JP2008170779A - Image quality control device, image quality control method, image display device and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image quality control device that carries out measurement of γ characteristics and picture quality control with high accuracy at a high speed. <P>SOLUTION: The image quality control device 1 includes a measuring device measuring the intensity of projected light from a projector, and an integration control device 3. The integration control device 3 includes: a γ characteristics accumulating means 31 for accumulating the γ characteristics data; a γ characteristics averaging means 32 for obtaining the average γ characteristics from the accumulated γ characteristics data; a measurement point determining means 34 for determining an input value for measurement from the average γ characteristics; a designated measurement point measuring means 35 for measuring the intensity of light while controlling the projector by the measurement input value; a γ characteristics computing means 36 for computing the γ characteristics by obtaining an interpolation function that connects points plotted by rendering an output value corresponding to the measurement input value of the average γ characteristics into a value on the abscissa axis and by rendering a measurement value measured by the measuring means 35 into a value on the vertical axis in a graph where the abscissa axis and the vertical axis represent output values of the average γ characteristics; and a γ correction data generating means 37 for generating γ correction data of the projector based on the calculated γ characteristics. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image quality adjustment device, an image quality adjustment method, an image display device, and a projector.

  The projector creates a unique RGB color space by the optical system inside the product, and has different characteristics for each individual. In order to suppress individual variations in manufacturing, it is necessary to perform electronic correction on the light valve. For this purpose, it is necessary to accurately measure the VT (voltage-transmittance) γ characteristic of the product. This is necessary not only for projectors but also for image display devices such as liquid crystal displays.

In order to suppress such individual variations, there is known a correction characteristic determining device for a liquid crystal display device that reduces the individual variation by considering W (white) γ in addition to γ of RGB single color (Patent Document 1). .
There is also known a color image display device capable of making the halftone temperature constant and improving color reproducibility by performing correction processing by calculation based on the three attributes of CIE and XYZ (Patent Document 2). .

JP 2003-248467 A JP 2005-196156 A

Patent Documents 1 and 2 are devices and methods that aim to perform γ correction processing according to an individual by grasping γ characteristics of an image display device, both of which take time. There was a problem.
In other words, Patent Documents 1 and 2 require high accuracy for grasping the γ characteristic, and it is necessary to increase the number of measurement points in order to perform highly accurate measurement. However, if the number of measurement points is increased, naturally the time for measurement increases and the productivity is lowered. For example, in Patent Document 1, there is an embodiment that requires measurement of a total of 256 points of 64 for each of RGBW, and a lot of time is spent on the measurement.

  An object of the present invention is to provide an image quality adjustment device, an image quality adjustment method, an image display device, and a projector that enable high-precision and high-speed γ characteristic measurement and can perform image quality adjustment.

  The present invention relates to an image quality adjusting device for adjusting the image quality of an image display device capable of displaying a color image, the light intensity measuring device receiving light projected from the image display device and measuring the light intensity, and a plurality of Γ characteristics for storing γ characteristic data representing the relationship between the input value for driving control of each image display apparatus and the output value that is the light intensity of light projected from each image display apparatus at that time Accumulating means, γ characteristic averaging means for obtaining an average γ characteristic from γ characteristic data accumulated in the γ characteristic accumulating means, measurement point determining means for determining an input value for measurement based on the average γ characteristic, An input value for measurement is input to and controlled by an image display device subject to image quality adjustment, and a specified measurement point measuring means for measuring the light intensity at that time by the light intensity measuring device, and an output value of the average γ characteristic on the horizontal axis And the vertical axis In the average γ characteristic, the output value corresponding to the measurement input value is a value on the horizontal axis, and the measurement value measured by the designated measurement point measurement unit is plotted as the value on the vertical axis. Γ characteristic calculating means for calculating an interpolating function for connecting points to calculate the γ characteristic of the image display device subject to image quality adjustment, and the γ characteristic of the image display device based on the γ characteristic obtained by the γ characteristic calculating means And γ correction data generating means for generating γ correction data for correcting.

In the present invention, the γ characteristic data of a plurality of image display devices are accumulated by the γ characteristic accumulation means, and the accumulated γ characteristic data is averaged by the γ characteristic averaging means to obtain the average γ characteristic. For this reason, even if the γ characteristics vary among individual image display apparatuses, the average γ characteristics can reduce the influence of individual variations, and can approximate the γ characteristics of a standard image display apparatus.
Then, the measurement input value (measurement point) is determined by the measurement point determination means, the image display device is controlled by the measurement input value by the designated measurement point measurement means, and the light intensity at that time is measured by the light intensity measurement device. Therefore, the relationship between the input value and the output value (light intensity) can be obtained.
In this case, if the relationship between the input value and the output value (γ characteristic) is graphed, it becomes a non-linear and complicated S-curve, so accurate γ characteristic data can be obtained unless the number of measurements (measurement points) is increased. I can't.
On the other hand, according to the present invention, in the γ characteristic calculation means, in the graph in which the output value of the average γ characteristic is the horizontal axis and the vertical axis, that is, the graph in which the average γ characteristic is a linear line (linear), Since the measurement input value and the output value of the image display apparatus are plotted, the interpolation function connecting these plotted points, that is, the γ characteristic, has a form that approximates the linearized average γ characteristic. That is, since it can be a shape close to a linear straight line instead of a complicated shape like the S-shaped curve, it can be easily and accurately obtained by cubic curve interpolation or spline curve interpolation even if the number of measurements is small. it can.
As described above, according to the present invention, a complicated γ characteristic can be obtained by a relatively simple curve by the γ characteristic calculating means, and a highly accurate γ characteristic can be obtained even with a small number of measurement points. Therefore, the γ characteristic of the image display device subject to image quality adjustment can be acquired at high speed and with high accuracy, and the γ correction data generating means can also generate γ correction data based on the γ characteristic at high speed and with high accuracy. it can. For this reason, the production efficiency of the image display device can be improved and the manufacturing cost can be reduced as compared with the case where γ correction data is generated by performing many measurements for each image display device.

Here, it is preferable that the γ characteristic calculating means calculates an interpolation function by cubic curve interpolation based on each point plotted on the graph, and calculates the γ characteristic of the image display device to be image quality adjusted.
Since an interpolation function based on cubic curve interpolation can be obtained from four pieces of measurement data, the γ characteristic can be acquired in a short time. For example, when measuring each single color of red, green, and blue, it is only necessary to measure with four input values (gradation values), so when adjusting the image quality of one image display device, four times by three colors. = 12 measurements can be performed. Therefore, the number of times of measurement can be greatly reduced as compared with the prior art that requires measurement of 256 points, and accordingly, the processing time required for image quality adjustment of one image display device can be greatly shortened.

Here, it is preferable that the γ characteristic accumulation means measures γ characteristics of a predetermined number of image display devices in advance and accumulates the γ characteristic data.
At this time, the γ characteristic data stored in the γ characteristic storage means may be stored, for example, γ characteristic data of about 50 to 100 image display devices. Note that these γ characteristic data may be precisely measured by setting the input value to about 64 levels as in the conventional case.

The γ characteristic accumulating means can sequentially accumulate the γ characteristic data when obtaining the γ characteristic in the image display device subject to image quality adjustment. However, especially when the number of accumulated data is small, the variation of each γ characteristic data. If the value is large, the average γ characteristic may be greatly deviated from the original average value.
On the other hand, when the predetermined number of γ characteristic data of the image display device is stored in advance as in the present invention, the predetermined number of γ characteristic data obtained by precise measurement can be stored. Therefore, the average γ characteristic can also be set to the original average value, and the accuracy of the γ characteristic obtained by the γ characteristic calculating means can be improved.
Further, when the γ characteristics of a predetermined number of image display devices are measured precisely, for example, by switching input values to 64 levels, the same time as before is obtained until the γ characteristics of these predetermined number of image display devices are acquired. However, the γ characteristic of the image display apparatus after that can be measured, for example, by simply switching the input value in four stages, and the time can be greatly shortened. At this time, since the ratio of the predetermined number of about 50 to 100 units is very small with respect to the number of image display devices produced, even if it takes time to measure the γ characteristics of the predetermined number of image display devices, the image display device The overall acquisition time of the γ characteristic can be greatly reduced as compared with the conventional method.

Moreover, it is preferable that the measurement point determination means determines a measurement input value based on an inflection point in the average γ characteristic.
In an image display device, since a liquid crystal panel or the like is usually used as a light valve, the relationship between an input value and an output value is a substantially S-shaped curve, and two inflection points are generated. There are many. Since the inflection point portion has a large change in the output value relative to the change in the input value, if the measurement input value is determined in the vicinity of the inflection point and actually measured, the interpolation function in the γ characteristic calculation means That is, the accuracy of the γ characteristic can be improved.

  Here, the image display device is configured to be capable of projecting monochromatic light of red, green, and blue, and the γ characteristic storage means stores γ characteristic data of m image display devices, and the γ characteristic average The converting means uses the red monochromatic measurement value (XRn_i, YRn_i, ZRn_i), the green monochromatic measurement value (XGn_i, YGn_i, ZGn_i), and the blue monochromatic measurement value as the γ characteristic data ( When XBn_i, YBn_i, and ZBn_i), it is preferable to obtain the average γ characteristic by the equations (1) to (3) for each color of red, green, and blue.

Here, m may be about 10 to 50, but m is preferably about 50 to 100 in that the influence of variation of each image display device can be reduced.
According to such a configuration, since the average γ characteristic is obtained based on the γ characteristic data for m units, even if there is a large variation in some γ characteristic data, the influence can be reduced. For this reason, the accuracy of the γ characteristic of the image display device to be adjusted based on the average γ characteristic can be improved.

The image display device includes a light source, a light modulation device that modulates a light beam emitted from the light source based on image information, and a projection optical device that projects the light beam modulated by the light modulation device. The projector is preferably provided.
If the image display device is a projector, the image quality of the projector can be adjusted quickly and accurately, and an image can be projected with an image quality suitable for the video signal.

  The present invention relates to an image quality adjustment method for adjusting the image quality of an image display device capable of displaying a color image, the input value for driving control of each image display device in a plurality of image display devices, and each image display at that time Γ characteristic accumulation process for accumulating γ characteristic data representing the relationship with the output value that is the light intensity of the light projected from the apparatus, and the γ characteristic for obtaining the average γ characteristic from the γ characteristic data accumulated in the γ characteristic accumulation process An averaging step, a measurement point determining step for determining a measurement input value based on the average γ characteristic, and controlling the input value for measurement to be input to an image display device to be adjusted in image quality. In the graph with the designated measurement point measurement step for measuring and the output value of the average γ characteristic as the horizontal axis and the vertical axis, the output value corresponding to the measurement input value in the average γ characteristic as the value of the horizontal axis, Measured in the specified measurement point measurement process Plotting the measured values as the values on the vertical axis, obtaining an interpolation function connecting these plotted points, and calculating the γ characteristics of the image display device subject to image quality adjustment, and the γ characteristics calculation And a γ correction data generation step of generating γ correction data for correcting the γ characteristic of the image display device based on the γ characteristic obtained by the process.

  In the present invention as described above, the same effects as the image quality adjusting device of the image display device can be obtained.

  The present invention is an image display device capable of displaying a color image, the correction value storage unit storing the γ correction data generated by the γ correction data generation means of the image quality adjustment device, and the correction value storage unit And an arithmetic processing unit that corrects the video signal using the stored γ correction data.

  The present invention is a projector including a light source, a light modulation device that modulates a light beam emitted from the light source based on image information, and a projection optical device that projects the light beam modulated by the light modulation device. The light modulation device uses the correction value storage unit that stores the γ correction data generated by the γ correction data generation unit of the image quality adjustment device, and the γ correction data stored in the correction value storage unit. And an arithmetic processing unit for correcting the signal.

  In each of these inventions, since the video signal can be corrected using highly accurate γ correction data, the image quality of the image projected on each image display device or projector can be improved.

[Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Configuration of image quality adjustment device]
FIG. 1 is a block diagram illustrating a configuration of the image quality adjustment apparatus 1. The image quality adjustment device 1 is a device (system) that measures the γ characteristic of the projector 100 that is an image display device that is an image quality adjustment target, performs the γ correction process, and adjusts the variation in image quality of each projector 100.
The image quality adjusting device 1 includes a measuring device 2 for measuring the γ characteristic of the projector 100 to be adjusted, an integrated control device 3 (such as a personal computer) that controls the projector 100 and the measuring device 2, and an integrated control device. 3 includes an input device 4 (keyboard, mouse, etc.) and an output device 5 (monitor, printer, etc.) for displaying the measurement results.
The measuring device 2 can be used as long as it can measure the intensity (brightness) of light, such as a tristimulus sensor or a spectrocolorimeter.

[Configuration of projector optical system]
FIG. 2 is a block diagram showing the configuration of the optical system of projector 100 (three-plate liquid crystal projector) to be adjusted.
The projector 100 includes a lamp 101, a dichroic mirror 102 that transmits a red component of the light from the lamp 101 and reflects a green / blue component, and a blue component of light reflected by the dichroic mirror 102 that transmits a green component. A dichroic mirror 103 for reflection, three total reflection mirrors 104A, 104B, and 104C, three light valves (liquid crystal panels) 105, 106, and 107, a dichroic prism 108, and a projection lens 109 are provided.

The light 110 emitted from the lamp 101 of the projector 100 is split by the dichroic mirror 102 into red component light 110R and green / blue component light.
The red component light 110 </ b> R is reflected by the total reflection mirror 104 </ b> A, passes through the light valve 105, and reaches the dichroic prism 108.
The green / blue component light reflected by the dichroic mirror 102 is split by the dichroic mirror 103 into green component light 110G and blue component light 110B.
The green component light 110G is reflected by the dichroic mirror 103, passes through the light valve 106, and reaches the dichroic prism 108.
The blue component light 110B passes through the dichroic mirror 103, is reflected by the total reflection mirrors 104B and 104C, passes through the light valve 107, and reaches the dichroic prism 108.
The red, green, and blue component lights 110R, 110G, and 110B are combined by a dichroic prism 108 and projected through a projection lens 109.
Accordingly, the light valves 105 to 107 and the dichroic prism 108 constitute a light modulation device, and the projection lens 109 constitutes a projection optical device.

[Configuration of projector control circuit]
FIG. 3 is a block diagram of a light valve control circuit 120 that controls the light valves 105, 106, and 107 in the projector 100. The light valve control circuit 120 converts analog video signals such as RGB signals, composite signals, and component signals into digital signals by an analog-digital conversion circuit (A / D) 121.
Thereafter, the arithmetic processing unit 122 performs arithmetic processing using the digital signal and the correction value stored in the correction value storage unit 123 so as to obtain a driving voltage suitable for the light valves 105, 106, and 107. After the arithmetic processing, the digital signal is converted into an analog signal by the digital / analog conversion circuit (D / A) 124, and a drive voltage corresponding to the video signal is applied to the light valves 105, 106, and 107 to modulate each pixel. .

[Configuration of integrated control unit]
FIG. 4 is a block diagram showing the configuration of the integrated control device 3.
The integrated control device 3 averages the γ characteristics based on the γ characteristic accumulation means 31 that accumulates the γ characteristics of the plurality of projectors 100 obtained by the measuring device 2 and the γ characteristic accumulation data accumulated in the γ characteristic accumulation means 31. Γ characteristic averaging means 32 for performing measurement, measurement point determining means 34 for determining a measurement point based on the averaged γ characteristic (average γ characteristic), and measurement based on the measurement point obtained by the measurement point determining means 34 Specified measurement point measurement means 35, γ characteristic calculation means 36 for calculating the γ characteristic of the projector by cubic curve interpolation from the measurement value measured by the specified measurement point measurement means 35 and the average γ characteristic, and γ characteristic calculation means 36 Γ correction data generating means 37 for generating γ correction data for correcting the γ characteristic of the projector 100 to a desired γ characteristic based on the γ characteristic obtained in the above.

[Adjustment method in image quality adjustment device]
Next, a method for measuring the γ characteristic of the projector 100 using the image quality adjustment apparatus 1 as described above and performing γ correction will be described with reference to the flowchart of FIG.
In the integrated control device 3 of the image quality adjustment device 1, when the image quality adjustment target projector 100 is set and execution of image quality adjustment processing is instructed by the input device 4 or the like, first, γ characteristic data is accumulated in the γ characteristic accumulation means 31. It is determined whether it has been performed (step S1).
Of course, the greater the number of stored data, the higher the accuracy. However, it is desirable that at least 10 or more gamma characteristic data is accumulated, and normally about 50 to 100 gamma characteristic data are accumulated. Preferably it is. In the present embodiment, the integrated control device 3 determines that the γ characteristic data is accumulated if 100 γ characteristic data is accumulated, and if 100 γ characteristic data is not accumulated. Therefore, it is determined that the γ characteristic data is not accumulated.

If it is determined in step S1 that the γ characteristic data is not accumulated, the integrated control device 3 performs precise measurement of the γ characteristic (step S2).
In step S <b> 2, the integrated control device 3 uses the measurement device 2 to measure the brightness (CIE XYZ) of the projector 100 with respect to each monochrome (RGB) red (green) drive voltage as a γ characteristic. The number of samplings at this time is precisely measured by measuring 30 points or more for each color.

The integrated control device 3 adds the γ characteristic precisely measured in step S2 to the γ characteristic accumulation data by the γ characteristic accumulation unit 31 (step S3). FIG. 6 is a graph showing the RED measured with 100 samples (projector 100) and the brightness with respect to the input gradation value as γ characteristics.
Therefore, when the image quality adjustment apparatus 1 executes the flowchart of FIG. 5, the first 100 units are determined as “No” in S1, and thus steps S2 and S3 are executed. As a result, a predetermined number (100 units) of γ characteristic data is stored in the γ characteristic storage means 31.

On the other hand, when it is determined in step S1 that the γ characteristic data is accumulated, the integrated control device 3 performs a γ characteristic averaging process (step S4).
In the γ characteristic average processing, the γ characteristic averaging means 32 calculates the average γ characteristic. The γ characteristic averaging means 32 uses the γ characteristic data for 100 units accumulated in the γ characteristic accumulating means 31, and calculates the average of each γ characteristic of RED, GREEN, and BLUE according to the following equations (4) to (6). A value (average γ characteristic) is obtained. That is, the γ characteristic averaging means 32 _obtains the average γ characteristic (X _RAi , Y _RAi , Z _RAi ) of RED by the equation (4), and the average γ characteristic (X _GAi , Y _GAi , _GRAEN ) of the GREEN by the equation (5). Z _GAi ) is obtained, and an average γ characteristic (X _BAi , Y _BAi , Z _BAi ) of BLUE is obtained by equation (6).
In the equations (4) to (6), the RED monochromatic measurement value at the input gradation value i is (X _{Rn_i} , Y _{Rn_i} , Z _{Rn_i} ), and the GREEN monochromatic measurement value is (X _{Gn_i} , Y _{Gn_i} , Z _{Gn_i} ) and BLUE monochromatic measurement values are ( _{XBn_i} , _{YBn_i} , _{ZBn_i} ). The input gradation value i is specifically a drive voltage gradation value input to each light valve 105, 106, 107, and is a 10-bit digital value in this embodiment. That is, “i = 0, 1, 2,..., 1021, 1022, 1023”.

FIG. 7 illustrates an average γ characteristic X _RAi of the X value of RED obtained by the equation (1). Similarly, average γ characteristics are also obtained for Y, Z values of RED, X, Y, Z values of GREEN, and X, Y, Z values of BLUE.

Next, the integrated control device 3 determines the measurement point by the measurement point determination unit 34 based on the average γ characteristic obtained by the γ characteristic averaging unit 32 (step S5). Specifically, the measurement point determination means 34 analyzes the average γ characteristic and sets several measurement points near the inflection point.
That is, as shown in FIG. 7, the average γ characteristic is a substantially S-shaped curve, and there are two inflection points. For this reason, the measurement point determination means 34 sets a total of four measurement points (input gradation values), two each before and after the inflection point.

In the example shown in FIG. 7, the input tone value i ₁ (= 470) at which the brightness is about “15”, the input tone value i ₂ (= 675) at which the brightness is “150”, and the brightness is “ An input tone value i ₃ (= 790) that is “600” and an input tone value i ₄ (= 900) that is “720” are set as measurement points.
In FIG. 7, the brightness when the input gradation value is the maximum (1023) is “750”. Therefore, when this brightness is 100%, the brightness “15” is the maximum brightness. 2%. Hereinafter, the brightness “150” is 20%, the brightness “600” is 80%, and the brightness “720” is 96%. In other words, in the present embodiment, the measurement point determination unit 34 sets the input gradation value at which the brightness is 2%, 20%, 80%, and 96% with respect to the maximum brightness as the measurement point.

As described above, based on the average γ characteristic of RED, four measurement points when the light valve 105 is controlled to measure the γ characteristic of a single red color are set.
Similarly, based on the average γ characteristic of GREEN, four measurement points when the light valve 106 is controlled to measure the γ characteristic of a single green color are set. Based on the average γ characteristic of BLUE, the light valve 107 is set. Is set to four measurement points when measuring the γ characteristic of a single blue color.

Next, the integrated control device 3 performs measurement processing by the designated measurement point measurement unit 35 based on the designated measurement point determined by the measurement point determination unit 34 (step S6). Specifically, the designated measurement point measurement unit 35 controls the transmittance of the light valve 105 by sequentially inputting the input gradation value of the measurement point after controlling so that a single red color is projected. The light beam projected from 100 is measured by the measuring device 2.
Similarly, the transmittance of the light valve 106 is sequentially controlled with four levels of input tone values, and the green monochromatic projection light is measured by the measuring device 2, and the transmittance of the light valve 107 is measured with four levels of input tone values. The measurement device 2 measures blue single color projection light by sequentially controlling.

Next, the integrated control device 3 calculates the γ characteristic from the average γ characteristic obtained by the γ characteristic averaging means 32 and the measured value obtained in step S6 by the γ characteristic calculating means 36 (step S6). S7).
As shown in FIG. 8, the γ characteristic calculating means 36 sets a graph 81 with the output value of the average γ characteristic as the horizontal axis and the vertical axis. Therefore, in this graph 81, the average γ characteristic is a linear line 82 passing through the origin.
Then, the γ characteristic calculation means 36 plots the measurement values obtained in step S6 on the graph 81 in FIG. At this time, the value on the vertical axis of each plot is the measurement value itself, but the value on the horizontal axis is an output value corresponding to the measurement input values i _{1 to} i ₄ in the average γ characteristic. For example, in the average γ characteristic, the output value corresponding to the measurement point (input gradation value) i ₁ = 470 is brightness “15”. Therefore, when the measurement value obtained at the measurement point i ₁ is plotted on the graph 81, the value on the horizontal axis is the brightness “15”. Similarly, the horizontal axis value of the measurement value at measurement point i ₂ is “150”, the horizontal axis value of the measurement value at measurement point i ₃ is “600”, and the horizontal axis value of the measurement value at measurement point i ₄ is “720”.

Next, the γ characteristic calculation means 36 obtains an interpolation function passing through the four plotted points. In this embodiment, cubic curve interpolation is used, and γ characteristics [RED (X _{RH — i} , Y _{RH — i} , Z _{RH — i} ), GREEN (X _{GH — i} , Y _{GH — i} , Z _{GH — i} ) are _obtained by the following equations (7) to (9). , BLUE (X _{BH — i} , Y _{BH — i} , Z _{BH — i} )].

Here, in the equations (7) to (9), each coefficient is obtained by solving simultaneous equations from the measured values when the gradation values are i = i ₁ , i ₂ , i ₃ , i ₄ . For example, the coefficients a _{RX_H} , b _{RX_H} , c _{RX_H} , and d _{RX_H} in the equation for _obtaining X _{RH — i} are _obtained by the following equation (10).

Similarly, the simultaneous equations are solved for the coefficients of RED _{YRH_i} , _{ZRH_i} , GREEN ( _{XGH_i} , _{YGH_i} , _{ZGH_i} ) and BLUE ( _{XBH_i} , _{YBH_i} , _{ZBH_i} ). By seeking.
FIG. 8 shows curves 83 to 87 showing the γ characteristics of the five projectors 100. These curves 83 to 87 are gentle curves substantially along the linear line 82, and an accurate interpolation function can be obtained even when the number of measurements is small compared to the complicated S-shaped curve as shown in FIG. it can.

Next, the γ characteristic calculating means 36 converts the value on the horizontal axis into the input gradation value in the graph 81 of FIG. 8, and shows the relationship between the input gradation value and the brightness as shown in FIG. 91 is determined.
That is, in the graph 81 of FIG. 8, since the horizontal axis is the brightness of the average γ characteristic, the input gradation value corresponding to each brightness is determined from the relationship between the input gradation value and the brightness in the average γ characteristic of FIG. For conversion. For example, when the brightness of the average γ characteristic is “600”, the input gradation value is “790” as described above. Therefore, the vertical axis value of the brightness of the average γ characteristic of FIG. The value of the vertical axis of the input gradation value “790” in FIG. When such conversion is performed, the curves 83 to 87 in FIG. 8 are converted into the curves 93 to 97 in FIG. 9. Therefore, even with a small number of measurement points, the γ characteristic of a complicated S-shaped curve as shown in FIG. 9 can be obtained with high accuracy.

  Next, the γ correction data generation unit 37 of the integrated control device 3 generates γ correction data based on the γ characteristic obtained in step S7 (step S8). That is, since the normal video signal is set based on the CRT characteristic in which the γ characteristic indicating the output value (brightness) with respect to the input value is γ = 2.2, the γ characteristic shown in FIG. It is necessary to correct so that γ = 2.2. For this reason, the γ correction data generating unit 37 converts the input gradation value based on the video signal into an input gradation value corresponding to each of the light valves 105 to 107 so that γ = 2.2. Γ correction data is generated by creating a table or the like. Since a specific method of generating γ correction data in the γ correction data generating unit 37 can use a known method described in Patent Documents 1 and 2, etc., description thereof is omitted.

Then, the γ correction data generation unit 37 stores the γ correction data (lookup table) obtained in step S8 in the correction value storage unit 123 of the projector 100 (step S9).
Thus, the image quality adjustment processing of the projector 100 is performed.

[Projection with projector]
When an image is displayed on the projector 100 in which image quality adjustment has been performed as described above, when an analog video signal is input from the outside, the light valve control circuit 120 is connected to the analog-digital conversion circuit 121 as described above. The analog video signal is converted into a digital signal, and the arithmetic processing unit 122 performs arithmetic processing using the γ correction data stored in the correction value storage unit 123. At this time, since the γ correction data is correction data according to the characteristics of the light valves 105, 106, and 107 of the projector 100, an appropriate drive voltage (input gradation) is obtained by the arithmetic processing by the arithmetic processing unit 122. Value). Then, after the arithmetic processing, a digital signal is converted into an analog signal by the digital-analog conversion circuit 124, and a driving voltage corresponding to the video signal is applied to the light valves 105, 106, and 107, so that an appropriate one according to the analog video signal is obtained. An image can be projected.

According to this embodiment, there are the following effects.
(1) An average γ characteristic is obtained based on the γ characteristic data of each projector 100 accumulated in the γ characteristic accumulating means 31 by the γ characteristic averaging means 32, and the output value of the average γ characteristic is obtained by the γ characteristic calculating means 36. A graph 81 having an axis and a vertical axis is set. Since the measured values measured by the designated measuring point measuring means 35 are plotted on the graph 81, the interpolation function that connects these plotted points, that is, the γ characteristic, has a complicated shape such as an S-shaped curve. In addition, since it can be approximated to an average γ characteristic that becomes a linear line, it can be easily and accurately obtained by cubic curve interpolation even if the number of measurements is small.
Therefore, the γ characteristic of the projector 100 can be acquired at high speed and with high accuracy, and the γ correction data generating means 37 can also generate γ correction data based on the γ characteristic at high speed and with high accuracy. Therefore, compared to the case where the gamma correction data is generated by performing many measurements for each projector 100, the image quality adjustment processing time for each projector 100 can be greatly shortened, the production efficiency can be improved, and the manufacturing cost can be increased. Can be reduced.

(2) Since the γ characteristic calculating means 36 obtains the γ characteristic by cubic curve interpolation, it can be obtained from four measurement data. For this reason, the number of times of measurement can be greatly reduced, and the image quality adjustment processing of the projector 100 can be performed in a short time.

(3) Since the γ characteristic storage means 31 stores γ characteristic data of 100 projectors 100, even if some projectors 100 having different characteristics from other projectors 100 are mixed, the average γ characteristic Can be the original average value. For this reason, when storing the γ characteristic data, it is not necessary to store the projector 100 while evaluating the individual projectors 100. Therefore, the data storage process can be easily performed. In other words, when the number of stored data is small, if there is data with significantly different characteristics, the average γ characteristic cannot be calculated appropriately due to the influence. Therefore, it is necessary to take measures such as evaluating the measurement values of the projector 100 and eliminating data having different characteristics. However, since this embodiment has a large number of samples, such measures can be eliminated.

(4) Since the measurement point determination means 34 determines the input value for measurement near the inflection point and actually measures it, the accuracy of the interpolation function, that is, the γ characteristic in the γ characteristic calculation means 36 can be improved.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in the above embodiment, the γ characteristic calculation means 36 calculates the γ characteristic by cubic curve interpolation, but may calculate it by other interpolation methods such as spline curve interpolation.

The number of γ characteristic data stored in the γ characteristic storing means 31 is not limited to 100. For example, it may be about 10-50 units, but it is preferable to store about 50-100 units.
Further, in the above-described embodiment, the first 100 projectors 100 are measured accurately, the data is stored in the γ characteristic storage means 31, and the γ characteristics calculation means 36 calculates the γ characteristics for the subsequent projectors 100. The calculated γ characteristic data is not stored in the γ characteristic storage means 31, but the γ characteristic data calculated by the γ characteristic calculation means 36 is stored in the γ characteristic storage means 31 to calculate the average γ characteristic. May be used. In this case, even if the number of projectors 100 to be precisely measured in the initial stage is reduced, the number of stored data can be increased as the image quality adjustment process is performed.

  The measurement points determined by the measurement point determination means 34 are not limited to those based on the inflection point of the average γ characteristic, but the advantage that the measurement accuracy can be improved by setting according to the inflection point as in the above embodiment. There is.

In the above embodiment, a three-plate liquid crystal projector having a liquid crystal light valve using a TFT element or the like is used as an image display device for image quality adjustment. However, the present invention is not limited to DMD (Direct Mirror Device) or LCOS (Liquid Crystal). It can also be applied to image quality adjustment in other projectors such as On Silicon.
Furthermore, it can be used not only for projectors but also for image quality adjustment of various image display devices such as liquid crystal flat panel displays, plasma displays, rear projection televisions and the like. In short, the present invention can be widely used for image quality adjustment of an image display device capable of emitting monochromatic light such as red, green, and blue.

1 is a block diagram illustrating a configuration of an image quality adjustment apparatus according to an embodiment. FIG. 2 is a schematic diagram showing a configuration of an optical system of a projector that is an image display device in the embodiment. The block diagram which shows the structure of the light valve control circuit of the projector in the said embodiment. The block diagram which shows the structure of the integrated control apparatus in the said embodiment. 5 is a flowchart showing an image quality adjustment process in the embodiment. The graph which shows the example of the gamma characteristic data in the said embodiment. The graph which shows the example of the average (gamma) characteristic in the said embodiment. The graph explaining the (gamma) characteristic calculation process in the said embodiment. The graph which shows the gamma characteristic calculated | required in the said embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image quality adjustment apparatus, 2 ... Measurement apparatus, 3 ... Integrated control apparatus, 31 ... Gamma characteristic accumulation means, 32 ... Gamma characteristic averaging means, 34 ... Measurement point determination means, 35 ... Designated measurement point measurement means, 36 ... Gamma Characteristic calculation means, 37... Γ correction data generation means, 100... Projector, 120... Light valve control circuit, 122.

Claims (9)

An image quality adjustment device for adjusting the image quality of an image display device capable of displaying a color image,
A light intensity measuring device that receives light projected from the image display device and measures the light intensity;
Γ that accumulates γ characteristic data representing the relationship between the input value for drive control of each image display device in a plurality of image display devices and the output value that is the light intensity of light projected from each image display device at that time Characteristic storage means;
Γ characteristic averaging means for obtaining an average γ characteristic from the γ characteristic data stored in the γ characteristic storage means;
Measurement point determining means for determining an input value for measurement based on the average γ characteristic;
The measurement input value is input to an image display device to be adjusted in image quality and controlled, and the designated measurement point measuring means for measuring the light intensity at that time by the light intensity measuring device;
In the graph in which the output value of the average γ characteristic is the horizontal axis and the vertical axis, the output value corresponding to the input value for measurement in the average γ characteristic is the value of the horizontal axis, and is measured by the designated measurement point measuring unit. Γ characteristic calculating means for plotting the measured value as a value on the vertical axis, calculating an γ characteristic of the image display device subject to image quality adjustment by obtaining an interpolation function connecting these plotted points,
Γ correction data generating means for generating γ correction data for correcting the γ characteristics of the image display device based on the γ characteristics obtained by the γ characteristic calculating means;
An image quality adjusting apparatus comprising: The image quality adjustment apparatus according to claim 1,
The γ characteristic calculating means includes
An image quality adjustment apparatus, wherein an interpolation function by cubic curve interpolation is obtained based on each point plotted on the graph, and a γ characteristic of the image display apparatus targeted for image quality adjustment is calculated. The image quality adjustment apparatus according to claim 1 or 2,
The image quality adjusting device, wherein the γ characteristic storage means measures γ characteristics of a predetermined number of image display devices in advance and stores the γ characteristic data. In the image quality adjustment device according to any one of claims 1 to 3,
The image quality adjusting apparatus, wherein the measurement point determining means determines an input value for measurement based on an inflection point in the average γ characteristic. The image quality adjustment apparatus according to any one of claims 1 to 4,
The image display device includes:
It is configured to be able to project red, green and blue monochromatic light,
The γ characteristic storage means stores γ characteristic data of m image display devices,
The γ characteristic averaging means uses the red monochromatic measurement value (X _{Rn_i} , Y _{Rn_i} , Z _{Rn_i} ) and the green monochromatic measurement value (X _{Gn_i} , Y _{Gn_i} , Z _{Gn_i} ), and the blue single color measurement value is (X _{Bn_i} , Y _{Bn_i} , Z _{Bn_i} ), the average γ characteristic is obtained by equations (1) to (3) for each color of red, green, and blue. Image quality adjustment device.

In the image quality adjustment apparatus according to any one of claims 1 to 5,
The image display device includes a light source, a light modulation device that modulates a light beam emitted from the light source based on image information, and a projection optical device that projects the light beam modulated by the light modulation device. An image quality adjusting device characterized by that. An image quality adjustment method for adjusting the image quality of an image display device capable of displaying a color image,
Γ that accumulates γ characteristic data representing the relationship between the input value for drive control of each image display device in a plurality of image display devices and the output value that is the light intensity of light projected from each image display device at that time A characteristic accumulation process;
Γ characteristic averaging step for obtaining an average γ characteristic from the γ characteristic data accumulated in the γ characteristic accumulation step;
A measurement point determination step for determining an input value for measurement based on the average γ characteristic;
A designated measurement point measuring step for controlling the input value for measurement to be input to an image display device subject to image quality adjustment and measuring the light intensity at that time, and
In the graph in which the output value of the average γ characteristic is the horizontal axis and the vertical axis, the output value corresponding to the input value for measurement in the average γ characteristic is the value of the horizontal axis, and measured in the designated measurement point measurement step. Γ characteristic calculation step of plotting the measured value as the value of the vertical axis and calculating the γ characteristic of the image display device subject to image quality adjustment by obtaining an interpolation function connecting these plotted points;
Γ correction data generation step for generating γ correction data for correcting the γ characteristic of the image display device based on the γ characteristic obtained by the γ characteristic calculation step;
An image quality adjustment method comprising: An image display device capable of displaying a color image,
A correction value storage unit for storing γ correction data generated by the γ correction data generation means of the image quality adjustment device according to claim 1;
An image display device comprising: an arithmetic processing unit that corrects a video signal using γ correction data stored in the correction value storage unit. A projector comprising: a light source; a light modulation device that modulates a light beam emitted from the light source based on image information; and a projection optical device that projects the light beam modulated by the light modulation device,
The light modulation device comprises:
A correction value storage unit for storing γ correction data generated by the γ correction data generation means of the image quality adjustment device according to claim 1;
A projector comprising: an arithmetic processing unit that corrects a video signal using γ correction data stored in the correction value storage unit.

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