| 摘要 |
PURPOSE:To detect the height defect of an object to be inspected regardless of the shape of the reference surface thereof by providing a photographing device, an extraction means, a characteristic quantity comparison means and a defect decision means. CONSTITUTION:The photographing device 1 photographs the object to be inspected 2 from plural distances (a1) - (a3). Besides, it is no matter whether the photographing device 1 obtains either a one-dimensional image or a two-dimensional image. The characteristic quantity extraction means 3 extracts the characteristic quantity of the brightness distribution of a photographed image, for example, peak height, peak width, peak area in the brightness distribution in a direction of crossing the object to be inspected, or the one that the peak height is divided by the peak width or the like. The characteristic quantity comparison means 4 compares the characteristic quantities on the different distances. The height defect decision means 5 decides whether a defect exists on the height of the object to be inspected or not on the basis of the compared result of the characteristic quantities. Then, by utilizing the condition of focusing, the height defect of the object to be inspected is detected. Therefore, the reference surface is fixed in accordance with the distance of the photographing device and the height defect is detected regardless of the shape of the reference surface of the object to be inspected. |
