JPH07154807A - Convergence adjusting device - Google Patents

Abstract

PURPOSE:To provide a convergence adjusting device capable of performing a convergence adjustment with high precision at high speed. CONSTITUTION:This device is provided with a liquid crystal projector 1 projecting the test pattern for every color, a camera 3 imaging this video, a thresholding part 4 for the imaged image based on the thresholding level that a thresholding level memory 7 stores, a thresholding level setting part 6 successively changing the thresholding level and setting an optimum thresholding level from a series of binary images, a location detection part 10 detecting the location of a liquid crystal panel from a binary image signal, a reference location memory 11 storing detected positional information as reference positional information and a positional information comparison part 15 comparing this reference positional information and the positional information on and after the second time, judging whether the positional information on and after the second time is within an allowable range or not as a result and instructing the correction of the thresholding level when the positional information is not within the allowable range.

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 In general, a liquid crystal projector electrically switches each dot of a large number of liquid crystal panels arranged in each of three liquid crystal panels by a signal output from a signal generating section, thereby generating three primary colors R (red). , G (green), B (blue) images are combined on the screen to create a color image, which is enlarged and projected on the screen. The deviation of the convergence of the color image projected here is caused by the deviation of the alignment accuracy of each liquid crystal panel.

Conventionally, the adjustment of the convergence of a liquid crystal projector is performed by projecting a test pattern image (for example, a cross hatch) on a screen, visually detecting a deviation between the colors, and using an image of one color (G) as a reference. , The positions of the liquid crystal panels of other colors (R, B) are adjusted to match the R and B images. However, such visual detection of color misalignment requires the skill of an adjuster, and there are individual differences.

Therefore, the applicant of the present invention, by capturing the test pattern image with an image input device such as a black-and-white camera instead of visual observation, does not require the skill of an adjuster and is capable of highly accurate deviation detection. Japanese Patent Application 4
Proposed in −355706. In this conventional device, a signal for displaying a dot pattern for each color as a test pattern is output from a signal generation unit to a liquid crystal panel, the image is displayed on a screen, and the image is captured by a video input device and input 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 position information of the liquid crystal panel of each color from this binarized dot image, and the deviation is calculated from the position information. However, the adjustment amount is displayed by a predetermined method. Here, three cameras are installed, for example, in the vertical direction in the center of the screen, and the dot pattern, which is a test pattern, is an image projected by 2 dots (or 1 dot) at each installation position of this camera.

The dot image represents the brightness in each portion of the dot, and the plane distribution of the brightness level has a Gaussian distribution. The size of the binarized dot image gradually changes like a horizontal section of a Gaussian distribution depending on the binarization level when binarizing this dot image. For example, when the binarization level is increased stepwise, the binarized dot image suddenly becomes small at first, there is almost no change in the middle, and it becomes suddenly small again at the end and disappears. 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 judged as "H", and the size change. When the number of pixels is small, the binarization level is dot-searched and set, and binarization is performed based on this binarization level to obtain a binarized dot image for detecting position information of the liquid crystal panel. The means for detecting the position information of the liquid crystal panel from the binarized dot image detects the set of white pixels of the binarized dot image and calculates the center or center of gravity of the set to obtain the position information.

[0006]

In the conventional device,
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 characteristic of the camera, and the binary value is set. There is a problem in that a pixel having a brightness similar to the conversion level changes, and the center or the center of gravity also changes.

FIG. 3 is a diagram for explaining the influence of noise due to a change in outside light, and shows a binarized dot image when the surrounding becomes bright due to a change in outside light. In FIG. 3, a rectangular portion is an image of the test pattern, which is binarized and represented as “H”, and noise such as reflected light is 2 on the right side.
It is quantized and represented as "H". When the surroundings are brightened by the external light, the level of image information obtained by the camera is raised overall. Then, even with the same binarization level, noise such as reflected light with a low brightness level that was not detected until then is detected, and accurate position information is obtained because the center and the center of gravity calculated from the binarized dot image are different. I will not be able to. Therefore, there is a method of constantly updating the binarization level, or a method of solving it by performing multi-tone image processing or two-dimensional noise removal processing. Is difficult to do.

Further, since the camera used as the image input device of the 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 the G (green) image dot installed at the center of the three liquid crystal panels is captured at the center. Then, the image dots of R (red) and B (blue), which are deviated from the image dots of G due to the convergence deviation, are captured on the peripheral side of the camera. As described above, in the camera using the wide-angle lens, the condition of the binarization level varies depending on the location because of its light receiving characteristic. FIG. 4 is an explanatory diagram showing a binarized dot image obtained by binarizing the dot images located in the central portion and the peripheral portion of the camera screen with the same binarizing level. As shown in FIG. 4, there is a difference in the brightness level between the one captured in the peripheral portion and the one captured in the central portion due to the characteristics of the camera, and as shown in FIG. 4, the dot size is different between the central portion and the peripheral portion of the screen. fluctuate. As a result, when the binarization level is constant, when the position of the liquid crystal panel is adjusted and the position where the same dot is captured moves on the camera screen, the binarized dot image fluctuates and the binarized image is changed. Positional information such as the center and center of gravity of each liquid crystal panel detected from the digitized dot image also fluctuates, making it impossible to perform highly accurate convergence adjustment.

Further, in the image of the liquid crystal projector, the focus of R and B is slightly deviated from the focus of the reference color (G) due to the difference in color wavelength, so that the dot size of the dot image is different from the reference color (G) and R, Different from B.

FIG. 5 is an explanatory diagram showing a binarized dot image. FIG. 5 (a) shows a binarized dot image when the reference G image is binarized at a predetermined binarization level.
(b) shows a binarized dot image when R and B images are binarized. Here, when the R or B dot image is binarized at the binarization level at which the dot state (G) shown in FIG. 5 (a) is obtained, the dot state is as shown by D ₁ in FIG. 5 (b). It is larger and taller than that shown in Fig. 5 (a). This is because, as described above, the wavelength of G is different from the wavelengths of R and B, and defocus occurs. Therefore, when obtaining R and B dot images, it is not the binarization level used when the binarized dot image 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 raised, D ₁ → D ₂ → D _{3 in FIG.}
→ The binarized dot image becomes smaller gradually like D ₄ .
Among them, the binarization level when the binarized dot image (D ₃ ) substantially the same as that shown in FIG. 5A is obtained is set to 2 for obtaining the position information of the R and B liquid crystal panels. It is necessary to set it again as the digitization level.

The present invention has been made in view of the above circumstances, and is improved by providing a means for correcting the binarization level for each color and each time the position of the liquid crystal panel is adjusted. An object of the present invention is to provide a convergence adjusting device that can perform precision convergence adjustment at high speed.

[0012]

A convergence adjusting device according to a first aspect of the present invention captures a test pattern displayed on a liquid crystal panel and displayed on a screen, and captures the captured image based on a binarization level. In the convergence adjusting device, which repeats the process of binarizing and detecting the relative displacement of the liquid crystal panels for a plurality of colors based on the binarized image, means for displaying a test pattern for each color, and Means for picking up a video image projected by the means, means for binarizing the image picked up by the means based on the binarization level to generate a binarized image, and the binarization level sequentially changed Based on the means and the series of binarization levels
Means for setting a binarization level at which the change in the binarized image is relatively small from the plurality of binarized images, as a binarization level for each color, and a value set by the means. Means for detecting the position information of the liquid crystal panel from the binarized image binarized based on the binarization level, and means for storing the position information of the liquid crystal panel for the reference color detected by the means as the reference position information. And a means for comparing the reference position information stored by the means with the subsequent position information obtained from the binarized image binarized based on the set binarization level, and the means for comparing. As a result, the judgment means for judging whether or not the subsequent position information is within a predetermined range with respect to the reference position information, and if the judgment result is not within the predetermined range, the binarization level is corrected. And means for And butterflies.

In the convergence adjusting device according to the second aspect of the present invention, in the first aspect of the present invention, when the result of the determination by the determining means is that the positional information of the liquid crystal panel for the reference color obtained thereafter is within a predetermined range. It is characterized by comprising means for updating the reference position information to the position information.

[0014]

According to the first aspect of the present invention, before the adjustment, the test pattern for each color is projected, the image thereof is picked up, and the image is picked up at 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 where there is little change in these binarized images is set as the binarization level during adjustment. Since the setting of the binarization level is performed for each color, it is possible to reduce the influence of focusing deviation due to the difference in wavelength.

As described above, a reference test pattern of, for example, G is projected, imaged, binarized at this set binarization level, and the binarized image obtained by this is used for G The position of the liquid crystal panel is detected and stored as reference position information. Then, 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 by using the binarization level set as described above is compared with the reference position information. Since the binarization level is corrected, it is possible to suppress the influence even under conditions different from the conditions at the time of setting the binarization level due to changes in the timing of the lamp of the liquid crystal projector, changes in external light, and the like.

In the second aspect of the invention, in addition to the operation of the first aspect of the invention, when the G binary image is obtained at the time of adjustment, the obtained position information is compared with the reference position information, and is outside the predetermined range. If so, the correction is performed as described above, and the reference position information is updated within the predetermined range. Therefore, even if the image pickup position of the same dot moves due to the position adjustment of the previous liquid crystal panel, The binarized dot image rarely changes due to the influence of the light receiving characteristic.

[0017]

DETAILED 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 the configuration of a convergence adjustment device according to the present invention. In the figure, reference numeral 2 denotes a screen, and a liquid crystal panel (not shown) is provided inside the one surface of the screen 2, 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 applied from the signal generator 9 to the liquid crystal panel. By this dot pattern signal, one dot (one pixel) is projected at each of three positions in the central vertical direction of the screen 2.

On the other side of the screen 2, the screen 2
Three cameras (only one is shown) are provided in the central vertical direction of the screen 2 for capturing the image projected on the screen and converting it into dot image data (A). These three cameras 3 are connected to the binarization unit 4 via the frame switch 19, and the binarization unit 4 is connected to the 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. There is.

The binarized dot image data (a) binarized by the binarization unit 4 is given to the image memory 5 so that one screen of the screen 2 is stored in the image memory 5. There is. In the binarization level setting unit 6, the image memory 5 has two
If it is determined that the binarized dot image data (a) is stored,
Raise the level by one step and set the binarization level,
The set level signal (c) is given to the binarized level memory 7. The binarization level setting unit 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.

Further, when the position detecting section 10 reads all the binarized dot image data (a) for one screen of the screen 2 stored in the image memory 5 from the image memory 5, the image capturing request signal (o ) Is output to the frame switch 19. Then, the position detection unit 10 reads the binarized dot image data (a) read from the image memory 5.
The position coordinates and size of the dot are detected from the dot size data, and this dot size data is stored in the binarization level setting unit 6. Binarization level setting unit 6
Then, the optimum level is determined from the accumulated dot size data based on a series of binarization levels, the binarization level is set, the setting level signal (c) is written to the binarization level memory 7, and A switching request signal (X) is output to the color switching unit 8.

The color switching section 8 has a color switching request signal (K).
When receiving, the color selection signal (f) is given to the signal generator 9,
The signal generator 9 outputs the dot pattern signal of the color based on the applied color selection signal (f) to the liquid crystal projector 1 as described above.

The position information data (G) output from the position detector 10 is given to any of the reference position memory 11, G position memory 12, R position memory 13 or B position memory 14 via the memory selection switch 20. It is designed to be used. The memory selection switch 20 is controlled by a color selection signal (SI) 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 passed through the memory selection switch 21 which is also controlled based on the color selection signal (sigma) output from the color switching unit 8. It is adapted to be given to the position information comparison unit 15.

Further, the position information stored in the R position memory 13 and the B position memory 14 is adapted to be given to the deviation detecting unit 16, and the position information stored in the G position memory 12 is stored in the position information comparing unit. The reference position memory 11 is supplied via a switch 23 which is controlled by a signal output from the controller 15. The position information signal read from the reference position memory 11 is applied to the position information comparison unit 15 and the deviation detection 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 comparison unit 15 determines
When the correction of the binarization level is required, the binarization correction request signal (K) is output to the binarization level memory 7.

The above-described structure for processing the data picked up 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 are provided.
The information from 14 is provided to the deviation detection unit 16. The deviation detection unit 16 detects the deviation based on the information of three cameras provided from the reference position memory 11, the R position memory 13, or the B position memory 14, and applies the detection signal to the adjustment amount calculation unit 17. Yes. The adjustment display signal (SA) calculated by the adjustment amount calculation unit 17 is given to the monitor 18 and a predetermined display is made on the monitor 18. The adjuster adjusts the position of the liquid crystal panel by operating the 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 the operating procedure in the device of the present invention. The following processing operations are performed before adjustment. First, the binarization level of each color R, G, B is set separately (step S1). First, as described above, the camera 3 outputs a dot pattern signal for capturing only one dot from the signal generator 9, and the liquid crystal projector 1 outputs the dot pattern signal to the screen 2.
A video image is projected onto the camera, and the video image is captured by the camera 3. Then, the binarization level setting unit 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, the dot image data (a), which is a dot image of one frame based on the dot image captured by the camera 3, is given to the binarizing unit 4. Then, the binarization unit 4 binarizes this dot image data (a) with the initial value stored in the binarization level memory 7 into binarized dot image data (a), and stores it in the image memory 5. Write.

The position detector 10 takes in the binarized dot image data (a) written in the image memory 5 and detects the dot size. When this dot size data is given to the binarization level setting unit 6, the binarization level setting unit 6
However, after the setting level signal (C) changed by one step is written in the binarization level memory 7, the process proceeds to the dot image data (A) acquisition again. Usually, most of the dot images are "H" at the initial value of the low level, and as the set level is raised, the dots represented by "H" gradually become small, and eventually almost all become "L". The time when the step change is completed is the time when it becomes almost "L". The above operation is performed until the end of this step change.

The binarization level setting unit 6 is capable of recognizing dots from the accumulated data when the data acquisition up to the end of the step change is completed and the level at which the size change with respect to the step change is small is optimal. Final writing is performed in the binary level memory 7 as a set level. Then, the color switching request signal (K) is output to switch the color displayed on the screen 2. The above processing is repeated to set the binarization level for the three colors of R, G and B.

Subsequently, the color switching section 8 outputs the color selection signal (SI) to the memory selection switches 20 and 21 to select the G position memory 12 for G which is the reference for the convergence adjustment, and the binarization level. A color selection signal (f) for selectively reading the binarization level for G from the binarization levels for R, G, B 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 unit 4 writes binarized dot image data (a) at the selected binarization level for G and writes it in the image memory 5. The position detection unit 10 detects position information based on the data obtained from the image memory 5, and this position information data (K) is selected by the color selection signal (S) to the reference position memory 11. It is given to the reference position memory 11 via the switch 20 and 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 liquid crystal projector 1 displays the R, G, and B images selected by the color selection signal (F) output by the color switching unit 8.
The dot image data (a) is captured by the image capture request signal (e) (step S3). Then, the position detection unit 10 detects the position information of the liquid crystal panel of the color displayed at that time from the binarized dot image data (a) stored in the image memory 5 through the binarization unit 4 (step S4). This 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 by the color selection signal (SI) output from the color switching unit 8.
13 or B position memory 14 stores the present position information.

Then, it is judged whether or not the color selected at that time is G (step S5), and if it is not G (R or B), the R position memory 13 or the B position memory 14 is determined.
Is stored in the reference position memory 11 within the allowable range with respect to the position information stored in the position information comparison unit 15 (step S6), the current position information is outside the allowable range. If there is, the position information comparison unit 15 gives an up or down binarization correction request signal (K) to the binarization level memory 7. By this binarization correction request signal (K), the binarization level given to the binarization unit 4 is read by reading the binarization level which is one step up or down from the binarization level at that time. Corrected (step S
7). In step S6, the processes of steps S3 to S6 are repeated until the current position information falls within the predetermined range. If the current position information is within the predetermined range in step S6, deviation detection is performed (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 judged whether or not the adjuster has operated the key for ending the adjustment (step S10), and if it is judged that the key has been operated, the processing is ended. When 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) from the color switching unit 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 comparison 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). It is determined whether or not it is (inside) (step S12), and if it is normal, the reference position information is updated (step S13), and the process proceeds to step S8 to detect the deviation.
In this update, when the adjustment amount is displayed by the previous shift detection and the adjuster adjusts the position of the liquid crystal panel, the reference position information of G may have changed.
Each time the position information within a predetermined range of the liquid crystal panel for use is obtained, the position information detected at that time is used as the reference position information. If the current position information is abnormal in step S12, the position information comparison unit 15 outputs a binarization correction request signal (K) to correct the binarization level given to the binarization unit 4, After further invalidating the current position information (step S14), the process proceeds to step S10, 3
It is determined whether or not the color convergence adjustment is completed.

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

[0034]

As described above, since the convergence adjusting apparatus according to the present invention sets the optimum binarization level for each color before the adjustment, the influence of the focusing deviation due to the difference in wavelength can be reduced. . Before adjustment, the position of the liquid crystal panel for the reference color is detected and stored as reference position information, and at the time of subsequent adjustment, the position information of the liquid crystal panel obtained by displaying the test pattern for each color is displayed. Since the binarization level is corrected when compared with the reference position information and exceeds the allowable range, even under conditions different from the binarization level setting conditions due to time change of the lamp of the liquid crystal projector, external light change, etc. By suppressing the influence, it is possible to perform accurate position determination and displacement detection at high speed. Further, if the position information of the liquid crystal panel for the reference color 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 characteristic of the camera is reduced. be able to. As described above, the present invention has excellent effects such as highly accurate convergence adjustment.

[Brief description of drawings]

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

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

FIG. 3 is a diagram illustrating an 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]

 1 Liquid crystal 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 Deviation detection unit

Claims (2)

[Claims] 1. A test pattern displayed on a liquid crystal panel and projected on a screen is imaged, the imaged image is binarized based on a binarization level, and based on the binarized image. In the convergence adjustment device that repeats the process of detecting the relative displacement of the liquid crystal panels for a plurality of colors, a unit that projects a test pattern for each color, a unit that captures an image projected by the unit, The image picked up by the means is binarized based on the binarization level to obtain 2
A means for generating a binarized image, a means for sequentially changing the binarized level, and a plurality of binarized images binarized based on a series of binarized levels are used to change the binarized image. A means for setting a relatively small binarization level as a binarization level for each color, and a binarized image binarized on the basis of the binarization level set by the means, Means for detecting position information, means for storing position information of the liquid crystal panel for the reference color detected by the means as reference position information, reference position information stored by the means, and the set binarization level 2 binarized based on
Means for comparing subsequent position information obtained from the binarized image, 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 comparison by the means. And a means for correcting the binarization level if the result of the judgment by the judgment means is not within a predetermined range. 2. If the position information of the liquid crystal panel for the reference color obtained thereafter is within a predetermined range as a result of the judgment by the judgment means, a means for updating the reference position information to the position information is provided. The convergence adjusting device according to claim 1, wherein: