Color image conversion method and system for reducing color image data size

• US 20040258298A1
• Filed: 06/18/2003
• Published: 12/23/2004
• Est. Priority Date: 06/18/2003
• Status: Active Grant

• Current Assignee: Pirmax Electronics, Ltd.
• Original Assignee: Pirmax Electronics, Ltd.
• Inventors: Chen, Guo-Tai
• Granted Patent: US 7,298,894 B2
• Time in Patent Office: Days
• US Class Current: 382/162
• CPC Class Codes: H04N 1/40012 Conversion of colour to monochrome
• CPC Class Codes: H04N 1/40062 Discrimination between different image types, e.g. two-tone, continuous tone
• CPC Class Codes: H04N 1/56 Processing of colour picture signals H04N1/52 takes precedence

Abstract

A color image conversion method and the associated system are disclosed. An allowed error range of pixels is determined. After an image input device reads a document, the pixel information and the pixel allowed error range are compared to determine whether the document is a color or black-and-white (BW) one. If it is a BW document, the image file is directly converted into a monochromic and grey-level one and stored in 8-bit or even 1-bit format, thereby reducing the storage space occupied by the image file.

Claims

1. A color image conversion method for reducing the image data size of a colorless document scanned by a image input device, comprising the steps of:

setting a tolerable error range for pixels;

reading a source document to generate an original color image file;

checking whether the pixel values in the original color image file fall within the tolerable error range;

converting the original color image file into a colorless image file to reduce the data; and

storing the converted file.

2. The method of claim 1, wherein the original color image file is a 24-bit image file.

3. The method of claim 1, wherein the colorless image file is a 1-bit monochromatic image file.

4. The method of claim 1, wherein the colorless image file is an 8-bit grey-level image file.

5. The method of claim 1, wherein the original color image file is stored when its pixel values are determined to fall outside the tolerable error range.

6. The method of claim 1, wherein the step of converting the original color image file into a colorless image file to reduce the data is followed by the step of checking whether the colorless image file is a grey-level image file.

7. The method of claim 6, wherein the colorless image file is stored as a monochromatic image file when it is determined not to be a grey-level image file.

8. A color image conversion system for reducing the image data size of a colorless document scanned by a image input device, comprising:

a reading module, which reads in a source document to generate an original color image file;

a central processing module, which analyzes the pixel information in the original color image file and converts the original color image file into a colorless image file; and

a storage module, which stores the colorless image file converted by the central processing module.

9. The system of claim 8, wherein the original color image file is a 24-bit image file.

10. The system of claim 8, wherein the colorless image file is a 1-bit monochromatic image file.

11. The system of claim 8, wherein the colorless image file is an 8-bit grey-level image file.