Image processing apparatus and method

• US 7,366,350 B2
• Filed: 11/26/2003
• Issued: 04/29/2008
• Est. Priority Date: 11/29/2002
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Kajihara, Tamotsu
• Primary Examiner(s): Wu; Jingge
• Assistant Examiner(s): MOTSINGER, SEAN T
• Application Number:
  US10/722,957
• Publication Number:
  US 20040156544A1
• Time in Patent Office: 1,616 Days
• Field of Search: None
• US Class Current: 382/167
• CPC Class Codes: G06V 10/56 relating to colour
• CPC Class Codes: H04N 1/62 Retouching, i.e. modification of isolated colours only or in isolated picture areas only
• CPC Class Codes: H04N 1/628 Memory colours, e.g. skin or sky

Abstract

An apparatus for performing image processing on image data including a memory color includes: a characteristic value calculation part calculating a characteristic value from the image data; an area extraction part extracting a specific color area and its background area from the image data, using the characteristic value and the color information of the memory color stored in a storage part; a target value calculation part calculating a target value for correcting the preferable color of the specific color from the characteristic value, the extracted specific color and background areas, and the color information of the preferable color; and an image data correction part calculating a correction for correcting the preferable color based on the calculated target value and the characteristic value, and correcting a color of the specific color area based on the calculated correction and the characteristic value.

Claims

1. An apparatus for performing image processing on image data, comprising:

a characteristic value calculation part calculating a characteristic value from the image data;

an area extraction part extracting a specific color area of a specific color and a background area thereof from the image data, using the characteristic value and color information of a memory color stored in a storage part;

a target value calculation part calculating a target value for correcting a preferable color of the specific color from the characteristic value, the extracted specific color and background areas, and color information of the preferable color stored in the storage part; and

an image data color correction part calculating an amount of correction for correcting the preferable color based on the calculated target value and the characteristic value, and correcting a color of the specific color area based on the calculated amount of correction and the characteristic value,

wherein said target value calculation part sets an intersection of a straight line and an ellipsoid as the target value of the preferable color, the straight line being parallel to a segment connecting chromaticity coordinates of the background area and an origin, and passing through chromaticity coordinates of the preferable color of the specific color, the ellipsoid being formed by a range of the preferable color of the specific color.

2. The apparatus as claimed in claim 1, further comprising an attribute information obtaining part obtaining attribute information added to the image data,

wherein said image data color correction part corrects the color of the specific color area based further on the obtained attribute information.

3. The apparatus as claimed in claim 2, wherein the attribute information obtaining part obtains information on a condition for capturing the image data as the attribute information, the condition being one of a scene capture type, an F number, a shutter speed, white balance, and presence or absence of a flash.

4. The apparatus as claimed in claim 3, wherein said image data color correction part corrects the color of the specific color area by multiplying the calculated correction by a correction factor set according to the condition for capturing the image data.

5. The apparatus as claimed in claim 1, wherein said characteristic value calculation part splits the image data into a plurality of regions, and calculates, for each region, at least one of an average, a median, a mode, and a standard deviation in color information, and a percentage of the region in the image data.

6. The apparatus as claimed in claim 1, wherein the color information of the preferable color of the memory color stored in the storage part comprises chromaticity coordinates in a color space and a range of the chromaticity coordinates.

7. The apparatus as claimed in claim 1, wherein said image data color correction part corrects chromaticity coordinates of the specific color area of the image data by a predetermined distance calculated based on the characteristic value of the image data along an axis formed by the target value and the characteristic value of the specific color area.

8. The apparatus as claimed in claim 7, wherein the predetermined distance is calculated based on a percentage of the specific color area in the image data.

9. A method of performing image processing on image data, the method comprising the steps of:

(a) calculating a characteristic value from the image data;

(b) extracting a specific color area of a specific color and a background area thereof from the image data, using the characteristic value and color information of a memory color stored in a storage part;

(c) calculating a target value for correcting a preferable color of the specific color from the characteristic value, the extracted specific color and background areas, and color information of the preferable color stored in the storage part; and

(d) calculating an amount of correction for correcting the preferable color based on the calculated target value and the characteristic value, and correcting a color of the specific color area based on the calculated amount of correction and the characteristic value,

wherein an intersection of a straight line and an ellipsoid is set in step (c) as the target value of the preferable color, the straight line being parallel to a segment connecting chromaticity coordinates of the background area and an origin, and passing through chromaticity coordinates of the preferable color of the specific color, the ellipsoid being formed by a range of the preferable color of the specific color.

10. The method as claimed in claim 9, further comprising the step of (e) obtaining attribute information added to the image data,

wherein said (d) corrects the color of the specific color area based further on the obtained attribute information.

11. A computer readable medium tangibly embodying a program for causing a computer to perform the method as set forth in claim 9.

12. A computer-readable recording medium on which a program for causing a computer to execute a method as set forth in claim 9 is recorded.