Image processing and image forming with modification of a particular class of colors

• US 7,817,303 B2
• Filed: 10/11/2005
• Issued: 10/19/2010
• Est. Priority Date: 10/12/2004
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kato, Minako, Nagoshi, Shigeyasu
• Primary Examiner(s): Poon; King Y
• Assistant Examiner(s): Cammack; David S
• Application Number:
  US11/246,300
• Publication Number:
  US 20060075918A1
• Time in Patent Office: 1,834 Days
• Field of Search: 358/1.9, 358/515, 358/518, 358/520, 358/448, 358/453, 348/713, 348/255, 382/162, 382/164, 382/165, 382/167, 382/199, 382/254, 382/274, 382/286
• US Class Current: 358/1.9
• CPC Class Codes: B41J 2/17509 Whilst mounted in the printer
• CPC Class Codes: B41J 2/17513 Inner structure

Abstract

This invention provides an image processing device and a printing apparatus that obviate the need for manual processing on the part of the user or operator and which can automatically perform an optimum image correction without using added information such as photographing information. For this purpose, this invention including: a highly chromatic color area detection unit to detect highly chromatic color area in an original image according to the input color image data; a concentration calculation unit to calculate a concentration level of the highly chromatic color area; and a print data generation unit to generate output color image data according to the concentration level of the highly chromatic color area.

Claims

1. An image processing device for outputting an image from image data, comprising:

a determination unit configured to determine a size by which to divide the image data into pixel groups based on a resolution of the image data and a size of a printed output of the image;

a dividing unit configured to divide, according to the determined size, the image data into a plurality of pixel groups, each of the pixel groups comprising a plurality of pixels;

an averaging unit configured to average, for each of the pixel groups, luminance values of the pixels;

a calculation unit configured to calculate, for each group, the chroma value from the averaged luminance values;

a highly chromatic pixel group extraction unit configured to extract, out of the plurality of pixel groups, a plurality of highly chromatic pixel groups, each of whose averaged chroma value is higher than a predetermined value;

a determining unit configured to determine an adjoined pixel group comprising a plurality of the extracted highly chromatic pixel groups of a particular color adjoining each other;

a concentration calculation unit configured to calculate a concentration level for the adjoined pixel group, wherein the concentration level indicates a ratio of the area coverage of the adjoined pixel group to the area coverage of the image;

a parameter setting unit configured to set a chroma parameter for a chroma of the adjoined pixel group such that (a) the chroma is suppressed when the concentration level for the adjoined pixel group is high, and (b) the chroma is emphasized when the concentration level for the adjoined pixel group is low; and

a correction unit configured to correct the adjoined pixel group of the image data using the parameter set by the parameter setting unit, to produce a modified image data.

2. The image processing device according to claim 1, wherein the determining unit is configured to determine the adjoined pixel group comprising the plurality of the extracted pixel groups adjoining each other by applying a filter operation.

3. The image processing device according to claim 1, further comprising a printer configured to print the modified image data.

4. The image processing device according to claim 1, wherein a size of the pixel group is determined based on a size of the printed modified image.

5. The image processing device according to claim 1, wherein the determining unit is configured to determine the adjoined pixel group comprising the plurality of the extracted pixel groups adjoining each other based on the averaged chroma values.

6. The image processing device according to claim 1, wherein the adjoining unit is configured to determine the adjoined pixel group comprising the plurality of the extracted pixel groups adjoining each other based on having a same averaged chroma value.

7. An image processing method for outputting an image from image data, the method comprising the steps of:

determining a size by which to divide the image data into pixel groups based on a resolution of the image data and a size of a printed output of the image;

dividing, according to the determined size, the image data into a plurality of pixel groups, each of the pixel groups comprising a plurality of pixels;

averaging, for each of the pixel groups, luminance values of the pixels;

calculating, for each group, the chroma value from the averaged luminance values;

extracting, out of the plurality of pixel groups, a plurality of highly chromatic pixel groups, each of whose averaged chroma value is higher than a predetermined value;

determining an adjoined pixel group comprising a plurality of the extracted highly chromatic pixel groups of a particular color adjoining each other;

calculating a concentration level for the adjoined pixel group, wherein the concentration level indicates a ratio of the area coverage of the adjoined pixel group to the area coverage of the image;

setting a parameter for a chroma of the adjoined pixel group such that (a) the chroma is suppressed when the concentration level for the adjoined pixel group is high, and (b) the chroma is emphasized when the concentration level for the adjoined pixel group is low; and

correcting the adjoined pixel group of the image data using the parameter set in the setting step, to produce a modified image data.