| 摘要 |
PROBLEM TO BE SOLVED: To provide an apparatus capable of detecting any type of flaws such as a dot-like flaw, a long flaw in the width direction of a body to be tested, and a long flaw in the length direction of the body to be tested. SOLUTION: In the apparatus, a light source 4 which is disposed in a detecting head 3 irradiates a surface of a steel sheet 1 with parallel light having wavelength values in the visible region at a large incident angleθof approximate 90 degrees. The surface of the steel sheet 1 is irradiated at the above incident angle after the parallel light is reflected by a mirror 5. The light reflected by the surface of the steel sheet 1 is focused to make an image on a translucent screen 6. The image is photographed by a two-dimensional camera 7 from the rear face of the screen 6, and irregular flaws are detected by an image processing device 8 executing its image processing. The incident angle of the parallel light which is set at an intermediate position of the steel sheet 1 in both width and length directions, is determined from a shape of the above minute irregular flaw being an object to be detected in the width direction, a shape in the length direction and a shape of the body to be tested. COPYRIGHT: (C)2004,JPO
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