US 6,982,766 B1
Digital raster correction
John Barrett George, Carmel, Ind. (US); and Frank Albert Glad, El Paso, Tex. (US)
Assigned to Thomson Licensing, Boulogne-Billancourt (France)
Appl. No. 9/485,940
PCT Filed Aug. 28, 1998, PCT No. PCT/US98/17920
§ 371(c)(1), (2), (4) Date Feb. 18, 2000,
PCT Pub. No. WO99/11054, PCT Pub. Date Mar. 04, 1999.
Claims priority of provisional application 60/057250, filed on Aug. 29, 1997.
Int. Cl. H04N 3/22 (2006.01); H04N 3/26 (2006.01)
U.S. Cl. 348—806 17 Claims
OG exemplary drawing
 
1. A video display apparatus, comprising:
a plurality of cathode ray tubes for projecting an image subject to image distortion on a display screen,
each of said cathode ray tubes having at least one vertical deflection coil and at least one convergence coil mounted thereupon,
a first correction signal generator providing a first correction signal to said vertical deflection coils;
a second correction signal generator providing a second correction signal to said convergence coils;
a video pattern generator for generating said image upon said display, said image comprising rows and columns of spaced points generally defining a cross hatch grid;
wherein said first correction signal provides correction for selected columns of said cross hatch grid;
wherein said second correction signal provides correction for at least one column of said cross hatch grid other than said selected columns.