Image processing method, image processing apparatus and recording medium

• US 20030210430A1
• Filed: 06/09/2003
• Published: 11/13/2003
• Est. Priority Date: 12/11/2000
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Sato, Kazuhiko, Nose, Masaki
• Granted Patent: US 7,130,081 B2
• Time in Patent Office: Days
• US Class Current: 358/2.1
• CPC Class Codes: H04N 1/52 Circuits or arrangements for halftone screening

Abstract

The present invention relates to an image processing method, an image processing apparatus and a recording medium that convert a grey scale image into an area gradation image. The present invention intends to provide an image processing method, an image processing apparatus and a recording medium capable of increasing processing speed in a state where high image quality is maintained. In the image processing method and the image processing apparatus according to the present invention, image data of a C component and image data of an M component in grey scale image data are converted into halftone image data in accordance with an error diffusion method, and image data of a Y component are converted into halftone image data in accordance with a blue noise mask method.

Claims

1. An image processing method for obtaining an image by performing a gradation process for a plurality of kinds of image data, comprising the step of:

performing the gradation process by selectively applying a gradation processing method from one of an error diffusion method and a blue noise mask method for each of said kinds of the image data.

5. The image processing method as claimed in claim 1, wherein said gradation processing methods for said kinds of the image data are allowed to be switched.

2. The image processing method as claimed in claim 2, wherein in said gradation processing method, one gradation process is performed for image data of a color component sensitive to a human being in said kinds of image data, and another gradation process different from said one gradation process is performed for image data of a color component less sensitive to a human being.

3. The image processing method as claimed in claim 2, wherein said kinds of image data include image data of at least color components of yellow, cyan and magenta, and the gradation process is performed for image data of the color components of the cyan and the magenta in accordance with the error diffusion method and for image data of the color component of the yellow in accordance with the blue noise mask method.

4. The image processing method as claimed in claim 2, wherein said kinds of image data include image data of at least color components of red, green and blue, and the gradation process is performed for image data of the color components of the red and the green in accordance with the error diffusion method and for image data of the color component of the yellow in accordance with the blue noise mask method.

6. An image processing apparatus for obtaining an image by performing a gradation process for a plurality of kinds of image data, comprising:

an image processing part performing the gradation process for each of said kinds of image data by selectively applying a gradation processing method from one of an error diffusion method and a blue noise mask method.

10. The image processing apparatus as claimed in claim 6, further comprising a selection part capable of selecting a gradation processing method for the kinds of the image data.

7. An image processing apparatus for obtaining an image by performing a gradation process for a plurality of kinds of image data, comprising:

an image processing part performing one gradation process for image data of a color component sensitive to a human being in the kinds of the image data and another gradation process different from said gradation process for image data of a color component less sensitive to a human being.

8. The image processing apparatus as claimed in claim 7, wherein said kinds of the image data include image data of at least color components of yellow, cyan and magenta, and said switching part controls to process image data of the color components of the cyan and the magenta in accordance with said error diffusion processing part and image data of the color component of the yellow in accordance with said blue noise mask processing part.

9. The image processing apparatus as claimed in claim 7, wherein said kinds of the image data include image data of at least color components of red, green and blue, and said switching part controls to process image data of the color components of the red and the green in accordance with said error diffusion processing part and image data of the color component of the yellow in accordance with said blue noise mask processing part.

11. A computer readable recording medium for storing a program, the program causing a computer to execute the steps of:

performing one gradation process for image data of a color component sensitive to a human being in a plurality of kinds of image data; and

performing another gradation process different from said one gradation process for image data of a color component less sensitive to a human being in the kinds of image data.