| US 7,538,909 B2 | ||
| Defective nozzle compensation | ||
| Peter Mitchell Ilbery, Dundas NSW (Australia); Noribumi Koitabashi, Yokohama (Japan); Shoji Kanemura, Sagamura (Japan); and James Robert Metcalfe, Killara NSW (Australia) | ||
| Assigned to Canon Kabushiki Kaisha, Tokyo (Japan) | ||
| Filed on Feb. 22, 2006, as Appl. No. 11/358,106. | ||
| Application 11/358106 is a division of application No. 09/859437, filed on May 18, 2001, granted, now 7,085,002. | ||
| Claims priority of application No. PQ7663 (AU), filed on May 22, 2000. | ||
| Prior Publication US 2006/0139663 A1, Jun. 29, 2006 | ||
| Int. Cl. G06K 15/00 (2006.01); H04N 1/405 (2006.01) | ||
| U.S. Cl. 358—3.03 [358/3.06; 358/3.13; 358/3.26] | 29 Claims |
| 1. A method, in printing an image comprising a plurality of image values each assuming one of a number of possible intensity
values per pixel, of compensating for one or more defective printer nozzles in a plurality of printer nozzles, said method
comprising the steps of:
biasing, for each first image value to be printed at a first pixel position associated with a first nozzle, at least one second
image value to be printed at a second pixel position associated with another nozzle, said second pixel position being different
from said first pixel position and said biasing being dependent upon said first image value and a printing desirability factor
for said first nozzle;
halftoning said at least one biased second image value by error diffusion or dithering to form at least one corresponding
nozzle firing value assuming one of a reduced number of possible intensity values per pixel; and
printing the image using said at least one nozzle firing value, thereby reducing print artefacts otherwise caused by the one
or more defective nozzles.
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