| 摘要 |
PROBLEM TO BE SOLVED: To inspect internal distortion of a plate material and/or the smoothness of the surface thereof by a method wherein an inspection pattern projected from a projector, which passes through a plate material forms an image on a first screen as projection image and that which is reflected on the surface thereof forms an image on a second screen as projection image, and the images are taken by first and second cameras to analyze. SOLUTION: An inspection pattern is projected by a projector 1 to pass through a sample plate 2 while being reflected on the surface thereof to present projection images on first and second screens 3 and 4. When a distortion exists at any point as the pattern passes, the projection image of the first screen 3 is deformed oval or into other shapes according to the degree of the distortion. When the smoothness at the position of the reflection is inferior, the projection image on the second screen 4 is deformed oval or into other shapes according to the degree of waving or the like. The projection images thus obtained are taken by the CCD cameras 5 and 6. Image signals of the projection image taken are sent to the image analysis section 7 to be binary coded by an image processing part 8 thereby enabling obtaining a round shape enough to limit a measuring range. A distortion inspection part 9 calculates and judges a standard deviation ratio in the vertical and horizontal directions per round shape. |
