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:
Jan. 19, 1982
Filed:
Dec. 11, 1979
Josef A Huber, Zurich, CH;
Gretag Aktiengesellschaft, Regensdorf, CH;
Abstract
The differences between the scanned values of corresponding image points of a specimen and an original are formed by point-by-point scanning and comparison with an original. The difference values are subjected to a tone or shade correction, and then a weighting process and a minimum threshold correction. In the shade or tone correction, a mean value formed from the difference values in a specific surrounding area of the associated image point is subtracted from each difference value. The weighting process is effected individually for each image point and results in systematic errors and critical image zones not producing faulty assessments. The weighting factors are determined by statistical analysis of specimens which are assessed as good visually. The minimum threshold correction eleminates all those pre-treated difference values which are below a certain minimum threshold. The difference values of the points surrounding each image point are added algebraically with distance-dependent weighting to the remaining difference values of each image point. The resulting values are compared with a threshold value for each image point. If these values exceed the threshold value at least at one image point, the specimen is assessed as faulty.