The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 13, 1994
Filed:
Oct. 29, 1991
Hiroyuki Onishi, Kyoto, JP;
Tetsuo Hoki, Kyoto, JP;
Dainippon Screen Mfg. Co., Ltd., Kyoto, JP;
Abstract
A printed board, on which a wiring pattern and a through hole to be inspected are provided, is scanned pixel by pixel and is read optically. The data obtained by scanning is converted into an electric signal to obtain image data. On the basis of the image data thus obtained, a pattern image representing the wiring pattern an a hole image representing the through hole are obtained. A center and a radius of the hole image are obtained from the image data. Then, a plurality of ring-shaped masks are obtained by magnifying the hole image at a plurality of magnifications. The size of the pattern image is normalized by the size of the hole image, and the, respective areas of overlapped regions between a plurality of the ringshaped masks and the pattern image are detected. Since these areas are obtained with an isotropic method, they do not depend on the directions of a line entering a land. By simulation, correspondence between the area of the overlapped regions and a relative positional relation between the wiring pattern and the through hole is obtained in advance. On the basis of this known correspondence, a relative positional relation between the wiring pattern and the through hole is evaluated by utilizing a neural network that has been taught such known correspondence.