Image processing method and apparatus for converting colors in a color image

• US 6,927,877 B2
• Filed: 04/11/2002
• Issued: 08/09/2005
• Est. Priority Date: 12/17/1993
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kanno, Akiko, Suzuki, Takashi
• Primary Examiner(s): Grant, II, Jerome
• Application Number:
  US10/119,757
• Publication Number:
  US 20020145745A1
• Time in Patent Office: 1,216 Days
• Field of Search: 358/500, 358/501, 358/515, 358/518, 358/519, 358/520, 358/1.2, 358/3.07, 358/3.08, 358/3.1, 358/3.2, 358/536, 382/162, 382/167, 382/264
• US Class Current: 358/3.1
• CPC Class Codes: H04N 1/6075 Corrections to the hue

Abstract

A color image signal is generated and an arbitrary color in the color image signal is set as a color to be converted. A color after conversion is designated. The color to be converted or a color similar to the color to be converted is converted into the color after conversion or a color similar to the color after conversion. By this processing, a color-converted image, in which a conversion boundary is unnoticeable, can be produced.

Claims

1. A color image processing apparatus comprising:

sensing means for sensing the density of screen lines of a halftone dot image;

computing means for computing an area processing characteristic with respect to image data having plural components on the halftone dot image according to the result of said sensing means;

processing means for processing the image data having plural components according to the area processing characteristic computed by said computing means; and

determination means for determining a color on the basis of the image data having plural components processed by said processing means.

2. An apparatus according to claim 1, wherein the area processing includes at least one of filtering processing and majority decision processing.

3. An apparatus according to claim 2, wherein said filtering processing is smoothing using a spatial filter.

4. An apparatus according to claim 1, wherein said determination means has equal color determination means which determines image data having the same color as a color previously designated in the processed image data having plural components.

5. A color image processing method comprising the steps of:

sensing the density of screen lines of a halftone dot image;

computing an area processing characteristic with respect to image data having plural components on the halftone dot image according to the result of said sensing step;

processing the image data having plural components according to the area processing characteristic computed in said computing step; and

determining a color on the basis of the image data having plural components processed in said processing step, wherein said determining step determines image data having the same color as a color previously designated in the processed image date having plural components.