System for detecting difference between image on primary sheet and image on secondary sheet
US4747146A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 6, 1985 |
| Grant date | May 24, 1988 |
| Priority date | — |
| Expiry date | May 6, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T7/00
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
There is disclosed a system for detecting a difference between an image on a primary sheet and an image on a secondary sheet. A microprocessor unit determines whether corresponding ones of first and second image elements representative respectively of the images on the primary and secondary films differ in optical density from each other below a predetermined level. The two corresponding first and second image elements different above the predetermined level are emphasized in optical density difference and alternately displayed on a display screen at a short time interval, so that the dot of the display screen which alternately display these image elements is caused to flicker.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.