Image processing apparatus configured to trapping process and non-transitory computer-readable recording medium storing instructions for image processing including trapping process

Patent metadata

Field	Value
Publication number	US-10457068-B2
Application number	US-201815938523-A
Country	US
Kind code	B2
Filing date	Mar 28, 2018
Priority date	Aug 30, 2017
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

In an image processing apparatus, a controller sequentially selects a plurality color determination pixels within a determination area, determine whether the color determination pixel has a chromatic color, whether a first pixel adjacent to the color determination pixel is black, and determine whether a second pixel apart from the color determination pixel by one pixel. The controller determines that a first trapping process is to be executed when the color determination pixel has a chromatic color and the first pixel is black, and a second trapping process when the color determination pixel has a chromatic color, the second pixel is black, and the intermediate pixels located between the color determination pixel and the second pixel are black. Thereafter, the controller executes a first trapping process and a second trapping process, but restricts the second trapping process to the pixel on which the first trapping process is to be executed.

First claim

What is claimed is:

1. An image processing apparatus, comprising:
a storage configured to store image data; and
a controller,
wherein the controller is configured to execute:
receiving image data configured such that a plurality of pixel arrays each including a plurality of pixels are arranged in a main scanning direction, the plurality of pixel arrays being aligned in a sub scanning direction which is perpendicular to the main scanning direction;
setting a determination area having a particular number of pixels within a particular area of three lines or more in the sub scanning direction and three pixels or more in the main scanning direction;
sequentially selecting a plurality of pixels within the determination area as color determination pixels;
determining whether a color determination pixel of the selected color determination pixels has a chromatic color;
determining black pixels including:
determining whether a first pixel adjacent to the color determination pixel is black; and
determining whether a second pixel apart from the color determination pixel with one or more intermediate pixels therebetween is black;

determining execution of trapping processes including:
determining that a first trapping process to add a color component of the color determination pixel to the first pixel is to be executed when the controller determines that the color determination pixel has a chromatic color and the first pixel is black; and
determining that a second trapping process to add the color component of the color determination pixel to the second pixel is to be executed when it is determined that the color determination pixel has a chromatic color, the second pixel is black, and the intermediate pixels located between the color determination pixel and the second pixel are black;

executing trapping processes including:
executing the first trapping process on a pixel on which the first trapping process is determined to be executed; and
executing the second trapping process on a pixel on which the second trapping process is determined to be executed;

restricting execution of trapping processes including:
restricting execution of the second trapping process on the pixel on which the first trapping process is determined to be executed,

wherein a position of the second pixel within the determination area varies depending on the color determination pixel.

2. The image processing apparatus according to claim 1 ,
the controller is further configured to execute:
adding flag information representing a result of a determination of the pixel on which the first trapping process is determined to be executed and the pixel on which the second trapping process is determined to be executed; and
restricting, by referring to the flag information, execution of the second trapping process on the pixel on which the first trapping process is determined to be executed.

3. The image processing apparatus according to claim 1 ,
wherein the determination area is an area including four or more lines in the sub scanning direction and four or more pixels in the main scanning direction,
wherein the determining black pixels further includes:
determining whether a third pixel apart from the color determination pixel with two intermediate pixels therebetween is a black pixel;

wherein the determining execution of trapping processes further includes:
determining that a third trapping process to add the color component of the color determination pixel is to be executed on the third pixel when the color determination pixel is determined to have the chromatic color, the third pixel is determined to be a black pixel and the two intermediate pixels located between the color determination pixel and the third pixel are black pixels;

wherein the execution of trapping processes further includes:
executing the third trapping process with respect on the pixel on which the third trapping process is determined to be executed; and

wherein the restricting execution of the trapping processes further restricts execution of the third trapping process on the pixel on which the first trapping process is determined to be executed and the pixel on which the second trapping process is to be executed.

4. The image processing apparatus according to claim 3 ,
wherein the determining execution of trapping processes adds flag information representing the determination result to the pixel on which the first trapping process is determined to be executed, on the pixel on which the second trapping process is determined to be executed, and the pixel on which the third trapping process is determined to be executed, and
wherein the restricting execution of the trapping processes further restricts execution of the second trapping process on the pixel on which the first trapping process is determined to be executed, and execution of the third trapping process on the pixel to which the first trapping process is determined to be executed and the pixel on which the second trapping process is determined to be executed.

5. The image processing apparatus according to claim 3 ,
wherein the determination area includes four central pixels located at a central part of the determination area and a plurality of surrounding pixels arranged around and adjacent to the four central pixels,
wherein the color determination pixel is selected from the plurality of surrounding pixels, and
wherein the determining black pixels includes, at every selection of the color determination pixel:
determining whether a first pixel which is adjacent to the color determination pixel in a direction from a position of the color determination pixel to a position of the central part is the black pixel;
determining whether a second pixel sandwiching, in association with the color determination pixel, the first pixel is the black pixel.

6. The image processing apparatus according to claim 5 ,
wherein the determination area is a 4×4 pixel area including four lines of pixels in the sub scanning direction and four pixels in each line extending in the main scanning direction, and
wherein the plurality of surrounding pixels are pixels adjacent to four central pixels located at the center of the central part of the 4×4 pixel area in the main scanning direction and in the sub scanning direction.

7. The image processing apparatus according to claim 3 ,
wherein the determination area includes four central pixels located at the central part of the determination area and a plurality of surrounding pixels arranged around and adjacent to the four central pixels,
wherein the color determination pixel includes a first color determination pixel, a second color determination pixel and a third color determination pixel,
wherein the sequentially selecting a plurality of pixels includes:
sequentially selecting the plurality of surrounding pixels in order as an objective pixel; and
selecting, at every selection of the objective pixel, a pixel which is adjacent to the objective pixel in a direction from a position of the objective pixel to a position of the central part as the first color determination pixel, a pixel sandwiching, in association with the objective pixel, the first color determination pixel as the second color determination pixel, and a pixel sandwiching, in association with the objective pixel, the first color determination pixel and the second color determination pixel as the third color determination pixel,

wherein the determining black pixels determine, at every selection of the objective pixel, whether the objective pixel serving as the first pixel corresponding to the first color determination pixel, the second pixel corresponding to the second color determination pixel and the third pixel corresponding to the third color determin

Assignees

• Brother Ind Ltd

Inventors

• Sato Yuji

Classifications

• H04N1/58

  Edge or detail enhancement; Noise or error suppression, e.g. colour misregistration correction (H04N1/62 takes precedence) · CPC title

• B41J2/525 Primary

  Arrangement for multi-colour printing, not covered by group B41J2/21, e.g. applicable to two or more kinds of printing or marking process · CPC title

• H04N1/60

  Colour correction or control {(H04N1/54 takes precedence)} · CPC title