PURPOSE: To detect a push-in scratch accurately while discriminating automatically from disturbance, e.g. a flaw, by irradiating the surface of a wheel rim of automobile obliquely from the opposite sides in the axial direction of rim, picking up the image of the surface of rim from the direction perpendicular to the axis of rim by means of a CCD camera, and processing the image where the edge of scratch exhibits high illuminance by means of a CPU.
CONSTITUTION: A wheel rim 1 is irradiated, on the surface with light obliquely from the opposite sides in the axial direction of rim. Inner and outer circumferential surfaces of the rim are irradiated with light emitted from two light sources 6 respectively. Since the rim is irradiated obliquely, only the edge 3 of a push-in scratch 2 is rendered conspicuous in terms of luminance or density. Since the rim is irradiated with light from the opposite sides, the edge 3 on an arc is rendered conspicuous. Image of the rim surface is then picked up by means of a CCD camera from the direction perpendicular to the axis of rim and the image is processed by means of a CPU according to a detection algorithm. Since the CPU detects only the pull-in scratch while discriminating from disturbance, detection is automated and high speed processing is realized without requiring any skill.
TSUKUI SHINGO
TAKEUCHI YUGO
YAMADA AKIHIKO
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