Color correcting apparatus

Facsimile and static presentation processing – Static presentation processing – Attribute control

Reexamination Certificate

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Details

C358S001100

Reexamination Certificate

active

06356364

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a color correcting apparatus used to correct a color to be output to an output device in response to ambient light.
2. Description of the Related Art
FIG. 1
is a schematic block diagram showing configurations of a conventional image processing device. The conventional image processing device is provided with a computer
40
, a monitor
50
and a printer
60
. In the conventional image processing device, the monitor
50
displays an image to be printed on the printer
60
and the printer
60
prints the image displayed on the monitor
50
. Specifically, a user who operates the monitor
50
and printer
60
edits the image to be printed while watching the image being displayed on the monitor
50
and, after having checked the image displayed on the monitor
50
, prints the image that has been edited on the printer
60
.
Since the monitor
50
is configured to express a color using a process of additive mixture of color stimuli composed of three colors RGB (Red, Green and Blue), that is, displaying color data defining the color of the displayed image is represented by a RGB calorimetric system. On the other hand, the printer
60
is configured to express a color using a process of subtractive mixture of color stimuli composed of three colors CMY (Cyan, Magenta and Blue), that is, printing color data defining the color of the printed image is represented by a CMY colorimetric system. Therefore, conversions between the displaying color data and the printing color data are required. To achieve this, the conventional image processing device is provided with an RGB-XYZ converting section
62
to make conversions between the RGB colorimetric system and XYZ calorimetric system and with an XYZ-CMY converting section
66
to make conversions between the XYZ colorimetric system and the CMY colorimetric system.
Moreover, the color to be displayed by the monitor
50
varies depending on color reproduction characteristics of the monitor
50
, while the color to be printed by the printer
60
varies depending on the color reproduction characteristics of the printer
60
. The image processing device stores a monitor profile
61
obtained on the basis of the color reproduction characteristics of the monitor
50
which shows a relation between the color defined by the image color data that is input to the monitor
50
and the color that can be displayed actually by the monitor
50
and a printer profile
65
obtained on the basis of the color reproduction characteristics of the printer
60
which shows a relation between the color defined by the image color data that is input to the printer
60
and the color that can be printed actually by the printer
60
. The image processing device corrects displaying color data that has been input to the monitor
50
according to the above monitor profile
61
and further printing color data which is the displaying color data that has been corrected according to the above printer profile
65
and then the printer
60
prints the color defined by the corrected printing color data.
In the image processing device, the RGB-XYZ converting section
62
converts the displaying color data (R, G and B) output from a RGB signal storing section
43
to CIE (Commission Internationale de l'echlairage) CYZ values (X, Y and Z) according to the monitor profile
61
. Then an illuminant converting section
64
makes illuminant conversions of the above CIE XYZ values (X, Y and Z) and outputs the CIE XYZ values (X′, Y′ and Z′) obtained by having made illuminant conversions. Moreover, the XYZ-CMY converting section
66
converts the CIE XYZ values (X′, Y′ and Z′) output from the illuminant converting section
64
to printing color data (C, M and Y) according to the printer profile
65
. The printer
60
prints the color based on the printing color data (C, M, Y).
The above printer profile
65
is created in the ambient light from a specified illuminant. Therefore, if the printer profile
65
has been created in the ambient light produced by using, for example, an illuminant D
50
, while the monitor
50
and the printer
60
are put in the ambient light produced by using any illuminant other than the illuminant D
50
, even if the printer profile
65
is used as it is, the printed color looks differently from its original one because the different two illuminants have been employed.
To solve this problem, in the conventional image processing device, an observation ambient illuminant information storing section
42
stores illuminant data that can correspond to a plurality of illuminants including, for example, a D
50
illuminant, A illuminant, D
65
illuminant, each having a different wavelength distribution, and an observation ambient illuminant information selecting section
41
, in response to information, given by a user, about the illuminant producing the ambient light in which the monitor
50
and the printer
60
are put, selects best-suited illuminant data from two or more pieces of the illuminant data stored in the observation ambient illuminant information storing section
42
and outputs the selected illuminant data to the illuminant converting section
64
. The illuminant converting section
64
makes illuminant conversions based on correction data calculated from the illuminant producing the ambient light in which the monitor
50
and the printer
60
are put and from the illuminant producing the ambient light used when the printer profile
65
has been created.
When the user who is putting the monitor
50
and the printer
60
in the ambient light produced by, for example, the A illuminant, inputs information requiring the A illuminant, the observation ambient illuminant information selecting section
41
selects A illuminant data XA, YA and ZA that can correspond to the information input by the user from the observation ambient illuminant information storing section
42
and outputs the selected illuminant data XA, YA and ZA to the illuminant converting section
64
.
The printer
60
, by using D
50
illuminant data XD
50
, YD
50
, ZD
50
that produces the ambient light used when the printer profile
65
is created, which is stored in a colorimetry illuminant information storing section
63
, and the A illuminant data XA, YA and ZA that produces the ambient light in which the monitor
50
and the printer
60
are put, which has been fed from the observation ambient illuminant information selecting section
41
, calculates correction data (X′, Y′ and X′) using the equation (1) in FIG.
15
and calibrates the printing color data based on the obtained correction data (X′, Y′ and X′).
However, the conventional image processing device has the following problem. That is, even when the printing color data is corrected by using the correction data (X′, Y′ and X′) calculated using the above equation (1) based on the illuminant producing the ambient light used when the profile
65
of the printer
60
has been created and on the illuminant producing the ambient light in which the monitor
50
and the printer
60
are actually put, since the ambient light in which the monitor
50
and the printer
60
are put contains light emitted from two or more kinds of illuminants, the color printed on the printer
60
looks differently from its original one due to an influence by light emitted from the two or more kinds of the illuminants. That is, there is the problem that the conventional image processing device cannot reproduce faithfully the original color. In addition, since the printer working as the output device is affected by the ambient light, there is the problem that the printer cannot reproduce the original color faithfully as well.
SUMMARY OF THE INVENTION
In view of the above, it is an object of the present invention to provide a color correcting apparatus capable of more faithfully reproducing an original color to be output from an output device.
According to an aspect of the present inventio

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