Color image processing apparatus and method, and storage medium

• US 7,057,764 B1
• Filed: 03/08/2000
• Issued: 06/06/2006
• Est. Priority Date: 03/09/1999
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sakaue, Tsutomu
• Primary Examiner(s): Coles, Edward
• Assistant Examiner(s): Park, Chan S.
• Application Number:
  US09/521,379
• Time in Patent Office: 2,281 Days
• Field of Search: 358/1.18, 358/1.9, 358/232, 358/243, 358/296, 382/244, 382/245, 382/248, 382/254, 382/276, 382/266, 382/267, 382/268, 382/269
• US Class Current: 358/1.9
• CPC Class Codes: G06K 15/02 using printers
• CPC Class Codes: G06K 15/1807 relating to the print image preparation
• CPC Class Codes: G06K 15/1814 including print-ready data, i.e. data already matched to the printing process
• CPC Class Codes: H04N 1/506 Reproducing the colour component signals picture-sequentially, e.g. with reproducing heads spaced apart from one another in the subscanning direction
• CPC Class Codes: H04N 1/56 Processing of colour picture signals H04N1/52 takes precedence

Abstract

A full-color image input from an external apparatus can undergo an optimal adaptive process using an image area separation circuit mounted in a color copying machine main body, and also attribute map information, thus providing a higher-quality image. When a color copying machine (18) prints an image such as a computer graphics image sent from a host computer (10), a raster image processor (13) renders bitmap data of a given recording color on an image memory (15) on the basis of that print data, and stores attribute information in an attribute map memory (16) in units of pixels. The color copying machine (18) forms an image on the basis of image data of respective recording color components, which are frame-sequentially input from the raster image processor (13), and attribute information from the attribute map memory (16).

Claims

1. A color image processing apparatus rendering an image from a command by generating attribute information and bitmap image data, said apparatus comprising:

attribute information generation means for generating attribute information indicating an attribute of the image from the command indicating the image;

bitmap image data generation means for generating bitmap image data by rendering the command;

image area separation means for detecting at least an edge of the bitmap image generated by said bitmap image data generation means and for performing image area separation of the bitmap image data on the basis of the detected edge; and

control means for controlling an image process for the bitmap image data on the basis of the attribute information and the image area separation performed by said image area separation means in a copy mode, while controlling the image processing of the bitmap image data without using the image area separation performed by said image area separation means in a print mode.

2. An apparatus according to claim 1, wherein the image process performed by said apparatus is a resolution switching process.

3. An apparatus according to claim 1, wherein image area separation performed by said image area separation means includes determination of character thickness.

4. An apparatus according to claim 1, wherein the image process performed by said apparatus is a multi-valued black character process.

5. An apparatus according to claim 1, wherein the image rendered by said apparatus includes a computer graphics image.

6. An apparatus according to claim 1, wherein the image process performed by said apparatus, without using the image separation performed by said image area separation means, prevents an image from being recorded at different resolutions in units of color planes that form the image.

7. An apparatus according to claim 1, wherein an area of the image which is determined to be a character on the basis of at least one of the attribute information and the image area separation performed by said image area separation means undergoes a smoothing process.

8. An apparatus according to claim 7, wherein the resolution of the area is increased by the smoothing process.

9. An apparatus according to claim 1, wherein the attribute information generated by said attribute information generation means includes at least one of a character flag, an edge flag, and an edge boundary flag.

28. An apparatus according to claim 1, wherein said image area separation means detects character thickness in the bitmap image data generated by said bitmap image data generation means to perform image area separation of the bitmap data.

10. A color image processing method for rendering an image from a command by generating attribute information and bitmap image data, said method comprising:

an attribute information generation step of generating attribute information indicating an attribute of the image from the command indicating the image;

a bitmap image data generation step of generating bitmap image data by rendering the command;

an image area separation step of detecting at least an edge of the bitmap image generated in said bitmap image data generation step and performing image area separation of the bitmap image data on the basis of the detected edge; and

a control step of controlling an image process for the bitmap image data on the basis of the attribute information and the image area separation performed in said image area separation step in a copy mode, while controlling the image processing of the bitmap image data without using the image area separation performed in said image area separation step in a print mode.

11. A method according to claim 10, wherein the image process performed by said method is a resolution switching process.

12. A method according to claim 10, wherein image area separation performed in said image area separation step includes determination of character thickness.

13. A method according to claim 10, wherein the image process performed by said method is a multi-valued black character process.

14. A method according to claim 10, wherein the image rendered by said method includes a computer graphics image.

15. A method according to claim 10, wherein the image process performed by said method, without using the image area separation performed in said image area separation step, prevents an image from being recorded at different resolutions in units of color planes that form the image.

16. A method according to claim 10, wherein an area of the image which is determined to be a character on the basis of at least one of the attribute information and the image area separation performed in said image area separation step undergoes a smoothing process.

17. A method according to claim 16, wherein the resolution of the area is increased by the smoothing process.

18. A method according to claim 10, wherein the attribute information generated in said attribute information generation step includes at least one of a character flag, an edge flag, and an edge boundary flag.

19. A storage medium for storing a program for executing a color image processing method for rendering an image from a command by generating attribute information and bitmap image data, said program comprising:

code for an attribute information generation step of generating attribute information indicating an attribute of the image from the command indicating the image;

code for a bitmap image data generation step of generating bitmap image data by rendering the command;

code for an image area separation step of detecting at least an edge of the bitmap image generated by said bitmap image data generation code and performing image area separation of the bitmap image data on the basis of the detected edge; and

code for a control step of controlling an image process for the bitmap image data on the basis of the attribute information and the image area separation performed by said image area separation code in a copy mode, while controlling the image processing of the bitmap image data without using the image area separation performed by said image area separation code in a print mode.

20. A storage medium according to claim 19, wherein the image process performed by the program stored in said storage medium is a resolution switching process.

21. A storage medium according to claim 19, wherein said image area separation step performed by said image area separation code includes determination of character thickness.

22. A storage medium according to claim 19, wherein the image process performed by the program stored in said storage medium is a multi-valued black character process.

23. A storage medium according to claim 19, wherein the image rendered by the program stored in said storage medium includes a computer graphics image.

24. A storage medium according to claim 19, wherein the image process performed by the program stored in said storage medium, without using the image area separation performed by said image area separation code, prevents an image from being recorded at different resolutions in units of color planes that form the image.

25. A storage medium according to claim 19, wherein an area of the image which is determined to be a character on the basis of at least one of the attribute information and the image area separation performed by said image area separation code undergoes a smoothing process.

26. A storage medium according to claim 25, wherein the resolution of the area is increased by the smoothing process.

27. A storage medium according to claim 19, wherein the attribute information generated by said attribute information generation code includes at least one of a character flag, an edge flag, and an edge boundary flag.

29. A color image processing apparatus rendering an image from a command by generating attribute information and bitmap image data, said apparatus comprising:

attribute information generation means for generating attribute information indicating an attribute of the image from the command indicating the image;

bitmap image data generation means for generating bitmap image data by rendering the command;

image area separation means for detecting at least an edge of the bitmap image generated by said bitmap image data generation means and for performing image area separation of the bitmap image data on the basis of the detected edge; and

control means for changing the resolution at the detected edge portion of the bitmap image, detected by said image area separation means, to a higher resolution on the basis of the attribute information and the image area separation performed by said image area separation means.

30. A color image processing method for rendering an image from a command by generating attribute information and bitmap image data, said method comprising:

an attribute information generation step of generating attribute information indicating an attribute of the image from the command indicating the image;

a bitmap image data generation step of generating bitmap image data by rendering the command;

an image area separation step of detecting at least an edge of the bitmap image generated in said bitmap image data generation step and performing image area separation of the bitmap image data on the basis of the detected edge; and

a control step of changing the resolution at the detected edge portion of the bitmap image, detected in said image area separation step, to a higher resolution on the basis of the attribute information and the image area separation performed in said image area separation step.