Patent ID: 11948026
Assignee: CANON KABUSHIKI KAISHA
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 0:
1. An image printing apparatus comprising:
a storing unit configured to store a dither pattern having a quantization resolution in which a plurality of thresholds are set corresponding to pixel positions;
a quantization unit configured to compare a threshold in the dither pattern, the threshold corresponding to a processing target pixel in image data, with a multi-value gradation value of the processing target pixel to generate quantization data having the quantization resolution; and
a control unit configured to perform a predetermined control in which an image is printed by moving a printing unit and a printing medium relative to each other in a predetermined direction, based on the quantization data generated by the quantization unit, at a printing resolution higher than the quantization resolution in at least one of the predetermined direction and a direction crossing the predetermined direction,
wherein the dither pattern is formed in line with the following steps and then stored in the storing unit:
a generation step of generating an extended pattern corresponding to the printing resolution, a part of a plurality of subpixels included in the extended pattern being determined as dot-arrangeable-subpixels in which dots are allowed to be printed and the other part of the plurality of subpixels included in the extended pattern being determined as dot-not-arrangeable-subpixels in which dots are not allowed to be printed according to the predetermined control;
a selecting step of selecting a number of the dot-arrangeable-subpixels which number corresponds to a predetermined gradation value from among the plurality of the dot-arrangeable-subpixels in the extended pattern, so that an arrangement of the selected dot-arrangeable-subpixels has a predetermined dispersibility; and
a setting step of specifying, from a plurality of pixels in the dither pattern having the quantization resolution, pixels which correspond to the dot-arrangeable-subpixels selected in the extended pattern having the printing resolution, and setting thresholds to the specified pixels.