JP2000232663A - Device and method for color adjustment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a color adjustment device whose entire size can be miniaturized and to realize a color adjustment method where the color adjustment processing can be simplified. SOLUTION: In the color adjustment method that adjusts a display color of a display device displaying a color picture, a color signal in a prescribed color is generated and a color temperature of the prescribed color displayed on the display device while displaying the prescribed color on the display device on the basis of the color signal (SP3), and the color temperature of the prescribed color that is measured is adjusted to be a reference color temperature (SP4-SP6). Thus, the color adjustment device that can be miniaturized is realized and the color adjustment method simplifying color adjustment processing can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color adjusting device and a color adjusting method, and more particularly to a color adjusting device and a color adjusting method for performing a so-called white balance adjustment on a monitor of a television receiver. is there.

[0002]

2. Description of the Related Art Conventionally, a television receiver manufactured in a factory performs white balance adjustment on a monitor at a stage before shipment, so that the monitor can be connected to another monitor with another television receiver. Variations in display colors of displayed color images can be prevented beforehand.

As a device for performing such white balance adjustment, there is a white balance adjustment device 1 as shown in FIG. The white balance adjusting device 1 includes a signal generator 2, a measuring device 3, and an adjusting device 4, and functions individually with respect to a television receiver 5 to be adjusted.

The signal generator 2 of the white balance adjusting device 1 is, for example, NTSC (National Television).
System Committee) standard white (color temperature: 90)
00 [K]) is generated. At the time of white balance adjustment, the output end of the signal generator 2 is connected to a video input terminal (not shown) provided on the back surface of the television receiver 5 via a wiring (not shown).

[0005] The measuring device 3 includes a tube surface 5AB of the monitor 5A.
The probe 3A which can be detachably attached to the monitor 3 is pulled out from the main body via a wiring (not shown), and the white signal S1 displayed on the tube surface 5AB of the monitor 5 using the probe 3A.
The color temperature of the white screen corresponding to the measurement is measured, and the measurement result is displayed on the display panel 3B provided in the main body.

Here, the color temperature is the absolute temperature of a perfect radiator having a chromaticity equal to the chromaticity of sample radiation. The color temperature becomes reddish at a low temperature, and changes from blue to whitish at a higher temperature. With.

The adjusting device 4 has a setting input section 4A, and when a parameter is set and input by the operator with a desired value, the R in the monitor 5A is set according to the parameter value.
(Red), G (Green), and B (Blue) output an adjustment signal S2 for adjusting the output luminance of the electron beam. At the time of white balance adjustment, the output terminal of the adjustment device 4 is connected to a panel (not shown) inside the monitor 5A of the television receiver 5 via a wire (not shown).

When adjusting the white balance of the television receiver 5 by using the white balance adjusting device 1, the operator causes the probe 3A to be sucked and held on the tube surface 5AB of the monitor 5A, and the signal generator 2 and the adjusting device. 4 are connected to the television receiver 5.

Subsequently, the operator causes the signal generator 2 to generate a white signal S1 representing the reference white, and displays a white screen based on the white signal S1 on the tube surface 5AB of the monitor 5A. Is started, and the color temperature of the reference white displayed on the tube surface 5AB of the monitor 5A from the probe 3A is measured. As a result, the display panel 3B of the measuring instrument 3
Shows a numerical value of the color temperature as a measurement result.

The operator operates the setting input section 4A of the adjusting device 4 while visually observing the numerical value of the color temperature displayed on the display panel 3B, and operates the numerical value-displayed color temperature and the target reference white color. The difference from the color temperature is set and input as a parameter. As a result, the output brightness of the R, G, and B electron beams in the monitor 5A is adjusted according to the parameters, so that the difference between the measured color temperature and the reference white color temperature is eliminated, and thus the white balance is reduced. Adjusted.

[0011]

By the way, the monitor 5 of the television receiver 5 changes with time after shipment from the factory.
When the current ratio of each cathode that determines the output luminance of the R, G, and B electron beams in A is shifted, the screen 5AB of the monitor 5A
, The balance of each color displayed is shifted as a whole. In this case, the above-described white balance adjustment processing is required at a place other than the manufacturing factory.

However, since the signal generator 2, the measuring device 3, and the adjusting device 4 are independent devices from each other, the white balance adjusting device 1 shown in FIG. There is no problem when installed in a factory, but it is very difficult to transport it to an outdoor environment such as an exhibition or presentation.

Further, even when indoors, when white balance adjustment is sequentially performed on a plurality of television receivers arranged in a line, a structure that can easily move the white balance adjustment device is required.

The present invention has been made in view of the above points, and an object of the present invention is to propose a color adjustment apparatus which can be downsized as a whole apparatus and a color adjustment method which can simplify color adjustment processing.

[0015]

According to the present invention, there is provided a color adjusting apparatus for adjusting a display color of a display device for displaying a color image, comprising: a recording medium on which a predetermined program is recorded; A control unit for executing a program, the program generating a color signal of a predetermined color, and displaying the predetermined color on a display device based on the color signal; and a first step of displaying the predetermined color on the display device. And a third step of adjusting the measured color temperature of the predetermined color to be a reference color temperature.
Steps.

As a result, in this color adjusting apparatus, a series of color adjustment processes until the color temperature of a predetermined color displayed on the display device is adjusted to a reference color temperature is performed by software processing by the control means. Can be performed by

Further, according to the present invention, in a color adjustment method for adjusting a display color of a display device for displaying a color image,
A color signal of a predetermined color is generated, and a predetermined color is displayed on a display device based on the color signal. In this state, the color temperature of the predetermined color displayed on the display device is measured, and the measured color temperature of the predetermined color is adjusted to be the reference color temperature.

As a result, in this color adjustment method, a series of color adjustment processes until the color temperature of a predetermined color displayed on the display device is adjusted to a reference color temperature is executed by software processing. be able to.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

(1) Configuration of White Balance Adjusting Apparatus In FIG. 1 in which parts corresponding to those in FIG. 7 are assigned the same reference numerals, reference numeral 10 denotes a white balance adjusting apparatus to which the present invention is applied as a whole. One personal computer 1 in place of the measuring device 2, the measuring device 3, and the adjusting device 4.
1, the above-mentioned white balance adjustment can be performed by software processing.

The personal computer 11 is provided with a serial communication connector (not shown), and a connection terminal (hereinafter referred to as a connection terminal) of a port switching circuit 13 through a communication line 12.
This is called a PC side terminal) 13A. In this case, the connector of the personal computer 11, the communication line 12, and the port switching circuit 13 constitute an RS-232C serial interface.

The port switching circuit 13 has two connection terminals 13B and 13C in addition to the PC side connection terminal 13A.
A probe 14 is connected to one of the connection terminals (hereinafter, referred to as a first connection terminal) 13B via a wiring (not shown), and the other connection terminal (hereinafter, referred to as a second connection terminal). Wiring (not shown) at 13C.
Is connected.

Actually, the port switching circuit 13 includes the RS-2
RS-232C transceiver IC (In
integrated circuit) is provided so that software setting can be performed through a plurality of communication ports.

PC side connection terminal 13 of port switching circuit 13
Among the connectors provided with A, DTE (Data Termina
l Equipment) / DCE (Data Circuit Terminating E)
The DTE / DCE control pin corresponding to the port is connected to the personal computer 11 or the port switching circuit 1.
3, and a data terminal ready (DTR) pin is used as a switch for selectively switching the first connection terminal 13B or the second connection terminal 13C.

Thus, the port switching circuit 13 responds to the switching control of the personal computer 11 by the DTE / DE
By switching the C control pin and the data terminal ready pin to the H level or the L level, respectively, only one of the first connection terminal 13B and the second connection terminal 13C connected to the television receiver 5 is connected to the personal computer. 11 and is connected to the PC-side connection terminal 13A, and the transmission direction of a signal passing through the PC-side connection terminal 13A is determined.

When adjusting the white balance of the television receiver 5 using the white balance adjustment device 10, the operator connects the wiring (not shown) drawn from the personal computer 11 to the video input of the television receiver 5. A terminal (not shown) and a wiring (not shown) drawn from a second connection terminal of the port switching circuit 13 are connected to a panel (not shown) inside the monitor 5A of the television receiver 5. Let it. Further, the probe 14 connected to the first connection terminal of the port switching circuit 13
Is sucked and held on the tube surface 5AB of the monitor 5A of the television receiver 5.

Here, the personal computer 11 has an input unit 20 composed of, for example, a mouse or a keyboard, which is connected to an interface (I / F) 21 and a bus 22 via a CPU.
23, so that the operator can give various commands to the CPU 23 via the input unit 20.

When adjusting the white balance, the CPU 23
RAM based on commands given by the operator
The operation process is started by reading the working program stored in the ROM 24. First, the white signal S10 representing the reference white (color temperature: 9000 [K]) stored in the ROM 25 is read, and the bus 22 and the interface (I
/ F) 26.

Subsequently, the CPU 23 sends a switching signal S11 to the port switching circuit 13 via the bus 22 and the interface 26 to connect the first connection terminal 13B to the PC-side connection terminal 13A. Thereafter, when the CPU 23 sends out the measurement start signal S12 via the bus 22 and the interface 26, the measurement start signal S12 is given to the probe 14 via the port switching circuit 13.

Thus, the white color temperature based on the white signal S10 displayed on the screen 5AB of the monitor 5A of the television receiver 5 is measured by the probe 14, and the color temperature measurement signal S13 representing the measurement result is switched to the port. Circuit 1
3 and is stored in the RAM 24 via the interface 26 and the bus 22 in the personal computer 11 and is also provided to the display unit 27. As a result, the color temperature corresponding to the given color temperature measurement signal S13 is numerically displayed on the result display unit 27 as a measured value.

Actually, the display unit 27 has a graphical user interface (Graphical) in which a white screen WF based on the white signal S10 is displayed in the center as shown in FIG.
A UserInterface screen (hereinafter referred to as a GUI screen) 27A is displayed, and various icons and menu selection functions displayed on the GUI screen 27A can be executed in response to an operation of the input unit 20 by an operator. Has been made.

More specifically, the GUI screen 27A shown in FIG.
When the (Alance) button P1 is operated, the execution of the program corresponding to the white balance adjustment processing is started. When the color temperature setting button P2 is operated, 9300 [K] or 6500
One of the color temperatures [K] is set, and the CPU 23
Reads out the white signal S10 corresponding to the color temperature from the ROM 25 and outputs it.

The operator operates the input unit 20 to
After selecting the color temperature setting button P2 on the GUI screen 27A and then clicking the auto-set white balance button P1, during the execution of the white balance adjustment processing, instead of the GUI screen 27A shown in FIG.
A GUI screen 27B from which various function displays are deleted as shown in FIG. 4 is displayed.

At this time, the CPU 23 uses the steepest descent method among the mathematical programming methods described below to calculate the currently measured white color temperature with the reference white color temperature as the target value read from the ROM 25. Adjust so that

Actually, the steepest descent method is an iterative method in which an evaluation function consisting of a nonlinear function is monotonously reduced with respect to a point sequence of the variable, and a value converged as the limit is obtained as an optimal solution.

As a premise, a chromaticity (that is, a combination of hue and saturation) diagram adopted by the International Commission on Illumination (CIE) as shown in FIG. 5 is used. This chromaticity diagram is
X (= X / X + Y + Z) in order to numerically represent all real emission colors using the light of the virtual three primary colors X, Y, and Z
And y (= Y / X + Y + Z), which are represented two-dimensionally in an xy coordinate axis system.

In the chromaticity diagram displayed on the xy coordinate system,
The outermost curve of the horseshoe HF represents a single wavelength color (the most saturated color), and all colors are inside the horseshoe HF. The degree of saturation decreases toward the inside of the horseshoe HF, and the central portion C becomes white. R inside the horseshoe HF,
A triangle TF having G and B as vertices represents chromaticity points of three primary colors standardized by the NTSC system, and the range of colors that can be reproduced by the NTSC system is inside the triangle TF. The chromaticity point P of the reference white color representing the three primary colors of the NTSC system in Japan has a color temperature of 9300 K, that is, (x _C , y _C ) = (0.284, 0.289) in the xy coordinate system.

In this embodiment, the evaluation function E (x _K ,
y _K ) by the following equation:

[0039]

(Equation 1)

As described above, the difference between the target values x _C and y _C that are the chromaticity points of the reference white and the measured values x _K and y _K that are the chromaticity points of the white at the current time point k (k is a variable). As a square error function. According to such a steepest descent method,
Evaluation function E (x _K, y _K) is measured x _K in a direction decreases, so as to update the y _K, measurements x _K, the target gradually y value x _C, be close to y _C Can be.

Here, white light is obtained by additively mixing R (red), G (green), and B (blue), so that R is a fixed parameter and B _K and G _K are each in the x coordinate system. And the variable parameter for the variable k in the y coordinate system, the variable parameters B _K and G _K can correspond to the measured values x _K and y _K , respectively, which are white chromaticity points.

The equations for updating these variable parameters B _K and G _K are as follows:

[0043]

(Equation 2)

[0044]

(Equation 3)

Is expressed as a discrete time system as
Is updated, that is, according to the measured values x _{K + 1} and y _{K + 1} at the next time point (k + 1),
_{K + 1} and G _{K + 1} are updated.

[0046] Thus CPU23 is variable parameter B _K, with obtaining a variable parameter _{B K + 1, G K +} 1 has been updated as described above with respect to G _K, switching signal via the bus 22 and interface 26 S11 is the port switching circuit 1
To the PC-side connection terminal 1C.
Connect to 3A.

Thereafter, the CPU 23 sets a parameter update signal S1 based on the updated variable parameters B _{K + 1} and G _{K + 1.}
3 through the bus 22 and the interface 26, the parameter update signal S13 is transmitted through the port switching circuit 13 to the monitor 5A of the television receiver 5.
It is supplied to an internal panel (not shown).

As a result, on the monitor 5A of the television receiver 5, the output brightness of the R, G, and B electron beams is adjusted according to the parameter update signal S13.

Subsequently, the CPU 23 sends the switching signal S1 to the port switching circuit 13 to connect the first connection terminal 13B to the PC connection terminal 13A in the same manner as described above, and then sends the measurement start signal S12 to the port switching circuit. Probe 1 through 13
4, the probe 14 measures the color temperature of the white signal S10 displayed on the screen 5AB of the monitor 5A of the television receiver 5 by the probe 14.

The color temperature measurement signal S1 as the measurement result
3 is stored in the RAM 24 and given to the display unit 27, the display unit 27 displays the given color temperature measurement signal S
The color temperature corresponding to 13 is numerically displayed on the display unit 27 as the chromaticity point (that is, the variable parameters B _{K + 1} , G _{K + 1} ).

Specifically, the GU of the display unit 27 shown in FIG.
In I screen 27A, above the predetermined position P3 of the white screen WF is variable parameter B _K, measurements x _K corresponding to G _K, is displayed as a corresponding number of from 0 to 256 in the y 256-color display and which, when the variable parameter B _K, G _K is updated to a variable parameter _{B K + 1, G K +} 1 , the variable parameter _{B K + 1, G K +} 1 measurements corresponding to x _{K + 1} , Y _{K + 1} are updated to the predetermined position P3 and numerically displayed.

Thus, the CPU 23 sets the variable parameters B _{K + 1} and G _{K + 1} based on the color temperature measurement signal S13 read from the RAM 24 in the same manner at time (k + 2),
By repeating the operation of measuring the color temperature while updating (k + 3),... (Hereinafter, this operation is referred to as a parameter update operation), the measured white chromaticity point is set as the target white color. Converge to a point.

In this way, the output brightness of the R, G, and B electron beams is adjusted on the monitor 5A of the television receiver 5, and the white color temperature measured by using the probe 14 and the target are obtained. There is almost no difference from the color temperature of the reference white, and the white balance is adjusted.

(2) White Balance Adjustment Procedure The CPU 23 in the personal computer 11 actually
By executing the white balance adjustment processing procedure RT1 shown in FIG. 6 and updating the variable parameters B _K and G _K as described above, the white chromaticity point measured by the probe 14 is set as a target reference. The white balance is adjusted so as to converge to the white chromaticity point.

First, when the white balance adjustment device 10 is attached to the television receiver 5 by the operator, the CPU 23 enters the white balance adjustment processing procedure RT1 from step SP0. First, in step SP1, the CPU 23 stores the target reference white color temperature set and input by the operator in the RAM 24 (FIG. 2).
To memorize.

Subsequently, in step SP2, the CPU 23 controls the port switching circuit 13 to control the first connection terminal 1
After switching to 3B, the process proceeds to step SP3, in which the probe 14 is activated to measure the color temperature of white currently displayed on the monitor 5A of the television receiver 5.

Thereafter, in step SP4, the CPU 23 controls the port switching circuit 13 to control the second connection terminal 1
After switching to 3C, the process proceeds to step SP5, and executes the above-described parameter updating operation based on the difference between the chromaticity point of the reference white as the target value and the chromaticity point as the measured value.

At this time, in step SP6, the CPU 23 determines whether the chromaticity point as the measured value has converged to the chromaticity point as the target value, and when an affirmative result is obtained,
The process directly proceeds to step SP7 to end the white balance adjustment processing procedure RT1.

On the other hand, if the CPU 23 obtains a negative result in step SP6, this indicates that the chromaticity point as the measured value has not yet converged to the chromaticity point as the target value. At this time, the CPU 23 returns to step SP2 again and proceeds to step SP2-S as described above.
The processing procedure of P3-SP4-SP5-SP6 is repeated.

(3) Operation and Effect of the Embodiment In the above configuration, the white balance adjusting device 1
At 0, the white color temperature based on the white signal S10 displayed on the screen 5AB of the monitor 5A of the television receiver 5 is measured while outputting the white signal S10 representing the reference white using the personal computer 11. At the same time, by repeating a series of operations such as executing a parameter update operation based on the measurement result, the measured white color temperature can be made to converge to the target reference white color temperature.

At this time, the port switching circuit 13 is connected to the PC side connection terminal 1 for connecting to the personal computer 11.
3A to the CPU 2 in the personal computer 11
3, the personal computer 1 is selectively connected to either the first connection terminal 13B or the second connection terminal 13C in accordance with the switching control.
The white balance adjustment process described above can be executed even when the personal computer 11 is, for example, a laptop type and only one of the serial communication connectors provided on the personal computer 11 can be connected.

Thus, one personal computer 1
1 can execute such white balance adjustment processing by software processing, and as a result, a device (signal generator) that outputs a white signal S10 representing a reference white as in the conventional white balance adjustment apparatus 1 (FIG. 7) 2), the screen 5AB of the monitor 5A of the television receiver 5
It is not necessary to separately provide a device (measuring device 3) for measuring the color temperature based on the white signal S10 displayed on the display device and a device (adjustment device 4) for executing the parameter updating operation based on the measurement result. .

According to the above configuration, in the white balance adjustment device 10, the white signal S1 representing the reference white
Monitor 5A of the television receiver 5 while outputting 0.
A series of operations such as measuring the white color temperature based on the white signal S10 displayed on the display unit and executing a parameter updating operation based on the measurement result are repeated to set the measured white color temperature as a target. Since the white balance adjustment process until the color temperature of white is converged can be executed by software processing by one personal computer 11, the white balance adjustment process can be performed using a plurality of devices as in the related art. The entire apparatus can be significantly reduced in size as compared with the case where it is performed individually.

(4) Other Embodiments In the above embodiment, the white balance adjustment device 10 as a color adjustment device according to the present invention is applied to a television receiver (display device) 5. However, the present invention is not limited to this, and can be widely applied to display devices other than television receivers that can display various color images.

In the above-described embodiment, a white signal (color signal) S10 of white (predetermined color) is generated, and white is displayed on the monitor 5A of the television receiver 5 based on the color signal. The CPU 23 as a control means performs a series of color adjustment processing until the white color temperature displayed on the monitor 5A is measured and the measured white color temperature is adjusted to be a reference color temperature. Has been described using a single personal computer 11 including, but the present invention is not limited to this, the color temperature of a predetermined color displayed on a display device may be set as a reference color temperature. If a series of color adjustment processes up to the adjustment can be software-processed as a program, it can be widely applied to an apparatus including other various control means.

Further, in the above-described embodiment, when the measured white color temperature is adjusted to the reference color temperature, the measured white color temperature and the reference color temperature are adjusted by using the steepest descent method. Although the case where the white color temperature is updated and set for the television receiver 5 so as to eliminate the difference with the above has been described, the present invention is not limited to this.
In short, various arithmetic methods other than the steepest descent method may be applied as long as the measured white color temperature can be adjusted to the reference color temperature by software processing of the CPU 23 as the control means.

Further, in the above-described embodiment, a case has been described where the RAM 24 provided inside the personal computer 11 is applied as a recording medium on which a program for realizing the above-described color adjustment processing is recorded. The invention is not limited to this.
As long as the above-mentioned program can be read and written under the control of the third control, the present invention may be widely applied to various other recording media.

Further, in the above-described embodiment, the port switching circuit 13 as the switching means includes the PC side connection terminal 13A as the serial communication input / output terminal connected to the personal computer 11, and the television receiver 5
A first connection terminal 13B as a first communication line for measuring the color temperature of white displayed on the monitor 5A of
A second connection terminal 13C as a second communication line for adjusting the measured white color temperature to a reference color temperature; and a second connection terminal 13C as a control means. Although the case where one of the first connection terminal 13B and the second connection terminal 13C is switched so as to be connected to the PC-side connection terminal 13A has been described, the present invention is not limited to this, and the control means is not limited to this. If any one of the first and second communication lines can be selectively connected to the connected serial communication input / output terminal under the control of the control means, the switching means In addition, various configurations may be applied.

[0069]

As described above, according to the present invention, in a color adjusting apparatus for adjusting a display color of a display device for displaying a color image, a recording medium on which a predetermined program is recorded, and a control for executing the program Means, the program generates a color signal of a predetermined color, and causes the display device to measure the color temperature of the predetermined color displayed on the display device while displaying the predetermined color on the display device based on the color signal; By setting the measured color temperature of the predetermined color to be adjusted to the reference color temperature, it is possible to realize a color adjustment device that can be reduced in size as a whole device.

As described above, according to the present invention, in a color adjustment method for adjusting a display color of a display device for displaying a color image, a color signal of a predetermined color is generated, and the predetermined color is displayed based on the color signal. By causing the device to measure the color temperature of the predetermined color displayed on the display device while displaying it on the device, and adjusting the measured color temperature of the predetermined color to the reference color temperature, the color adjustment process is performed. Can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a white balance adjustment device according to an embodiment.

FIG. 2 is a block diagram showing an internal configuration of the personal computer shown in FIG.

FIG. 3 is a schematic plan view illustrating a GUI screen displayed on a display unit.

FIG. 4 is a schematic plan view illustrating a GUI screen displayed on a display unit.

FIG. 5 is a schematic plan view showing a chromaticity diagram adopted by the International Commission on Illumination.

FIG. 6 is a flowchart illustrating a white balance adjustment processing procedure.

FIG. 7 is a block diagram showing a configuration of a conventional white balance adjustment.

[Explanation of symbols]

1, 10... White balance adjusting device, 5... Television receiver, 5A... Monitor, 5AB.
... personal computer, 12 ... communication line, 1
3 ... Port switching circuit, 13A ... PC side connection terminal, 1
3B ... first connection terminal, 13C ... second connection terminal,
14: Probe, 20: Input unit, 21, 26 ...
Interface, 23 CPU, 24 RAM, 2
5 ROM, 27 display unit.

Claims (5)

[Claims] 1. A color adjustment device for adjusting a display color of a display device for displaying a color image, comprising: a recording medium on which a predetermined program is recorded; and control means for executing the program. A first step of generating a color signal of a color and displaying the predetermined color on the display device based on the color signal, and a second step of measuring a color temperature of the predetermined color displayed on the display device And a third step of adjusting the measured color temperature of the predetermined color to a reference color temperature. 2. The display device according to claim 3, wherein the third step of the program uses a steepest descent method so that the difference between the measured color temperature of the predetermined color and the reference color temperature is eliminated. 2. The color adjustment device according to claim 1, wherein the color temperature of the predetermined color is updated and set. 3. An input / output terminal for serial communication connected to the control means; a first communication line for measuring a color temperature of the predetermined color displayed on the display device; A second communication line for adjusting the color temperature of the predetermined color to be a reference color temperature, wherein one of the first and second communication lines is controlled according to the control of the control means. 2. The color adjustment device according to claim 1, wherein the color adjustment device is selectively switched so as to be connected to the input / output terminal. 4. A color adjusting method for adjusting a display color of a display device for displaying a color image, wherein a color signal of a predetermined color is generated, and the predetermined color is displayed on the display device based on the color signal. And a second step of measuring the color temperature of the predetermined color displayed on the display device; and a third step of adjusting the measured color temperature of the predetermined color to be a reference color temperature. And a color adjusting method comprising: 5. The display device according to claim 3, wherein the third step of the program uses the steepest descent method so that the difference between the measured color temperature of the predetermined color and the reference color temperature is eliminated. 5. The color adjustment method according to claim 4, wherein the color temperature of the predetermined color is updated and set.