JP2001186538A - Video projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of the conventional video projector that has caused complicated installation of the projector and a complicated distortion correction work and by which distortion correction has not been completely able to eliminate, depending on an operator because the distortion correction is performed for each installation of the projector through manual adjustment. SOLUTION: The video projector of this invention consists of a projection angle sensor 21, that detects the projection angle of a projection lens 18, an installation angle sensor 22 that senses the installation angle of the video projection means, and a CPU 20 that calculates an angle of field magnification- deformation amount of a video signal, on the basis of the projection angle and the installation angle sensed by the projection angle sensor 21 and the installation angle sensor 22 respectively so as to control the field angle magnification-deformation amount, and a field angle conversion circuit 13 corrects trapezoidal distortion of a video image in response to the projection angle and the installation angle sensed by each sensor and projects the corrected image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video projector apparatus and, more particularly, to a method for correcting trapezoidal distortion of a projected image.

[0002]

2. Description of the Related Art The size of color television receivers has been increased, and the size of a cathode ray tube (CRT) type receiver, which is directly viewed, is naturally limited because the size of the cathode ray tube increases in weight. come. Therefore, using a projection type cathode ray tube or liquid crystal display panel, the image on the cathode ray tube surface or the liquid crystal display panel surface is enlarged and projected by a lens,
A video projector device (hereinafter simply referred to as a projector) for displaying on a screen has been developed, and a large-screen TV receiver of a direct-view type, which is difficult to realize, has been put to practical use.

[0003] The projector is of a type in which a projector is arranged in front of a screen to view an image reflected from the screen (hereinafter referred to as a reflection type projector), and a projector is arranged in the back of the screen to transmit light through the screen. (Hereinafter referred to as a transmissive projector).

On the other hand, the projector is installed horizontally,
Install the screen vertically so that the center of the projected image from the projector and the center of the screen are on the same horizontal line, and the projection angles from the center of the projected image of the projector to the top, bottom, left and right edges of the image displayed on the screen are equal It is desirable to be arranged so that it becomes. The screen size of an image displayed on the screen is determined by the magnification of a lens that enlarges and projects the image and the projection distance from the projector to the screen.

In the case of the reflection type projector, the screen is vertically arranged along the wall surface of the living room, and the projector is horizontally arranged in the living room in front of the screen to secure a predetermined projection distance between the screen and the projector. Although it is possible, to arrange the projection distance between the center of the projected image of the projector and the upper, lower, left and right edges of the displayed image on the screen, the projector must be installed horizontally on a high pedestal, It is expected that the behavior of the resident will be hindered, or the projector will fall into an unstable state such as falling down. For this reason, the projector is generally mounted directly on the floor or suspended from the ceiling. However, the distance from the center of the projected image of the projector to the top, bottom, left and right edges of the image displayed on the screen A difference occurs in the distance, and a phenomenon occurs in which the image displayed on the screen is distorted into a trapezoid.

[0006] In the case of a transmissive projector, the projector and the screen are arranged in the same housing, and the projection distance of the image light projected from the projector to the screen is secured by using a reflection mirror. This transmission type projector has an advantage that the projector and the screen can be fixed in the housing and the depth dimension of the housing can be reduced, but the image displayed on the screen from the center of the projected image of the projector via the reflecting mirror is reduced. The distance between the top and bottom ends and the left and right ends differs, and a phenomenon occurs in which the image displayed on the screen is distorted in a trapezoidal shape.

A projector having a function of correcting and correcting trapezoidal distortion of an image resulting from the positional relationship between the projector and the screen has been developed and put to practical use. A projector having a function of correcting and correcting trapezoidal distortion of the projector will be described with reference to FIG. In addition, FIG.
In the projector, a function of projecting an image on a screen after correcting trapezoidal distortion is mainly shown.

Reference numeral 30 in the figure denotes a projector. An input terminal 31 receives and tunes a television broadcast channel to generate a baseband video signal, and performs video processing, chroma processing and synchronization on the baseband video signal. An analog video signal subjected to deflection processing or an analog video signal reproduced and supplied from various video devices is input.

The analog video signal supplied to the input terminal 31 is digitally converted by an A / D conversion circuit 32, and the converted digital video signal is supplied to a view angle conversion circuit 33. The angle-of-view conversion circuit 33 changes the magnification (enlargement / reduction) and deformation (keystone correction, etc.) of the displayed image based on the input digital video signal under the control of a CPU 40 described later.
Perform processing. The digital video signal that has been scaled and transformed by the view angle conversion circuit 33 is converted to an analog video signal by a D / A conversion circuit 34 and supplied to a liquid crystal panel drive circuit 35. This liquid crystal panel drive circuit 35
An image is displayed on the liquid crystal display panel 36 based on the input analog video signal. The image displayed on the liquid crystal display panel 36 is projected by irradiation light from a lamp 37 arranged on the back of the liquid crystal display panel 36, and the projected image is a variable-magnification image arranged on the front of the liquid crystal display panel 36. Mode (the aspect ratio of the projection screen is 4:
3) and are projected or displayed on the screen 39 after being enlarged or reduced to projection images in the wide mode (the aspect ratio of the projection screen is 16: 9). The CPU 40 controls the angle-of-view conversion circuit 33 based on a built-in scaling and deformation processing sequence to perform scaling and deformation processing on the digital video signal supplied from the A / D conversion circuit 32. Then, a digital video signal with trapezoidal distortion corrected is generated.

In the projector 30 having such a configuration, as described above, the screen 39 is installed vertically, the projector 30 is installed horizontally, and the distance between the center of the projected image of the projector 30 and the top, bottom, left and right edges of the screen 39 is set. If they are the same, the image is projected on the screen 39 as an image of a rectangle with a correct aspect ratio (such as an aspect ratio of 4: 3 or 16: 9).

However, when projecting from above or below onto a vertically installed screen 39, the projector 30 must be installed upward or downward. In this case, the projected image is distorted into a trapezoidal shape due to a difference in the distance (projection angle) between the upper and lower ends of the projector 30 and the screen 39. The degree of the trapezoidal distortion is large when the projection lens 38 is set to the wide mode, and becomes small when the projection lens 38 is set to the tele mode. That is, it changes according to the zoom amount (projection angle) of the image light projected from the projector 30.

The state in which the trapezoidal distortion occurs will be described with reference to FIG. In FIG. 2, a rectangle surrounded by sides (a, b) is an outer frame of the originally projected image, and a trapezoid surrounded by sides (m, n) is distorted into a trapezoid by the installation angle θp of the projector 30 and projected. This is the outer frame of the image to be displayed. The zoom amount is indicated by the projection angles θ1 and θ2. As shown in FIG. 2, trapezoidal distortion occurs depending on the projection angles θ1 and θ2.

The correction of the trapezoidal distortion generated in this way is as follows.
The angle-of-view conversion circuit 33 generates an angle-of-view converted digital video signal in which the vertical / horizontal magnification (enlargement / reduction) ratio and the display position are changed for each line of the digital video signal. That is, magnification and display position correction are performed for each line of the digital video signal so that the outer frame of the image surrounded by the side (m, n) shown in FIG. by doing,
Generate a digital video signal with trapezoidal distortion corrected
The signal is supplied to the liquid crystal display panel 36 via the / A conversion circuit 34 and the liquid crystal panel drive circuit 15 to display the video with the trapezoidal distortion corrected.

[0014]

A conventional angle-of-view correction circuit 3
In the projector 30 having the number 3, the manual adjustment means (not shown) is used so that a rectangular image having an original aspect ratio is projected on the screen 39 in accordance with the relationship between the installation position of the projector 30 and the screen 39. Need to adjust. For this reason, especially when the projector 30 cannot be installed in a permanent installation place like a reflection type projector, the projector 30 is re-installed every time the projector 30 and the screen 39 are used, and a trapezoidal shape is set according to the display mode of the projected image. There is a problem that it is necessary to perform angle-of-view correction for removing distortion, and the use of the projector 30 becomes very inconvenient.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a video projector device capable of detecting an installation angle and a projection angle of the video projector device and automatically adjusting a trapezoidal correction process of a projected image.

[0016]

A video projector apparatus according to the present invention comprises: an angle-of-view converting means for changing the angle of view of an input video signal; Video projection means for projecting the projected video signal onto a screen, projection angle detection means for detecting the projection angle of the video projection means, installation angle detection means for detecting the installation angle of the video projection means, and projection angle detection means And calculating and calculating the magnification / deformation of the angle of view of the video signal based on the projection angle and the installation angle detected by the installation angle detection means, and controlling the magnification / deformation of the view angle conversion means. And a quantity operation control means.

The video projector of the video projector according to the present invention comprises: video display means for displaying a video based on a video signal whose view angle has been scaled or deformed by the view angle conversion means;
A zoom drive projection lens for enlarging and reducing the image displayed on the image display means on a screen is provided.

The projection angle detecting means of the video projector device of the present invention detects a zoom driving position of a projection lens of the video projecting means, and converts the detected zoom driving position into an electric signal from a zoom amount detecting sensor. It is characterized by becoming.

The installation angle detecting means of the video projector device of the present invention detects an inclination of the video projecting means,
It is characterized by comprising a gravitational acceleration sensor that converts the detected inclination into an electric signal.

According to the present invention, it is possible to realize a video projector device capable of detecting the installation angle and the projection angle of the video projector device and automatically adjusting the trapezoidal distortion correction processing of the image projected on the screen.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of a video projector device according to the present invention. FIG. 1 mainly shows a function of projecting an image on a screen by performing trapezoidal distortion correction processing in a video projector apparatus.

A reference numeral 10 in FIG. 1 denotes a projector. A television broadcast channel is received and tuned to an input terminal 11 to generate a baseband video signal. The baseband video signal is subjected to video processing, chroma processing and synchronization. An analog video signal subjected to deflection processing or an analog video signal reproduced and supplied from various video devices is input.

The analog video signal supplied to the input terminal 11 is digitally converted by an A / D conversion circuit 12, and the converted digital video signal is supplied to a view angle conversion circuit 13. The angle-of-view conversion circuit 13 changes the magnification (enlargement / reduction) and deformation (keystone correction, etc.) of the displayed image under the control of a CPU 20 described later on the input digital video signal.
Perform processing. The digital video signal that has been scaled and transformed by the view angle conversion circuit 13 is converted to an analog video signal by a D / A conversion circuit 14 and supplied to a liquid crystal panel drive circuit 15. This liquid crystal panel drive circuit 15
An image is displayed on the liquid crystal display panel 16 based on the input analog video signal. The image displayed on the liquid crystal display panel 16 is projected by light projected from a lamp 17 disposed on the back of the liquid crystal display panel 16 and converted into a projected image. This projected image is projected in a telemode (projection screen aspect ratio 4: 3) and a wide mode (projection screen aspect ratio 16: 9) by a variable-magnification projection lens 18 arranged in front of the liquid crystal display panel 16. Is projected or displayed on the screen 19.

A zoom amount detection sensor 21 is attached to the projection lens 18 and supplies a signal indicating a zoom amount according to the zooming operation of the projection lens 18 to the CPU 21. Further, a gravitational acceleration sensor 22 for measuring a gravitational acceleration acting in a lateral direction of the projector is provided at a predetermined position of a casing (not shown) of the projector 10,
A signal indicating the gravitational acceleration detected by the gravitational acceleration sensor 22 is supplied to the CPU 20.

The CPU 20 calculates and calculates the projection angle of the projected image based on the zoom amount signal from the zoom amount detection sensor 21, and also sets the projector installation angle based on the gravitational acceleration signal from the gravitational acceleration sensor 22. Calculate
calculate. Based on the calculated and calculated projection angle and installation angle, a built-in transformation is performed so that the image projected on the screen 19 becomes an original rectangle (such as an aspect ratio of 4: 3 or 16: 9). The amount of scaling (enlargement / reduction) and the amount of deformation (trapezoidal correction, etc.) in the angle-of-view conversion circuit 13 are controlled in the magnification and deformation processing sequence.

Next, detection of the zoom amount by the zoom amount detection sensor 21 provided on the projection lens 18, that is, detection of the projection angle will be described with reference to FIG.

FIG. 3 shows an example of a projection angle detecting method. In general, when optical zooming is performed by the projection lens 18, a zoom lens 18a (here, a single zoom lens is shown for simplicity). , The actual zoom lens may be plural) mechanically by sliding in the horizontal direction in the figure to change the angle θ of the projection light projected from the projection lens 18. Therefore, if the position of the zoom lens 18a is detected, the projection angle θ can be obtained based on the position data of the zoom lens 18a using a conversion formula, a conversion table, and the like. In order to electrically detect the position of the zoom lens 18a, a variable resistor 21a that slides in conjunction with the zoom lens 18a is used, and a voltage change accompanying the mechanical movement of the zoom lens 18a is detected by a PWM signal or a DUTY signal. And so on, the projection angle can be detected.

Next, the detection of the installation angle of the projector 10 by the gravitational acceleration detection by the gravitational acceleration sensor 22 will be described with reference to FIG.

The gravitational acceleration sensor 22 converts the gravitational acceleration Gh acting in the lateral direction of the projector 10 into an electric signal (a voltage signal, a PWM signal, or a DUTY signal) and outputs it. As shown in FIG.
When 0 is installed horizontally on the ground plane, only the gravitational velocity (g) acting in the vertical direction (Gv) of the projector 10 becomes zero, and the gravitational velocity (g) acting in the lateral direction (Gh) becomes zero.
That is, Gh = 0 g and Gv = 1 g. However, as shown in FIG. 4B, when the projection light from the projector 10 is tilted so as to project upward in the drawing, the vertical gravity speed Gv = 1g is decomposed in the vertical direction and the horizontal direction. .

That is, the horizontal direction (G
h) also acts on the gravitational velocity, the lateral gravitational velocity Gh at this time
Is Gh = 1g × sin θp, and the vertical gravity speed Gv is Gv = 1g × cos θp. The relationship between the gravitational acceleration Gh acting in the lateral direction of the projector 10 and the installation angle θp can be expressed by θp = sin−1 (Gh / 1). From this equation, the CPU 20 calculates the lateral gravitational acceleration Gh detected by the gravitational acceleration sensor 22 to calculate the installation angle.

In this manner, the projection angle and the installation angle of the projector 10 are obtained based on the electric signals from the zoom amount detection sensor 21 and the gravitational acceleration sensor 22.

Next, the operation of trapezoidal distortion correction in the view angle conversion circuit 13 based on the projection angle and the installation angle calculated by the CPU 20 will be described. In order to completely correct the trapezoidal distortion, distortion in both horizontal and vertical directions must be corrected. Here, as an example, only a method for correcting horizontal distortion will be described.

As shown in FIG. 2, in a projected image having a trapezoidal distortion, a rectangle surrounded by sides (a, b) is an outer frame of the originally projected image, and is surrounded by sides (m, n). The trapezoid to be projected is distorted into a trapezoid by the installation angle θp of the projector 10 and is an outer frame of the projected image. The zoom amount is represented by the projection angles θ1 and θ2.

Here, assuming that the side a is multiplied by Z due to the trapezoidal distortion and becomes the side m (m = Za), the enlargement ratio Z is given by the following equation 1. The side a: b = 4: 3 and the projection lens 1
8 is assumed to be 100%.

Z = 3/2 {cos θ1 · cos θp / sin θ1 · cos (θ1 + θp)} tan θ2 / 2 Expression 1 To return the side m to the original length a (correct the trapezoid), set the side m to 1 / What is necessary is just to multiply by Z. Further, assuming that the number of lines of the image is L, each time a line changes from the top to the bottom of the image displayed on the screen 19, (Z-1) / L is subtracted from the denominator term of the magnification and displayed on the screen. It becomes 1/1 times at the bottom line of the image. As a result, the projected image is corrected to a parallelogram. Further, if the horizontal display position of each line is adjusted to the center of the projection range, the line is corrected to a rectangle.

That is, in the trapezoidal distortion correction, a correction value for each line is calculated and calculated by the CPU 20, and the angle-of-view conversion circuit 13 is controlled based on the calculated correction value to convert the angle-of-view converted digital video signal. Generate. The digital video signal generated by the angle-of-view conversion circuit 13 is supplied to a liquid crystal panel 16 via a D / A conversion circuit 14 and a liquid crystal panel drive circuit 15. When the image displayed on the liquid crystal panel 16 is projected on the screen 19 via the projection lens 18, a rectangular image having a predetermined aspect ratio without trapezoidal distortion can be displayed.

When the projector 10 is installed on a ceiling or the like and the image is projected from above a vertically installed screen 19, the trapezoidal distortion described above is displayed in reverse. Therefore, the trapezoidal correction can be performed for the magnification of each horizontal line in the trapezoidal distortion correction calculation processing by performing the above-described reverse calculation calculation processing.

As described above, the video projector device of the present invention uses the zoom amount sensor 21 and the gravitational acceleration sensor 22 provided on the projector 10 to project the projection angle of the image projected on the screen 19 and the installation of the projector 10. An angle is detected, and a correction value for each line of an image displayed on the screen 19 is calculated and calculated by the CPU 20 based on the detected projection angle and the installation angle, and the angle of view conversion is performed using the calculated correction value. The circuit 13 is controlled to display an image having a predetermined aspect ratio.

[0039]

The video projector device of the present invention can detect the installation angle and the projection angle of the video projector device and automatically adjust the trapezoidal correction processing. There is an effect that a rectangular image having a predetermined aspect ratio without trapezoidal distortion can be displayed without any distortion.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a video projector device according to the present invention.

FIG. 2 is an explanatory diagram illustrating trapezoidal distortion of a projected image in the video projector device.

FIG. 3 is an explanatory diagram illustrating a projection angle detection method of the video projector device according to the present invention.

FIG. 4 is an explanatory diagram illustrating a method of detecting an installation angle of a video projector device according to the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional video projector device.

[Explanation of symbols]

10 video projector device, 11 input terminal, 12
... A / D conversion circuit, 13 ... View angle conversion circuit, 14 ... D / A
Conversion circuit, 15: Liquid crystal panel drive circuit, 16: Liquid crystal panel, 17: Lamp, 18: Projection lens, 19: Screen, 20: CPU, 21: Zoom amount sensor, 22:
Gravity acceleration sensor.

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[Procedure amendment]

[Submission date] December 28, 1999 (1999.12.
28)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0030

[Correction method] Change

[Correction contents]

That is, the horizontal direction (G
h) also acts on the gravitational velocity, the lateral gravitational velocity Gh at this time
Is Gh = 1g × sin θp, and the vertical gravity speed Gv is Gv = 1g × cos θp. The relationship between the gravitational acceleration Gh acting in the lateral direction of the projector 10 and the installation angle θp can be expressed by θp = sin ⁻¹ (Gh / 1). From this equation, the CPU 20 calculates the lateral gravitational acceleration Gh detected by the gravitational acceleration sensor 22 to calculate the installation angle.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09G 5/36 H04N 5/74 D H04N 5/74 G09G 5/36 520D F-term (Reference) 5C058 BA35 EA02 EA12 EA26 5C060 BA09 BB13 BC01 GA01 GD08 HD05 JA01 5C082 AA21 BA41 CA01 CB01 CB03 MM09 MM10 5G435 AA00 BB12 BB15 BB17 CC09 DD02 DD03 DD04 GG02 LL15

Claims (4)

[Claims] 1. An angle-of-view converting means for scaling / deforming the angle of view of an input video signal, and an image projecting means for projecting a video signal whose angle of view is scaled / deformed by the angle-of-view converting means onto a screen. A projection angle detection unit that detects a projection angle of the video projection unit; an installation angle detection unit that detects an installation angle of the video projection unit; and a projection angle detected by the projection angle detection unit and the installation angle detection unit. And a magnification / deformation amount calculation control means for calculating and calculating the magnification / deformation amount of the image signal based on the installation angle and controlling the magnification / deformation amount of the view angle conversion means. Video projector device. 2. An image display means for displaying an image based on a video signal whose angle of view has been scaled or deformed by said angle of view conversion means, and an image displayed on said image display means. 2. A video projector device according to claim 1, further comprising a zoom drive projection lens for enlarging and reducing the image on a screen. 3. The projection angle detection means comprises a zoom amount detection sensor for detecting a zoom drive position of a projection lens of the video projection means and converting the detected zoom drive position into an electric signal. The video projector device according to claim 1. 4. The video projector device according to claim 1, wherein said installation angle detection means comprises a gravitational acceleration sensor for detecting a tilt of said video projection means and converting the detected tilt into an electric signal. .