Image processing method, image processing apparatus, and computer program product

Patent metadata

Field	Value
Publication number	US-9734438-B2
Application number	US-201514635148-A
Country	US
Kind code	B2
Filing date	Mar 2, 2015
Priority date	Mar 4, 2014
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

An image processing method generates image data of an image made up of a plurality of dots and having resolution in a first direction and resolution in a second direction. The second direction intersects the first direction. The resolution in the first direction is different from the resolution in the second direction. The image processing method includes performing contour portion correction including adding a dot at a correction target pixel, the correction target pixel being a pixel adjacent to a step-like contour portion in the image, and when a dot is arranged at a pixel adjacent to a pixel of interest adjacent to the correction target pixel, deleting the dot at the pixel of interest.

First claim

What is claimed is:

1. An image processing method that generates image data for controlling a liquid-ejecting recording head to form, on an image recording medium, an image made up of a plurality of dots and having resolution in a first direction and resolution in a second direction, the second direction intersecting the first direction, the resolution in the first direction being higher than the resolution in the second direction, the image processing method comprising performing contour portion correction including
(a) adding image data corresponding to a dot to be formed by the liquid-ejecting recording head at a correction target pixel on the image recording medium, the correction target pixel being a pixel adjacent to a step-like contour portion in the image, and
(b) when a dot is to be formed at a pixel adjacent to a pixel of interest in the first direction having the higher resolution than that in the second direction, deleting image data corresponding to the dot at the pixel of interest, the pixel of interest being adjacent to the correction target pixel in the second direction having a lower resolution than that in the first direction.

2. The image processing method according to claim 1 , wherein the deleting the image data corresponding to the dot at the pixel of interest is performed in (b) when the step-like contour portion corresponds to an oblique line with an angle equal to or smaller than a predetermined angle.

3. The image processing method according to claim 1 , wherein the deleting the image data corresponding to the dot at the pixel of interest is performed in (b) when the contour portion corresponds to an oblique line with a thickness equal to or smaller than a predetermined thickness.

4. The image processing method according to claim 1 , wherein the step-like contour portion is detected by pattern matching using a mask pattern, the mask pattern depending on the resolutions.

5. The image processing method according to claim 1 , wherein whether or not to perform the contour portion correction is determined based on color of the image.

6. The image processing method according to claim 1 , wherein the contour portion correction further includes:
(c) defining a pixel at which the dot is to be formed and which is adjacent to the correction target pixel in the second direction as the pixel of interest; and
(d) determining whether the dot is to be formed at the pixel adjacent to the pixel of interest,
wherein the image data corresponding to the dot at the pixel of interest is deleted in (b) when it is determined in (d) that the dot is to be formed at the pixel adjacent to the pixel of interest in the first direction.

7. The image processing method according to claim 1 , wherein the dot formed at the correction target pixel is a small dot that is smaller than the dot at the pixel of interest.

8. An image processing apparatus that generates image data for controlling a liquid-ejecting recording head to form, on an image recording medium, an image made up of a plurality of dots and having resolution in a first direction and resolution in a second direction, the first direction intersecting the second direction, the resolution in the first direction being higher than the resolution in the second direction, the image processing apparatus being configured to perform contour portion correction including:
adding image data corresponding to a dot to be formed by the liquid-ejecting recording head at a correction target pixel on the image recording medium, the correction target pixel being a pixel adjacent to a step-like contour portion in the image, and
when a dot is to be formed at a pixel adjacent to a pixel of interest in the first direction having the higher resolution than that in the second direction, deleting image data corresponding to the dot at the pixel of interest, the pixel of interest being adjacent to the correction target pixel in the second direction having a lower resolution than that in the first direction.

9. A computer program product comprising a non-transitory computer-readable medium containing an information processing program, the program causing a computer to perform image processing that generates image data for controlling a liquid-ejecting recording head to form, on an image recording medium, an image made up of a plurality of dots and having resolution in a first direction and resolution in a second direction intersecting the first direction, the resolution in the first direction being higher than the resolution in the second direction, the image processing comprising performing contour portion correction including:
adding image data corresponding to a dot to be formed by the liquid-ejecting recording head at a correction target pixel on the image recording medium, the correction target pixel being a pixel adjacent to a step-like contour portion in the image, and
when a dot is to be formed at a pixel adjacent to a pixel of interest in the first direction having the higher resolution than that in the second direction, deleting image data corresponding to a dot at the pixel of interest, the pixel of interest being adjacent to the correction target pixel in the second direction having a lower resolution than that in the first direction.

Assignees

• Hosaka Shigetoshi
• Ricoh Co Ltd

Inventors

• Hosaka Shigetoshi

Classifications

• G06K15/1873 Primary

  Increasing spatial resolution; Anti-aliasing · CPC title

• G06K15/1868

  for fitting to an output condition, e.g. paper colour or format · CPC title