JP2001230991A - Projector and image processor used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict an image distortion from occurring, when an image is shifted and projected not only in an input image but also in the image which is generated inside a projector and superimposed on the input image. SOLUTION: When it is indicated from a user that a specified superimposition image is superimposed on the input image expressed by an input image signal and displayed, a compositing image signal, which expresses a composite image obtained by superimposing the superimposition image on the input image in accordance with the indication is generated and outputted as a display image signal. The compositing image signal is adjusted to form a nearly trapezoidal image in an image forming part, in order to correct the image distortion occurring, when the nearly rectangular image formed in the image forming part is shifted and projected on a screen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a technique for adjusting a distortion of an image generated in a projector, particularly in a case of tilt projection.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory diagram showing an image projected using a projector. FIG. 4A shows a first positional relationship between the projector 100 and the screen SC, and FIG. 4B shows an image displayed on the screen SC in the positional relationship shown in FIG. 302 is shown. In the positional relationship shown in FIG.
The optical axis 100c of light (hereinafter, also referred to as "image light") representing an image emitted from 00 and a normal SCn of the screen SC
And match. In this case, the image 302 displayed on the screen SC as shown in FIG. 4B is an image without distortion (hereinafter, an image without distortion is also referred to as a “normal image”).

[0003] On the other hand, FIG.
FIG. 4D shows an image 304 displayed on the screen SC in the positional relationship shown in FIG. 4C. In the positional relationship shown in FIG. 4C, the optical axis 100c of the image light emitted from the projector 100 does not coincide with the normal SCn of the screen SC, and is shifted by an angle θ.
In such a case, as shown in FIG. 4D, the image 304 displayed on the screen SC is an image distorted in a substantially trapezoidal shape (hereinafter, the distorted image is also referred to as a “distorted image”).

[0006] As shown in FIG. 4 (C), when tilting and projecting image light, for example, an image (hereinafter, referred to as a “preliminary”) which is distorted into a substantially trapezoidal shape on a liquid crystal panel 200 provided inside the projector 100. Distorted image is called “distortion corrected image”
). Thus, the image projected on the screen SC is displayed as a distortion-free normal image 304A as shown by the broken line in FIG. 4D. FIG.
The normal image 304A of FIG. 4D is the same as the normal image 302 of FIG.
It is almost the same image as.

[0005]

FIG. 5 is an explanatory diagram showing a distortion-corrected image when a conventional projector performs tilt projection. In a conventional projector, an image represented by an input image signal shown in FIG.
(“Input image”) is adjusted so as to be a distortion-corrected image as shown in FIG. O shown in FIG.
The SD image is combined with the distortion-corrected image shown in FIG. 5B, as shown in FIG. The OSD image represents a menu image for setting operating conditions of the projector, conditions relating to image quality of a displayed image such as contrast and brightness, and a decoration image for decorating an input image. The decoration image is an image for decorating an input image such as a pointer image and an underline image. Distortion corrected image and OS
The combined image combined with the D image is projected and displayed as shown in FIG.

As shown in FIG. 5D, the OSD image is
The image is directly synthesized with the original image after the distortion correction. Therefore, only the OSD image among the projected and displayed images is distorted as shown in FIG. 5E due to the influence of the tilt projection. Note that this distortion is relatively inconspicuous when the OSD image is a character image, but is more remarkable when it is a graphic image.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art. In a projector, image distortion that occurs when an image is tilted and projected is reduced not only in an input image but also in the projector. It is an object of the present invention to provide a technique capable of suppressing even an image generated by the above and superimposed on an input image.

[0008]

In order to solve at least a part of the above problems, a projector according to the present invention includes an image processing unit that processes an input image signal and outputs a display image signal; An image forming unit for forming an image based on the display image signal, and a projection optical system for projecting a formed image formed on the image forming unit on a screen, the image processing unit includes: When a user instructs to display a specific superimposed image on the input image represented by the input image signal, a composite image representing a composite image in which the superimposed image is superimposed on the input image according to the instruction An image combining unit that generates a signal and outputs the combined image signal as the display image signal; and a substantially rectangular formed image formed in the image forming unit is projected on the screen. To correct image distortion caused when that is characterized by comprising, with the image distortion adjusting unit for adjusting a composite image signal to be substantially trapezoidal form image is formed in the image forming unit.

[0009] The projector of the present invention adjusts the image signal representing the composite image obtained by superimposing the superimposed image on the input image so as to correct the image distortion generated by the tilt projection. In addition, it is possible to correct image distortion of a superimposed image generated in the projector.

Here, the superimposed image includes a menu image for setting operating conditions of the projector.
Further, the overlay image may include a decoration image for decorating the input image.

The image processing apparatus of the present invention is used in a projector for projecting and displaying a formed image formed on an image forming section on a screen, and for processing an input image signal and outputting a display image signal. An image processing apparatus according to
When a user instructs to display a specific superimposed image on the input image represented by the input image signal, a composite image representing a composite image in which the superimposed image is superimposed on the input image according to the instruction An image synthesizing unit that generates a signal and outputs the synthesized image signal as the display image signal; and an image distortion that occurs when a substantially rectangular formed image formed in the image forming unit is tilted and projected on the screen. An image distortion adjusting unit that adjusts the composite image signal so that a substantially trapezoidal formed image is formed in the image forming unit for correction.

By applying the image processing apparatus of the present invention to an image processing section of a projector, the projector of the present invention can be configured.

[0013]

DETAILED DESCRIPTION OF THE INVENTION Next, an embodiment of the present invention will be described based on examples. FIG. 1 is a block diagram showing the overall configuration of an image display device as an embodiment of the present invention. This image display device has a first analog image input terminal 10 and a second analog image input terminal 1
2, a video decoder 20, and a video processor 22
A first image memory 24, an OSD memory 26, a second image memory 28, a liquid crystal panel driving circuit 30, a liquid crystal panel 32, and a remote controller control circuit 34.
And a computer system comprising:

This image display device is a so-called projector, and a lighting device 5 for illuminating the liquid crystal panel 32.
0, and a projection optical system 52 that projects light (image light) representing an image emitted from the liquid crystal panel 32 onto the screen SC. Note that the liquid crystal panel 32 is
It is used as a light valve (light modulator) for modulating the illumination light emitted from. In such a projector, the liquid crystal panel drive circuit 30 and the liquid crystal panel 32
It corresponds to the "image forming unit" of the present invention. Video decoder 2
0, a video processor 22, and a first image memory 24.
, The OSD memory 26, the second image memory 28, and the remote controller control circuit 34 correspond to the "image processing unit" or "image processing device" of the present invention. The liquid crystal panel drive circuit 30 may be included in the image processing unit instead of the image forming unit.

Although not shown, this image display device has three liquid crystal panels 32 for three colors of RGB. Further, each circuit described later has a function of processing image signals for three colors. The lighting device 50 emits 3 white light.
It has a color light separation optical system that separates color light,
The projection optical system 52 has a combining optical system that combines image light of three colors to generate image light representing a color image. The configuration of the optical system of such a projector is described in, for example, Japanese Patent Application Laid-Open No.
Since it is described in detail in Japanese Patent No. 1045, description thereof is omitted here.

The input image signal includes an analog image signal CG input to a first analog image input terminal 10;
Any one of the analog image signal TV input to the second analog image input terminal 12 and the analog image signal TV can be selectively used. The video decoder 20 converts the first analog image signal or the second analog image signal TV into a digital image signal including image signal components of three colors that can be input to the video processor 22.

The image signal input to the video processor 22 is supplied to a liquid crystal panel drive circuit 30 after various image processing described later is executed. LCD panel drive circuit 3
0 generates a drive signal for driving the liquid crystal panel 32 according to the given image signal. LCD panel 32
Modulates the illumination light according to the drive signal.

The user can use the remote controller 40 to input setting values for various adjustments relating to image display such as contrast adjustment and brightness adjustment, which will be described later, and operating conditions of the projector. Also, various decorative images for decorating an input image such as a pointer image and an underline image can be displayed. Although not shown, the main body of the image display device also has
Keys and buttons for inputting various set values and conditions are provided.

B. FIG. 2 is a block diagram showing the internal configuration of the video processor 22. The video processor 22 includes a memory controller 62, an enlargement / reduction processing circuit 64, and an image quality adjustment circuit 6.
6, OSD control circuit 68, and trapezoidal distortion correction circuit 70
, A CPU 72 and a control memory 74. The operation of each block is controlled by the CPU 72. The control memory 74 stores information for controlling the operation of each block.

The memory controller 62 receives the digital image signal DV supplied from the video decoder 20 shown in FIG.
0 is written to the first image memory 24, and control for reading a digital image signal from the first image memory 24 is performed. The enlargement / reduction processing circuit 64 has a function of executing enlargement or reduction of an image in accordance with a user setting, and performing interpolation processing as needed at the time of enlargement or reduction.

The image quality adjustment circuit 66 is a circuit for adjusting the contrast and brightness of the image according to the settings of the user. The image quality adjustment circuit 66 adjusts the image signal DV1 supplied from the enlargement / reduction processing circuit 64 according to the set image quality, and outputs it as an image signal DV2.

The OSD control circuit 68 includes a menu image for adjusting image quality and setting operating conditions, a decorative image such as a pointer image and an underline image (hereinafter referred to as an “OSD image”).
(Also referred to as OSD image signal), and synthesizes the generated image signal with the image signal DV2 supplied from the image quality adjustment circuit 66. The OSD image signal is generated when the user instructs the display of the OSD image from the remote controller 40 and the OSD control circuit 68 reads out the image data stored in the OSD memory 26.

The trapezoidal distortion correction circuit 70 corrects the image distortion (trapezoidal distortion) that occurs in the case of tilt projection, so that the composite image signal D supplied from the OSD control circuit 68 is corrected.
V3 is adjusted to obtain a distortion-corrected image signal D representing a distortion-corrected image.
This is a circuit for outputting V4. This trapezoidal distortion correction is performed by the image signal DV3 supplied from the OSD control circuit 68.
Is written into the second image memory 28 and is read out from the second image memory 28. As the trapezoidal distortion correction circuit 70, various trapezoidal distortion correction circuits can be used.

FIG. 3 is an explanatory diagram showing the image distortion correction performed in the trapezoidal distortion correction circuit 70. OSD
The control circuit 68 generates the OSD image shown in FIG. The OSD image in FIG. 3B shows an example of a menu screen, and a hatched area indicates a black screen area.
Then, the OSD image is superimposed on the superimposed position on the image (input image) represented by the image signal DV2 supplied to the image quality adjustment circuit 66 shown in FIG.
Is generated.

The trapezoidal distortion correction circuit 70 corrects the composite image represented by the composite image signal DV3 supplied from the OSD control circuit 68 for trapezoidal distortion by tilt projection, as shown in FIG.
A distortion-corrected image shown in (D) is generated. The hatched area in FIG. 3D indicates a black screen area. The generated distortion-corrected image is output as a distortion-corrected image signal DV4, and is projected and displayed on the screen SC. Screen S
As shown in FIG. 3E, the image projected and displayed on C is not only the image represented by the image signal DV2 but also the OSD image is a normal image without distortion. The hatched area in FIG. 3D is also projected and displayed on the screen SC. However, since this area is a black screen as described above, it hardly affects the display screen.

As described above, in the above embodiment, image distortion correction by tilt projection is performed on a composite image in which an OSD image is superimposed on an input image. OSD, which was a conventional problem
It is also possible to correct the image distortion of the image.

It should be noted that the present invention is not limited to the above examples and embodiments, but can be implemented in various modes without departing from the gist of the invention.
For example, the following modifications are possible.

In the above embodiment, the configuration of the projector using the transmissive liquid crystal panel as the image forming unit has been described. However, the present invention can be applied to other types of projectors. Other types of projectors use reflective liquid crystal panels or digital micromirror devices (Texas Instruments trademark).
And those using a CRT.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an image display device as an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a video processor 22.

FIG. 3 is an explanatory diagram showing image distortion correction performed in a trapezoidal distortion correction circuit 70.

FIG. 4 is an explanatory diagram showing an image projected using a projector.

FIG. 5 is an explanatory diagram showing a distortion-corrected image in the case of tilt projection in a conventional projector.

[Explanation of symbols]

 Reference Signs List 10 first analog image input terminal 12 second analog image input terminal 20 video decoder 22 video processor 24 first image memory 26 OSD memory 28 second image memory 30 liquid crystal panel drive circuit 32 liquid crystal panel 34 remote controller control circuit 40 remote controller 50 illumination device 52 projection optical system 62 memory controller 64 enlargement / reduction processing circuit 66 image quality adjustment circuit 68 OSD control circuit 70 trapezoidal distortion correction circuit 72 CPU 74 Control memory 100 Projector 100c Optical axis 200 Liquid crystal panel 302 Normal image 304 Image 304A Normal image SC Screen SCn Normal

Claims (4)

[Claims] An image processing unit configured to process an input image signal and output a display image signal; and an image forming unit configured to form an image based on the display image signal. A projection optical system for projecting a formed image formed on the image forming unit on a screen, the image processing unit superimposing a specific superimposed image on an input image represented by the input image signal. When the display is instructed by the user, a composite image signal representing a composite image in which the superimposed image is superimposed on the input image is generated according to the instruction, and the composite image signal is output as the display image signal. An image synthesizing unit, in order to correct an image distortion generated when a substantially rectangular formed image formed in the image forming unit is projected on the screen, A projector configured to adjust the composite image signal so that a substantially trapezoidal formed image is formed. 2. The projector according to claim 1, wherein the superimposed image includes a menu image for setting an operation condition of the projector. 3. The projector according to claim 1, wherein the superimposed image includes a decoration image for decorating the input image. 4. An image processing apparatus used for a projector for projecting and displaying a formed image formed on an image forming unit on a screen, processing an input image signal and outputting a display image signal, When a user instructs to display a specific superimposed image on the input image represented by the input image signal, a composite image representing a composite image in which the superimposed image is superimposed on the input image according to the instruction An image synthesis unit that generates a signal and outputs the synthesized image signal as the display image signal; and an image distortion generated when a substantially rectangular formed image formed in the image forming unit is tilted and projected on the screen. An image distortion adjusting unit that adjusts the composite image signal so that a substantially trapezoidal formed image is formed in the image forming unit. Image processing apparatus.