US 11,388,312 B2Granted

Image processing apparatus and image processing method

AssigneeSeiko Epson Corporation

InventorToshiaki Kakutani

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Abstract

An original image is divided in a primary scan direction, and an upstream overlapping segment that overlaps with the divided image on the upstream in the primary scan direction is provided from the division position. Halftone processors are provided in correspondence with the divided images, and the pixels on each raster line of each of the divided images are sequentially picked up as a pixel of interest, and an error diffusion method is applied to the pixel of interest. The halftone processor that processes the divided image on the downstream in the primary scan direction out of the plurality of divided images starts, after the halftone processor that processes the upstream divided image performs the halftone processing on a pixel on a raster line, halftone processing on a pixel on the raster line of the divided image to be processed and causes, in the halftone processing, the result of the halftone processing performed on the pixel of interest by a degree specified in advance with the result of halftone processing performed on the corresponding pixel in an upstream overlapping segment of the adjacent upstream divided image.

Claims7

Dependent claims

An image processing apparatus that sequentially performs halftone processing on a two-dimensional original image extending in horizontal and vertical directions and formed of a plurality of pixels with one of the vertical and horizontal directions being a primary scan direction,

a divider that divides the original image into n divided images (n is integer greater than or equal to 2) arranged in the primary scan direction, the divided images each having an upstream overlapping segment that overlaps with the divided image on an upstream in the primary scan direction by xa pixels (xa is integer greater than or equal to 1) arranged from a division position in each raster line along which pixels are arranged in the primary scan direction;
n halftone processors that are provided in correspondence with the divided images, sequentially pick up as a pixel of interest each of the pixels that belong to each of the raster lines of the divided images, and apply an error diffusion method to the pixel of interest to perform the halftone processing;
and
an output section that combines results of the processing performed by the halftone processors on the divided images with one another and outputs processed data having gradation values smaller than gradation values of the original image,
wherein the halftone processor that processes the divided image on a downstream in the primary scan direction out of the n divided images
starts, after the halftone processor that processes the upstream divided image adjacent to the downstream divided image performs the halftone processing on a pixel of the upstream divided image on a j-th raster line (j is integer greater than or equal to 1) in a secondary direction, the halftone processing on a pixel on the j-th raster line of the divided image to be processed and
carries out, in the halftone processing performed on the pixel that falls within the upstream overlapping segment on the j-th raster line of the divided image to be processed, a match process of matching by a degree specified in advance a result of the halftone processing performed on the pixel with a result of halftone processing performed on a corresponding pixel out of the xa pixels on the j-th raster line of the adjacent upstream divided image.

4 more elements

An image processing method for sequentially performing halftone processing on a two-dimensional original image extending in horizontal and vertical directions and formed of a plurality of pixels with one of the vertical and horizontal directions being a primary scan direction, the image processing method comprising:

dividing the original image into n divided images (n is integer greater than or equal to 2) arranged in the primary scan direction, the divided images each having an upstream overlapping segment that overlaps with the divided image on an upstream in the primary scan direction by xa pixels (xa is integer greater than or equal to 1) arranged from a division position in each raster line along which pixels are arranged in the primary scan direction;
performing halftone processing to which an error diffusion method is applied on each of the divided images in parallel;
starting, in the halftone processing performed on the divided image on a downstream in the primary scan direction, after the halftone processing performed on a pixel of the upstream divided image adjacent to the downstream divided image on a j-th raster line (j is integer greater than or equal to 1) in a secondary direction, processing to which the error diffusion method is applied on a pixel on the j-th raster line of the divided image to be processed;
carrying out, in the halftone processing performed on the pixel that falls within the upstream overlapping segment on the j-th raster line of the divided image to be processed, a match process of matching by a degree specified in advance a result of the halftone processing performed on the pixel with a result of the halftone processing performed on a corresponding pixel out of the xa pixels on the j-th raster line of the upstream divided image adjacent to the downstream divided image;
and
combining results of the halftone processing performed on the divided images with one another and outputting processed data having gradation values smaller than gradation values of the original image.

3 more elements

Dependencies are inferred from the claim text.