Photographic image reproduction using digital halftoning
Abstract
In the generation of screened halftones of photographic images for low resolution marking devices, conventional screen techniques are too coarse, and adaptive dither techniques are too fine. The present invention preserves the advantages of the adaptive dither techniques, while creating screen patterns with an adjustable degree of coarseness. The invention applies a hysteresis constant and recursion techniques previously limited to adaptive screening with fixed dot patterns to vary the size of dots in the screened image, thereby allowing adjustment of the image coarseness by adjusting the hysteresis constant.
Term
Term ended
Projected expiry passed 6 February 2011, 15.6 years ago.
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Every citation, both ways
| Document | Relation | Office | Category | Cited during |
|---|---|---|---|---|
| US4012584A | Cites | United States of America | AD | Search report |
| US4633327A | Cites | United States of America | A | Search report |
9 members in 5 offices
Priority claims3
| Document | Office | Kind | Date |
|---|---|---|---|
| 476060 | United States of America | – | |
| 47606090 | United States of America | A | |
| US19900476060 | – | – | – |
Members9
| Document | Office | Kind | |
|---|---|---|---|
| EP0441608A2 | European Patent Office (EPO) | A2 | |
| US5055942A | United States of America | A | |
| JPH04213964A | Japan | A | |
| EP0441608A3This record | European Patent Office (EPO) | A3 | |
| EP0441608B1 | European Patent Office (EPO) | B1 | |
| AT121581T | Austria | T | |
| DE69108951D1 | Germany | D1 | |
| DE69108951T2 | Germany | T2 | |
| USRE37907E | United States of America | E |
46 legal events, as 3 offices reported them to INPADOC
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| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
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| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| Gb: european patent ceased through non-payment of renewal feeCeasedGBPC | GBPC | EP | |
| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| Annual fee paid to national office [announced via postgrant information from national office to epo]GrantedPGFP | PGFP | EP | |
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| Annual fee paid to national office [announced via postgrant information from national office to epo]GrantedPGFP | PGFP | EP | |
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| Information on the status of an ep patent application or granted ep patentGrantedSTATUS: OPPOSITION PROCEDURE CLOSEDSTAA | STAA | EP | |
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| Opposition filedOpposition26 | 26 | EP | |
| Annual fee paid to national office [announced via postgrant information from national office to epo]GrantedPGFP | PGFP | EP | |
| Reply of patent proprietor to notice(s) of oppositionOppositionORIGINAL CODE: EPIDOS OBSOPLBF | PLBF | EP | |
| Opposition filedOppositionORIGINAL CODE: 0009260PLBI | PLBI | EP | |
| Unpublished change to opponent dataORIGINAL CODE: EPIDOS OPPOPLBQ | PLBQ | EP | |
| Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents actLapsedNLV1 | NLV1 | EP | |
| Fr: translation filedET | ET | EP | |
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| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| It: translation for a ep patent filedITF | ITF | EP | |
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| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
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| (expected) grantORIGINAL CODE: 0009210GRAA | GRAA | EP | |
| First examination report despatched17Q | 17Q | EP | |
| Request for examination filed17P | 17P | EP | |
| Designated contracting statesAK | AK | EP | |
| Search report despatchedORIGINAL CODE: 0009013PUAL | PUAL | EP | |
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| Public reference made under article 153(3) epc to a published international application that has entered the european phaseORIGINAL CODE: 0009012PUAI | PUAI | EP |
Numbers
- Publication
- 0441608
- Publication, DOCDB
- 0441608
- Publication, EPODOC
- EP0441608
- Application
- 300963
- Application, DOCDB
- 91300963
- Application, EPODOC
- EP19910300963
Titles3
- English
- Photographic image reproduction using digital halftoning
- German
- Digitale photographische Halbtonbildreproduktion
- French
- Reproduction photographique d'images par demi-teinte digitale
Classification
- CPC, 1
- H04N1/4057
- IPC, 1
- H04N1 405
Designated states13
- Contracting states, 13
- Austria
- Belgium
- Switzerland
- Germany
- Denmark
- Spain
- France
- United Kingdom
- Greece
- Italy
- Liechtenstein
- Netherlands (Kingdom of the)
- Sweden