| 摘要 |
PURPOSE:To delete a pseudodefect and to extract only a fatal defect by subtracting a prescribed pseudodefect digital picture from a picture obtained by subtracting the absolute values of digital array pictures of a reference parts and a parts to be tested. CONSTITUTION:A picture An-An' is obtained by subtracting the previously contracted picture An' of the digital picture of the reference parts from the previously expanded picture An by using an XY table 6, a controller device 7, a picture processor 2, etc. Subsequently, the picture A-B is found out by subtracting the absolute values of the digital array pictures of the reference parts and the parts to be tested. The picture A-B includes a pseudodefect. Said picture An-An' is added to a picture erased a picture B0-A subtracted the picture A from the picture B0 of the parts to be tested of which defect has been already known from a picture obtained by contracting or expanding the picture B0-A to form pseudodefect digital array G, then the array G is subtracted from said picture An-An'. Consequently, the pseudodefect can be deleted and only the fatal defect can be extracted. |
