| 摘要 |
PURPOSE:To easily and positively detect the presence of a depression by applying an illuminating light of a second illuminating device to the surface of an object to be observed from above in the slantwise direction while a first illuminating device is turned ON. CONSTITUTION:A first illuminating device 22 is placed right above the observing position to illuminate the whole of a component 1 in a vertical direction. A second illuminating device 23 is provided slantwise above the observing position, with casting an illuminating light slantwise in the downward direction towards the surface of the component 1. The illuminating intensity or the distance from the observing position of each illuminating device 22, 23 are set so that the brightness on the surface of the component 1 by the illuminating light of the second illuminating device 23 is 2-several times higher than that of the surface of the component 1 by the illuminating light of the first illuminating device 22. An image sensing device 24 is positioned immediately above the observing position, the visual field of which is set in a vertical direction to the component 1. |
