPARATUS FOR INSPECTING TRANSPARENT BODY

摘要

The present invention relates to a method for inspecting a transparent body, and an apparatus for inspecting a transparent body to prevent false defect detection caused by a thermal fluctuation defect from shot images gained from the Schlieren method under a high pressure environment and to detect both of a bright area and a dark area near an area, in which foam or foreign materials are found, from the shot images when there are some changes on a surface of a transparent body as foam or a foreign material exists in a plate-shaped or a thin film-shaped transparent body. A line selecting unit (11) selects each line in order from the shot images of a plate or thin film-shaped transparent body filmed by Schlieren method. A differentiation processing unit (12) calculates a differentiated value of a gray scale value of a pixel within one line in order. A labeling unit (13) compares the gray scale value with a first gray scale value threshold and a second gray scale value threshold for a pixel after the pixel when the labeling unit (13) detects a differentiated value greater than a first differentiated threshold or a pixel whose value is less than a second differentiated threshold.