JP4573719B2 - Image display device, white balance adjustment device, white balance adjustment system, and white balance adjustment method - Google Patents

Description

  The present invention relates to an image display device, a white balance adjustment device, a white balance adjustment system, and a white balance adjustment method, and more specifically, to adjust the white balance of a display screen in an image display device such as a television receiver. It is related with the white balance adjustment technology to do.

  For example, in a display device such as a television receiver or a computer display, white balance adjustment is performed in the manufacturing process. Here, the cut-off adjustment for adjusting the white balance of the dark screen and the gain adjustment for adjusting the white balance of the bright screen so that the screen is displayed with the same color temperature regardless of whether the screen is dark or bright. Is done.

  The white balance is adjusted by an operator in the manufacturing process of a television receiver, for example. At this time, as a screen for white balance adjustment, a dark screen and a bright screen are displayed on the display device, and adjustment is performed so that white has the same color temperature in the dark screen and the bright screen. An operation of storing in the memory of the receiver is performed. Then, based on the white balance adjustment value stored in the memory of the television receiver, a signal processing operation is performed by the signal processing unit of the television receiver, whereby a good image display is performed.

  FIG. 7 is a schematic diagram for explaining an example of a white balance adjustment process in a television receiver to which the present invention is applicable. In the figure, 1 is a television receiver, 4 is a white balance adjustment device, and 40 is a belt. A conveyor 41 is an aging tank. As shown in FIG. 7, in the white balance adjustment process in the television receiver 1, the television receiver 1 is passed through the interior of an aging tank 41 adjusted to a predetermined temperature level on the production line of the television receiver 1. The operation state of the John receiver 1 is stabilized. Then, on the subsequent line, the operator performs white balance adjustment work.

  FIG. 8 is a diagram illustrating an example of luminance characteristics during aging in the television receiver. The operation of the television receiver 1 is not stable unless a certain amount of time elapses after the power of the main body is turned on. For example, the fluorescent lamp of the backlight of the television receiver 1 is not stable in light emission characteristics unless the temperature rises to a certain level after the apparatus power is turned on. Also, the display characteristics of the liquid crystal panel itself change depending on the temperature. Accordingly, the luminance characteristics of the screen are not stabilized unless a certain amount of time has passed after the power is turned on. In addition, the driver IC for displaying an image on the liquid crystal panel also has some temperature dependence.

  In the example shown in FIG. 8, the screen brightness changes greatly immediately after the television receiver 1 is turned on, and then the characteristics gradually stabilize. When about one hour has passed after the power is turned on, the brightness characteristics are almost stable. To do. This is because the temperature of the television receiver 1 is almost constant.

  FIG. 9 is a diagram for explaining the chromaticity characteristics at the time of aging in the television receiver, and shows a part of the CIE chromaticity diagram defined by the International Lighting Commission. Here, the manner in which the coordinate values in the CIE chromaticity diagram change during aging of the television receiver is shown. FIG. 9 shows the above coordinate values when a gray display of 40% gradation is performed as an example.

  As described above, due to the temperature dependence of the fluorescent lamp, liquid crystal panel, or driver IC of the television receiver 1, the characteristics have changed since the television receiver 1 was turned on, and a certain level of time has passed. Later (about 1 hour in the above example), the characteristics of the television receiver 1 are stabilized. If attention is paid to the chromaticity of the screen at this time, in the example of FIG. 9, the chromaticity of the gray display of the 40% gradation changes from the point s at the time of power-on to the point e in the stable state with the passage of time. Go.

  As can be seen from the luminance characteristics and chromaticity characteristics as described above, after the power of the television receiver 1 is turned on, the image quality of the display screen of the television receiver 1 is increased until the temperature rises to a certain level. (Luminance and chromaticity values) are not stable.

When adjusting the white balance of the television receiver 1 having the above-described characteristics, the aging tank 41 as described above is used to adjust the temperature condition of the television receiver 1, and the television receiver 1 is set in a predetermined manner. The white balance is adjusted after warming up at the ambient temperature. An example of the set temperature of the aging tank 41 is about 40 ° C.
By using such an aging tank 41, the temperature of the television receiver 1 is set to a predetermined level so that white balance adjustment can be performed with high accuracy.

  Regarding white balance adjustment as described above, for example, Patent Document 1 discloses a white balance adjustment method in which adjustment work for auto white balance processing is easily performed. Here, a pre-white balance adjustment program for performing automatic adjustment work for auto white balance processing is stored in advance in an area such as a ROM in the DSP. This pre-white balance adjustment program controls to automatically adjust the white balance by switching to the operation mode. Then, the user can automatically execute the pre-white balance adjustment operation for each color temperature simply by switching the camera device to the pre-white balance mode, inputting a number indicating the color temperature, and changing the color temperature of the light source. This operation is performed at a required color temperature, the respective white balance gain and OPD data are acquired and stored in each parameter, thereby adjusting the auto white balance characteristics.

Patent Document 2 discloses a white balance correction circuit that reduces the required capacity of a memory for storing gradation correction data necessary for high-precision adjustment and enables correction data to be changed after the display device is completed. Has been. Here, the RAM which receives the white balance correction data from the arithmetic circuit, converts the input digital video signal RGB signal into data, performs white balance correction and outputs the digital video signal, and generates the white balance correction data and outputs the RAM. A control circuit that performs storage control of the image data, an arithmetic circuit that performs processing of gradation correction data using a predetermined arithmetic expression and outputs white balance correction data, and data correction having arithmetic parameters including coefficients and constants of the arithmetic expression And an MPU for supplying a control instruction to the control circuit.
JP 2004-23123 A JP 2004-104663 A

  As described above, when the temperature of the television receiver is stabilized using the aging tank, in practice, the temperature of the television receiver is not always constant due to various factors in the production line. . For example, since the operating state of the production line is different before and after a break time in the production factory, a temperature difference may occur between the television receiver after leaving the aging tank and the steady operation.

  Similarly, for example, temperature conditions due to aging may vary under various conditions such as temperature fluctuation due to morning and evening of the day, temperature fluctuation due to season, temperature fluctuation due to climatic conditions in the production area, and the like. If the temperature condition fluctuates, the white balance adjustment value fluctuates, and a problem arises in that the target image quality cannot be obtained when video signal processing based on the white balance adjustment value is performed. Similarly, when the production line speed changes, the temperature conditions also change.

  Conventionally, there has been a problem that highly reliable white balance adjustment cannot always be performed due to the influence of the temperature characteristics of the circuit unit and the like in the white balance adjustment target device and its environmental temperature. Such a problem has not been solved in Patent Documents 1 and 2.

  The present invention has been made in view of the above circumstances, and reflects temperature drift under various conditions without being affected by temperature characteristics of a circuit unit or the like in a white balance adjustment target device or its environmental temperature. It is an object of the present invention to provide an image display device, a white balance adjustment device, a white balance adjustment system, and a white balance adjustment method that can perform white balance adjustment.

In order to solve the above problems, a first technical means of the present invention includes an interface for inputting an adjustment value for performing γ correction of a display image from a white balance adjustment device for performing white balance adjustment, and an interface. In an image display device having an image processing unit that performs γ correction based on an input adjustment value and an image display unit that displays an image based on an image signal that has been γ-corrected by the image processing unit, the image display device includes: White balance adjustment image display means for displaying two types of white balance adjustment images with different gradations on the display means, a temperature sensor for measuring the temperature inside the image display apparatus, and a temperature change inside the image display apparatus And a temperature correction table in which the relationship between the change in the CIE chromaticity coordinate value of the image displayed on the image display means is tabulated in advance A temperature correction table holding unit, and the interface inputs an adjustment value of γ correction generated based on the imaging data of the white balance adjustment image, and uses the temperature data from the temperature sensor and the temperature correction table to generate an image. Means for correcting an adjustment value input from the interface based on a difference between a coordinate value of CIE chromaticity when the temperature of the display device is stable and a coordinate value of CIE chromaticity at the current temperature. The processing means is characterized in that γ correction is performed using the corrected adjustment value.

A second technical means is a white balance adjusting device for adjusting the white balance of the image display device. The white balance adjusting device is a temperature change in the image display device and CIE chromaticity of an image displayed on the image display device. A temperature correction table holding means for holding a temperature correction table in which the relationship between the coordinate values of the image data is tabulated in advance, an interface for inputting temperature data inside the image display device from the image display device, and a display of the image display device Imaging means for imaging two types of white balance adjustment images displayed on the screen with different gradations, means for calculating coordinate values of CIE chromaticity from the white balance adjustment images captured by the imaging means, and CIE color White balance adjustment means for adjusting γ correction data so as to be a target coordinate value based on the degree coordinate value Based on the difference between the CIE chromaticity coordinate value when the temperature of the image display device is stable and the CIE chromaticity coordinate value at the current temperature, using the temperature data input from the interface and the temperature correction table, And a means for correcting the adjustment value adjusted by the white balance adjustment means, and the interface outputs the corrected adjustment value to the image display device.

A third technical means is a white balance adjustment system comprising an image display device and a white balance adjustment device for adjusting the white balance of the image display device, wherein the image display device displays the display from the white balance adjustment device. An adjustment value input interface for inputting an adjustment value for performing γ correction of the image, an image processing means for performing γ correction based on the adjustment value input from the adjustment value input interface, and an image signal γ corrected by the image processing means An image display means for displaying an image based on the image, a white balance adjustment image display means for displaying two types of white balance adjustment images with different gradations on the image display means, and a temperature inside the image display device The white balance adjustment device has a temperature change in the image display device and an image display means. Temperature correction table holding means for holding a temperature correction table in which the relationship between the coordinates of the CIE chromaticity of the image to be displayed and the relationship in advance is tabulated, and the temperature at which the temperature data inside the image display device is input from the image display device A data input interface; an imaging unit that captures two types of white balance adjustment images displayed on the display screen of the image display device; and a CIE chromaticity value determined from the white balance adjustment image captured by the imaging unit. A means for calculating coordinate values; a white balance adjusting means for adjusting γ correction data so as to obtain a target coordinate value based on the coordinate values of CIE chromaticity; temperature data and temperature input from a temperature data input interface; Using the correction table, the coordinate value of CIE chromaticity when the temperature of the image display device is stable and the current temperature are used. And a means for correcting the adjustment value adjusted by the white balance adjustment means based on the difference from the coordinate value of the CIE chromaticity, and the white balance adjustment device outputs the corrected adjustment value to the image display device. The adjustment value input interface of the image display apparatus is characterized by inputting a corrected adjustment value.

A fourth technical means is a white balance adjustment system including an image display device and a white balance adjustment device for adjusting the white balance of the image display device, and the image display device displays the display from the white balance adjustment device. An adjustment value input interface for inputting an adjustment value for performing γ correction of the image, an image processing means for performing γ correction based on the adjustment value input from the adjustment value input interface, and an image signal γ corrected by the image processing means An image display means for displaying an image based on the image, a white balance adjustment image display means for displaying two types of white balance adjustment images with different gradations on the image display means, and a temperature inside the image display device Temperature sensor, temperature change inside the image display device, and CIE chromaticity coordinate value of the image displayed on the image display means And a temperature correction table holding means for holding a temperature correction table in which the relationship between changes is tabulated in advance, and the white balance adjustment device has two types of white having different gradations displayed on the display screen of the image display device. An imaging unit that captures an image for balance adjustment, a unit that calculates a coordinate value of CIE chromaticity from a white balance adjustment image captured by the imaging unit, and a target coordinate value based on the coordinate value of CIE chromaticity A white balance adjustment unit that adjusts the γ correction data so that the adjustment value input by the white balance adjustment unit is output to the image display device. Input the gamma correction adjustment value adjusted by the balance adjustment means, and use the temperature data from the temperature sensor and the temperature correction table. Means for correcting the adjustment value input from the adjustment value input interface based on the difference between the coordinate value of the CIE chromaticity when the temperature of the image display device is stable and the coordinate value of the CIE chromaticity at the current temperature; And the image processing means performs γ correction using the corrected adjustment value.

A fifth technical means is a white balance adjustment method for adjusting a white balance of a display image to be displayed on an image display device, wherein two types of white balance adjustment images having different gradation levels are displayed on the image display device. A step of capturing a white balance adjustment image, a step of measuring a temperature inside the image display device, a CIE chromaticity coordinate value is calculated from the captured white balance adjustment image, and a CIE chromaticity coordinate value is calculated. And adjusting the white balance by adjusting the γ correction data so as to obtain a target coordinate value, and the temperature change in the image display device and the CIE chromaticity coordinate value of the image displayed on the image display device change and, holds the temperature correction table in advance a table the relationship, using the temperature data and the temperature correction table measured, Correcting the adjustment value of the adjusted γ correction data based on the difference between the coordinate value of CIE chromaticity when the temperature of the image display device is stable and the coordinate value of CIE chromaticity at the current temperature; Performing γ correction based on the adjusted value and displaying an image based on the γ-corrected image signal.

According to the present invention, it is possible to perform white balance adjustment reflecting temperature drift under various conditions without being affected by temperature characteristics of a circuit unit or the like in a device targeted for white balance adjustment or its environmental temperature. It becomes like this.
For example, in the production line of the equipment to be adjusted, if there is a temperature drift due to various conditions such as the speed of the production line, before and after the break time of the production factory, morning and evening, the four seasons, the climate of the production area, Even when temperature drift occurs in various circuits of the device, white balance adjustment that reflects the temperature drift can be performed.
Here, by measuring the amount of white balance deviation due to the temperature of the target device in advance and making a table, it is possible to perform more stable white balance adjustment by applying the correction during white balance adjustment.

In the present invention, the white balance adjustment target device corrects a difference between an ideal state in which aging has been sufficiently performed (a state in which the operation of the adjustment target device is stable) and the actual temperature of the adjustment target device. Prepare a balance temperature correction table. Then, the temperature of the target device is measured by the temperature sensor provided in the white balance adjustment target device, or the accurate aging time is obtained by counting the energization time of the target device. The white balance is adjusted after applying correction using the information and the white balance temperature correction table.
As described above, the temperature state of the device to be adjusted is accurately measured, and the white balance adjustment is performed after correcting the state and a preset temperature correction table.

  FIG. 1 is a schematic diagram for explaining the configuration of a white balance adjustment system according to the present invention. In the figure, 1 is a television receiver which is an example of a white balance adjustment target device, 2 is a digital signal processor (DSP), 3 is a liquid crystal panel, 4 is a white balance adjusting device, 5 and 6 are cameras, and 7 is a bus line. The DSP 2 constitutes a digital signal processing circuit and performs various image processing on the input image signal.

In the system of FIG. 1, a television receiver 1 is a device for white balance adjustment, and the white balance adjustment image displayed on the liquid crystal panel 3 is picked up using the cameras 5 and 6, thereby white balance. Make adjustments.
When adjusting the white balance, first, an image for white balance adjustment is displayed on the liquid crystal panel 3 of the television receiver 1. Here, the white balance adjustment image displays light gray and dark gray on each of the two divided images. Light gray is an image for gain adjustment, and dark gray is an image for cut-off adjustment. For example, a light gray is a gray having a gradation of 80% when white is 100%, and a dark gray is a gray having a gradation of 40%, for example.

  The white balance adjustment image is held in the memory of the television receiver 1, for example, in response to an instruction to shift to an adjustment mode input from a predetermined remote control device or the white balance adjustment device 4. 1 can be displayed on one liquid crystal panel 3. At this time, the OSD display function of the television receiver 1 can be used to display the white balance adjustment image. Also, a white balance adjustment image is generated by a signal generation circuit included in the white balance adjustment device 4, transmitted to the television receiver 1 via the bus line, and processed as an input video signal by the television receiver 1. Thus, it may be displayed on the liquid crystal panel 3.

  The white balance adjustment device 4 includes a computer system having a control unit such as a CPU and a memory, and is used for white balance adjustment according to the present invention using a white balance adjustment program stored in the memory. Process. The memory of the white balance adjusting device 4 can hold a temperature correction table, which will be described later, and corresponds to the temperature correction table holding means of the present invention. Further, the control unit of the white balance adjustment device 4 is a CIE chromaticity calculation unit according to the present invention, a white balance adjustment unit that adjusts data by γ correction, and a unit that corrects the adjustment value using a temperature correction table. Applicable.

Two cameras 5 and 6 are connected to the white balance adjustment device 4, and the cameras 5 and 6 respectively capture light gray and dark gray displayed on the liquid crystal panel 3. These cameras 5 and 6 correspond to the imaging means of the present invention.
Images captured by the cameras 5 and 6 are input to the white balance adjustment device 4, and coordinate values x and y on the CIE chromaticity diagram are measured. In the following description, the coordinate values on the CIE chromaticity diagram will be simply referred to as “coordinate values”.

An operator who adjusts the white balance adjusts the image quality based on the measured coordinate values so that the coordinate values x and y become predetermined target values.
In this embodiment, a temperature correction table for correcting the image quality adjustment value according to the temperature of the television receiver 1 is provided. Image quality adjustment using this temperature correction table will be described later.

  In the white balance adjustment device 4, an adjustment value is generated for each RGB based on images taken by the cameras 5 and 6, and the adjustment value is transferred to the television receiver 1 via the bus line 7. In the television receiver 1, the RGB signal levels are adjusted using the adjustment values transferred from the white balance adjustment device 4. In the television receiver 1, white balance can be adjusted by performing γ correction using a γ correction circuit provided in the DSP 2 using the adjustment value.

  When the coordinate values x and y of the display screen displayed on the liquid crystal panel 3 as a result of the adjustment are determined to correspond to the target coordinate values by the white balance adjusting device 4, the television receiver 1 at that time Is stored in its own memory, and the subsequent video display is performed using the adjustment value.

Next, the above image quality adjustment processing example will be described more specifically.
FIG. 2 is a diagram illustrating an example of a white balance adjustment image displayed on the liquid crystal panel 3. As shown in the screen example of FIG. 2, in the white balance adjustment image, dark gray is displayed on one of the two divided screens (the right side in FIG. 2) and on the other divided screen (the left side in FIG. 2). Display light gray. Here, when the gradation of an image is displayed with 8 bits and 256 gradations, for example, light gray is 207 gradations and dark gray is 64 gradations.

  A target chromaticity is determined for the television receiver 1. That is, the target coordinate values x and y are determined for each of the light gray and the dark gray. When adjusting the white balance, adjustment is performed based on the display screen of the light gray and the dark gray so as to obtain target coordinate values x and y for each gray.

  When displaying the white balance adjustment screen, for example, the operator inputs an instruction to display the white balance adjustment screen to the television receiver 1 or the white balance adjustment device 4. An instruction input and various setting inputs to the white balance adjustment device 4 may be performed using a remote control device. The television receiver 1 displays a white balance adjustment image on the liquid crystal panel 3 in accordance with the display input. The operator can enter either one of the image adjustment screens by selecting the left and right screens.

At the time of actual adjustment, first, dark gray is selected and cut-off adjustment is performed.
FIG. 3 is a diagram for explaining the cut-off adjustment, in which the horizontal axis indicates the gradation and the vertical axis indicates the output value (output value of the RGB signal). The white balance adjustment device 4 holds a default RGBγ table. The line indicated by the arrow a in FIG. 3 shows the default RGBγ table, and the operator adjusts the output value at 64 gradations with respect to this default value. The adjustment range of the output value is determined in advance as, for example, -128 to 127. Along with the adjustment of the cut-off, the output value shifts in parallel in 64 to 255 gradations. The output value has a predetermined value (1024 here) as the upper limit.

  The adjustment function is provided for each of RGB, and the operator appropriately adjusts one or a plurality of γ tables of RGB so that the target coordinate values x and y of the dark gray can be obtained. .

  FIG. 4 is a diagram for explaining gain adjustment. After performing the cut-off adjustment shown in FIG. 3, the operator performs gain adjustment for the output value of light gray of 207 gradations. The output value adjustment range is determined in advance, for example, from -128 to 127, as in the above-described cutoff. In this case, as shown in FIG. 4, the output value of 64 gradations that have already been adjusted is fixed, and the slope of the output value changes according to the gain adjustment at 207 gradations.

  The gain adjustment function is also provided for each of RGB, and the operator appropriately adjusts one or a plurality of γ tables of RGB so as to obtain the coordinate values x and y that are the targets of the bright gray. .

  The adjustment value adjusted by the above processing is transmitted from the white balance adjustment device 4 to the television receiver 1 via the bus line 7. The television receiver 1 stores the adjustment value in a memory, and performs image correction based on the adjustment value by performing γ correction using the adjustment value. By such adjustment by the white balance adjusting device 4, an image having the target coordinate values x and y can be displayed.

  Then, as a feature of the present embodiment, a correction table for compensating for the temperature change of the television receiver is prepared, the temperature of the television receiver at the time of white balance adjustment is measured, and the temperature measurement result and the correction described above are measured. Using the table, the adjustment amount for adjusting the coordinate value to the target value is corrected from the difference (deviation amount) of the coordinate value between the current temperature and the stable temperature.

  The temperature correction table measures changes in coordinate values from when the television receiver 1 is powered on until the temperature is stable, and stores the relationship between the temperature and the coordinate values in the specifications as a temperature correction table. deep. This temperature correction table may be held in the white balance adjustment device 4 or may be held in the television receiver 1.

  When the temperature correction table is held in the white balance adjusting device 4, the following operation is performed. First, the operator starts white balance adjustment according to the procedure described above, and displays the white balance adjustment image composed of light gray and dark gray as described above on the liquid crystal panel 3 of the television receiver 1. Then, the respective white balance adjustment images are taken by the cameras 5 and 6 connected to the white balance adjustment device 4, and the coordinate values x and y at that time are obtained.

  The television receiver 1 is provided with a temperature sensor, and the temperature measurement information is sent to the white balance adjustment device 4 via the bus line 7. The temperature sensor is preferably provided in the vicinity of a unit of a liquid crystal panel and a backlight whose display characteristics change depending on temperature.

  Then, the white balance adjustment device 4 further corrects the adjustment value at that time using the temperature measurement information sent from the television receiver 1 and the temperature correction table when the cut-off and gain are adjusted. Add The correction amount at this time is determined based on the difference in coordinate values between the current temperature and the stable temperature.

  Then, the corrected adjustment value is sent from the white balance adjusting device to the television receiver 1. In the television receiver 1, an adjustment value is stored in a memory, and γ correction is performed using the adjustment value, thereby displaying an image based on the adjustment value. As a result, the liquid crystal panel 3 of the television receiver 1 displays an image when the temperature is stable based on the temperature correction table, and an image obtained by adjusting the white balance becomes the target coordinate values x and y when the temperature is stable. You can check whether it is.

  On the other hand, when the temperature correction table is held in the television receiver 1, the following operation is performed. First, the operator starts white balance adjustment according to the procedure described above, and displays a white balance adjustment image composed of light gray and dark gray on the liquid crystal panel 3 of the television receiver 1. Then, the respective white balance adjustment images are taken by the cameras 5 and 6 connected to the white balance adjustment device 4, and the coordinate values x and y at that time are obtained.

When the cutoff and gain are adjusted by the white balance adjustment device 4, the adjustment value is sent to the television receiver 1.
The television receiver 1 is provided with a temperature sensor. The television receiver 1 uses the temperature measurement information measured by the temperature sensor and the temperature correction table held by itself to adjust the correction value (white balance adjustment value) in which the cutoff and gain are corrected. ) To perform γ correction. As a result, an image is displayed on the liquid crystal panel 3 that has been corrected to be in a stable temperature state. The correction amount at this time is determined based on the difference in coordinate values between the current temperature and the stable temperature.
With such an operation, it is possible to confirm whether the image obtained by adjusting the white balance has the target coordinate values x and y when the temperature is stable.

  In the configuration in which the television receiver 1 holds the temperature correction table, the television receiver 1 uses the temperature correction table so as to absorb the temperature drift based on the temperature measurement result of its own temperature sensor. Thus, it is possible to display an image while always performing correction. On the other hand, in the configuration in which the temperature correction table is held in the white balance adjustment device 4, it is not necessary to hold the temperature correction table in the television receiver 1, so that the resources of the television receiver 1 can be rationalized. The cost of the television receiver 1 can be reduced.

  Although the embodiment of the white balance adjustment system of the present invention has been described above, the present invention is characterized by performing correction in consideration of the temperature drift of the image display device when adjusting the white balance. The adjustment method itself is not limited to the above embodiment, and a conventionally known white balance adjustment method can be appropriately applied.

  In the above example, the γ correction adjustment value is corrected based on the temperature measurement value by the temperature sensor, but means for counting the energization time after the image display device is turned on is provided. Further, a table for estimating the temperature of the image display device from the energization time may be provided in either the white balance adjustment device or the image display device. In this case, the white balance adjustment value can be corrected using the temperature correction table based on the temperature of the image display device estimated from the energization time.

FIG. 5 is a diagram showing an example of an image display device to which the present invention can be applied, and shows an example of a liquid crystal television receiver configured as an image display device.
In the television receiver 1, the tuner 12 selects a channel from the television broadcast signal received by the antenna 11. The video input terminal 13 inputs a video signal from an AV device built in or externally connected to the television receiver 1. Then, the switching unit 14 switches and outputs the television broadcast signal selected by the tuner 12 and the video signal input via the video input terminal 13.
Further, the television receiver 1 is provided with an external input / output I / F 15 that realizes an interface with an external device, and can be connected to the white balance adjusting device 4 through a bus line.

  The video signal output from the switching unit 14 is processed by the video processing unit 17 and output to the LCD control unit 18. The video processing unit 17 performs video signal generation processing, various image quality adjustment processing, and the like from the input video signal. The video processing unit 17 includes a γ correction processing unit related to the white balance adjustment of the present invention, and uses the adjustment value for γ correction input from the white balance adjustment device via the external input / output I / F 15 to display the video. Perform γ correction on the signal. In addition to the above-described γ correction processing, the video processing unit 17 also performs, for example, composite signal YC separation processing, RGB signal decoding processing for generating RGB signals from YC signals, AD conversion processing, color space conversion processing, IP conversion processing, scaling Processing, FRC processing, color correction processing, synchronization detection processing, OSD display processing, and the like are appropriately performed.

The LCD control unit 18 generates gradation data and a signal line control signal to be output to the source driver of the LCD 19 according to the RGB image display signal output from the video processing unit 17 and also outputs the scanning line control signal to be output to the gate driver. Then, the image display control on the LCD 19 is performed. The LCD control unit 18 generates a backlight control signal to be output to the light source driving unit 20 including an inverter circuit and the like, and performs light emission driving control of the fluorescent lamp of the backlight 21.
The audio signal output from the switching unit 14 is processed by the audio processing unit 22 and output from the speaker 23.

The temperature sensor 16 measures the temperature inside the television receiver 1. The temperature sensor 16 is preferably provided in the vicinity of the backlight 21, the LCD 19, and the LCD control unit 18.
The remote control light receiving unit 24 receives a remote control operation signal by infrared rays transmitted from the remote control device 30 and sends it to the control unit 25. The control unit 25 detects and analyzes the remote control operation signal received by the remote control light receiving unit 24, and performs these operations on the tuner 12, the switching unit 14, the video processing unit 17, the LCD control unit 18, the audio processing unit 22, and the like. A control signal to be controlled is output. Here, programs and data stored in the memory 26 are used.

  The video processing unit 17 corresponds to the image processing means of the present invention, and the LCD 19 corresponds to the image display means of the present invention. The control unit 25 corresponds to the white balance adjustment image display unit of the present invention, and the memory 26 corresponds to the temperature correction table holding unit of the present invention.

  FIG. 6 is a flowchart for explaining a processing example of the white balance adjustment method according to the present invention. First, two types of white balance adjustment images having different gradation levels are displayed on the image display device (step S1). The white balance adjustment image displayed in step S1 is picked up using a camera (step S2). Further, the temperature inside the image display device is measured by a temperature sensor provided in the image display device (step S3).

Next, a coordinate value of CIE chromaticity is calculated from the imaged white balance adjustment image, and the γ correction data is adjusted to a target coordinate value based on the coordinate value of the CIE chromaticity to adjust the white balance. Adjustment is performed (step S4). Then, using the temperature data and the temperature correction table, based on the difference between the CIE chromaticity coordinate value at the temperature where the temperature of the image display device is stable and the CIE chromaticity coordinate value at the current temperature, step S4 is performed. The adjustment value of the γ correction data adjusted in step S5 is corrected (step S5).
In the image display device, γ correction is performed based on the adjustment value corrected in step S5, and image display is performed based on the γ-corrected image signal (step S6).

It is the schematic for demonstrating the structure of the white balance adjustment system by this invention. It is a figure which shows an example of the image for white balance adjustment displayed on a liquid crystal panel. It is a figure for demonstrating cut-off adjustment. It is a figure for demonstrating gain adjustment. It is a figure which shows an example of the image display apparatus which can apply this invention. It is a flowchart for demonstrating the process example of the white balance adjustment method concerning this invention. It is the schematic for demonstrating an example of the white balance adjustment process in the television receiver which can apply this invention. It is a figure which shows an example of the luminance characteristic at the time of aging in a television receiver. It is a figure for demonstrating the chromaticity characteristic at the time of aging in a television receiver.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Television receiver, 2 ... Digital signal processor (DSP), 3 ... Liquid crystal panel, 4 ... White balance adjustment device, 5, 6 ... Camera, 7 ... Bus line, 11 ... Antenna, 12 ... Tuner, 13 ... Video Input terminal 14, switching unit, 15 external input / output I / F, 16 temperature sensor, 17 image processing unit, 18 LCD control unit, 19 LCD, 20 light source drive unit, 21 backlight, 22 DESCRIPTION OF SYMBOLS ... Voice processing part, 23 ... Speaker, 24 ... Remote control light-receiving part, 25 ... Control part, 26 ... Memory, 30 ... Remote control apparatus, 40 ... Belt conveyor, 41 ... Aging tank.

Claims (5)

An interface for inputting an adjustment value for performing γ correction of a display image from a white balance adjustment device for performing white balance adjustment, an image processing means for performing γ correction based on the adjustment value input from the interface, In an image display device having image display means for displaying an image based on an image signal that has been γ-corrected by the image processing means,
The image display device includes: white balance adjustment image display means for displaying two types of white balance adjustment images having different gradation levels on the image display means;
A temperature sensor for measuring the temperature inside the image display device;
Temperature correction table holding means for holding a temperature correction table in which the relationship between the temperature change in the image display device and the change in the CIE chromaticity coordinate value of the image displayed on the image display means is tabulated in advance. And
The interface inputs an adjustment value of γ correction generated based on imaging data of the image for white balance adjustment,
Using the temperature data from the temperature sensor and the temperature correction table, a difference between the coordinate value of the CIE chromaticity when the temperature of the image display device is stable and the coordinate value of the CIE chromaticity at the current temperature is calculated. Based on the adjustment value input from the interface,
The image display device, wherein the image processing unit performs the γ correction using the corrected adjustment value. In the white balance adjustment device for adjusting the white balance of the image display device,
The white balance adjusting device has a temperature that maintains a temperature correction table in which the relationship between the temperature change in the image display device and the change in the CIE chromaticity coordinate value of the image displayed on the image display means is tabulated in advance. Correction table holding means;
An interface for inputting temperature data inside the image display device from the image display device;
Imaging means for imaging two types of white balance adjustment images with different gradations displayed on the display screen of the image display device;
Means for calculating coordinate values of CIE chromaticity from the white balance adjustment image imaged by the imaging means;
White balance adjusting means for adjusting γ correction data so as to be the target coordinate value based on the coordinate value of the CIE chromaticity;
Using the temperature data input from the interface and the temperature correction table, the difference between the CIE chromaticity coordinate value when the temperature of the image display device is stable and the CIE chromaticity coordinate value at the current temperature. And a means for correcting the adjustment value adjusted by the white balance adjusting means,
The white balance adjustment device, wherein the interface outputs the corrected adjustment value to the image display device. A white balance adjustment system comprising an image display device and a white balance adjustment device for adjusting the white balance of the image display device,
The image display device is an adjustment value input interface for inputting an adjustment value for performing γ correction of a display image from the white balance adjustment device;
Image processing means for performing γ correction based on the adjustment value input from the adjustment value input interface;
Image display means for displaying an image based on the image signal γ-corrected by the image processing means;
White balance adjustment image display means for displaying two types of white balance adjustment images having different gradations on the image display means;
A temperature sensor for measuring the temperature inside the image display device,
The white balance adjusting device has a temperature that maintains a temperature correction table in which a relationship between a change in temperature inside the image display device and a change in the coordinate value of CIE chromaticity of an image displayed on the image display unit is tabulated in advance. Correction table holding means;
A temperature data input interface for inputting temperature data inside the image display device from the image display device;
Imaging means for imaging two types of white balance adjustment images with different gradations displayed on the display screen of the image display device;
Means for calculating coordinate values of CIE chromaticity from the white balance adjustment image imaged by the imaging means;
White balance adjusting means for adjusting γ correction data so as to be the target coordinate value based on the coordinate value of the CIE chromaticity;
Using the temperature data input from the temperature data input interface and the temperature correction table, the coordinate value of the CIE chromaticity when the temperature of the image display device is stable and the coordinate value of the CIE chromaticity at the current temperature And a means for correcting the adjustment value adjusted by the white balance adjustment means based on the difference between
The white balance adjustment device outputs the corrected adjustment value to the image display device, and the adjustment value input interface of the image display device inputs the corrected adjustment value. Adjustment system. A white balance adjustment system comprising an image display device and a white balance adjustment device for adjusting the white balance of the image display device,
The image display device is an adjustment value input interface for inputting an adjustment value for performing γ correction of a display image from the white balance adjustment device;
Image processing means for performing γ correction based on the adjustment value input from the adjustment value input interface;
Image display means for displaying an image based on the image signal γ-corrected by the image processing means;
White balance adjustment image display means for displaying two types of white balance adjustment images having different gradations on the image display means;
A temperature sensor for measuring the temperature inside the image display device;
Temperature correction table holding means for holding a temperature correction table in which the relationship between the temperature change in the image display device and the change in the coordinate value of the CIE chromaticity of the image displayed on the image display means is preliminarily tabulated. And
The white balance adjusting device includes: an image pickup unit that picks up two types of white balance adjustment images with different gradation levels displayed on a display screen of the image display device;
Means for calculating coordinate values of CIE chromaticity from the white balance adjustment image imaged by the imaging means;
White balance adjusting means for adjusting γ correction data so as to be the target coordinate value based on the coordinate value of the CIE chromaticity;
Means for outputting the adjustment value adjusted by the white balance adjustment means to the image display device;
The adjustment value input interface of the image display device inputs an adjustment value of γ correction adjusted by the white balance adjusting means,
Using temperature data from the temperature sensor and the temperature correction table, a difference between the coordinate value of the CIE chromaticity when the temperature of the image display device is stable and the coordinate value of the CIE chromaticity at the current temperature is calculated. On the basis of the adjustment value input from the adjustment value input interface,
The white balance adjustment system, wherein the image processing unit performs the γ correction using the corrected adjustment value. A white balance adjustment method for adjusting a white balance of a display image displayed on an image display device,
Displaying two types of white balance adjustment images with different gradations on the image display device;
Capturing the white balance adjustment image;
Measuring the temperature inside the image display device;
A coordinate value of CIE chromaticity is calculated from the imaged white balance adjustment image, and white balance adjustment is performed by adjusting γ correction data so as to be a target coordinate value based on the coordinate value of CIE chromaticity. The steps of
A temperature correction table in which a relationship between a change in temperature inside the image display device and a change in the coordinate value of the CIE chromaticity of the image displayed on the image display device is stored in advance is held, and the measured temperature data Using the temperature correction table, the adjustment is made based on the difference between the CIE chromaticity coordinate value when the temperature of the image display device is stable and the CIE chromaticity coordinate value at the current temperature. correcting the adjustment value of the γ correction data;
Performing white correction on the basis of the corrected adjustment value and displaying an image on the basis of the image signal subjected to the gamma correction.

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