Processing for accurate reproduction of symbols and other high-frequency areas in a color image

• US 7,221,790 B2
• Filed: 10/11/2005
• Issued: 05/22/2007
• Est. Priority Date: 07/12/2000
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Toda, Yukari
• Primary Examiner(s): Alavi; Amir
• Application Number:
  US11/246,301
• Publication Number:
  US 20060029280A1
• Time in Patent Office: 588 Days
• Field of Search: 382/162, 382/165, 382/168, 382/172, 382/199, 382/251, 382/256, 382/264, 382/272, 358/2.1, 358/3.21, 358/3.06, 358/466, 358/500
• US Class Current: 382/162
• CPC Class Codes: G06T 2207/10008 from scanner, fax or copier
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/30176 Document
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/162 Quantising the image signal
• CPC Class Codes: G06V 30/413 Classification of content, e.g. text, photographs or tables
• CPC Class Codes: H04N 1/403 Discrimination between the two tones in the picture signal of a two-tone original
• CPC Class Codes: H04N 1/41 Bandwidth or redundancy reduction by scanning H04N1/17 ; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00
• CPC Class Codes: H04N 19/12 Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/60 using transform coding
• CPC Class Codes: H04N 19/90 using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals

Abstract

In an image processing apparatus, color image data is binarized, and a symbol area in the color image data is detected. There are obtained, from N colors that form a symbol in the symbol area, M colors that are equal to or smaller than N in number. A symbol cutting process is performed on the symbol area, and one of the M colors is allocated for each symbol cut unit that is obtained by the symbol cutting.

Claims

1. An image processing apparatus comprising:

binarizing means for binarizing color image data;

detection means for detecting a symbol area in said color image data;

color reduction means for obtaining, from N colors that form a symbol in said symbol area, M colors that are equal to or smaller than N;

symbol cutting means for performing a symbol cutting process for said symbol area; and

color allocation means for allocating one of said M colors for each symbol cut unit that is obtained by said symbol cutting means.

2. An image processing method comprising the steps of:

binarizing color image data;

detecting a symbol area in said color image data;

obtaining, from N colors that form a symbol in said symbol area, M colors that are equal to or smaller than N;

performing a symbol cutting process for said symbol area; and

allocating one of said M colors for each symbol cut unit that is obtained by said symbol cutting.

3. A computer readable storage medium storing executable commands to perform an image processing method comprising the steps of:

binarizing color image data ;

detecting a symbol area in said color image data;

obtaining, from N colors that form a symbol in said symbol area, M colors that are equal to or smaller than N;

performing a symbol cutting process for said symbol area; and

allocating one of said M colors for each symbol cut unit that is obtained by said symbol cutting.