Color image processing apparatus

• US 20030185438A1
• Filed: 03/24/2003
• Published: 10/02/2003
• Est. Priority Date: 09/16/1997
• Status: Active Grant

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Yamaguchi, Masahiro, Ohyama, Nagaaki, Obi, Takashi, Ohya, Yuri, Osawa, Kenro
• Granted Patent: US 7,010,162 B2
• Time in Patent Office: Days
• US Class Current: 382/162
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: H04N 1/60 Colour correction or control H04N1/54 takes precedence
• CPC Class Codes: H04N 1/6033 using test pattern analysis H04N1/6055 takes precedence
• CPC Class Codes: H04N 1/6083 controlled by factors external to the apparatus
• CPC Class Codes: H04N 1/6086 by scene illuminant, i.e. conditions at the time of picture capture, e.g. flash, optical filter used, evening, cloud, daylight, artificial lighting, white point measurement, colour temperature
• CPC Class Codes: H04N 1/6088 by viewing conditions, i.e. conditions at picture output
• CPC Class Codes: H04N 23/88 for colour balance, e.g. white-balance circuits or colour temperature control

Abstract

A color image processing apparatus reproduces color data of a subject at higher accuracy by estimating the spectral reflectance of the subject from the color chip basis function vn (λ) which can expand the spectral reflectances of all color chips of the reference chart and the expansion coefficients B of the color chips. The color image processing apparatus uses an image processing device to which a subject shooting signal Q shot by the color image input device and a reference chart shooting signal G taken from a plurality of color chips each having a spectral reflectance, is known.

Claims

1. (New) A color image processing apparatus comprising image processing means for processing an input image signal of an object, in order to reproduce color data of the object, wherein

the image processing means estimates a spectral reflectance of the object, using:

a color image signal of at least four bands, of a reference matter whose spectral reflectance is known,

a color image signal of the object obtained under the same illumination condition and the same number of bands as those in obtaining the color image signal of the reference matter,

and spectral reflectance data of the reference matter,

thereby carrying out a reproduction process of the color data of the object.

2. (New) A color image processing apparatus comprising image processing means for processing an input image signal of an object, in order to reproduce color data of the object, wherein the image processing means further comprises:

color image input means for obtaining a color image signal of each of the object and a reference matter whose spectral reflectance is known and having a plurality of colors, from a same image in which the object and the reference matter are taken at the same time in lighting for photographing,

pixel value reading means for detecting a position of the reference matter from the color image signal and reading a pixel value thereof, and

spectral reflectance estimating means for estimating the spectral reflectance of the object using the read pixel value of the reference matter, the color image signal of the photographed object and spectral reflectance data of the object or the reference matter.

3. (New) The color image processing apparatus according to claim 2, wherein:

the spectral reflectance data is a basis function of the spectral reflectance of the reference matter, and which further comprises means for calculating a matrix that represents a correlation between the color image signal of the reference matter in lighting for photographing and a coefficient for the basis function of the spectral reflectance of the reference matter, by using the color image signal of the reference matter and the spectral reflectance of the reference matter, and

the spectral reflectance estimating means estimates the spectral reflectance of the object using the calculated matrix.

4. (New) The color image processing apparatus according to claim 2, wherein:

the spectral reflectance data is a basis function of the spectral reflectance of the reference matter, and which further comprises means for calculating a matrix that represents a correlation between the color image signal of the reference matter in lighting for photographing and a coefficient for the basis function of the spectral reflectance of the reference matter, by using the color image signal of the reference matter, the spectral reflectance of the reference matter and the basis function of the spectral reflectance of the object, and

the spectral reflectance estimating means estimates the spectral reflectance of the object using the calculated matrix.

7. (New) The color image process processing apparatus according to claim 2, wherein the reference matter is a color chart including a plurality of colors.

8. (New) A color image process processing apparatus according to claim 3, wherein the reference matter is a color chart including a plurality of colors.

9. (New) The color image process processing apparatus according to claim 4, wherein the reference matter is a color chart including a plurality of colors.

12. (New) The color image processing apparatus according to claim 2, wherein the reference matter is a color chip including a plurality of colors.

13. (New) The color image processing apparatus according to claim 3, wherein the reference matter is a color chip including a plurality of colors.

14. (New) The color image processing apparatus according to claim 4, wherein the reference matter is a color chip including a plurality of colors.

5. (New) A color image processing apparatus comprising image processing means for processing an input image signal of an object, in order to reproduce color data of the object,

wherein the image processing means adds, as header data, to the obtained color image signal of the object,

a color image signal of a reference matter whose spectral reflectance is known, which is obtained with a same lighting condition as in the photographing of the object,

a basis function of the spectral reflectance of the reference matter,

an expansion coefficient for the basis function of the reference matter, and

a basis function of a spectral reflectance of the object, and

stores thus obtained data as image data.

10. (New) The color image process processing apparatus according to claim 5, wherein the reference matter is a color chart including a plurality of colors.

15. (New) The color image processing apparatus according to claim 5, wherein the reference matter is a color chip including a plurality of colors.

6. (New) A color image processing apparatus comprising image processing means for processing an input image signal of an object, in order to reproduce color data of the object,

wherein the image processing means adds, as header data, to a color image in which the object and a reference matter whose spectral reflectance is known, are photographed at a same time in a same frame,

a color image signal of a reference matter whose spectral reflectance is known, which is photographed with a same lighting condition as in the photographing the object,

a basis function of the spectral reflectance of the reference matter,

an expansion coefficient for the basis function of the reference matter, and

a basis function of a spectral reflectance of the object, and

stores thus obtained data as image data.

11. (New) The color image process processing apparatus according to claim 6, wherein the reference matter is a color chart including a plurality of colors.

16. (New) The color image processing apparatus according to claim 6, wherein the reference matter is a color chip including a plurality of colors.

17. (New) An image processing method used in a color image processing apparatus for reproducing color data of an object, comprising:

obtaining a color image signal of at least four bands, of a reference matter whose spectral reflectance is known,

obtaining a color image signal of the object under the same illumination condition and the same number of bands as those in obtaining the color image signal of the reference matter,

obtaining spectral reflectance data of the reference matter,

estimating the spectral reflectance of the object by using the color image signal of the object and the spectral reflectance of the reference matter, and

re-processing the color data of the object using the estimated spectral reflectance of the object.

21. (New) The color image processing method according to claim 17, wherein the reference matter is a color chart including a plurality of colors.

25. (New) The color image processing method according to claim 17, wherein the reference matter is a color chip including a plurality of colors.

18. (New) An image processing method used in a color image processing apparatus for reproducing color data of an object, comprising:

photographing the object and a reference matter whose spectral reflectance is known and having a plurality of colors, at a same time in a same frame in lighting for photographing;

reading a pixel value by detecting a position of the reference matter from the color image signal obtained;

estimating the spectral reflectance of the object using the read pixel value of the reference matter, the color image signal of the photographed object and spectral reflectance data of the object or the reference matter; and

re-processing the color data of the object using the estimated spectral reflectance of the object.

19. (New) The color image processing method according to claim 18, wherein the spectral reflectance data is a basis function of the spectral reflectance of the reference matter, and which further comprises calculating a matrix that represents a correlation between the color image signal of the reference matter in lighting for photographing and a coefficient for the basis function of the spectral reflectance of the reference matter, by using the color image signal of the reference matter and the spectral reflectance of the reference matter, and

estimating the spectral reflectance of the object by further using the calculated matrix.

20. (New) The color image processing method according to claim 18, wherein the spectral reflectance data is a basis function of the spectral reflectance of the reference matter, and which further comprises calculating a matrix that represents a correlation between the color image signal of the reference matter in lighting for photographing and a coefficient for the basis function of the spectral reflectance of the reference matter, by using the color image signal of the reference matter, the spectral reflectance of the reference matter, and a basis function of a spectral reflectance of the object, and

estimating the spectral reflectance of the object by further using the calculated matrix.

22. (New) The color image processing method according to claim 18, wherein the reference matter is a color chart including a plurality of colors.

23. (New) The color image processing method according to claim 19, wherein the reference matter is a color chart including a plurality of colors.

24. (New) The color image processing method according to claim 20, wherein the reference matter is a color chart including a plurality of colors.

26. (New) The color image processing method according to claim 18, wherein the reference matter is a color chip including a plurality of colors.

27. (New) The color image processing method according to claim 19, wherein the reference matter is a color chip including a plurality of colors.

28. (New) The color image processing method according to claim 20, wherein the reference matter is a color chip including a plurality of colors.

29. (New) An image data storage method used in a color image processing apparatus for reproducing color data of an object, comprising:

obtaining a color image signal of an object,

obtaining a color image signal of a reference matter whose spectral reflectance is known, which is photographed with a same lighting condition as in the obtaining of the color image signal of the object,

adding, as header data, to the obtained color image signal of the object, the color image signal of the reference matter, a basis function of the spectral reflectance of the reference matter, an expansion coefficient for the basis function of the reference matter, and a basis function of a spectral reflectance of the object, and

storing image data thus obtained by adding the header data to the color image signal of the object.

31. (New) The image data storage method according to claim 29, wherein the reference matter is a color chart including a plurality of colors.

33. (New) The image data storage method according to claim 29, wherein the reference matter is a color chip including a plurality of colors.

30. (New) An image data storage method used in a color image processing apparatus for reproducing color data of an object, comprising:

photographing the object and a reference matter whose spectral reflectance is known, at a same time in a same frame,

adding, as header data, to a color image in which the object and reference matter are photographed at the same time, a basis function of the spectral reflectance of the reference matter, an expansion coefficient for the basis function of the reference matter, and a basis function of a spectral reflectance of the object, and

storing image data obtained by adding the header data to the color image signal in which the object and reference matter are photographed at the same time.

32. (New) The image data storage method according to claim 30, wherein the reference matter is a color chart including a plurality of colors.

34. (New) The image data storage method according to claim 30, wherein the reference matter is a color chip including a plurality of colors.