Process for assessing the quality of a printed product
US4303832A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 11, 1979 |
| Grant date | Dec 1, 1981 |
| Priority date | — |
| Expiry date | Dec 11, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07D7/121
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
Specimens, the quality of whose print is to be examined, are scanned photoelectrically point-by-point and compared point-by-point with one or more originals. The resulting reflectance differences are processed in different correction stages and then subjected to a point-by-point threshold decision, an individual threshold value being used for each image point. The threshold values are produced by analysis of specimens which have acceptable deviations, the maximum positive and negative reflectance differences due to their deviations being used directly as the threshold values. The analysis is effected by reference to electronically simulated specimens, an original or originals and a specimen being electronically displaced relatively to one another and reflectances being electronically varied in order to simulate register deviations and shade or tone deviations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.