JP3258794B2 - Convergence adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a convergence adjusting device used for adjusting a deviation of convergence of an image projected by a liquid crystal projector.

[0002]

2. Description of the Related Art Generally, a liquid crystal projector electrically switches each dot of a large number of liquid crystal panels arranged on each of three liquid crystal panels according to a signal output from a signal generating unit, and outputs three primary colors R (red). , G (green) and B (blue) are synthesized on the screen to produce a color image, which is enlarged and projected on the screen. The deviation of the convergence of the projected color image is caused by the deviation of the alignment accuracy of each liquid crystal panel.

Conventionally, convergence of a liquid crystal projector is adjusted by projecting a test pattern image (for example, a cross hatch or the like) on a screen, visually detecting a shift between the colors, and using a single color (G) image as a reference. The adjustment is performed by adjusting the positions of the liquid crystal panels of the other colors (R, B) to match the R, B images. However, when the color difference is visually detected as described above, the skill of the adjuster is required, and there are individual differences.

Therefore, the present applicant captures a test pattern image with a video input device such as a black-and-white camera in place of visual observation, thereby eliminating the necessity of a skilled skill of an adjuster and detecting a deviation with high accuracy. To Japanese Patent Application 4
-355706. This conventional device outputs a signal for projecting a dot pattern for each color as a test pattern from a signal generator to a liquid crystal panel, projects the image on a screen, captures the image with a video input device, and inputs the image as a dot image. Then, this is converted into a binarized dot image that can be recognized as a dot, the center of the dot is detected as the position information of the liquid crystal panel of each color from the binarized dot image, and the deviation is calculated from the position information. Then, the adjustment amount is displayed by a predetermined method. Here, for example, three cameras are installed in the vertical direction at the center of the screen, and the dot pattern which is a test pattern is an image projected two dots (or one dot) each at the installation position of the camera.

[0005] The dot image represents the luminance of each portion of the dot, and the planar distribution of the luminance level has a Gaussian distribution. The size of the binarized dot image gradually changes according to the binarization level when binarizing the dot image, as in a horizontal cross section of a Gaussian distribution. For example, when the binarization level is gradually increased, the binarized dot image suddenly becomes smaller at first, hardly changes in the middle, and suddenly becomes smaller again at the end. Therefore, the means for converting the dot image obtained from the video input device into a binarized dot image detects the dot size by counting the pixels on the camera which are binarized and determined to be "H", and changes the size. By performing a dot search on the binarization level when the number is small, and binarizing based on the binarization level, a binarized dot image for detecting position information of the liquid crystal panel is obtained. The means for detecting the position information of the liquid crystal panel from the binarized dot image detects a set of white pixels of the binarized dot image and calculates the center or the center of gravity of the set to obtain position information.

[0006]

In the conventional apparatus,
When the test pattern image of the liquid crystal projector is binarized and detected, the condition at the time of setting the binarization level changes during adjustment due to the time change of the lamp of the liquid crystal projector, the change of external light, and the light receiving characteristics of the camera. There is a problem that a pixel having the same level of luminance as the image level fluctuates, and the center or the center of gravity also fluctuates.

FIG. 3 is a diagram for explaining the effect of noise due to a change in external light, and shows a binarized dot image when the surroundings are brightened by the change in external light. In FIG. 3, a portion indicated by a rectangle is a binarized image of the test pattern and represented as “H”.
It is quantified and represented as "H". When the surroundings are brightened by external light, the level of image information obtained by the camera is increased as a whole. Then, at the same binarization level, noise such as reflected light whose luminance level has not been detected until then is detected, and the center and the center of gravity calculated from the binarization dot image are different, and accurate position information is obtained. Can not be. Therefore, there is a method of constantly updating the binarization level, or a method of solving the problem by performing multi-tone image processing and two-dimensional noise removal processing. However, since the processing requires a lot of time, the processing is performed continuously and in real time. It is difficult to do.

Further, since a camera used as a video input device of a conventional device is a close-up type, a wide-angle lens is used. Then, in order to improve the accuracy, a camera is installed so that a G (green) image dot provided at the center of the three liquid crystal panels is captured at the center. Then, the R (red) and B (blue) image dots that are shifted from the G image dots due to the convergence shift are captured on the peripheral side of the camera. As described above, in a camera using a wide-angle lens, the condition of the binarization level differs depending on the location due to its light receiving characteristics. FIG. 4 is an explanatory diagram showing a binarized dot image obtained by binarizing the dot images located at the center and the periphery of the camera screen at the same binarization level. As shown in FIG. 4, there is a difference in brightness level between the image captured at the peripheral portion and the image captured at the central portion due to the characteristics of the camera. As shown in FIG. 4, the dot size is different between the central portion and the peripheral portion of the screen. fluctuate. Thus, when the binarization level is constant, if the adjustment is performed and the position of the liquid crystal panel changes, the position where the same dot is captured on the camera screen moves, and the binarized dot image fluctuates. The position information such as the center and the center of gravity of each liquid crystal panel detected from the simulated dot image also fluctuates, so that highly accurate convergence adjustment cannot be performed.

Further, the image of the liquid crystal projector is slightly shifted from the focus of the reference color (G) with respect to the focus of the reference color (G) due to the difference in the color wavelength. B and different.

FIG. 5 is an explanatory diagram showing a binarized dot image. FIG. 5 (a) shows a binarized dot image in the case where a reference G image is binarized at a predetermined binarization level.
(b) shows a binarized dot image when the R and B images are binarized. Now binarized dot images of R or B with dot state (G) binarization level is obtained shown in FIG. 5 (a), the dot state as shown in D ₁ shown in FIG. 5 (b) It is larger and longer than that shown in FIG. This is because the wavelength of G differs from the wavelengths of R and B as described above, and a focus shift occurs. Therefore, when obtaining the R and B dot images, it is not the binarization level when the binarized dot image shown in FIG. 5A is obtained, but a two-dimensional image having the same size as that shown in FIG. It is necessary to correct the binarization level to obtain a binarized dot image. When the binarization level for binarizing the dot image is gradually increased, D ₁ → D ₂ → D _{3 in FIG.}
→ 2 value of dot image as D ₄ gradually decreases.
Among these, the binarization level at which a binarized dot image (D ₃ ) substantially equivalent to that shown in FIG. 5A is obtained is determined by the binary level for obtaining the R and B liquid crystal panel position information. It is necessary to reset it as a value level.

The present invention has been made in view of the above circumstances, and has a structure including means for correcting the binarization level for each color and each time the position of the liquid crystal panel is adjusted. It is an object of the present invention to provide a convergence adjustment device capable of performing accurate convergence adjustment at high speed.

[0012]

A convergence adjusting apparatus according to a first aspect of the present invention captures a test pattern displayed on a liquid crystal panel and projected on a screen, and converts the captured image based on a binarization level. Based on the binarized image, based on the binarized image, a convergence adjustment device that detects a relative shift between the liquid crystal panels for a plurality of colors and repeats a process of adjusting the detected shift is used to determine a test pattern for each color. Means for projecting, means for capturing an image projected by the means, means for binarizing an image taken by the means based on a binarization level to generate a binarized image, By sequentially changing the binarization level, a plurality of binarized images binarized on the basis of a series of binarization levels, the binarization level at which the change of the binarized image is relatively small Each color 2 to be set as a binary level
Binarization level setting means ; means for detecting position information of the liquid crystal panel from a binarized image binarized based on the binarization level set by the binarization level setting means; Means for storing the position information of the reference color liquid crystal panel as reference position information, and a binarized image binarized based on the reference position information stored by the means and the set binarization level. Means for comparing with the subsequent position information obtained from, and, as a result of comparison by the means, determining means for determining whether the subsequent position information is within a predetermined range with respect to the reference position information, As a result of the judgment by the judging means, if it is not within the predetermined range, it is within the predetermined range
Wherein a binarization level compensation means for correcting the binarization level where the binarization level setting means is set to a binary
The subsequent position information is obtained by the
Corrected to be within the specified range for quasi-position information
Based on the image binarized by the binarization level, a plurality
Detects the relative displacement of the color LCD panel and does not detect
It is characterized in that the processing for adjusting this is repeated .

The convergence adjusting device according to a second aspect of the present invention is the convergence adjusting device according to the first aspect, wherein as a result of the determination by the determination means, the position information of the liquid crystal panel for the reference color obtained thereafter is within a predetermined range. There is provided a means for updating the reference position information to the position information.

[0014]

According to the first aspect of the present invention, before adjustment, a test pattern for each color is projected, an image of the test pattern is captured, and a test pattern is obtained by a series of binarization levels gradually increased from a predetermined low level.
A plurality of binarized images that have been binarized are obtained, and the binarization level at which there is little change in these binarized images is set as the binarization level at the time of adjustment. Since the setting of the binarization level is performed for each color, it is possible to reduce the influence of a focusing shift due to a difference in wavelength.

Further, as described above, for example, a test pattern of G is projected, imaged, binarized at the set binarization level, and a binary image for G is obtained from the binarized image obtained thereby. The position of the liquid crystal panel is detected and stored as reference position information. At the time of the subsequent adjustment, the test pattern of each color is displayed, and the position information of the liquid crystal panel obtained using the binarization level set as described above is compared with the reference position information. The binarization level is corrected, and a plurality of binarized binarized at this binarization level.
Since a binarized image is obtained , the influence can be suppressed even under conditions different from the conditions at the time of setting the binarization level due to a change in the time of the lamp of the liquid crystal projector, a change in external light, and the like.

In the second invention, in addition to the operation of the first invention, even when a binary image of G is obtained at the time of adjustment, the obtained position information is compared with the reference position information, and the position information outside the predetermined range is obtained. If so, the correction is performed as described above, and if it is within a predetermined range, the reference position information is updated. The binarized dot image rarely fluctuates under the influence of the light receiving characteristics.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a block diagram showing a configuration of a convergence adjusting device according to the present invention. In the figure, reference numeral 2 denotes a screen, and on one side of the screen 2, a liquid crystal panel (not shown) is provided, and a liquid crystal projector 1 for enlarging and projecting an image formed by the liquid crystal panel onto the screen 2 is provided. ing. A signal generator 9 is connected to the liquid crystal projector 1, and a dot pattern signal as a test pattern signal is supplied from the signal generator 9 to the liquid crystal panel. By this dot pattern signal, one dot (one pixel) is projected at three places in the center longitudinal direction of the screen 2.

On the other side of the screen 2, a screen 2
There are provided three cameras 3 (only one is shown) in the vertical direction at the center of the screen 2 for capturing an image projected on the screen 2 and converting the image into dot image data (A). Each of these three cameras 3 is connected to a binarization unit 4 via a frame switch 19, and the binarization unit 4 is connected to a binarization level memory 7. The binarization unit 4 binarizes the dot image data (A) given from the camera 3 based on the binarization level signal (D) stored in the binarization level memory 7. I have.

The binarized dot image data (a) binarized by the binarizing section 4 is supplied to the image memory 5, so that one screen of the screen 2 is stored in the image memory 5. It is. The binarization level setting unit 6 determines that the image memory 5
If it is determined that the digitized dot image data (a) has been stored,
Increase the level by one step, set the binarization level,
The set level signal (C) is supplied to the binarized level memory 7. The binarization level setting section 6 also outputs an image capture request signal (E) for turning on the frame switch 19 to the frame switch 19 for the first time.

When the position detecting section 10 reads out all the binary dot image data (a) for one screen of the screen 2 stored in the image memory 5, from the image memory 5, the image detecting request signal (E) ) Is output to the frame switch 19. Then, the position detecting unit 10 reads the binarized dot image data (a) read from the image memory 5.
The dot size data is detected by the binarization level setting unit 6. Binarization level setting section 6
Then, an optimum level is determined from a plurality of dot size data based on a series of stored binarization levels, a binarization level is set, a set level signal (c) is written to the binarization level memory 7, and a color level is set. The switching request signal (K) is output to the color switching unit 8.

The color switching section 8 outputs a color switching request signal
Receiving the color selection signal (f) to the signal generator 9
The signal generator 9 outputs a dot pattern signal of a color based on the given color selection signal (f) to the liquid crystal projector 1 as described above.

The position information data (g) output from the position detecting section 10 is supplied to one of a reference position memory 11, a G position memory 12, an R position memory 13 and a B position memory 14 via a memory selection switch 20. It is supposed to be. The control of the memory selection switch 20 is performed by a color selection signal (S) output from the color switching section 8.
The position information stored in the G position memory 12, the R position memory 13 or the B position memory 14 is transmitted via a memory selection switch 21 which is also controlled based on a color selection signal (S) output from the color switching unit 8. The information is provided to the position information comparing unit 15.

The position information stored in the R position memory 13 and the B position memory 14 is provided to a shift detecting unit 16, and the position information stored in the G position memory 12 is used as a position information comparing unit. The signal is output to the reference position memory 11 via a switch 23 controlled by a signal output from the reference numeral 15. The position information signal read from the reference position memory 11 is provided to a position information comparing unit 15 and a displacement detecting unit 16. Based on the position information given from the reference position memory 11, the G position memory 12, the R position memory 13 or the B position memory 14, the position information comparing unit 15
When the binarization level needs to be corrected, a binarization correction request signal (K) is output to the binarization level memory 7.

The above configuration for processing the data captured by the camera 3 is provided for the number of cameras 3 and these reference position memory 11, R position memory 13 or B position memory.
The information from 14 is provided to the shift detecting unit 16. The shift detecting unit 16 detects a shift based on information of three cameras provided from the reference position memory 11, the R position memory 13 or the B position memory 14, and supplies a detection signal to the adjustment amount calculating unit 17. There is something. The adjustment display signal (S) calculated by the adjustment amount calculation unit 17 is provided to the monitor 18 so that a predetermined display is made on the monitor 18. The adjuster adjusts the position of the liquid crystal panel by operating a screw or the like according to the displayed contents.

Next, the operation of the device of the present invention will be described.
FIG. 2 is a flowchart showing an operation procedure in the apparatus of the present invention. Perform the following processing operations before adjustment. First, the binarization level of each color R, G, B is set individually (step S1). First, as described above, the camera 3 outputs a dot pattern signal that captures only one dot from the signal generator 9, and the liquid crystal projector 1 outputs the dot pattern signal to the screen 2.
And the camera 3 captures the image. Then, the binarization level setting section 6 writes an initial value of a predetermined low level as the binarization level in the binarization level memory 7, outputs an image capture request signal (E), and turns on the frame switch 19. . As a result, dot image data (A) in which a dot image captured by the camera 3 is converted into a dot image of one frame is supplied to the binarizing unit 4. Then, the binarization unit 4 binarizes the dot image data (A) with the initial values stored in the binarization level memory 7 to obtain binarized dot image data (A). Write.

The position detector 10 takes in the binary dot image data (a) written in the image memory 5 and detects the dot size. When the dot size data is given to the binarization level setting section 6, the binarization level setting section 6
However, after writing the set level signal (C) changed by one step into the binarized level memory 7, the process shifts to the fetching of the dot image data (A) again. Usually, most of the dot image is "H" at the initial value of the low level, and as the set level is increased, the dot represented by "H" gradually becomes smaller and eventually becomes "L". This almost “L” time is defined as the end of the step change. The above operation is performed until the end of this step change.

The binarization level setting section 6 determines the level at which the dot can be recognized from the accumulated data when the data capture until the end of the step change is completed and where the size change with respect to the step change is small is optimum. The final writing is performed in the binary level memory 7 as the set level. Then, a color switching request signal (k) is output to switch colors displayed on the screen 2. By repeating the above process, the binarization level is set for the three colors R, G, and B.

Subsequently, the color switching section 8 outputs a color selection signal (S) to the memory selection switches 20 and 21 to select the G position memory 12 for G, which is a reference for convergence adjustment. A color selection signal (f) for selectively reading out the G binarization level from the R, G, B binarization levels stored in the memory 7 is output to the binarization level memory 7. Here, since the image capture request signal (e) is given from the binarization level setting section 6 to the frame switch 19, the dot image data (a) is captured by the binarization section 4. The binarization section 4 converts the selected G binarization level into binarized dot image data (a) and writes it into the image memory 5. The position detecting section 10 detects position information based on the data obtained from the image memory 5, and the position information data (g) is selected by the memory selection selectively connected to the reference position memory 11 by the color selection signal (g). The data is supplied to the reference position memory 11 via the switch 20, is stored, and the initial setting of the reference position information is completed (step S2).

The processing operation during the subsequent adjustment is as follows. The R, G, and B images selected by the color selection signal (f) output from the color switching unit 8 are displayed on the liquid crystal projector 1.
Is displayed, and dot image data (A) is captured by the image capture request signal (E) (step S3). Then, from the binarized dot image data (a) stored in the image memory 5 via the binarization section 4, the position detection section 10 detects the position information of the liquid crystal panel of the color currently displayed (step). S4). The position information data (G) is stored in the G position memory 12 and the R position memory, which are selectively connected by the memory selection switch 20 according to the color selection signal (S) output from the color switching section 8.
13 or B position memory 14 is stored as current position information.

Then, it is determined whether or not the color selected at this time is G (step S5). If it is not G (R or B), the R position memory 13 or the B position memory 14
The position information comparing unit 15 determines whether the current position information stored in the position information is within an allowable range with respect to the position information stored in the reference position memory 11 (step S6). If there is, the position information comparing section 15 gives an up or down binarization correction request signal (k) to the binarization level memory 7. The binarization level given to the binarization unit 4 is read by reading the binarization level one step up or down from the binarization level at that time by the binarization correction request signal (K). Is corrected (step S
7). Steps S3 to S6 are repeated until the current position information falls within the predetermined range in step S6. If the current position information is within the predetermined range in step S6, a deviation is detected (step S8). The deviation detection adjustment amount thus obtained is given to the monitor 18 as an adjustment display signal (S), and a predetermined display is performed on the monitor 18 to instruct the adjustment (step S9).

Thereafter, it is determined whether or not the adjuster has operated the key for ending the adjustment (step S10). If it is determined that the key has been operated, the process is terminated. If it is determined that the adjustment end key has not been operated, the color is switched by the output of the color selection signal (f) of the color switching section 8 (step S1).
1) Return to step S3 and repeat the following processing.

On the other hand, if it is determined in step S5 that the selected color is G, the position information comparing unit 15
As a result of comparing the current position information stored in the G position memory 12 with the reference position information stored in the reference position memory 11, the current position information stored in the G position memory 12 is normal (a predetermined range different from the predetermined range). (Step S12), and if it is normal, the reference position information is updated (Step S13), and the process proceeds to Step S8 to detect a deviation.
This update is performed when the adjustment amount is displayed by the previous deviation detection and the adjuster adjusts the position of the liquid crystal panel, because the reference position information of G may have changed.
Each time the position information within a predetermined range of the liquid crystal panel is obtained, the position information detected at that time is used as reference position information. If the current position information is abnormal in step S12, the position information comparing unit 15 outputs a binarization correction request signal (K), thereby correcting the binarization level given to the binarization unit 4, Further, after the current position information is invalidated (step S14), the process proceeds to step S10.
It is determined whether or not the color convergence adjustment has been completed.

In the present embodiment, three cameras are provided in the vertical direction at the center of the screen 2.
The number of cameras and their installation positions are not limited to these. For example, three units in the lateral direction at the center and a total of five units at the center and four corners may be appropriately selected.

[0034]

As described above, the convergence adjusting apparatus according to the present invention sets the optimum binarization level for each color before adjustment, so that the influence of focusing deviation due to the difference in wavelength can be reduced. . Before the adjustment, the position of the liquid crystal panel for the reference color is detected and stored as reference position information. During the subsequent adjustment, the position information of the liquid crystal panel obtained by displaying the test pattern of each color is used. Compared with the reference position information, when the binarization level exceeds the allowable range, the binarization level is corrected. It is possible to perform accurate position determination and displacement detection at high speed by suppressing the influence. Further, if the position information of the reference color liquid crystal panel obtained at the time of adjustment is within a predetermined range with respect to the reference position information, the reference position information is updated to the position information, so that the influence of the light receiving characteristics of the camera is also reduced. be able to. As described above, the present invention has excellent effects, such as high-accuracy convergence adjustment.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a convergence adjustment device according to the present invention.

FIG. 2 is a flowchart showing a processing procedure in the apparatus of the present invention.

FIG. 3 is a diagram illustrating the influence of noise due to a change in external light.

FIG. 4 is an explanatory diagram showing a binarized dot image of a camera when the binarization level is constant.

FIG. 5 is an explanatory diagram showing a binarized dot image.

[Explanation of symbols]

 Reference Signs List 1 LCD projector 2 Screen 3 Camera 4 Binarization unit 6 Binarization level setting unit 9 Signal generation unit 10 Position detection unit 11 Reference position memory 15 Position information comparison unit 16 Displacement detection unit

Claims (2)

(57) [Claims] An image of a test pattern displayed on a liquid crystal panel and projected on a screen is captured, the captured image is binarized based on a binarization level, and based on the binarized image. , The relative displacement of the LCD panels for multiple colors
Detecting, repeating the process of adjusting the detected shift particular
A convergence adjusting device for adjusting convergence, a unit for projecting a test pattern for each color, a unit for capturing an image projected by the unit, and an image captured by the unit based on a binarization level. Means for generating a binarized image by binarizing the plurality of binarized images based on a series of binarized levels by sequentially changing the binarized level. binarization change of coded image to set the binarization level at relatively low as binary levels for each color
Level setting means ; means for detecting position information of the liquid crystal panel from a binarized image binarized based on the binarization level set by the binarization level setting means; Means for storing the position information of the liquid crystal panel for the reference color as reference position information; and obtaining the reference position information stored by the means and a binary image binarized based on the set binarization level. Means for comparing the subsequent position information with the reference position information, and judging means for judging whether or not the subsequent position information is within a predetermined range with respect to the reference position information, as a result of the comparison by the means; If the result is not within the specified range
The binarization level setting means is set until the value falls within a predetermined range.
Binarization level correction means for correcting the specified binarization level
And a step , wherein
Position information is within a predetermined range with respect to the reference position information.
Binarized with the binarization level corrected so that
Based on the image, the relative displacement of the LCD panel for multiple colors
Repeat the process of detecting and adjusting the detected deviation
Convergence adjusting apparatus characterized by and are. 2. If the result of the judgment by the judging means indicates that the position information of the liquid crystal panel for the reference color obtained thereafter is within a predetermined range, there is provided means for updating the reference position information to the position information. The convergence adjusting device according to claim 1, wherein: