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US 10,477,067 B2Granted
Image forming apparatus, image forming method, and storage medium
AssigneeCanon Kabushiki Kaisha
InventorTaiki Tezuka
Life of this patent
Estimating the term…
Abstract
An image forming apparatus in which a lighting position of a dot to be firstly generated by screen processing is changed, in a vertical direction, between a first sub-matrix and a second sub-matrix that are included in a dithering matrix and that are adjacent to each other in a lateral direction, in order not to generate a region where no dot exists in a main scanning direction.
Claims11
An image forming apparatus comprising:
- a screen processing unit configured to perform screen processing on image data based on a result of comparison between a value of a pixel in the image data and a threshold of a dithering matrix corresponding to the pixel;
- and
- a determination unit configured to determine whether a pixel of interest is included in a halftone image in the image data having been subjected to the screen processing by the screen processing unit, based on a pixel value in a region having a predetermined length in a lateral direction from the pixel of interest,
- wherein the dithering matrix includes a plurality of sub-matrices,
- wherein out of the plurality of sub-matrices, a first sub-matrix and a second sub-matrix that have a same number of pixels in a vertical direction and in the lateral direction are adjacent to each other in the lateral direction,
- wherein a threshold at a growth center in the first sub-matrix and a threshold at a growth center in the second sub-matrix are located at different positions in the vertical direction, and
- wherein the predetermined length is larger than that corresponding to the number of pixels in the lateral direction of the first sub-matrix.
4 more elements
An image forming method comprising:
- performing screen processing on image data based on a result of comparison between a value of a pixel in the image data and a threshold of a dithering matrix corresponding to the pixel;
- and
- determining whether a pixel of interest is included in a halftone image in the image data having been subjected to the screen processing, based on a pixel value in a region having a predetermined length in a lateral direction from the pixel of interest,
- wherein the dithering matrix includes a plurality of sub-matrices,
- wherein, out of the plurality of sub-matrices, a first sub-matrix and a second sub-matrix that have a same number of pixels in a vertical direction and in the lateral direction are adjacent to each other in the lateral direction,
- wherein a threshold at a growth center in the first sub-matrix and a threshold at a growth center in the second sub-matrix are located at different positions in the vertical direction, and
- wherein the predetermined length is larger than that corresponding to the number of pixels in the lateral direction of the first sub-matrix.
4 more elements
A non-transitory computer-readable storage medium storing a computer program for causing a computer to execute a method of controlling an image forming apparatus, the method comprising:
- performing screen processing on image data based on a result of comparison between a value of a pixel in the image data and a threshold of a dithering matrix corresponding to the pixel;
- and
- determining whether a pixel of interest is included in a halftone image in the image data having been subjected to the screen processing, based on a pixel value in a region having a predetermined length in a lateral direction from the pixel of interest,
- wherein the dithering matrix includes a plurality of sub-matrices,
- wherein, out of the plurality of sub-matrices, a first sub-matrix and a second sub-matrix that have a same number of pixels in a vertical direction and in the lateral direction are adjacent to each other in the lateral direction,
- wherein a threshold at a growth center in the first sub-matrix and a threshold at a growth center in the second sub-matrix are located at different positions in the vertical direction, and
- wherein the predetermined length is larger than that corresponding to the number of pixels in the lateral direction of the first sub-matrix.
4 more elements
Dependencies are inferred from the claim text.