JP3445759B2 - Automatic pixel position 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 an automatic pixel position adjusting technique for a projection type display device which improves the resolution and brightness of the entire image by displaying the images of a plurality of projectors by superimposing them on the same screen and displaying them. It is about.

[0002]

2. Description of the Related Art In a projection type display device, it is possible to display images from a plurality of projectors such as to improve brightness on a screen, to perform stereoscopic display by a polarization method, and to improve resolution by a superposition projection method. It is common practice to project and display the same screen. In such a case, it is necessary to accurately adjust the projection position of each projector with an accuracy of not more than the pixel size on the screen.

Conventionally, when such an adjustment is performed, a specific pattern such as a lattice pattern is displayed from each projector as shown in FIG. 7, and an observer manually adjusts the pixel position of each projector. It was

[0004]

In the prior art described above, it is necessary to display a specific pattern such as a lattice pattern when adjusting the pixel position, and the pixel position is adjusted when a normal image is displayed. I can't. Therefore, in the case of displaying for a long time, there is a problem that a large projection type projector that consumes a large amount of power causes a shift in the projection position due to a temperature change, and thus it is not possible to prevent temporal deterioration of display characteristics. Further, since the operation is performed manually, there is a problem that operation cost is high. The present invention has a problem that the conventional technique has a problem that the pixel position cannot be adjusted during normal image display and the operation cost is high. An object of the present invention is to provide an automatic pixel position adjusting device capable of adjusting the pixel position even at the time of normal image display in which a plurality of projectors overlap each other and further reducing the operation cost. .

[0005]

In order to solve the above-mentioned problems, an automatic pixel position adjusting apparatus according to the present invention is a projection type display for displaying images by superimposing images of a plurality of projectors on the same screen. In the apparatus, pattern generating means for generating a pattern signal for pixel position detection, and signal synthesizing means for synthesizing the pattern signal from the pattern generating means and a normal original image signal and displaying them on a screen,
Image pickup means for picking up an image on the screen on which the pattern signal for pixel position detection is synthesized and displayed, pixel position detection means for detecting the pixel position of each projector from the image picked up by the image pickup means, and the detected pixel and a pixel position adjustment means of each projector by feeding back the position information to adjust the pixel positions of the projectors, the signal combining means
For a certain frame of the original image signal for each projector
The pattern signal for pixel position detection is added to the original image signal and displayed.
In the next frame, the pattern signal for detecting the pixel position is shown.
Is displayed by subtracting the number from the original image signal.
The pixel position detecting means picks up an image of the certain frame.
Subtract the image of the image of the next frame from the image
The pixel position is detected by the difference image signal.
Characterized in that there.

Alternatively, in the above automatic pixel position adjusting device, the pixel position detecting means is an image of a certain frame.
Image of the image of the next frame from the image of
The difference after subtracting the image is less than the preset threshold value.
It is characterized in that the pixel position is detected only in the case below .

Alternatively, in the above automatic pixel position adjusting device, the signal synthesizing means displays the pixel position detecting pattern signal in an extremely narrow arbitrary area on the screen.
It is characterized in that the imaging means is for enlarging and imaging the region .

[0008] Alternatively, in the automatic pixel position adjusting device described above, the signal combining means is a <br/> shall be displayed a pattern signal for detecting picture element position imaging means only a minimum period possible imaging It is characterized by

[0009]

In the present invention, the pattern for detecting the pixel position is combined with the normal original image signal and displayed on the screen, the image on the screen is picked up, and the pixel position is determined for each projector from the pattern signal in the image. By detecting, the pixel position can be adjusted even during normal image display.

[0011]

According to the present invention, the pixel position detecting pattern is not displayed by completely replacing it with the original image signal, but is displayed in addition to the display image signal in a frame having an image signal.
In the next frame, the pixel position detection pattern signal is subtracted from the display image signal for display, and in the pixel position detection means, the image signal obtained by subtracting the image signal obtained by capturing the latter image from the image signal obtained by capturing the former image. It makes it possible to detect the pixel position by extracting the pattern signal, and the afterimage characteristic of the human eye causes the images of both frames to cancel each other out as a temporal average, resulting in the display of the pixel position detection pattern. Don't let it go unnoticed. Furthermore, the pixel
When combining and displaying the pattern for position detection, the entire image
Normally, only in the very small area required for pixel position detection
The original image signal of
Can be captured by an image capture device such as a video camera
The minimum normal period of several frames, that is, several tens
By setting a period of about msec,
Layers, most observers even when adjustments are made during normal image display
Make it invisible to.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

[Embodiment 1] FIG. 1 is a diagram for explaining a first embodiment for illustrating the principle of the present invention, in which 101 and 102 are projectors,
Reference numeral 03 is a screen, 104 is an image pickup device such as a video camera, 105 is a pixel position detection device, 106 and 107 are projector pixel position adjustment devices, 108 is an observer, 109
Is a pixel position detection pattern generator, and 110 and 111 are normal original image signals and pixel position detection pattern generator 109.
Is a signal synthesizing device for synthesizing the pattern signals of.

In the present embodiment, the number of projectors is two in order to simplify the explanation, but it is obvious that the present invention can be applied to three or more projectors. Further, although the projector is configured to project from the back of the screen, it is also possible to project from the front of the screen. It is also possible to insert a mirror in the optical path between the projector and the screen in order to shorten the overall depth.

The signal synthesizing devices 110 and 111 input an image signal obtained by synthesizing the original image signal and the pixel position detecting pattern signal of the pixel position detecting pattern generator 109 to the respective projectors 101 and 102. The images from the projectors 101 and 102 based on this input image signal are displayed on the screen 1
03, and the pixel position is projected by the video camera 104.
Take an enlarged image with. From this imaged image, the pixel position detection device 105 detects the pixel positions of the projectors 101 and 102, and the information is used as the pixel position adjustment devices 106 and 1.
By feeding back to 07, the pixel position is automatically adjusted. The procedure for detecting the pixel position information will be described in detail below.

FIG. 2 is a diagram showing the relationship between the original image and the pixel position detection pattern.

Now, in order to explain the principle of the present invention, in a portion where a pixel position is to be detected (here, it is assumed to be the central portion of the screen), a certain area is assumed to be a pixel as shown in FIG. It will be replaced with a pattern for position detection (actually, as described later in the second embodiment, the original pattern is used).
Composite display of image and pixel position detection pattern) . The size of the region depends on how much pixel deviation can be adjusted. However, in the case of the projection display device as the object of the present invention, the pixel deviation should be accurate to within a few pixels at the maximum. I think I have. Therefore,
In general, one side may be a very narrow rectangular area having a size of about several pixels. In the figure, for the sake of clarity, they are shown in a considerably large size. In this area, it is assumed that the pixel position detection pattern (FIG. 2B) is replaced with a normal image signal (original image (FIG. 2A)) and displayed (FIG. 2C). There are various possible patterns, but the simplest one is one in which one white dot is displayed on a black background. The magnification of the video camera for imaging needs to be set so that this one dot can be captured as a large image. A general method can be applied to the method for detecting the pixel position from the captured image. For example, the center of the pixel position can be determined by calculating the center of gravity of the captured image.

FIG. 3 illustrates the procedure for adjusting the pixel position with a temporal flow.

First, in a certain frame, the pattern is displayed only by the projector 101, and the other projectors 1
02 displays a uniform pattern (usually black) in the same area, and the imaging device 104 images this area. In the next frame, only the projector 102 displays a pattern, the other projectors 101 display a uniform pattern (usually black) in the same area, and the imaging device 104 images this area. In this way, the mutual position of each projector can be detected by repeating this procedure for the number of projectors. With this information, the pixel position of the corresponding projector is automatically adjusted. As a method or means for adjusting the pixel position, a method or means for mounting the projector itself on a precision optical stage and mechanically adjusting this stage is also conceivable. A method of adjusting the pixel position is suitable. There are many such devices, and there is no problem in terms of feasibility.

The pixel position detection and pixel position adjustment operations by the pixel position detection device 105 are performed by the pixel position detection device 10.
5, the detection operation of the pixel position detection pattern is always performed, and the operation may be started by the detection of the pattern, or may be started by the instruction from the signal synthesizing means 110 and 111 in conjunction with the synthetic display of the pattern. .

[Embodiment 2] FIG. 4 illustrates a second embodiment of the present invention.

The present embodiment example is the same as the original image in the present invention.
To explain the combined display of patterns for pixel position detection
There, instead of completely replacing the display of the original image and the pattern of the pixel position detecting as assumed in the first embodiment, the signal synthesizer 110 and 111, the pixel position in the original image in a certain frame A pattern for detection is added and displayed, and in the next frame, the pattern for pixel position detection is subtracted from the original image signal for display, and in the pixel position detection device 105, the latter captured image is subtracted from the former captured image. Let the image be an image for pixel position detection. This will be described in detail below.

In a certain frame, the original image signal P0
In addition to (x, y), a pixel position detection pattern P1
A display obtained by adding (x, y) is displayed (FIG. 4A). In the next frame, the original image signal P0 ′ (x, y) minus the pixel position adjustment pattern is displayed (FIG. 4B). 4A and 4B show the composite image
In the figure, the horizontal axis is taken in the direction of the line and the pixel value is taken in the vertical axis.

The above image is displayed on the screen, and when the latter image signal is subtracted from the former image signal obtained by capturing the image, {P0 (x, y) + P1 (x, y)}-{P0 '(x,
y) −P1 (x, y)} = {P0 (x, y) −P0 ′
(X, y)} + 2P1 (x, y).

Since a normal image signal has a strong correlation between frames, if the difference between frames is taken, P0 (x, y)-
P0 ′ (x, y) becomes almost 0. However, since the polarity of the pixel position adjustment pattern is inverted and added, the amplitude doubles, and only the pixel position adjustment pattern can be detected (FIG. 4C). On the other hand, in the image displayed to the eyes of the observer in a very short time of about the frame period, the pixel position detection pattern portion is canceled by the integration characteristic of the eyes and is hardly perceived. This principle is based on the NTSC signal system, which is one of the current color television signal systems, even if the color subcarrier signal is added to the luminance signal and displayed, the phase of the color subcarrier signal is increased between frames and between upper and lower lines. The effect is clear from the fact that it is difficult to perceive because it is inverted.

The procedure for detecting the pixel position of each projector 101, 102 is basically the same as that of the first embodiment. In addition, it can be easily inferred that signals for several frames can be used to improve the signal-to-noise ratio (S / N ratio).

[Embodiment 3] FIGS. 5 and 6 are views for explaining a third embodiment of the present invention.

As shown in the second embodiment, when a difference is taken between consecutive frames, the difference becomes large in a scene with a lot of motion (FIG. 5), and a pixel detection pattern is successfully extracted. It may not be possible.
Therefore, in the pixel position detection device 105, the difference between the frames of the original image is calculated in the area where the pattern for pixel position detection is displayed, and the pixel position detection is performed only when the difference is less than a threshold value (FIG. 6). If the difference is large (FIG. 5), the process is skipped so that the automatic adjustment of the pixel position can be prevented even if there is a scene with a lot of movement.

[0030]

As described above, according to the present invention, automatic pixel position adjustment is possible even when a normal image signal is displayed. Therefore, it is not necessary to perform the pixel position adjustment operation before the operation of the apparatus or during the screening. Therefore, it is possible to improve the display characteristics of the projector device, and there is a remarkable effect that the operation cost can be reduced by reducing the maintenance staff cost.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an exemplary embodiment of the present invention.

FIGS. 2A, 2B, and 2C are diagrams for explaining the first embodiment of the present invention, and are diagrams showing the relationship between an original image and a pixel position adjustment pattern. .

FIG. 3 is a diagram for explaining an example of the first embodiment,
It is a figure which shows the temporal display sequence for detecting a pixel position.

4 (a), (b), (c) are diagrams for explaining the second embodiment of the present invention, and a diagram showing a temporal display sequence for detecting a pixel position. Is.

5 (a), (b), and (c) are diagrams for explaining a third embodiment of the present invention (and are diagrams showing a case where a difference between frames is large. FIG.

6A, 6B, and 6C are diagrams for explaining the third embodiment example, and are diagrams showing a case where a difference between frames is small.

FIG. 7 is a diagram for explaining a conventional technique.

[Explanation of symbols]

101, 102 ... Projector 103 ... Screen 104 ... Imaging device 105 ... Pixel position detection device 106, 107 ... Projector pixel position adjustment device 108 ... Observer 109 ... Pixel position detection pattern generator 110, 111 ... Original image and pixel position Signal synthesizer for synthesizing signals from detection pattern generator

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-168039 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03B 21/00-21/30 G02F 1 / 13 G02F 1/1335-1/13363 H04N 5/74

Claims (4)

(57) [Claims] 1. A projection type display device for displaying images by superimposing images of a plurality of projectors on the same screen to display the images, and pattern generating means for generating a pattern signal for pixel position detection, and the pattern generating means. Signal synthesizing means for synthesizing the pattern signal of the above and the normal original image signal and displaying it on the screen, image pickup means for picking up the image on the screen on which the pattern signal for detecting the pixel position is synthesized and displayed, comprising a pixel position detecting means for detecting a pixel position of each projector from the image captured, a pixel position adjustment means of each projector by feeding back the pixel position information the detected adjusting the pixel positions of the respective projector means, the The signal synthesizing means calculates the original image signal for each projector.
In the frame, the pattern signal for pixel position detection is used as the original image.
Display in addition to the signal, and detect the pixel position in the next frame
The pattern signal for the display is subtracted from the original image signal and displayed
The pixel position detecting means captures an image of the certain frame.
The image of the next frame from the captured image
Detection of pixel position by subtracted image signal
Automatic pixel alignment device comprising a Dearuko. 2. The pixel position detecting means is configured to detect a pixel position only when a difference obtained by subtracting an image of an image of a next frame from an image of an image of a certain frame is less than or equal to a preset threshold value. 2. The automatic pixel position adjusting device according to claim 1, wherein 3. The signal synthesizing means displays the pattern signal for pixel position detection in an extremely narrow arbitrary area on the screen, and the image pickup means magnifies and picks up the area. The automatic pixel position adjusting device according to claim 1 or 2, wherein . 4. The signal synthesizing means displays the pattern signal for pixel position detection only for a minimum period during which the image pickup means can pick up an image.
Or the automatic pixel position adjusting device described in 3 .