| 摘要 |
PURPOSE: To provide a device for detecting the defect of a sheet-shaped object capable of automatically and accurately detecting the type, size, and position of the dent defect or internal defect of the sheet-shaped object. CONSTITUTION: The defect detecting device 5 is formed by a light projector 7A for applying illumination light Q to an expandable sheet 1a with a dent defect 1b and an internal defect 1h (Fig. 9), a light receiver 8A for receiving reflection light R and outputting defect information as an image signal, and an image processing device 9 for electrically processing the image signal from the light receiver. The light projector 7 applies light to a position which is at a specific inclination angle of θ1 and where the application point is offset from a defect position by a specific distance E and at the same time, the light receiver 8A employs a diffusion reflection lighting system where a reflection angle θ2 of the reflection light from the defect point is within 70-90 degrees for a sheet-shaped object plane. Also, an image processing device 9 employs a differential system. |
