United States Patent [19] [li] Patent Number: 4,800,442
Riseman, deceased et al. [45] Date of Patent: Jan. 24,1989
Related U.S. Application Data
Continuation of Ser. No. 931,941, Nov. 19, 1986, abandoned, which is a continuation of Ser. No. 765,938, Aug. 15, 1985, abandoned.
Int. CI.« H04N 1/40
U.S. a 358/280; 358/283;
358/298
Field of Search 358/280, 283, 284, 296,
358/298, 302
References Cited
U.S. PATENT DOCUMENTS
3,197,558 7/1965 Ernst 358/302
3,230,303 1/1966 Macovski 358/283
3.393.269 7/1968 Zeuthen 358/298
3,461,229 8/1969 Oppenheimer 358/296
3,643,016 2/1972 Dattilo 358/260
3.882.270 5/1975 Ogawa 358/260
3,916,096 10/1975 Everett 358/283
3,965,290 6/1976 Tisue 358/280
4,040,094 8/1977 Everett 358/283
4,329,717 5/1982 Logie 358/282
4,346,409 8/1982 Ishida 358/280
4,400,740 8/1983 Traino 358/285
4,467,364 8/1984 Konagaya 358/284
4,485,408 11/1984 Kamizyo 358/283
4,535,413 9/1985 Shiota 358/80
4,593,297 6/1986 Suzuki 358/283
4,626,923 12/1986 'Yoshida 358/283
FOREIGN PATENT DOCUMENTS
50-017919 2/1975 Japan .
2120896 1/1987 United Kingdom .
OTHER PUBLICATIONS
"Declaration Submitted Pursuant to 37 C.F.R. §1.56 and M.P.E.P. §609" by Applicants. Science, vol. 224, p. 44
Press release of Demonics Ltd., Feb. 24, 1984. Four (4) pages prepared on Demonics ETP-1 Electronic Technical Publishing System.
Primary Examiner—Howard W. Britton
Attorney, Agent, or Firm—Fitzpatrick, Cella, Harper &
Scinto
[57] ABSTRACT
An apparatus for generating a high quality image from a digital video signal includes a system for gamma correcting the digital video signal with a digital look up table and for converting the resultant digital signal to an analog video signal. Another circuit generates a triangular wave reference pattern signal and a comparator compares the analog video signal with the triangular wave reference pattern signal to form a pulse-widthmodulated signal. A raster scanning print engine producing, for example, a laser beam, scans over a recording medium in accordance with the pulse-widthmodulated signal, thereby forming an image of high quality on the recording medium of a print engine. This apparatus can also be used with an analog video signal by first converting the analog video signal to a digital video signal with an analog to digital converter.
96 Claims, 13 Drawing Sheets
