Image processing method and image forming apparatus

• US 20030142355A1
• Filed: 01/25/2002
• Published: 07/31/2003
• Est. Priority Date: 01/25/2002
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Tec Corporation (Toshiba Corporation)
• Original Assignee: Toshiba Tec Corporation (Toshiba Corporation)
• Inventors: Hirayama, Masatsugu
• Granted Patent: US 7,054,036 B2
• Time in Patent Office: Days
• US Class Current: 358/2.1
• CPC Class Codes: H04N 1/4092 Edge or detail enhancement

Abstract

A main CPU calculates filter coefficient values corresponding to area discrimination signals on the basis of an input sharpness adjustment value and original mode and a base filter coefficient set and a difference filter coefficient set stored in a ROM, and performs a filtering process by selecting a filter coefficient value in accordance with an area discrimination signal of a pixel of interest in input image data.

Claims

1. An image forming apparatus which reads a color image on an original and subjects the read image data to image processing, thus forming a color image, the apparatus comprising:

a storage section which prestores a first filter coefficient set and a second filter coefficient set;

a setting section which presets a sharpness adjustment code value in the image processing;

a mode select section which selects an original mode;

an instruction section which instructs start of an image forming operation in the image forming apparatus;

a reading section which reads the color image on the original when the instruction section has issued a start instruction;

an area discrimination section which discriminates an area of each of pixels of interest in the color image data read by the reading section;

a calculation section which calculates, when the instruction section has issued the start instruction, filter coefficient values associated with areas discriminated by the area discrimination section, on the basis of the first filter coefficient set and second filter coefficient set stored in the storage section, the sharpness adjustment code value set by the setting section, and the original mode selected by the select section;

a temporary storage section which temporarily stores the plural filter coefficient values calculated by the calculation section;

a selection section which selects one of the plural filter coefficient values temporarily stored in the temporary storage section, on the basis of an area discrimination result of the area discrimination section; and

a process section which performs a filtering process for the image data, using the filter coefficient value selected by the selection section.

2. An image forming apparatus according to claim 1, wherein the first filter coefficient set stored in the storage section is a base filter coefficient set, and the second filter coefficient set is a difference filter coefficient set.

3. An image forming apparatus according to claim 1, wherein the setting section is preset by a serviceman of the image forming apparatus.

4. An image forming apparatus according to claim 1, wherein the sharpness adjustment code value set by the setting section is commonly used for the respective areas discriminated by the area discrimination section.

5. An image forming apparatus according to claim 1, wherein the sharpness adjustment code value set by the setting section is set specifically for each of respective original modes, which is selected by the mode select section.

6. An image forming apparatus according to claim 1, wherein the sharpness adjustment code value set by the setting section is set specifically for each of respective original modes, which is selected by the mode select section, and is commonly used for the respective areas discriminated by the area discrimination section.

7. An image forming apparatus according to claim 1, wherein when the calculation section calculates the filter coefficient values corresponding to the areas discriminated by the area discrimination section, a predetermined ratio is preset among the coefficients corresponding to the areas discriminated by the area discrimination section.

8. An image forming apparatus which reads a color image on an original and subjects the read image data to image processing, thus forming a color image, the apparatus comprising:

a storage section which prestores a first filter coefficient set and a second filter coefficient set;

a setting section which presets a sharpness adjustment code value in the image processing;

an adjustment section which adjusts the sharpness adjustment code value set by the setting section;

a mode select section which selects an original mode;

an instruction section which instructs start of an image forming operation in the image forming apparatus;

a reading section which reads the color image on the original when the instruction section has issued a start instruction;

a conversion section which converts the color image data read by the reading section to color signals;

an area discrimination section which discriminates an area of each of pixels of interest in the color image data read by the reading section;

a calculation section which calculates, when the instruction section has issued the start instruction, filter coefficient values associated with areas discriminated by the area discrimination section, on the basis of the first filter coefficient set and second filter coefficient set stored in the storage section, the sharpness adjustment code value set by the setting section, the value adjusted by the adjustment section and the original mode selected by the select section;

a temporary storage section which temporarily stores the plural filter coefficient values calculated by the calculation section;

a selection section which selects one of the plural filter coefficient values temporarily stored in the temporary storage section, on the basis of an area discrimination result of the area discrimination section; and

a process section which performs a filtering process for the color signals converted by the conversion section, using the filter coefficient value selected by the selection section.

9. An image forming apparatus according to claim 8, wherein when no adjustment has been effected by the adjustment section, the sharpness adjustment code value set by the setting section is used as a default for sharpness adjustment.

10. An image processing method which subjects supplied image data to image processing, comprising:

prestoring a first filter coefficient set and a second filter coefficient set;

presetting a sharpness adjustment code value in the image processing;

selecting an original mode;

discriminating an area of each of pixels of interest in the supplied image data;

calculating filter coefficient values associated with the discriminated areas on the basis of the stored first filter coefficient set and second filter coefficient set corresponding to the selected original mode, and the set sharpness adjustment code value;

temporarily storing the calculated filter coefficient values associated with the respective areas;

selecting one of the temporarily stored plural filter coefficient values in accordance with a result of the discrimination of the areas; and

performing a filtering process for the image data, using the selected filter coefficient value.