Image processing apparatus and method

• US 20040156544A1
• Filed: 11/26/2003
• Published: 08/12/2004
• Est. Priority Date: 11/29/2002
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Kajihara, Tamotsu
• Granted Patent: US 7,366,350 B2
• Time in Patent Office: Days
• 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 including a memory color, 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 the 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 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.

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 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 slope of 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.

8. The apparatus as claimed in claim 7, 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.

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

10. A method of performing image processing on image data including a memory color, 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 the 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 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.

11. The method as claimed in claim 10, 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.

28. A program for causing a computer to execute a method as set forth in claim 10.

31. A computer-readable recording medium on which a program for causing a computer to execute a method as set forth in claim 10 is recorded.

12. An apparatus for performing image processing on image data including a memory color, comprising:

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

a characteristic value calculation part calculating a characteristic value of at least one of the specific color area and the background area;

a target value calculation part calculating a target value and a correction for correcting a preferable color of the specific color from a result of the calculation by said characteristic value calculation part and color information of the preferable color stored in the storage part; and

an image data correction part correcting a color of the specific color area based on the correction calculated by said target value calculation part.

13. The apparatus as claimed in claim 12, further comprising:

an attribute information obtaining part obtaining image attribute information,

wherein said target value calculation part calculates the target value and the correction for correcting the preferable color of the specific color further from the obtained image attribute information.

14. The apparatus as claimed in claim 13, wherein the image attribute information relates to a condition for capturing the image data.

15. The apparatus as claimed in claim 14, wherein said target value calculation part increases the correction when the condition for capturing the image data is a portrait mode.

16. The apparatus as claimed in claim 12, wherein the characteristic value is a statistic of a color distribution of pixels in the specific color area for the specific color area, and is a statistic of a color distribution of pixels in the background area for the background area.

17. The apparatus as claimed in claim 16, wherein each of the statistics employs at least one of a variance, a standard deviation, a median, a mode, and an average in a frequency distribution of the image data.

18. The apparatus as claimed in claim 12, wherein the target value causes the color information of the preferable color of the specific color to shift toward the background area in accordance with the characteristic value.

19. The apparatus as claimed in claim 12, wherein the target value is shiftable to a position dividing a segment connecting the color information of the preferable color of the specific color and a representative color of the background area proportionally in accordance with the characteristic value.

20. The apparatus as claimed in claim 19, wherein the position dividing the segment proportionally is calculated from the characteristic value, the characteristic value being a hue distribution of the specific color area.

21. The apparatus as claimed in claim 19, wherein the position dividing the segment proportionally is calculated from the characteristic value, the characteristic value being a chroma distribution of the specific color area.

22. An apparatus for performing image processing on image data including a human image, comprising:

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

a characteristic value calculation part calculating a characteristic value of at least one of the area of the skin color and the background area;

a target value calculation part calculating a target value and a correction for correcting a preferable color of the skin color from a result of the calculation by said characteristic value calculation part and color information of the preferable color stored in the storage part; and

an image data correction part correcting a color of the area of the skin color based on the correction calculated by said target value calculation part.

23. The apparatus as claimed in claim 22, further comprising:

an attribute information obtaining part obtaining image attribute information,

wherein said target value calculation part calculates the target value and the correction for correcting the preferable color of the skin color further from the obtained image attribute information.

24. A method of performing image processing on image data including a memory color, comprising the steps of:

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

(b) calculating a characteristic value of at least one of the specific color area and the background area;

(c) calculating a target value and a correction for correcting a preferable color of the specific color from a result of the calculation by said step (b) and color information of the preferable color stored in the storage part; and

(d) correcting a color of the specific color area based on the correction calculated by said step (c).

25. The method as claimed in claim 24, further comprising the step of (e) obtaining image attribute information,

wherein said step (c) calculates the target value and the correction for correcting the preferable color of the specific color further from the obtained image attribute information.

29. A program for causing a computer to execute a method as set forth in claim 24.

32. A computer-readable recording medium on which a program for causing a computer to execute a method as set forth in claim 24 is recorded.

26. A method of performing image processing on image data including a human image, comprising the steps of:

(a) extracting an area of a skin color and a background area thereof from the image data, using color information of a memory color stored in a storage part;

(b) calculating a characteristic value of at least one of the area of the skin color and the background area;

(c) calculating a target value and a correction for correcting a preferable color of the skin color from a result of the calculation by said step (b) and color information of the preferable color stored in the storage part; and

(d) correcting a color of the area of the skin color based on the correction calculated by said step (c).

27. The method as claimed in claim 26, further comprising the step of (e) obtaining image attribute information,

wherein said step (c) calculates the target value and the correction for correcting the preferable color of the skin color further from the obtained image attribute information.

30. A program for causing a computer to execute a method as set forth in claim 26.

33. A computer-readable recording medium on which a program for causing a computer to execute a method as set forth in claim 26 is recorded.