JP2011150110A - Image processor, image display system, image processing method, and method for generating unevenness correction value - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor capable of correctly performing unevenness correction for stack images, and to provide an image display system, an image processing method, and a method for generating unevenness correction value or the like. <P>SOLUTION: The image processor for correcting unevenness of the stack images generated by using a plurality of image forming parts includes: a storing part for storing an unevenness correction value generated on the basis of a ratio of a color characteristic value of each image composing the stack images; and a processing part for performing unevenness correction processing of image signals corresponding to each image forming part by using the unevenness correction value stored to the unevenness correction value storing part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an image processing apparatus, an image display system, an image processing method, an unevenness correction value generation method, and the like.

Display technology using multiple projectors (image projection devices), a type of image display device (
Hereinafter, “stack display technology”) is known as a technology for achieving high resolution and high resolution by shifting pixels. For example, a high-luminance image can be displayed by superimposing images projected from a plurality of projectors so that the positions of the respective pixels coincide. In addition, by displaying images projected from a plurality of projectors so that the position of each pixel is shifted by a predetermined amount of less than one pixel (for example, 0.5 pixels in the horizontal direction and the vertical direction), it is simulated. A high-resolution image can be displayed. Hereinafter, an image displayed by the stack display technique is referred to as a “stack image”. This stack image also has unevenness (color unevenness, brightness unevenness) depending on device characteristics such as a light source, a light valve, and a lens constituting each projector, and is generally corrected for each projector. Stack display may be performed using a plurality of projectors in which unevenness correction has been performed for each projector in this way, but various techniques for performing more efficient unevenness correction have been proposed.

For example, Patent Document 1 does not correct color unevenness for each projector, but uses a light source color (R
A technique is disclosed in which the intensity profile summed up for each GB) is calculated and color unevenness correction is performed so as to be uniform in a stacked state in which a stack image is displayed. According to the technique disclosed in Patent Document 1, it is not necessary to reduce the color unevenness for each projector, and it is only necessary to reduce the color unevenness of the stack image even if the individual is not uniform.

Further, for example, Patent Literature 2 discloses a technique for easily obtaining correction data for color unevenness based on input / output characteristics of a projector.

JP 2005-352171 A JP 2001-209358 A

However, in Patent Document 1, the unevenness correction target value in the stack state is obtained after obtaining the sum of the profiles (unevenness distribution) of each projector for each light source color (see paragraph 0214 of Patent Document 1). Then, from the first projector among the n projectors (
n-1) The unevenness correction of the stack image is realized by performing correction with the nth projector while making use of the original characteristics up to the first projector. For this reason, there is a possibility that the correction amount of the n-th projector may be remarkably large. In this case, correction must be performed with a correction amount that is a negative value, and correction cannot be performed correctly. Also,
Patent Document 2 merely discloses a technique for generating unevenness correction data.
Therefore, the techniques disclosed in Patent Literature 1 and Patent Literature 2 have a problem in that unevenness correction cannot be performed correctly on a stack image.

The present invention has been made in view of the above technical problems. According to some aspects of the present invention, it is possible to provide an image processing apparatus, an image display system, an image processing method, an unevenness correction value generation method, and the like that can correctly perform unevenness correction on a stack image.

(1) According to one aspect of the present invention, an image processing apparatus that corrects unevenness of a stack image generated using a plurality of image forming units generates based on a ratio of color characteristic values of the images constituting the stack image. A non-uniformity correction value storage unit that stores the non-uniformity correction value, and a non-uniformity correction processing unit that performs non-uniformity correction processing of an image signal corresponding to each image forming unit using the non-uniformity correction value stored in the non-uniformity correction value storage unit. Including.

In this aspect, the unevenness correction value generated based on the ratio of the color characteristic values of the images constituting the stack image generated using the plurality of images formed by the plurality of image forming units is stored, and the unevenness is stored. Using the correction value, unevenness correction processing of the image signal corresponding to each image forming unit is performed. As a result, it is possible to avoid a situation in which the unevenness correction amount becomes large in one image forming unit and the uneven correction cannot be performed correctly, and the unevenness correction amount for each image forming unit can be balanced and correct unevenness correction can be performed. It becomes like this.

(2) In the image processing apparatus according to another aspect of the present invention, the unevenness correction value is obtained by distributing the unevenness correction amount of the stack image to the image forming units in accordance with a ratio of the color characteristic values of the images. Corresponds to the correction amount.

According to this aspect, for example, when the level of the in-plane intensity distribution of one image forming unit is extremely lower than the level of the in-plane intensity distribution of the other image forming unit, the unevenness correction amount is set to be less than that of the other image forming unit. You can make it smaller. As a result, even when the level of the in-plane intensity distribution varies, the unevenness correction can be correctly performed in all the image forming units.

(3) In the image processing apparatus according to another aspect of the present invention, the unevenness correction value is a color characteristic value of each image based on a color characteristic value for a black solid image formed by each image forming unit. Based on the ratio of

According to this aspect, in addition to the above effect, it is possible to prevent black float. Further, the processing can be simplified by uniformly using the color characteristic value for the solid black image for all gradations.

  (4) In the image processing apparatus according to another aspect of the present invention, the color characteristic value is a tristimulus value.

According to this aspect, in addition to the above effects, unevenness correction can be performed using the unevenness correction value based on the ratio of color characteristic values that match human visual characteristics. Unevenness correction is possible.

(5) An image processing apparatus according to another aspect of the present invention includes a gamma correction value storage unit that stores a gamma correction value corresponding to the unevenness correction value stored in the unevenness correction value storage unit, and the gamma correction value. A gamma correction unit that corrects an image signal using the gamma correction value stored in the storage unit, and the unevenness correction processing unit performs the unevenness correction process on the image signal corrected by the gamma correction unit. I do.

According to this aspect, an image subjected to desired gamma correction in addition to the above effect by correcting the image signal using the gamma correction value corresponding to the unevenness correction without changing the chromaticity due to the unevenness correction. It will be possible to contribute to the display of.

(6) The image processing apparatus according to another aspect of the present invention distributes the unevenness correction target value of the stack image according to the ratio of the color characteristic values of the images, thereby corresponding to the unevenness corresponding to the image forming units. The unevenness correction target value calculation unit for calculating the correction target value and the unevenness correction target value corresponding to each image forming unit calculated by the unevenness correction target value calculation unit, the unevenness corresponding to each image forming unit. A nonuniformity correction value generation unit that generates a correction value, and the nonuniformity correction value storage unit stores the nonuniformity correction value generated by the nonuniformity correction value generation unit.

According to this aspect, the unevenness correction target value corresponding to each image forming unit is calculated by distributing the unevenness correction target value of the stack image according to the ratio of the color characteristic values of the images constituting the stack image. Since the unevenness correction value corresponding to each image forming unit is generated using the unevenness correction target value, the unevenness correction amount for each image forming unit can be balanced and correct unevenness correction can be performed. The unevenness correction value can be easily generated.

(7) According to another aspect of the present invention, an image display system corresponds to each of the plurality of image forming units that displays the stack image using an image formed by each image forming unit, and each of the image forming units. The image processing apparatus according to any one of the above, which performs unevenness correction processing of an image signal and supplies the image signal after the unevenness correction processing to each of the image forming units.

According to this aspect, it is possible to provide an image display system to which an image processing apparatus that can correctly perform uneven correction on a stack image is applied.

(8) According to another aspect of the present invention, there is provided an image processing method for correcting unevenness of a stack image generated using a plurality of image forming units based on a ratio of color characteristic values of respective images constituting the stack image. Using the generated unevenness correction value, the unevenness correction processing step of performing unevenness correction processing of the image signal corresponding to each image forming unit, and the image signal after the unevenness correction processing performed in the unevenness correction processing step, Supplied to the image forming unit.

According to this aspect, using the unevenness correction value generated based on the ratio of the color characteristic values of the images constituting the stack image generated using the plurality of images formed by the plurality of image forming units,
Since the unevenness correction processing of the image signal corresponding to each image forming unit is performed, it is possible to avoid a situation where the unevenness correction amount becomes large in one image forming unit and correct unevenness correction cannot be performed. The unevenness correction amount can be balanced and correct unevenness correction can be performed.

(9) An image processing method according to another aspect of the present invention includes a gamma correction step of correcting an image signal using a gamma correction value corresponding to the unevenness correction value stored in the unevenness correction value storage unit, The unevenness correction processing step performs the unevenness correction processing on the image signal corrected in the gamma correction step.

According to this aspect, since the gamma correction is performed using the gamma correction value corresponding to the unevenness correction value, the chromaticity is not changed by the unevenness correction, and the display of the image subjected to the desired gamma correction is performed. You can contribute.

(10) In the image processing method according to another aspect of the present invention, the unevenness correction processing step configures the stack image based on a color characteristic value for a black solid image formed by each image forming unit. Using the unevenness correction value generated based on the ratio of the color characteristic values of each image, the unevenness correction processing of the image signal corresponding to each image forming unit is performed.

According to this aspect, in addition to the above effect, it is possible to prevent black float. Further, the processing can be simplified by uniformly using the color characteristic value for the solid black image for all gradations.

(11) According to another aspect of the present invention, an unevenness correction value generation method for generating unevenness correction values for correcting unevenness in a stack image generated using a plurality of image forming units includes each image constituting the stack image. The unevenness correction target value calculation step of calculating the unevenness correction target value corresponding to each image forming unit by distributing the unevenness correction target value of the stack image according to the ratio of the color characteristic values of the image, and the unevenness correction target value calculation And a non-uniformity correction value generating step of generating non-uniformity correction values corresponding to the image forming units based on the non-uniformity correction target values corresponding to the image forming units calculated in the step.

According to this aspect, the unevenness correction target value corresponding to each image forming unit is calculated by distributing the unevenness correction target value of the stack image according to the ratio of the color characteristic values of the images constituting the stack image. Since the unevenness correction value corresponding to each image forming unit is generated using the unevenness correction target value, the unevenness correction amount for each image forming unit can be balanced and correct unevenness correction can be performed. The unevenness correction value can be easily generated.

(12) The unevenness correction value generation method according to another aspect of the present invention includes a reference measurement value acquisition step of acquiring a color characteristic value of a black solid image formed by each image forming unit, and the unevenness correction target In the value calculation step, the unevenness correction target value is calculated based on a ratio of the color characteristic values of the images with reference to the color characteristic value of the solid image acquired in the reference measurement value acquisition step.

According to this aspect, in addition to the above effects, it is possible to contribute to the generation of uneven correction values for preventing black float.

(13) In the unevenness correction value generation method according to another aspect of the present invention, the measurement value is a tristimulus value.

According to this aspect, in addition to the above-described effects, it contributes to the unevenness correction using the unevenness correction value based on the ratio of the color characteristic values that match the human visual characteristic, and the correct unevenness correction value that matches the human vision is obtained. Can be generated.

1 is a block diagram of a configuration example of an image display system according to an embodiment of the present invention. FIG. 2 is a block diagram of a configuration example of the image processing apparatus in FIG. 1. The flowchart of the example of a process of an image processing apparatus. FIG. 4 is a flowchart of a processing example of unevenness measurement processing in step S2 of FIG. 3. FIG. 4 is a flowchart of a processing example of unevenness correction target value calculation processing in step S3 of FIG. 3. Operation | movement explanatory drawing of a nonuniformity correction target value calculation part. FIGS. 7A and 7B are diagrams showing examples of the white intensity distribution of the first image display device and the white intensity distribution of the second image display device. 8A and 8B are diagrams illustrating examples of uneven correction target values of the image display apparatuses with respect to the intensity distributions of FIGS. 7A and 7B. 9A and 9B are diagrams showing examples of uneven correction target values of each image display device with respect to the intensity distributions of FIGS. 7A and 7B according to the prior art. FIG. 4 is a flowchart of a processing example of unevenness correction LUT generation processing in step S4 of FIG. 3. Explanatory drawing of VT characteristic. 12A, 12B, and 12C are tristimulus obtained by measuring a projection image by the first image display device at the pixel position (i, j) before and after correction. The figure which shows an example of a value. FIGS. 13A, 13B, and 13C are diagrams showing examples of RGB values before and after correction at a pixel position (i, j) after conversion. FIG. 4 is a flowchart of a processing example of a VT characteristic measurement process in step S6 of FIG. 3. FIG. 4 is a flowchart of a processing example of a gamma correction LUT generation process in step S7 of FIG. 3. FIG. 7 is an operation explanatory diagram of the unevenness correction processing unit in which the vicinity of black in FIG. 6 is enlarged. 17A and 17B are diagrams illustrating an unevenness correction process for the intensity near black in FIG. FIG. 9 is a block diagram of a configuration example of an image display system according to a third embodiment. FIG. 2 is a diagram illustrating a configuration example of a first image forming unit in FIG. 1.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, all of the configurations described below are not necessarily indispensable configuration requirements for solving the problems of the present invention.

In the embodiment described below, an example in which a stack image is displayed using two image display devices will be described, but the present invention can also be applied to a case where a stack image is displayed using three or more image display devices.

1. Embodiment 1
FIG. 1 shows a block diagram of a configuration example of an image display system according to an embodiment of the present invention.

The image display system 10 displays a stack image generated by superimposing a plurality of projection images from a plurality of image display devices on the screen SCR. The image display system 10 includes a first image display device (projector in a narrow sense) PJ1, a second image display device PJ2, an image processing device 100, an image signal supply device 200, an unevenness measurement device 300,
A chromaticity measuring apparatus 400.

The first image display device PJ1 includes a first image forming unit (not shown), and the image processing device 1
An image formed by the first image forming unit based on the image signal from 00 is displayed on the screen SCR.
Project to. More specifically, the first image display device PJ1 includes a light source, a light valve configured using a transmissive liquid crystal panel, and a projection lens, and is based on an image signal from the image processing device 100. The light from the light source is modulated for each color component by the light valve, and the modulated light is projected onto the screen SCR by the projection lens. Similarly, the second image display device PJ2 includes a second image forming unit (not shown), and the second image display device PJ2 is based on the image signal from the image processing device 100.
The image formed by the image forming unit is projected onto the screen SCR. At this time, each image display device is installed so that the image projected by the second image display device PJ2 overlaps the image projected by the first image display device PJ2 on the screen SCR. The configuration of the second image display device PJ2 is the same as the configuration of the first image display device PJ1.

The image processing device 100 performs unevenness correction processing corresponding to each image display device on the input image signal supplied from the image signal supply device 200, and outputs the image signal after the unevenness correction processing to each image display device.

The image signal supply device 200 is configured by a DVD (Digital Versatile Disc) device, a personal computer (PC), or the like.
To 00. In addition, the image signal supply device 200 performs RGB at the time of unevenness measurement described later.
The tone value of each color component is equal to gray, or only the tone value of one color component of RGB is included (
The image signal corresponding to the solid image of the RGB color is output to the image processing apparatus 1.
00 can be supplied. Furthermore, the image signal supply device 200 can supply the image processing device 100 with an image signal corresponding to a gray solid image (gray image) in VT characteristic measurement described later.

The unevenness measuring apparatus 300 is a two-dimensional image sensor such as a CCD (Charge Coupled Device) sensor, and is installed so that an image projected on the screen SCR can be measured. The unevenness measuring apparatus 300 uses a screen SC by each image display device during unevenness measurement.
A gray image displayed on R and a solid image including a halftone of 0% to 100% of RGB are taken. Then, the unevenness measuring apparatus 300 acquires in-plane distribution (intensity distribution) information of the XYZ tristimulus values of the CIE 1931 color system as color characteristic values. As such an unevenness measuring apparatus 300, an image is obtained using a filter having a spectral sensitivity approximating xyz color matching function, and an XYZ tristimulus value is obtained by matrix correction calculation (for example, Prof of Radiant Imaging)
Metric etc.). The in-plane distribution information acquired by the unevenness measuring device 300 for each image display device in this way is sent to the image processing device 100 as a color characteristic value (intensity distribution of luminance and chromaticity) that is an unevenness measured value. Note that the measurement process performed by the unevenness measuring apparatus 300 may be performed under the control of the image processing apparatus 100.

Here, one of the advantages of the first embodiment will be described in comparison with Patent Document 1. In Patent Document 1, the maximum brightness of white that can be achieved evenly is obtained for each light source color from the measurement values for each RGB light source by a light intensity distribution measuring means such as a light detection device for an image displayed by one projector. (Paragraphs 0131 to 0136 of Patent Document 1), comparing the light source colors with each other (
Paragraphs 0137 to 0141) of Patent Document 1 define the final white target luminance. And
This is extended to a plurality of projectors, and the maximum white brightness that can be achieved uniformly is obtained for each of the stacked light sources and is compared between the light source colors (RGB) (paragraph 021 of Patent Document 1).
4) The target brightness of white in the final stack state is defined.

However, Patent Document 1 assumes that the characteristics of the light source color are approximately the same among a plurality of projectors (paragraph 0033 of Patent Document 1). Here, even if the Rs are the same, if the spectral characteristics differ greatly between the projectors, it is meaningless to add Rs. For example, there is R of another projector between the G and R wavelengths of one projector, one projector is a laser light source, and the other projector is UHP (Ultra High Per
For example, it is meaningless to add R together. As described above, when the wavelength sensitivity characteristic of the light detection device or the like is greatly different from the human visual characteristic (color matching function), the output of the light detection device or the like is originally different from that of human vision. Therefore, when considering a stack of projectors having significantly different spectral sensitivities, a sensor that conforms to human visual characteristics (based on a color matching function) is used as shown in FIG. 1 rather than obtaining an uneven distribution for each light source color (RGB). It is desirable to directly measure the in-plane distribution of XYZ tristimulus values.

In FIG. 1, a chromaticity measuring device 400 is a colorimeter, and is installed so as to measure the central portion of an image projected on a screen SCR. The chromaticity measuring apparatus 400 acquires a chromaticity measurement value for generating a new gamma correction value in order to increase the accuracy of gamma correction that may be slightly shifted as a result of the unevenness correction processing. The chromaticity measuring device 400 measures, for example, a gray image displayed on the screen by each image display device at the time of measurement. As such a chromaticity measuring apparatus 400, a spectral color luminance meter (for example, PR-705 of Photo Research) or a color illuminance meter (for example, of Konica Minolta Co., Ltd.) using an XYZ filter and a photocell is used. There are point measuring colorimeters such as CL-200). Thus, the XY acquired by the chromaticity measuring device 400 for each image display device
The Z tristimulus values are sent to the image processing apparatus 100 as chromaticity measurement values. This chromaticity measuring device 40
The measurement by 0 is performed on the image after the unevenness correction process reflecting the measurement result by the unevenness measuring apparatus 300. Note that the measurement processing by the chromaticity measuring apparatus 400 may be performed by control by the image processing apparatus 100.

The image processing apparatus 100 forms the unevenness correction amount of the stack image in each image display device according to the ratio of the color characteristic values (unevenness measurement value, intensity distribution) of each image display device acquired by the unevenness measurement device 300. Distributes the amount of uneven image correction. More specifically, the image processing apparatus 10
For 0, the unevenness correction target value of each image processing apparatus is obtained according to the ratio of the unevenness measurement values, and the unevenness correction value corresponding to the unevenness correction target value is obtained for each image display device. Here, as the color characteristic value, in addition to the tristimulus value, for example, a physical quantity obtained by measuring an image such as a psychophysical quantity, a light intensity, an image measurement value, and a color measurement value may be employed.

In this way, the image processing apparatus 100 performs unevenness correction processing for each image display apparatus on the input image signal from the image signal supply apparatus 200 using the unevenness correction value corresponding to the correction amount distributed for each image display apparatus. The image signal after the unevenness correction processing is supplied to each image display device. At this time, the image processing apparatus 100 performs gamma correction that reflects the result measured by the chromaticity measuring apparatus 400 on the image after the unevenness correction process, thereby responding to a change in chromaticity due to the unevenness correction process. Images can be displayed. Such an image processing apparatus 100 has a central processing unit (hereinafter referred to as CPU) and a memory (not shown), and a CPU that reads a program stored in the memory executes processing corresponding to the program. By doing so, the above-described unevenness correction processing can be realized. Alternatively, the function of the image processing apparatus 100 may be realized by a logic circuit such as an ASIC (Application Specific Integrated Circuit).

In FIG. 1, the image display system 10 may have a configuration in which at least one of these is omitted. In FIG. 1, the function of the image processing apparatus 100 may be incorporated in one of the first image display apparatus PJ1 and the second image display apparatus PJ2.

[Image processing device]
FIG. 2 is a block diagram showing a configuration example of the image processing apparatus 100 shown in FIG. 2 shows an image signal supply device 200, an unevenness measurement device 300, a chromaticity measurement device 400, in addition to the image processing device 100.
The first image display device PJ1 and the second image display device PJ2 are shown together. In FIG. 2, the same parts as those in FIG.

The image processing apparatus 100 includes a non-uniformity correction look-up table (hereinafter referred to as LU).
T) A storage unit (unevenness correction value storage unit in a broad sense) 110 and an unevenness correction processing unit 120 are included.
Further, the image processing apparatus 100 can include an image correction unit 130, a gamma correction LUT storage unit (gamma correction value storage unit) 140, and a gamma correction unit 150.

The image correction unit 130 performs known contrast correction or the like for desired gradation reproduction or color reproduction on the input image signal from the image signal supply apparatus 200. Gamma correction LUT storage unit 1
Reference numeral 40 stores a gamma correction LUT in which gamma correction values for performing gamma correction are tabulated. The gamma correction unit 150 refers to the gamma correction LUT stored in the gamma correction LUT storage unit 140, and applies gamma correction (corresponding to the VT characteristic of each image display device) to the image signal corrected by the image correction unit 130. Perform gamma 2.2).

The unevenness correction LUT storage unit 110 stores, for each image display device, an unevenness correction LUT in which unevenness correction values generated for each image display device (more specifically, an image forming unit included in the image display device) are tabulated. . The unevenness correction value stored in the unevenness correction LUT storage unit 110 is the unevenness correction amount of the stack image generated by the first image display device PJ1 and the second image display device PJ2, and each image constituting the stack image. This corresponds to the correction amount distributed to each image display device in accordance with the ratio of the color specific values (unevenness measurement values). The unevenness correction processing unit 120 uses the unevenness correction value corresponding to each image display device stored in the unevenness correction LUT storage unit 110 to use the gamma correction unit 1.
The image signal unevenness correction processing corresponding to each image display device after the gamma correction by 50 is performed.

The unevenness correction LUT is a correction value corresponding to the correction amount (ΔKRij, ΔKGij, ΔKBij) of the gradation value Kij (for example, gray gradation value) at the pixel position (i, j) in the image, for example.
This is prepared for each pixel position and for each gradation value. At this time, the unevenness correction processing unit 120 for the pixel value (Rij, Gij, Bij) at the pixel position (i, j) of the input image signal.
The pixel values (Rij ′, Gij ′, Bij ′) of the image signal after correction by are as follows.
Rij ′ = Rij + ΔKRij (1)
Gij ′ = Gij + ΔKGij (2)
Bij ′ = Bij + ΔKBij (3)

As described above, the unevenness correction processing unit 120 refers to the unevenness correction LUT according to the in-plane position and gradation of the image based on the input image signal from the image signal supply device 200, and corresponds to each image display device. Unevenness correction processing is performed. At this time, the unevenness correction processing unit 120 performs unevenness correction processing by interpolating between lattice points of the correction LUT by known linear interpolation or the like.

The image signal after the unevenness correction processing corresponding to the first image display device PJ1 by the unevenness correction processing unit 120 is output to the first image display device PJ1 (more specifically, the first image forming unit). . The image signal after the unevenness correction processing corresponding to the second image display device PJ2 by the unevenness correction processing unit 120 is output to the second image display device PJ2 (more specifically, the second image forming unit). .

The unevenness correction value stored in the unevenness correction LUT storage unit 110 may be generated in the image processing apparatus 100. In this case, the image processing apparatus 100 further includes the unevenness correction target value calculation unit 1.
60 and an unevenness correction LUT generation unit (in a broad sense, an unevenness correction value generation unit) 170 can be included. The unevenness correction target value calculation unit 160 distributes the unevenness correction target value of the stack image according to the ratio of the color characteristic values of the images by the image display devices measured by the unevenness measurement device 300 (ratio of the intensity distribution of each image). Thus, the unevenness correction target value corresponding to each image display device is calculated. The unevenness correction unevenness correction LUT generation unit 170 generates an unevenness correction value corresponding to each image display device based on the unevenness correction target value corresponding to each image display device calculated by the unevenness correction target value calculation unit 160. The unevenness correction values generated by the unevenness correction LUT generation unit 170 are tabulated and stored in the unevenness correction LUT storage unit 110 for each image display device.

In addition, when the chromaticity changes due to the unevenness correction, it is desirable to readjust the gamma correction. In this case, the image processing apparatus 100 further includes a gamma correction LUT generation unit 180.
And a gamma correction LU based on the chromaticity measurement value acquired by the chromaticity measurement apparatus 400
The T generation unit 180 obtains a gamma correction value for each image display device, and generates a gamma correction LUT in which the gamma correction values are tabulated. The gamma correction LUT storage unit 140 includes a gamma correction LU.
The gamma correction LUT generated by the T generation unit 180 is stored.

[Example of processing]
FIG. 3 shows a flowchart of a processing example of the image processing apparatus 100. When the image processing apparatus 100 implements the processing of FIG. 3 by software processing, a program for realizing the following processing is stored in a memory built in the image processing apparatus 100, and a CPU that reads the program corresponds to the program. Execute the process.
FIG. 4 shows a flowchart of a processing example of the unevenness measurement processing in step S2 of FIG. When the image processing apparatus 100 implements the processing of FIG. 4 by software processing, a program for realizing the following processing is stored in a memory built in the image processing apparatus 100, and a CPU that reads the program corresponds to the program. Execute the process.

The image processing apparatus 100 measures the original characteristics of each image display apparatus, so that the image correction unit 13
0, the operations of the gamma correction unit 150 and the unevenness correction processing unit 120 are stopped (step S1).
Thereby, in the image processing apparatus 100, the image correction performed in the image correction unit 130, the gamma correction performed in the gamma correction unit 150, and the unevenness correction performed in the unevenness measurement processing unit 120 are stopped. Next, the image processing apparatus 100 controls the unevenness measuring apparatus 300 to acquire the in-plane intensity distribution, which is a measurement result of the unevenness measuring apparatus 300, as an unevenness measurement value (color characteristic value) for each image display apparatus (step S2). ).

In step S2, first, for each image display device, one of the full images of the gray and RGB color gradations on the entire screen is projected onto the screen SCR (step S21). In this state,
The image processing apparatus 100 performs control to measure the in-plane intensity distribution by the unevenness measuring apparatus 300,
Obtained as an uneven measurement value (step S22). After that, when all measurements are not completed (
In step S23: N), the image processing apparatus 100 returns to step S21 to project the next solid image onto the screen SCR. In this way, when the unevenness measurement value is acquired for each of the full-screen images of gray and RGB color gradations (step S23: Y), the image processing apparatus 100 ends the process of step S2.

Subsequently, in the unevenness correction target value calculation unit 160, the image processing apparatus 100 performs step S2.
After calculating the unevenness correction target value (XYZ target value) in the stack state for each gradation from the unevenness measurement value of each gradation obtained for each image display device, the unevenness correction target value (target XYZ) for each image display device
Value) is calculated (step S3). Then, in the unevenness correction LUT generation unit 170, the image processing apparatus 100 generates an unevenness correction LUT for each image display device based on the unevenness measurement value and the unevenness correction target value (target XYZ value) for each image display device ( Step S4). Here, the input RGB value for outputting the unevenness correction target value is obtained by searching the VT characteristic of each image display device.

Next, the image processing apparatus 100 performs processing for recreating the gamma correction LUT. That is, the image processing apparatus 100 starts the operation of the unevenness correction processing unit 120 (step S5). Thereby, in the image processing apparatus 100, the unevenness correction performed in the unevenness measurement processing unit 120 is started, and the generation process of the gamma correction LUT is performed using the unevenness correction LUT generated in step S4. For example, the image processing apparatus 100 controls the chromaticity measuring apparatus 400 to acquire a chromaticity measurement value that is a measurement result of the VT characteristic of each image display apparatus in a state where unevenness correction is operating (step S6). As a result, gamma correction corresponding to the chromaticity changed by the unevenness correction process can be performed. In step S6, a smooth gradation can be obtained in the gamma correction by measuring the VT characteristic with a number of measurement gradations (for example, about twice) that is larger than the number of uneven measurement gradations. .

Subsequent to step S6, the image processing apparatus 100 obtains an input RGB value for outputting a target gamma characteristic or chromaticity by searching the VT characteristic of each image display device in the gamma correction LUT generation unit 180. Then, a gamma correction LUT is generated (step S7).

Finally, the image processing apparatus 100 starts the operations of the image correction unit 130 and the gamma correction unit 150 (step S8), and ends a series of processing (end). As a result, the image processing apparatus 1
In 00, image correction performed in the image correction unit 130, gamma correction performed in the gamma correction unit 150, and unevenness correction performed in the unevenness measurement processing unit 120 are performed.

[Unevenness correction target value calculation processing]
FIG. 5 shows a flowchart of a processing example of the unevenness correction target value calculation processing in step S3 of FIG. When the image processing apparatus 100 implements the processing of FIG. 5 by software processing, the image processing apparatus 1
A program for realizing the following processing is stored in a memory built in 00, and a CPU that reads the program executes processing corresponding to the program.

In the unevenness correction target value calculation process performed in the unevenness correction target value calculation unit 160, the unevenness correction target value is obtained by adding the first image display device PJ1 and the second image display device PJ2 for each of the XYZ tristimulus values. Is calculated. In the following, any one of the XYZ tristimulus values, which are unevenness measurement values acquired in the first image display device PJ1, is set to P1, and the second image display device PJ.
Any of the XYZ tristimulus values which are the unevenness measurement values acquired in 2 is defined as P2. “P” such as P1, P2 or Ptarget described later indicates one of X, Y, and Z of the XYZ tristimulus values.

The unevenness correction target value calculation unit 160 performs the first image display device PJ for each gradation from black to white.
The XYZ tristimulus values, which are unevenness measurement values acquired in step S2 for one image, and the XYZ tristimulus values, which are unevenness measurement values acquired in step S2 for the image of the second image display device PJ2. Add together (step S31).

Next, the unevenness correction target value calculation unit 160 calculates the unevenness correction target value in the stacked state (
Step S32). Here, since the white unevenness correction has to be corrected in the direction of decreasing the brightness, the correction is performed based on the lowest intensity in the intensity distribution in the image. On the other hand, black unevenness correction
Since correction must be made in the direction of increasing brightness, correction is performed based on the maximum intensity in the intensity distribution in the image. For the halftone, the unevenness correction target value calculation unit 160 corrects, for example, as follows.

FIG. 6 is an operation explanatory diagram of the unevenness correction target value calculation unit 160. In FIG. 6, the horizontal axis represents gradation, and the vertical axis represents intensity (stimulus values X, Y, or Z).

For example, the intensities (stimulus values) before correction at the center of white, halftone, and black in the stacked state are Pw, P, and Pk, respectively, and white and black unevenness correction target values Pwt and Pkt in the stacked state Then, the halftone unevenness correction target value Pt in the stacked state can be obtained from the following equation.
(Pw−P) :( P−Pk) = (Pwt−Pt) :( Pt−Pkt) (4)

By setting the unevenness correction target value according to the equation (4), the unevenness correction can be performed in all gradations from black to white, although the contrast is lowered.

  Hereinafter, white will be described, but the same applies to other gradations.

FIGS. 7A and 7B show an example of the white intensity distribution of the first image display device PJ1 and the white intensity distribution of the second image display device PJ2. 7A and 7B express one-dimensionally the white intensity distribution characteristic of each image display device using the pixel position x as a parameter. The intensity distribution of the first image display device PJ1 is shown in FIG. P1 (x), the intensity distribution of the second image display device PJ2 is P2
(X). 7A shows a case where the difference in intensity distribution between the images of the first image display device PJ1 and the second image display device PJ2 is within a predetermined range, and FIG. 7B shows the first image display device PJ1. This represents a case where the difference in intensity distribution between the images of the image display device PJ1 and the second image display device PJ2 is extremely large.

The unevenness correction target value in the stacked state is Ptarget (x), and the first image display device PJ1.
The nonuniformity correction target value is P1target (x), and the nonuniformity correction target value of the second image display device PJ2 is P2target (x). P1target (x) is Ptarget (x)
And P1 (x). P2target (x) is Ptarget (x) and P2
It is determined by (x). Here, assuming that the in-plane unevenness correction target value is flattened, Pt
The target (x) is equal to the in-plane minimum value Pmin of (P1 + P2) as shown in FIGS. 7 (A) and 7 (B).
Ptarget (x) = min (P1 (x) + P2 (x)) (5)

When the unevenness correction target value in the stack state is calculated as described above, the unevenness correction target value calculation unit 160 calculates the unevenness correction target value corresponding to each image display device following step S32 (step S33). Then, a series of processing is completed.

The unevenness correction target value calculation unit 160 distributes the unevenness correction amount of the stack image in accordance with the ratio of the color characteristic values (intensities) of the image display devices, so that the unevenness correction target value P1target (corresponding to each image display device). x), P2target (x) is calculated. More specifically, the unevenness correction target value calculation unit 160 calculates the correction target values Ptarget, P1, and P2 in the stacked state.
The difference (Ptarget− (P1 + P2)) from the sum of the intensities (P1 + P2) is distributed according to the ratio of the color characteristic values of the image display devices. That is, based on the ratio of the color characteristic values of each image display device,
The unevenness correction target value Ptarget is distributed.
P1target (x) = P1 (x) + (Ptarget (x) − (P1 (x) + P2
(X))) × P1 (x) / (P1 (x) + P2 (x))
= P1 (x) / (P1 (x) + P2 (x)) × Ptarget (x) (6)
P2target (x) = P2 (x) + (Ptarget (x) − (P1 (x) + P2
(X))) × P2 (x) / (P1 (x) + P2 (x))
= P2 (x) / (P1 (x) + P2 (x)) × Ptarget (x) (7)

FIGS. 8A and 8B show examples of unevenness correction target values of the image display devices for the intensity distributions of FIGS. 7A and 7B. FIG. 8A shows the unevenness correction target values P1target (x) and P2target (x) of each image display device for the intensity distribution of FIG. 7A. FIG.
(B) is a nonuniformity correction target value P1target of each image display apparatus for the intensity distribution of FIG.
et (x), P2target (x).

As shown in FIGS. 8A and 8B, the unevenness correction amount in the first image display device PJ1 and the second image display device PJ2 regardless of the difference in the intensity distribution of the images of the image display devices. The nonuniformity correction amount is balanced, and the nonuniformity correction amount does not increase only in one image display device. For example, in FIG. 8B, the correction amount of the second image display device PJ2 whose intensity distribution is lower than that of the first image display device PJ1 is smaller than the correction amount of the first image display device PJ1.

On the other hand, when the unevenness correction target value is obtained using the method disclosed in Patent Document 1, the following is obtained.

FIGS. 9A and 9B show examples of uneven correction target values of the image display devices for the intensity distributions of FIGS. 7A and 7B according to the conventional technique. FIG. 9A shows the nonuniformity correction target values P1target (x) and P2target (x) of each image display device for the intensity distribution of FIG.
). FIG. 9B shows the unevenness correction target values P1target (x) and P2target (x) of each image display apparatus with respect to the intensity distribution of FIG. 7B.

In this case, unevenness correction is performed by adjusting the intensity distribution of the second image display device PJ2 in a state where the intensity distribution of the first image display device PJ1 is fixed. Accordingly, the unevenness correction target value for each of the first image display device PJ1 and the second image display device PJ2 can be expressed as the following equation.
P1target (x) = P1 (x) (8)
P2target (x) = Ptarget (x) −P1 (x) (9)

For example, in FIG. 9A, the unevenness correction target value corresponding to each image display device takes a positive value, so that unevenness correction can be performed correctly. However, when the intensity distribution of one image display device is extremely lower than the intensity distribution of the other image display device, as shown in FIG. 7B, unevenness correction for the second image display device PJ2 is performed. The amount increases in the negative direction, P2target
et (x) is a negative value. This means that the second image display device PJ2 cannot correct correctly and cannot correct unevenness of the stack image.

On the other hand, in the first embodiment, as shown in FIG. 8B, even when the intensity distribution of one image display device is extremely lower than the intensity distribution of the other image display device, the unevenness correction target value P2tar.
get (x) never becomes negative. As a result, according to the first embodiment, the unevenness correction of the stack image can be performed correctly.

In the first embodiment, the unevenness correction target value in the stacked state is generated so as to be flat in the plane. However, the unevenness correction target value may be set so that the center in the plane is brightened and the periphery is darkened. .

[Unevenness correction LUT generation processing]
FIG. 10 shows a flowchart of a processing example of the unevenness correction LUT generation processing in step S4 of FIG.
When the image processing apparatus 100 implements the processing of FIG. 10 by software processing, a program for realizing the following processing is stored in a memory built in the image processing apparatus 100, and a CPU that reads the program corresponds to the program. Execute the process.

When the unevenness correction target value is calculated as described above in step S3 of FIG.
The UT generation unit 170 generates an unevenness correction LUT for each image display device from the intensity distribution for each image display device and the unevenness correction target value (target XYZ value).

First, the unevenness correction LUT generation unit 170 sets a gradation at one pixel position from among LUT lattice points corresponding to a predetermined pixel position and gradation in the screen (step S41).
. Next, the unevenness correction LUT generation unit 170 searches for a VT characteristic corresponding to the gradation at the pixel position set in step S41, and performs a process of determining an unevenness correction value set as the unevenness correction LUT (step S41). S42).

FIG. 11 is an explanatory diagram of VT characteristics. In FIG. 11, the horizontal axis represents the voltage V corresponding to the gradation value, and the vertical axis represents the transmittance T corresponding to the luminance Y.

In the first embodiment, for each image display device in which the liquid crystal panel is used as a light valve, the correction amount for correcting the output by (A) in the intermediate gradation range is (B). However, in the low gradation region and the high gradation region, the correction amount (D) for correcting the output by (C) becomes large.
The unevenness correction LUT generation unit 170 takes into account the VT characteristics as shown in FIG.
T is generated.

Subsequent to step S42, the unevenness correction LUT generation unit 170 returns to step S41 and returns to the next unevenness correction when unevenness correction values are not determined for all pixel positions and all gradations of the LUT lattice points (step S43: N). Repeat the process of determining the value. In this way, the unevenness correction LUT
The generation unit 170 determines unevenness correction values for all pixel positions and all gradations of the LUT lattice points, and generates an unevenness correction LUT in which the unevenness correction values are tabulated.

12A, 12B, and 12C show pixel positions (i, j) before and after correction.
An example of tristimulus values obtained by measuring a projection image by the first image display device PJ1 in FIG. FIG. 12A shows the measurement result of the stimulus value X. FIG. 12B shows the measurement result of the stimulus value Y. FIG. 12C shows the measurement result of the stimulus value Z. 12 (A) to 1
2 (C), the horizontal axis represents the gradation value, and the vertical axis represents one of the stimulation values X, Y, and Z.

Hereinafter, the tristimulus values before correction are (X1, Y1, Z1), and the tristimulus values corresponding to the unevenness correction target values are (X1t, Y1t, Z1t). In FIG. 12A, the plot of the stimulus value X before correction is F _X1 (Kij), and the plot of the unevenness correction target value X1t is F _X1t (Kij). In FIG. 12 (B), the plots before the correction stimulus value Y is _F Y1 (Kij), a plot of the unevenness correction target value Y1t is _{F Y1t} (
Kij). In FIG. 12C, a plot of the stimulus value Z before correction is F _Z1.
(Kij), and F _Z1t (Kij) is a plot of the unevenness correction target value Z1t. According to the characteristic curves shown in FIGS. 12A to 12C, the unevenness correction LUT generation unit 170 is corrected.
In this case, an input value for obtaining a desired unevenness correction target value is obtained, and an unevenness correction value corresponding to the correction amount for obtaining the input value is obtained.

When the characteristic curves shown in FIGS. 12A to 12C are obtained, the unevenness correction LUT generation unit 17
0 converts the tristimulus values XYZ in FIGS. 12A to 12C into RGB values using a known XYZ / RGB conversion matrix M- ¹ .

FIGS. 13A, 13B, and 13C show examples of RGB values before and after correction at the pixel position (i, j) after conversion. 13A to 13C, RG before correction
The B value is represented as (R1, G1, B1), and the corrected RGB value is represented as (R1t, G1t, B1t).
FIG. 13A shows the conversion result of the R value. FIG. 13B shows the G value conversion result. FIG.
3 (C) represents the conversion result of the B value. In FIGS. 13A to 13C, the horizontal axis represents a gradation value, and the vertical axis represents an RGB value.

In FIG. 13A, a plot of the conversion result of R1 before correction is F _R1 (Kij
F _R1t (Kij) is a plot of the R1t conversion result after correction.
In FIG. 13B, the result of conversion of G1 before correction is plotted as F _G1 (Kij).
F _G1t (Kij) is a plot of the G1t conversion result after correction. In FIG. 13C, F _B1 (Kij) plots the B1 conversion result before correction, and F _B1t (Kij) plots the B1t conversion result after correction.

Next, the unevenness correction LUT generation unit 170 searches the characteristic curves shown in FIGS. 13A to 13C to obtain a desired unevenness correction target value (Rt, Gt, Bt) as in the following equation. The corrected pixel values (Rij ′, Gij ′, Bij ′) for realization are obtained.
FR1t (Rij) = FR1 (Rij ′) (10)
FG1t (Gij) = FG1 (Gij ′) (11)
FB1t (Bij) = FB1 (Bij ′) (12)

The unevenness correction LUT generation unit 170 obtains the pixel value (R) obtained by the equations (10) to (12).
ij ′, Gij ′, Bij ′) and correction amounts (ΔKRij, ΔKGij, ΔKBij).
) Is calculated from equations (1) to (3).

The unevenness correction LUT generation unit 170 performs the above processing at each pixel position in the image.
This is done for each gradation. As a result, the unevenness correction LUT generation unit 170 generates an unevenness correction LUT in which unevenness correction values corresponding to the correction amounts (ΔKRij, ΔKGij, ΔKBij) of the gradation value Kij at the pixel position (i, j) are tabulated. Can do.

The unevenness correction LUT generation unit 170 that performs the above-described processing is performed on all pixel positions in the image,
Ideally, correction amounts for all gradation values are prepared as a table. However, for the purpose of reducing the storage capacity of the unevenness correction LUT storage unit 110, an unevenness correction LUT in which unevenness correction values corresponding to the correction amount at a specific pixel position and gradation value are tabulated is prepared, and appropriately used by a known interpolation process. You may make it supplement.

[VT characteristics measurement process]
In the unevenness correction process, it is desirable that the ratio of the tristimulus values XYZ before and after correction is maintained. However, even if the ratio of the tristimulus values XYZ is not maintained before and after the correction, the gamma correction LUT may be regenerated by measuring the VT characteristics as follows.

FIG. 14 shows a flowchart of a processing example of the VT characteristic measurement processing in step S6 of FIG. When the image processing apparatus 100 implements the processing of FIG. 14 by software processing, the image processing apparatus 10
A program that realizes the following processing is stored in a memory built in 0, and a CPU that reads the program executes processing corresponding to the program.

For each image display device, the image processing device 100 projects one of the full images of each gray gray level on the screen SCR (step S61). In this state, the image processing apparatus 100
Is controlled by the chromaticity measuring device 400 to measure, for example, the chromaticity at the center of the screen, and is acquired as a chromaticity measurement value (step S62). Thereafter, when all measurements have not been completed (step S63: N), the image processing apparatus 100 returns to step S61 to project the next solid image onto the screen SCR. In this way, when the unevenness measurement value is obtained for each of the full-screen images of each gradation of gray (step S63: Y), the image processing apparatus 100 ends the process of step S6.

FIG. 15 shows a flowchart of a processing example of the gamma correction LUT generation processing in step S7 of FIG. When the image processing apparatus 100 implements the processing of FIG. 15 by software processing, a program for realizing the following processing is stored in a memory built in the image processing apparatus 100, and a CPU that reads the program corresponds to the program. Execute the process.

When the VT characteristic is measured in step S6 of FIG. 3, the gamma correction LUT generation unit 180 is measured.
Sets one gradation from among the LUT lattice points corresponding to the predetermined gradation (step S71). Next, the gamma correction LUT generation unit 180 searches for a VT characteristic corresponding to the gradation set in step S71, and performs a process of determining a gamma correction value set as the gamma correction LUT (step S72). The gamma correction LUT generation unit 180 returns to step S71 when the gamma correction values have not been determined for all the gradations of the LUT lattice points (step S73: N), and repeats the process of determining the next gamma correction value. Thus, gamma correction LU
The T generation unit 180 determines gamma correction values for all the gradations of the LUT lattice points, and generates a gamma correction LUT in which the gamma correction values are tabulated.

As described above, according to the first embodiment, when the unevenness correction of the stack image is performed, the balance of the correction amount with respect to each image display device can be favorably performed, so that the correct unevenness correction can be performed.

[Others]
In the first embodiment, an example in which a stack image is displayed using two image display devices has been described. However, the number of image display devices is not limited. Even when a stack image is displayed using n (n is an integer of 3 or more) image display devices, the same effect can be obtained by calculating the unevenness correction target value in the same manner as described above. In this case, the unevenness correction target value for the m (m = 1 to n) -th image display device is expressed by the following expression when the pixel position is expressed by two-dimensional coordinates (x, y). In addition, Formula (13) shows the sum total of P1 (x, y)-Pn (x, y).
ΣPtotal (x, y) = P1 (x, y) + P2 (x, y) +... + Pn (x, y).
(13)
Pmtarget (x, y) = Pm (x, y) / ΣPtotal (x, y) × Ptar
get (x, y) (14)

Similarly to the above, the stack image displayed using n image display devices can be preferably balanced in the correction amount for each image display device, so that correct unevenness correction can be performed.

2. Embodiment 2
In the unevenness correction processing in the first embodiment, it is desirable to prevent black floating after unevenness correction. For example, black correction after unevenness correction can be prevented by not performing unevenness correction in the direction of increasing brightness in black.

  FIG. 16 is an operation explanatory diagram of the unevenness correction processing unit in which the vicinity of black in FIG. 6 is enlarged.

As shown in FIG. 16, by performing unevenness correction processing in the darkening direction not only for black but also for gradations brighter than black, black floating can be prevented. However, if the first embodiment is applied as it is to the unevenness correction target value Ptarget in the stacked state, the unevenness correction may not be performed correctly.

17A and 17B are explanatory diagrams of the unevenness correction processing for the intensity near black in FIG. FIG. 17A schematically illustrates a case where unevenness correction cannot be performed correctly. FIG. 17B schematically illustrates a case where unevenness correction can be performed correctly.

According to the first embodiment, the unevenness correction target values P1target and P2target are determined by the unevenness correction target value Ptarget in the stacked state. At this time, as shown in FIG. 17B, when the unevenness correction target values P1target and P2target are determined for each image display device, the gradation after unevenness correction can be specified, and thus the unevenness correction value can be calculated. On the other hand, in the case shown in FIG. 17A, the unevenness correction value can be calculated for the first image display device PJ1, but the floor to be output to the second image display device PJ2. There is no tone, and the unevenness correction value cannot be calculated.

Therefore, the unevenness correction target value calculation unit in the second embodiment uses the color characteristic value in each image as a reference for the black color characteristic value (intensity). That is, the unevenness correction target value calculation unit in the second embodiment
The unevenness correction target value corresponding to each image display device is calculated according to the ratio of the color characteristic values in each image with reference to the black color characteristic value as the reference measurement value. More specifically, the black intensity of the first image display device PJ1 is P1k (x), and the black intensity of the second image display device PJ2 is P2k (x
), P1 ′ (x) and P2 ′ (x) obtained by subtracting the black intensity from P1 (x) and P2 (x) are used instead of P1 (x) and P2 (x).
P1 ′ (x) = P1 (x) −P1k (x) (15)
P2 ′ (x) = P2 (x) −P2k (x) (16)

Then, from the unevenness correction target value Ptarget ′ (x) in the stack state, P1target
et (x) and P2target (x) are calculated.
Ptarget ′ (x) = Ptarget (x) − (P1k (x) + P2k (x)).
(17)
P1target (x) = P1 ′ (x) / (P1 ′ (x) + P2 ′ (x)) × Ptar
get ′ (x) + P1k (x) (18)
P2target (x) = P2 ′ (x) / (P1 ′ (x) + P2 ′ (x)) × Ptar
get ′ (x) + P2k (x) (19)

That is, the unevenness correction target value calculation unit according to the second embodiment converts the unevenness correction target value into an increment from the black color characteristic value by using the unevenness correction target value as a reference for the black color characteristic value, Distribution is performed based on the ratio of the increment of the color characteristic value from black of each image display device. As a result, FIG.
As shown in FIG. 5, both the first image display device PJ1 and the second image display device PJ2 can correct correct unevenness.

It should be noted that a predetermined gradation may be discriminated and applied only to the gradation near black using Expressions (17) to (19), but in order to simplify the processing, It is desirable to apply uniformly to all gradations.

[Others]
In the second embodiment, an example in which a stack image is displayed using two image display devices has been described. However, the number of image display devices is not limited. Even when a stack image is displayed using n (n is an integer of 3 or more) image display devices, the same effect can be obtained by calculating the unevenness correction target value in the same manner as described above. In this case, the non-uniformity correction target value Pmtarget for the m (m = 1 to n) -th image display device is expressed by a two-dimensional coordinate (x, y
) Is represented by the following formula. In addition, Formula (22) is P1k (x, y)-Pnk (x, y)
Equation (23) shows the sum of P1 ′ (x, y) to Pn ′ (x, y).
Pm ′ (x, y) = Pm (x, y) −Pmk (x, y) (20)
ΣPtotal (x, y) = P1k (x, y) + P2k (x, y) +... + Pnk (x
, Y) (21)
Ptarget ′ (x, y) = Ptarget (x, y) −ΣPtotal (x,
y) (22)
ΣPtotal ′ (x, y) = P1 ′ (x, y) + P2 ′ (x, y) +... + Pn ′ (x
, Y) (23)
Pmtarget (x, y) = Pm ′ (x, y) / ΣPtotal ′ (x, y) × Pt
target ′ (x, y) + Pmk (x, y) (24)

As described above, according to the second embodiment, in addition to the effects of the first embodiment, it is possible to perform unevenness correction processing for preventing black float.

3. Embodiment 3
In the first embodiment or the second embodiment, the configuration in which an external image processing apparatus is connected to two image display apparatuses each having an image forming unit has been described as an example. However, the present invention is not limited to the image display system. For example, the present invention can also be provided for an image display system that includes a plurality of image forming units in a housing and synthesizes image light from the image forming units in the housing and projects the combined light onto the screen SCR. In this case, the same effect can be obtained by replacing the phrase “image display device” in the first embodiment or the second embodiment with “image forming unit”.

FIG. 18 is a block diagram illustrating a configuration example of the image display system according to the third embodiment. FIG.
In FIG. 1, the same parts as those in FIG. In addition, about the structure of a 1st image formation part and a 2nd image formation part, the structure seen from the upper surface is represented typically.

The image display device PJ includes a first image forming unit 500, a second image forming unit 600, an image processing unit 700 (image processing device), and a polarization beam splitter (PBS) 7
80 and a projection lens 790. The image display device PJ can display a stack image on the screen SCR by superimposing and projecting two images formed by the first image forming unit 500 and the second image forming unit 600. It has become.

The configuration of the first image forming unit 500 is the same as the configuration of the second image forming unit 600. The image processing unit 700 has the function of the image processing apparatus 100 according to the first or second embodiment.

FIG. 19 shows a configuration example of the first image forming unit 500 of FIG. FIG. 19 schematically illustrates a configuration of the first image forming unit 500 as viewed from above.

The first image forming unit 500 includes a light source unit 510, integrator lenses 512, 514,
A polarization conversion element 516, a superimposing lens 518, a first dichroic mirror for color light 520 ₁ ,
Second color light dichroic mirror 520 ₂ , reflection mirror 522, first color light field lens 524 ₁ , second color light field lens 524 ₂ , first color light liquid crystal panel 5
30 ₁ , a second color light liquid crystal panel 530 ₂ , a third color light liquid crystal panel 530 ₃ , a relay optical system 540, and a cross dichroic prism 560 (color synthesis prism). The liquid crystal panels used as the first color light liquid crystal panel 530 ₁ , the second color light liquid crystal panel 530 _2, and the third color light liquid crystal panel 530 ₃ are transmissive liquid crystal display devices. Relay optical system 5
Reference numeral 40 includes relay lenses 542, 544, and 546, and reflection mirrors 548 and 550.

The light source unit 510 is constituted by, for example, an ultrahigh pressure mercury lamp, and at least the first color light (C
1) Light including the second color light (C2) and the third color light (C3) is emitted. The integrator lens 512 has a plurality of small lenses for dividing the light from the light source unit 510 into a plurality of partial lights. The integrator lens 514 has a plurality of small lenses corresponding to the plurality of small lenses of the integrator lens 512. The superimposing lens 518 superimposes the partial light emitted from the plurality of small lenses of the integrator lens 512 on the liquid crystal panel. The polarization conversion element 516 includes a polarization beam splitter array and a λ / 2 plate, and converts light from the light source unit 510 into substantially one type of polarized light. The polarization beam splitter array has a structure in which a polarization separation film that separates the partial light divided by the integrator lens 512 into p-polarization and s-polarization, and a reflection film that changes the direction of the light from the polarization separation film are alternately arranged. Have. The polarization direction of the two types of polarized light separated by the polarization separation film is aligned by the λ / 2 plate. This polarization conversion element 5
The superimposing lens 518 is irradiated with the light converted into substantially one type of polarized light by 16.

Light from the superimposing lens 518 is incident on the _first dichroic mirror 5201 for colored light. The first dichroic mirror 520 ₁ for color light reflects the first color light has a function of transmitting the second color light and third color light. First color light dichroic mirror 520 ₁
Light transmitted through the is irradiated a second dichroic mirror 520 ₂ color light, the light reflected by the dichroic mirror 520 ₁ first color light in the first field lens 524 ₁ for color light is reflected by the reflection mirror 522 Led.

Second color light dichroic mirror 520 ₂ reflects the second color light, having a function of transmitting the third color light. The light transmitted through the _second dichroic mirror for color light 5202 is
Is incident on the relay optical system 540, light reflected by the for second color light dichroic mirror 520 ₂ is guided in _two second color-light field lens 524.

In the relay optical system 540, first transmitted through the second color-light dichroic mirror 520 ₂ 3
In order to minimize the difference between the optical path length of the first color light and the optical path lengths of the other first color light and the second color light, the difference in the optical path length is corrected using the relay lenses 542, 544, and 546. The light transmitted through the relay lens 542 is guided to the relay lens 544 by the reflection mirror 548. The light transmitted through the relay lens 544 is guided to the relay lens 546 by the reflection mirror 550. The light transmitted through the relay lens 546 is irradiated to the third liquid crystal panel 530 ₃ color light.

The light applied to the first color light field lens 524 ₁ is converted into parallel light and is incident on the first color light liquid crystal panel 530 ₁ . The first color light liquid crystal panel 530 ₁ functions as a light modulation unit (light modulation element), and based on the first color light image signal constituting the image signal from the image processing unit 700, the transmittance (transmission rate, (Modulation rate) changes. Accordingly, the light incident for a first color light to the liquid crystal panel 530 ₁ is modulated based on the first color light image signal, the modulated light is incident on the cross dichroic prism 560. The light irradiated for the field lens 524 ₂ second color light is incident on the second liquid crystal panel 530 ₂ color light is converted into parallel light. ₂ the second liquid crystal panel 530 for color light functions as the light modulation unit, the second transmission rate based on the color light image signal constituting the image signal from the image processing unit 700 is adapted to change. Accordingly, the light incident for a second color light to the liquid crystal panel 530 ₂ is modulated based on the second color light image signal, the modulated light cross dichroic prism 5
60 is incident. The third liquid crystal panel for color lights light converted into parallel light by the relay lens 542,544,546 are irradiated 530 _3, third to serve as a light modulation section, constituting the image signal from the image processing unit 700 The transmittance changes based on the color light image signal. Therefore, light incident on the third liquid crystal panel 530 ₃ color light is modulated based on the image signal for the third color light, the modulated light is incident on the cross dichroic prism 560.

The first color light liquid crystal panel 530 ₁ , the second color light liquid crystal panel 530 ₂ , and the third color light liquid crystal panel 530 ₃ have the same configuration. Each liquid crystal panel is a liquid crystal, which is an electro-optical material, sealed in a pair of transparent glass substrates. For example, a polysilicon thin film transistor is used as a switching element to modulate the pass rate of each color light corresponding to an image signal. .

The cross dichroic prism 560 outputs combined light obtained by combining incident light from the first color light liquid crystal panel 530 ₁ , the second color light liquid crystal panel 530 _2, and the third color light liquid crystal panel 530 ₃ as outgoing light. It has a function.

As described above, the cross-dichroic prism 560 of the first image forming unit 500 combines the modulated color lights to generate image light.

On the other hand, the second image forming unit 600 has the same configuration as the first image forming unit 500 shown in FIG. 19, and each color light modulated by the cross dichroic prism of the second image forming unit 600. Are combined to generate image light.

In such a configuration, the optical system of the first image forming unit 500 and the second image forming unit 600 are used.
The optical system is reversed. For this reason, the second image forming unit 600 is supplied with an image signal in which the pixel arrangement of the image represented by the image signal supplied to the first image forming unit 500 is arranged in the direction opposite to the horizontal direction. As a result, the orientation of the image formed by the first image forming unit 500 and the orientation of the image formed by the second image forming unit 600 can be aligned. Accordingly, the image processing unit 700 can output image signals in which pixels are arranged in opposite directions in the horizontal direction of the image to each of the first image forming unit 500 and the second image forming unit 600. It has become.

The polarization combining prism (synthesizing unit) 780 includes the image light from the first image forming unit 500 and the second light.
The image light from the image forming unit 600 is synthesized, and the projection light 790 is irradiated with the synthesized light.
The projection lens 790 enlarges and projects the combined light from the polarization combining prism 780 and displays an image on the screen SCR.

Accordingly, the first image forming unit 500 and the second image forming unit 60 accommodated in one housing.
A stack image is displayed by projecting the image formed by each of 0 on the screen SCR in an overlapping manner. At this time, by performing the unevenness correction described in the first embodiment or the second embodiment in the image processing unit 700, the same effects as those in the first embodiment or the second embodiment can be obtained.

Each of the first image display device PJ1 and the second image display device PJ2 in the first embodiment or the second embodiment includes an image forming unit having the configuration shown in FIG. 19, and an image formed by the image forming unit. The image light corresponding to can be enlarged and projected by the projection lens, and the image can be displayed on the screen SCR.

As described above, the image processing apparatus, the image display system, the image processing method, the unevenness correction value generation method, and the like according to the present invention have been described based on any one of the above-described embodiments. The present invention is not limited to this, and can be implemented in various modes without departing from the scope of the invention. For example, the following modifications are possible.

(1) In the above embodiment, the image display device has been described as an example, but the present invention is not limited to this. It goes without saying that the present invention can be applied to all devices that display images superimposed on the basis of image signals.

(2) In the above embodiment, an example in which the image forming unit is configured by a light valve using a so-called three-plate transmissive liquid crystal panel has been described. A light valve using a transmissive liquid crystal panel can be employed. Moreover, although it demonstrated as using the light valve which used the transmissive liquid crystal panel as a light modulation element,
The present invention is not limited to this. As a light modulation element, for example, DLP (Digital Li
ght Processing) (registered trademark), LCOS (Liquid Crystal On Silicon), or the like may be employed.

(3) In the above-described embodiment, after the unevenness correction process, an image by each image display device is measured and V
Although it has been described that the T characteristic is acquired and the gamma correction LUT is generated for each image display elementary value, the present invention is not limited to this. For example, after the unevenness correction processing, the VT characteristic is measured for the stack image by the first image display device and the second image display device, and a gamma correction LUT common to each image display device may be generated. Good.

(4) In the above embodiment, the present invention has been described as an image processing apparatus, an image display system, an image processing method, an unevenness correction value generation method, and the like, but the present invention is not limited to this. For example, a program that describes the processing procedure of the image processing method and the unevenness correction value generation method according to the present invention, and a program that describes the processing procedure of the processing method (image display method) of the image display device for realizing the present invention A recording medium on which any one of these programs is recorded may be used.

DESCRIPTION OF SYMBOLS 10 ... Image display system, 100 ... Image processing apparatus, 110 ... Unevenness correction LUT memory | storage part,
120: Unevenness correction processing unit 130: Image correction unit 140: Gamma correction LUT storage unit,
150: Gamma correction unit 160: Unevenness correction target value calculation unit,
170: Unevenness correction LUT generation unit, 180 ... Gamma correction LUT generation unit,
200: Image signal supply device 300: Unevenness measuring device 400: Chromaticity measuring device,
500 ... first image forming unit, 600 ... second image forming unit, 700 ... image processing unit,
780 ... PBS, 790 ... projection lens, PJ ... image display device,
PJ1 ... first image display device, PJ2 ... second image display device, SCR ... screen

Claims (13)

An image processing apparatus that corrects unevenness of a stack image generated using a plurality of image forming units,
An unevenness correction value storage unit that stores an unevenness correction value generated based on a ratio of color characteristic values of the images constituting the stack image;
An image processing apparatus comprising: an unevenness correction processing unit that performs unevenness correction processing of an image signal corresponding to each image forming unit using the unevenness correction value stored in the unevenness correction value storage unit. In claim 1,
The unevenness correction value is
An image processing apparatus, wherein the correction amount of unevenness of the stack image corresponds to a correction amount distributed to the image forming units in accordance with a ratio of color characteristic values of the images. In claim 1 or 2,
The unevenness correction value is
An image processing apparatus generated on the basis of a ratio of color characteristic values of each image with reference to a color characteristic value for a black solid image formed by each of the image forming units. In any one of Claims 1 thru | or 3,
The image processing apparatus, wherein the color characteristic value is a tristimulus value. In any one of Claims 1 thru | or 4,
A gamma correction value storage unit for storing a gamma correction value corresponding to the unevenness correction value stored in the unevenness correction value storage unit;
A gamma correction unit that corrects an image signal using the gamma correction value stored in the gamma correction value storage unit,
The unevenness correction processing unit
An image processing apparatus that performs the unevenness correction process on the image signal corrected by the gamma correction unit. In any one of Claims 1 thru | or 5,
An unevenness correction target value calculation unit that calculates an unevenness correction target value corresponding to each image forming unit by distributing the unevenness correction target value of the stack image according to the ratio of the color characteristic values of the images,
An unevenness correction value generation unit that generates an unevenness correction value corresponding to each image forming unit based on the unevenness correction target value corresponding to each image forming unit calculated by the unevenness correction target value calculation unit,
The unevenness correction value storage unit
An image processing apparatus that stores the unevenness correction value generated by the unevenness correction value generation unit. The plurality of image forming units that display the stack image using images formed by the image forming units;
The image processing apparatus according to claim 1, further comprising: performing an unevenness correction process on an image signal corresponding to each of the image forming units, and supplying the image signal after the unevenness correction process to each of the image forming units. An image display system characterized by the above. An image processing method for correcting unevenness of a stack image generated using a plurality of image forming units,
An unevenness correction processing step of performing unevenness correction processing of the image signal corresponding to each image forming unit using the unevenness correction value generated based on the ratio of the color characteristic values of the images constituting the stack image;
An image processing method, wherein the image signal after the unevenness correction processing performed in the unevenness correction processing step is supplied to each of the image forming units. In claim 8,
A gamma correction step of correcting an image signal using a gamma correction value corresponding to the unevenness correction value stored in the unevenness correction value storage unit,
The unevenness correction processing step includes:
An image processing method comprising performing the unevenness correction process on the image signal corrected in the gamma correction step. In claim 8 or 9,
The unevenness correction processing step includes:
Using the unevenness correction value generated based on the ratio of the color characteristic values of each image constituting the stack image with reference to the color characteristic value for the black solid image formed by each image forming unit,
An image processing method comprising performing unevenness correction processing of an image signal corresponding to each image forming unit. An unevenness correction value generation method for generating an unevenness correction value for correcting unevenness of a stack image generated using a plurality of image forming units,
A nonuniformity correction target value calculating step of calculating a nonuniformity correction target value corresponding to each image forming unit by distributing the nonuniformity correction target value of the stack image according to the ratio of the color characteristic values of the images constituting the stack image. When,
A non-uniformity correction value generating step for generating non-uniformity correction values corresponding to the image forming units based on the non-uniformity correction target values corresponding to the image forming units calculated in the nonuniformity correction target value calculating step. An unevenness correction value generation method characterized by the above. In claim 11,
A reference measurement value acquisition step of acquiring a color characteristic value of a black solid image formed by each of the image forming units,
The unevenness correction target value calculation step includes:
The unevenness correction value generation characterized in that the unevenness correction target value is calculated based on a ratio of the color characteristic values of each image with reference to the color characteristic value of the solid image acquired in the reference measurement value acquisition step Method. In claim 11 or 12,
The unevenness correction value generation method, wherein the measurement value is a tristimulus value.

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