Image processing apparatus and image processing method

• US 8,031,203 B2
• Filed: 01/29/2008
• Issued: 10/04/2011
• Est. Priority Date: 02/22/2007
• Status: Expired due to Fees

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Une, Kiyoshi, Kawashima, Hidetoshi, Higashikata, Ryosuke, Tashiro, Yousuke, Ito, Akihiro, Yamauchi, Yasuki, Hasegawa, Noriko, Kishimoto, Yasunari
• Primary Examiner(s): Sajous; Wesner
• Application Number:
  US12/021,800
• Publication Number:
  US 20080204775A1
• Time in Patent Office: 1,344 Days
• Field of Search: 345427-428, 345/581, 345589-590, 345/591, 345/593, 345600-601, 345603-604, 345/619, 345/549, 348/557, 348/560, 348/562, 348/599, 348/630, 348/692, 358518-519, 358523-524, 382162-167, 382/254, 382/274, 382/276
• US Class Current: 345/604
• CPC Class Codes: H04N 1/603 controlled by characteristics of the picture signal generator or the picture reproducer
• 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

Abstract

In an image processing apparatus, a first conversion unit converts, on the basis of an input device profile, input data into first device-independent data expressed by a color space that is independent of an apparatus. A storage unit stores plural conversion profiles for converting using a color appearance model in the color space that is independent of the apparatus in correspondence with plural device characteristics that are dependent on apparatuses. A selection unit selects a conversion profile corresponding to characteristics of the input device, characteristics of an output device, observation conditions of the input data and the output data. A second conversion unit converts, on basis of the selected conversion profile, the first device-independent data into second device-independent data. A third conversion unit converts the second device-independent data into the output data on the basis of an output device profile.

Claims

1. An image processing apparatus comprising:

a first conversion unit that converts, on the basis of an input device profile corresponding to characteristics of an input device, input data into first device-independent data expressed by a color space that is independent of an apparatus;

a storage unit in which there are stored, on the basis of observation conditions representing environments in which the input data and output data outputted on the basis of the input data are observed, the characteristics of the input device and characteristics of an output device, and in correspondence with a plurality of device characteristics that are dependent on apparatuses, a plurality of conversion profiles for converting using a color appearance model such that color appearances of the input data and the output data become the same in the color space that is independent of the apparatus;

a selection unit that selects, from the plurality of conversion profiles stored in the storage unit, a conversion profile corresponding to the characteristics of the input device, the characteristics of the output device, the observation condition of the input data and the observation condition of the output data;

a second conversion unit that converts, on the basis of the conversion profile selected by the selection unit, the first device-independent data converted by the first conversion unit into second device-independent data; and

a third conversion unit that converts the second device-independent data converted by the second conversion unit into the output data on the basis of an output device profile corresponding to the characteristics of the output device.

2. The image processing apparatus of claim 1, wherein

the storage unit stores the plurality of conversion profiles in correspondence with a plurality of characteristics of the input device profile and the output device profile, and

the selection unit selects a conversion profile corresponding to the characteristics of the input device profile and the characteristics of the output device profile.

3. The image processing apparatus of claim 2, wherein the characteristics of the input device profile include a color space of the input device, and the plurality of conversion profiles are stored in correspondence to a plurality of color spaces.

4. The image processing apparatus of claim 3, wherein it is determined that the color space of the input device is sRGB or Adobe RGB by determining whether the chromaticity of an input green is close the chromaticity of green of sRGB or close to the chromaticity of green of Adobe RGB, and the plurality of conversion profiles include a conversion profile for use when it is determined that the color space is sRGB and a conversion profile for use when it is determined that the color space is Adobe RGB.

5. The image processing apparatus of claim 2, wherein the plurality of conversion profiles are further stored in correspondence to gamut compression methods, each of the methods being selected from brightness preservation, color hue preservation, or minimum color difference.

6. The image processing apparatus of claim 2, wherein the characteristics of the output device profile are gamut size and type of intent included in the output device profile.

7. The image processing apparatus of claim 6, wherein the type of intent comprises “

relative colorimetric”

, and the plurality of conversion profiles further include a conversion profile that performs gamut compression processing for when “

relative colorimetric”

is included in the output device profile and a conversion profile that does not perform gamut compression processing for when “

relative colorimetric”

is not included in the output device profile.

8. The image processing apparatus of claim 1, further comprising

a calculation unit that calculates the size of the gamut of the output device, and

a determination unit that determines whether or not the size of the gamut calculated by the calculation unit is equal to or less than a predetermined size, wherein

the second conversion unit performs conversion based on the conversion profile when the size of the gamut calculated by the calculation unit is more than the predetermined size, and

the third conversion unit converts the first device-independent data into the output data on the basis of the output device profile when the conversion based on the conversion profile has not been performed by the second conversion unit.

9. The image processing apparatus of claim 8, wherein the size of the gamut of the output device is calculated by saturations of basic colors.

10. The image processing apparatus of claim 1, wherein a color space of the input device is RGB, the color space that is independent of the apparatus is Lab, and a color space of the output device is CMYK.

11. The image processing apparatus of claim 1, wherein the color conversion profile is created such that the observation condition representing the environment in which the input data are observed is used to convert the first device-independent data into observation condition-independent data and such that the observation condition representing the environment in which the output data are observed is used to convert the observation condition-independent data into the second device-independent data.

12. The image processing apparatus of claim 11, wherein the color conversion profile is further created such that the observation condition-independent data are converted into second observation condition-independent data by gamut compression processing.

13. The image processing apparatus of claim 11, wherein the observation condition-independent data comprise JCh data.

14. The image processing apparatus of claim 1, wherein the input device profile and the output device profile are ICC profiles.

15. An image processing method of an image processing apparatus comprising a storage unit in which there are stored, on the basis of observation conditions representing environments in which input data and output data outputted on the basis of the input data are observed, characteristics of an input device and characteristics of an output device, and in correspondence with a plurality of device characteristics that are dependent on apparatuses, a plurality of conversion profiles for converting using a color appearance model such that color appearances of the input data and the output data become the same in a color space that is independent of an apparatus, the method comprising:

converting, on the basis of an input device profile corresponding to the characteristics of the input device, the input data into first device-independent data expressed by the color space that is independent of the apparatus;

selecting, from the plurality of conversion profiles stored in the storage unit, a conversion profile corresponding to the characteristics of the input device, the characteristics of the output device, the observation condition of the input data and the observation condition of the output data;

converting, on the basis of the selected conversion profile, the converted first device-independent data into second device-independent data; and

converting the converted second device-independent data into the output data on the basis of an output device profile corresponding to the characteristics of the output device.

16. The image processing method of claim 15, wherein

the storage unit stores the plurality of conversion profiles in correspondence with a plurality of predetermined characteristics of the input device profile and the output device profile, and

the selecting comprises selecting a conversion profile corresponding to the characteristics of the input device profile and the characteristics of the output device profile.

17. The image processing method of claim 15, wherein the characteristics of the output device profile are gamut size and type of intent included in the output device profile.

18. The image processing method of claim 15, further comprising

calculating the size of the gamut of the output device, and

determining whether or not the calculated size of the gamut is equal to or less than a predetermined size, wherein

when the calculated size of the gamut is more than the predetermined size, the conversion based on the conversion profile is performed, and

when the conversion based on the conversion profile has not been performed, the first device-independent data is converted into the output data on the basis of the output device profile.

19. An image processing apparatus comprising:

first conversion means for converting, on the basis of an input device profile corresponding to characteristics of an input device, input data into first device-independent data expressed by a color space that is independent of an apparatus;

storage means for storing, on the basis of observation conditions representing environments in which the input data and output data outputted on the basis of the input data are observed, the characteristics of the input device and characteristics of an output device, and in correspondence with a plurality of device characteristics that are dependent on apparatuses, a plurality of conversion profiles for converting using a color appearance model such that color appearances of the input data and the output data become the same in the color space that is independent of the apparatus;

selection means for selecting, from the plurality of conversion profiles stored in the storage means, a conversion profile corresponding to the characteristics of the input device, the characteristics of the output device, the observation condition of the input data and the observation condition of the output data;

second conversion means for converting, on the basis of the conversion profile selected by the selection means, the first device-independent data converted by the first conversion means into second device-independent data; and

third conversion means for converting the second device-independent data converted by the second conversion means into the output data on the basis of an output device profile corresponding to the characteristics of the output device.