JP2005077994A - Projector having tilt angle measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector having a tilt angle measuring device capable of inexpensively measuring a tilt angle in the vertical and/or horizontal direction of a projection surface to the projection optical axis of the projector in order to correct the distortion of a video. <P>SOLUTION: Uniform high-luminance light is projected to the projection surface from the projection lens 21 of a projecting device 20 and passes through one pinhole 51 provided on the front wall surface of the projector 10 at a specified interval from the projected optical axis 27, and reflected light is received by a light intensity measuring sensor 52 arranged at the same interval right and left with the vertically upper part of the optical axis 27 with respect to a reference surface as center on an inside reference line 29. The light intensity of the surrounding environment of the projector 10 is measured by a surrounding environment lightness measuring sensor 55, and a received light intensity analyzing tilt angle calculation part 53 acquires the difference of the light intensity between the right and left sides, combines it with the light intensity of the surrounding environment, obtains the tilt angle between the projection surface 70 and a surface vertical to the optical axis 27 on the reference surface from previously set correlation, and controls an image control part 23 so as to eliminate the distortion of a screen. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projector, and more particularly to a projector having a tilt angle measuring device for calculating a tilt angle between a projection optical axis of a projection device of a projector to be used and a projection surface.

  With the rapid development of liquid crystal technology and DLP (registered trademark) (digital light processing) technology, miniaturization and high performance of projectors have expanded the use of projectors for image projection, and display televisions at home. It is also attracting attention as a large-sized display device that can replace this.

  However, unlike a display-type television, a projector has a problem that a video image is distorted due to the relative relationship between the projection optical axis of the projector and the projection surface because the video screen is a screen or a wall. Disclosed is a method for adjusting the angle of a liquid crystal display unit according to an angle calculated from both detection results, having a detecting means for detecting an installation angle of a liquid crystal projector and a distance detecting means for detecting a distance between the liquid crystal projector and a projection target. (See Patent Document 1). In this case, it is necessary to mechanically adjust the angle of the liquid crystal display unit. In addition, the angled laser pointer light spot is projected onto a curved screen. On the other hand, a point image for measurement is generated and projected from the projector onto the screen, and taken by the camera to measure the position of the light spot and the point image. Distortion correction method is disclosed in which when the point image is moved while performing the above operation, the pixel coordinates on the frame memory of the point image are replaced with the coordinates on the input image of the light point and set in the coordinate conversion parameter memory (See Patent Document 2). In this case, it is necessary to control the angle of the laser pointer, and the structure becomes complicated.

On the other hand, when the vertical and horizontal inclinations of the screen with respect to the projection optical axis of the projector are known, a technique for projecting a distortion-free image on the screen by converting the coordinates of the frame memory of the projector has been put into practical use. Therefore, in order to measure the vertical tilt that is likely to cause distortion, the vertical tilt of the projector is detected by the gravity sensor on the premise that the screen is installed vertically, and distortion correction corresponding to the tilt is performed. Projectors have already been disclosed and sold (see Patent Document 3).
Japanese Patent Laid-Open No. 9-281597 Japanese Patent Application Laid-Open No. 2001-169211 JP 2003-5278 A

  However, the method described in Patent Document 3 is based on the premise that the screen is installed vertically, and when the screen is not installed vertically or is inclined in the horizontal direction with respect to the projection optical axis of the projector. There is a problem that accurate distortion correction cannot be performed. The inventor of the present invention can accurately measure the tilt angle of the screen in the vertical direction and the horizontal direction with respect to the projection optical axis of the liquid crystal projector using a digital camera having a laser pointer and an image sensor for image distortion correction. Has been filed in Japanese Patent Application No. 2003-143501. Although the tilt angle measuring device disclosed in Japanese Patent Application No. 2003-143501 is very good as a means for accurately obtaining the angle of the projector with respect to the screen, in order to use a digital camera having an image sensor as its component device The cost is high.

  An object of the present invention is to provide a projector having an inclination angle measuring device that can measure the inclination angle of the screen in the vertical direction and the horizontal direction with respect to the projection optical axis of the projector at a low cost for image distortion correction.

The projector having the tilt angle measuring device of the present invention is
A tilt angle measuring device that calculates the tilt angle between the projection optical axis of the projection device of the projector and the projection surface, and corrects distortion of the image on the projection surface by controlling the output image of the display unit according to the calculated tilt angle. In the projector, the projection device has a high-intensity light output function for projecting uniform high-intensity light onto the projection surface from the projection lens of the projection device, and the tilt angle measurement device has one light guide provided on the wall surface. A light intensity measurement sensor, an ambient lightness measurement sensor, and a received light intensity analysis inclination angle calculation unit.

  The light guide unit is provided on the front wall surface of the projector at a predetermined interval from the projection optical axis in a direction perpendicular to the reference plane including the projection optical axis for which an inclination angle is required. In order to receive the reflected light from the projection surface of the high-intensity light that passes through the light guide unit inside the projector, the reference is on the reference line that is the intersection of the plane parallel to the reference plane and the plane perpendicular to the projection optical axis. The ambient environment lightness measurement sensor is disposed on the wall surface of the projector so that the brightness of the ambient environment of the projector can be measured.

  The received light intensity analysis inclination angle calculation unit obtains the difference between each light intensity and the right and left light intensity from the light intensity measurement results of the two light intensity measurement sensors, and obtains the ambient light obtained from the ambient lightness measurement sensor. In combination with intensity, the projection surface and projection optical axis on the reference plane corresponding to the difference between the light intensity of each of the two preset light intensity measurement sensors and the left and right light intensity and the light intensity of the surrounding environment From the correlation with the tilt angle with the vertical plane, the tilt angle between the projection plane on the reference plane and the plane perpendicular to the projection optical axis is obtained, and the output video of the display unit is controlled.

  The reference plane may be horizontal or vertical, and may have a light guide and a light intensity measurement sensor for each of the horizontal and vertical directions.

  The present invention can easily calculate the vertical and / or horizontal tilt angle between the projection optical axis of the projection apparatus and the projection plane, and therefore, the projection image can be projected onto the projection plane by moving the arrangement of the image on the display unit to the pixels. There is an effect that the processed image can be corrected to a correct state.

  This is because uniform high-intensity light is projected onto the projection surface from the projection lens of the projection device, and at a predetermined interval from the projection optical axis in a direction perpendicular to the reference plane including the projection optical axis whose inclination angle is measured. Through a single light guide provided on the front wall surface, on the reference line that is the intersection of the plane parallel to the reference plane inside the projector and the plane perpendicular to the projection optical axis, vertically above the projection optical axis with respect to the reference plane The reflected light is received by the light intensity measurement sensor that is arranged at the same interval on the left and right with respect to the center, the ambient lightness measurement sensor measures the light intensity corresponding to the lightness of the ambient environment of the projector, and the received light intensity analysis inclination angle calculation unit From the light intensity measurement results of the two light intensity measurement sensors, the difference between the light intensity and the left and right light intensity is obtained, and is combined with the ambient light intensity obtained from the ambient lightness measurement sensor and set in advance. There are two places Based on the correlation between the light intensity of each intensity measurement sensor and the light intensity on the left and right, and the inclination angle between the projection surface on the reference surface corresponding to the light intensity of the surrounding environment and the plane perpendicular to the projection optical axis, This is because the image display unit can be controlled so as to eliminate the distortion of the screen by obtaining the inclination angle between the projection surface on the surface and the surface perpendicular to the projection optical axis.

  In addition, the tilt angle measuring device of the present invention can be configured at low cost. This is because measurement is possible by using three low-cost light intensity measurement sensors without using a high-cost digital camera.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram of a projector having a tilt angle measuring apparatus according to a first embodiment of the present invention, and FIG. 2 is a schematic diagram of a projector having a tilt angle measuring apparatus according to the first embodiment of the present invention. (A) is a front view, (b) is a side view, (c) is a top view, and FIG. 3 is a schematic view showing a state of reflected light of uniform high-intensity light projected from the projection device onto the projection surface. (A) is a state in which the tilt angle between the projection optical axis and the projection surface is 90 °, (b) is the first tilt angle α, and (c) is the second smaller than the first tilt angle. (D) is the light intensity distribution according to the incident angle of the light beam with respect to the projection surface and the reflected angle of the reflected light beam, and FIG. 4 shows the light intensity measurement sensor with the horizontal axis as the reference line. It is a schematic diagram showing the light intensity difference between the left and right when the position and the vertical axis are the light intensity measured by the light intensity measurement sensor. , (A) inclination angle of 90 ° state between the projection surface and the projection optical axis, (b) In the case of the first inclination angle, (c) is the case of the second inclination angle. Here, the light guide is described as a pinhole, but an optical lens may be used as described later.

  The projector 10 of the present invention includes an inclination angle measuring device 30 that calculates an inclination angle between the projection optical axis 27 of the projection device 20 and the projection surface 70, and controls the output image of the display unit 22 according to the calculated inclination angle. By doing so, the distortion of the image on the projection surface 70 is corrected.

  The projection device 20 has a high-luminance light output function for projecting uniform high-luminance light from the projection lens 21 onto the projection surface 70, and the tilt angle measuring device 30 has a projection optical axis 27 on which the tilt angle is measured. A pinhole 51 provided on the front surface of the projector 10 at a predetermined interval from the reference plane 28 including the reference plane 28 and a reflected light 32 of high-intensity light from the projection surface 70 passing through the pinhole 51 are received. Further, on the reference line 29, which is an intersection line with the plane parallel to the reference plane 28 and perpendicular to the projection optical axis 27 inside the projector 10, and to the left and right with respect to the reference plane 28 and vertically above the projection optical axis 27. The light intensity measurement sensors 52 (52R, 52L) arranged at the same interval, the ambient lightness measurement sensor 55 that measures the light intensity corresponding to the lightness of the ambient environment of the projector 10, and the received light intensity analysis inclination angle calculation unit 5 The light reception intensity analysis inclination angle calculation unit 53 acquires the difference between the light intensity and the left and right light intensity from the light intensity measurement results of the two light intensity measurement sensors 52 (52R, 52L), In combination with the light intensity of the ambient environment acquired from the ambient lightness measurement sensor 55, the difference between the light intensity of each of the two preset light intensity measurement sensors 52 (52R, 52L) and the right and left light intensity and the surroundings From the correlation between the inclination angle between the projection surface 70 on the reference surface 28 and the surface perpendicular to the projection optical axis 27 corresponding to the light intensity of the environment, the projection surface 70 and the projection optical axis 27 on the reference surface 28 The inclination angle with respect to the vertical plane is obtained, and the output video of the display unit 22 is controlled so as to eliminate the distortion of the screen.

  Next, the first embodiment of the present invention will be described in more detail with reference to the drawings. The main configuration and operation of the first embodiment are the same as those of the above-described best embodiment. As shown in FIG. 1, the projector 10 controls the overall operation of the projection device 20 having the projection lens 21 and the display unit 22, the image control unit 23 that controls the image of the display unit 22, and the tilt angle measuring device 30. CPU 60 to be provided. The projection device 20 has a high-luminance light output function for projecting uniform high-luminance light as a video image onto the projection surface 70 from the projection lens 21 when the tilt angle is measured. Reference numeral 30 denotes a pinhole 51 provided on the front wall surface of the projector 10 and two right and left light intensity measurement sensors 52 (52R, 52) that receive reflected light 32 of high-intensity light from the projection surface 70 that has entered the pinhole 51. 52L), the ambient lightness measurement sensor 55, the light intensity and the light intensity difference measured by the two light intensity measurement sensors 52, and the light intensity of the surrounding environment, and the vertical or horizontal of the projection device 20 with respect to the projection plane 70 A received light intensity analysis inclination angle calculation unit 53 that calculates the inclination of the direction. For example, phototransistors are used as the light intensity measurement sensor 52 and the ambient lightness measurement sensor 55.

  The present invention can be applied to the projector 10 regardless of whether it is a liquid crystal projector or a DLP (registered trademark) (digital light processing) type projector. The display unit 22 in the case of a liquid crystal projector is a liquid crystal display unit. The display unit 22 includes a DMD (digital micromirror device) display unit, a color wheel, and a light source.

  As shown in FIG. 2, the pinhole 51 is disposed in front of the casing of the projector 10 at a predetermined interval from the projection optical axis 27 in a direction perpendicular to the reference plane 28 including the projection optical axis 27 for which an inclination angle is required. The light intensity measurement sensor 52 provided on the wall surface receives the reflected light 32 from the projection surface 70 of the high-intensity projection light 31 passing through the pinhole 51 inside the housing of the projector 10. 28 is arranged on the reference line 29, which is the intersection of the plane parallel to the projection plane 28 and the plane perpendicular to the projection optical axis 27, at the same interval on the left and right with respect to the reference plane 28 with the vertical upper side of the projection optical axis 27 as the center. A place where the ambient lightness measurement sensor 55 that measures the light intensity corresponding to the lightness of the surrounding environment is not easily affected by the reflected light 32 from the projection surface 70 of the high-brightness projection light 31, for example, the housing of the projector 10. upon It is provided to.

  As shown on the left side of FIG. 3D, when the direction of the projection light 31 and the projection surface 70 are orthogonal to each other, the strongest reflected light 32 is obtained in the incident direction, and the light intensity decreases corresponding to the reflection angle. . As shown on the right side of FIG. 3D, if the direction of the projection light 31 and the projection surface 70 are inclined, the strongest main reflected light 33 is obtained in a direction symmetrical to the projection light 31 with respect to the projection surface 70. The light intensity decreases corresponding to the deviation from this direction. Therefore, if the angle between the direction of the optical axis 27 and the direction of the main reflected light 33 can be specified, this angle becomes the inclination angle between the plane perpendicular to the optical axis 27 on the reference plane 28 and the projection plane 70.

  Therefore, as shown in FIG. 3A, if the projection optical axis 37 is orthogonal to the projection plane 70, the light intensity arranged symmetrically with respect to the reference plane 28 around the vertical upper side of the projection optical axis 27. The light intensity of the measurement sensors 52L and 52R is the same value, and the light intensity difference 81 is 0 as shown in FIG. When the projection optical axis 37 intersects the projection surface 70 at the first angle α as shown in FIG. 3B, a light intensity difference 81 as shown in FIG. 4B is generated. As shown in FIG. 3C, the projection optical axis 37 intersects the projection surface 70 at a second angle β that is smaller than the first angle α, and the main reflection from the projection surface 70 on the left light intensity measurement sensor 52L. If the light 33 is incident, the light intensity of the left light intensity measurement sensor 52L is the strongest, and the light intensity difference 81 is further increased as shown in FIG. 4C.

  Thus, it can be seen that the difference between the outputs of the light intensity measurement sensor 52L and the light intensity measurement sensor 52R increases as the angle of the projector 10, that is, the projection optical axis 27 with respect to the projection surface 70 becomes steeper. Therefore, the difference between the light intensity of each of the two light intensity measurement sensors 52 (52R, 52L) and the light intensity on the left and right sides is calculated from this difference using a predetermined calculation formula set in advance or from the experimental results. From the table showing the correlation between the inclination angle between the projection surface 70 on the corresponding reference plane 28 and the plane perpendicular to the projection optical axis 27, the projection plane 70 on the reference plane 28 and the projection optical axis 27 are perpendicular to each other. The inclination angle with the surface can be obtained.

  However, when the inclination angle measuring device 30 having this function is actually mounted on the projector 10, the light intensity measuring sensor 52R and the light intensity measuring sensor 52L are controlled by the brightness of the surrounding environment (bright room, pure dark room). It can be seen that the output changes. Therefore, in addition to the light intensity measurement sensor 52, an ambient environment lightness measurement sensor 55 for obtaining the brightness of the surrounding environment is mounted, and the light intensity difference 81 between the light intensity measurement sensors 52R and 52L sensors and the ambient environment lightness measurement. In the present invention, a method of acquiring the projector angle by a two-dimensional table or calculation formula using the light intensity value measured by the sensor 55 as a variable and controlling the output image of the display unit 22 is realistic. An ambient lightness measurement sensor 55 is provided.

  FIG. 5 is a schematic flowchart showing a process of correcting the output image of the display unit 22 based on the light intensity difference 81 between the two light intensity measurement sensors 52 and the light intensity of the ambient lightness measurement sensor 55. The received light intensity analysis inclination angle calculation unit 53 generates a light intensity difference at two points from the light intensity of the two light intensity measurement sensors 52 (step S1), and acquires the light intensity of the ambient environment lightness measurement sensor 55 (step S1). S2) An inclination angle between the optical axis 27 of the projection device 20 and the projection surface 70 is generated by calculation or reference from the light intensity difference between the two points and the ambient light intensity (step S3), and the generated inclination angle is received. Then, the image control unit 23 generates LSI control parameters (step S4), and controls the projector image processing LSI (step S5), whereby the input video 24 is modified to become the output video 25 on the display unit 22. When the output video 25 is projected onto the projection surface 70, it becomes a video similar to the input video 24. In this method, it is desirable that the projection surface 70 is irradiated with uniform brightness. However, since the center portion tends to be irradiated more brightly, the angle calculation by calculation is performed in step S3 including correction for that amount. It is preferable to calculate the angle using a table.

  In the description so far, the horizontal inclination angle has been measured, but the vertical inclination is obtained by rotating the positions of the pinhole 51 and the light intensity measurement sensor 52 about the projection optical axis 27 by 90 °. It is possible to measure the angle.

  Although the light guide is described as a pinhole here, the same measurement can be performed even with an optical lens. FIG. 6 is a schematic diagram showing a light incident state of the reflected light 32 from the projection surface 70 to the light intensity measurement sensor 52 when the convex lens 56 is used as the light guide unit. Even when the convex lens 56 is used, the reflected light 32 from the projection surface 70 is input to the light intensity measurement sensor 52 in the same manner as the reflected light 32 from the projection surface 70 when the pinhole 51 is used.

  Next, a second embodiment of the present invention will be described. FIG. 7 is a schematic block diagram of a projector having the tilt angle measuring apparatus according to the second embodiment of the present invention. In the second embodiment, the inclination angle measuring device 30 is an inclination sensor (G sensor) that uses an acceleration detecting element that is also used for centering of machine installation, and the inclination angle with respect to the direction of gravity is precisely determined. Since the configuration and the operation are the same as those of the first embodiment except that the vertical inclination sensor 54 for measuring and outputting as numerical data is provided, the same components are denoted by the same reference numerals and the same parts are described. Omitted.

  The vertical inclination angle detected by the vertical inclination sensor 54 is input to the received light intensity analysis inclination angle calculation unit 53, and the received light intensity analysis inclination angle calculation unit 53 detects the light intensity difference measured by the light intensity measurement sensor 52 and the surrounding environment. The horizontal inclination angle is calculated based on the light intensity measured by the brightness measurement sensor 55, and is output to the image control unit 23 together with the vertical inclination angle detected by the vertical inclination sensor 54. The image control unit 23 An LSI control parameter is generated in consideration of horizontal and vertical inclinations. Also in this case, the same processing is performed as described in the first embodiment even if the light receiving portion is a convex lens 56 instead of the pinhole 51.

  Next, a third embodiment of the present invention will be described. FIG. 8 is a schematic block diagram of a projector having a tilt angle measuring apparatus according to the third embodiment of the present invention, and FIG. 9 is a schematic diagram of a projector having a tilt angle measuring apparatus according to the third embodiment of the present invention. (A) is a front view, (b) is a side view, and (c) is a top view.

  In the third embodiment, in addition to the pinhole 51 and the two light intensity measuring sensors 52 that are only used for measuring the tilt angle in the horizontal direction in the first embodiment, the pinhole for measuring the tilt angle in the vertical direction. 51 ′ and two light intensity measurement sensors 52 ′ are the same as those of the first embodiment except that they are connected to the received light intensity analysis inclination angle calculation unit 53. The same reference numerals are given and description of the same parts is omitted.

  The light intensity measured by the two light intensity measurement sensors 52 ′ for measuring the inclination angle in the vertical direction is also input to the received light intensity analysis inclination angle calculation unit 53, and the received light intensity analysis inclination angle calculation unit 53 receives the light intensity measurement sensor 54. The inclination angle in the horizontal direction is calculated from the measured light intensity difference and the light intensity measured by the ambient lightness measurement sensor 55, and the light intensity difference and the ambient lightness measurement sensor 55 measured by the light intensity measurement sensor 54 ′. The vertical inclination angle is calculated from the light intensity measured in step S1, and the horizontal inclination angle and the vertical inclination angle are combined and output to the image control unit 23. The image control unit 23 outputs the horizontal and vertical directions. An LSI control parameter is generated in consideration of the inclination. Also in this case, the same processing is performed as described in the first embodiment even if the light receiving portion is a convex lens 56 instead of the pinhole 51.

1 is a schematic block diagram of a projector having an inclination angle measuring apparatus according to a first embodiment of the present invention. 1 is a schematic diagram of a projector having an inclination angle measuring apparatus according to a first embodiment of the present invention. (A) is a front view. (B) is a side view. (C) is a top view. It is a schematic diagram which shows the state of the reflected light of the uniform high-intensity light projected on the projection surface from the projection apparatus. (A) is a state in which the inclination angle between the projection optical axis and the projection surface is 90 °. (B) is the case of the first tilt angle. (C) is a case of the 2nd inclination angle smaller than the 1st inclination angle. (D) is a light intensity distribution according to the incident angle of the light beam with respect to the projection surface and the reflected angle of the reflected light beam. It is a schematic diagram which shows the light intensity difference of right and left when the horizontal axis represents the position of the light intensity measurement sensor indicated by the reference line and the vertical axis represents the light intensity measured by the light intensity measurement sensor. (A) is a state in which the inclination angle between the projection optical axis and the projection surface is 90 °. (B) is the case of the first tilt angle. (C) is the case of the second tilt angle. It is a typical flowchart which shows the process which corrects the output image of a display part from the light intensity difference of two light intensity measurement sensors, and the light intensity of ambient environment lightness measurement sensors. It is a schematic diagram which shows the light-incidence state to the light intensity measurement sensor of the reflected light from a projection surface at the time of using a convex lens as a light guide part. It is a typical block block diagram of the projector which has the inclination angle measuring apparatus of the 2nd Example of this invention. It is a typical block block diagram of the projector which has the inclination angle measuring apparatus of the 3rd Example of this invention. These are the schematic diagrams of the projector which has the inclination angle measuring apparatus of the 3rd Example of this invention. (A) is a front view. (B) is a side view. (C) is a top view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Projector 20 Projection apparatus 21 Projection lens 22 Display part 23 Image control part 24 Input image 25 Output image 27 Projection optical axis 28 Reference plane 29 Reference line 30 Inclination angle measuring device 31 Projection light 32 Reflection light 33 Main reflection light 51, 51 ' Pinhole 52, 52L, 52R, 52 ′, 52′L, 52′R Light intensity measurement sensor 53 Light reception intensity analysis inclination angle calculation unit 54 Vertical direction inclination sensor 55 Ambient lightness measurement sensor 56 Convex lens 60 CPU
70 Projection surface 81 Light intensity difference S1-S5 step

Claims (10)

A tilt angle measuring device for calculating the tilt angle between the projection optical axis of the projector and the projection surface of the projector, and correcting the distortion of the image on the projection surface by controlling the output image of the display unit according to the calculated tilt angle. Projector
The projection device has a high-luminance light output function for projecting uniform high-luminance light from the projection lens of the projection device onto the projection surface, and the tilt angle measuring device is a single light guide provided on the wall surface. Part, two light intensity measuring sensors, ambient lightness sensor and received light intensity analysis inclination angle calculation part,
The light guide unit is provided on a front wall surface of the projector at a predetermined interval from the projection optical axis in a direction perpendicular to a reference plane including the projection optical axis for which the tilt angle is required.
The light intensity measurement sensor is provided on a surface parallel to the reference surface and the projection optical axis so as to receive the reflected light from the projection surface of the high-intensity light passing through the light guide unit inside the projector. On a reference line that is an intersection line with a vertical plane, the reference plane is arranged at the same interval on the left and right with the vertical upper side of the projection optical axis as the center,
The ambient lightness measurement sensor is disposed on the wall of the projector so that the lightness of the ambient environment of the projector can be measured.
The received light intensity analysis inclination angle calculation unit obtains the difference between the light intensity and the left and right light intensity from the light intensity measurement results of the two light intensity measurement sensors, and the ambient light obtained from the ambient lightness measurement sensor. In combination with the light intensity of the environment, the projection on the reference plane corresponding to the difference between the light intensity of each of the two light intensity measuring sensors set in advance and the light intensity of the left and right and the light intensity of the surrounding environment From the correlation between the tilt angle between the plane and the plane perpendicular to the projection optical axis, the tilt angle between the projection plane on the reference plane and the plane perpendicular to the projection optical axis is obtained. A projector having an inclination angle measuring device that controls an output image.   2. The tilt angle according to claim 1, wherein the measured tilt angle is a tilt angle between the projection optical axis and the projection plane on a horizontal plane, and the light guide unit is arranged in a direction perpendicular to the projection optical axis. A projector having a measuring device.   The tilt angle measuring device further includes a vertical tilt sensor that detects a tilt angle of the projection optical axis on a vertical plane including the projection optical axis of the projector, and the vertical plane detected by the vertical tilt sensor. The tilt according to claim 2, wherein the output image of the display unit is controlled by combining the tilt angle above and the tilt angle on the horizontal plane calculated using the light intensity measurement sensor and the ambient lightness measurement sensor. A projector having an angle measuring device.   2. The tilt according to claim 1, wherein the measured tilt angle is a tilt angle between the projection optical axis and the projection plane on a vertical plane, and the light guide unit is disposed in a horizontal direction with respect to the projection optical axis. A projector having an angle measuring device.   The measured tilt angles are the projection optical axis on the horizontal plane and the tilt angle of the projection plane, and the projection optical axis on the vertical plane and the tilt angle of the projection plane, and the light guide section is on the projection optical axis. The projector having the tilt angle measuring device according to claim 1, wherein the projector is arranged in a vertical direction and a horizontal direction, and the light intensity measurement sensor is provided for each.   The projector having the tilt angle measuring device according to any one of claims 1 to 5, wherein the output unit having the high luminance light output function includes an image control unit and a liquid crystal display unit.   The tilt angle according to any one of claims 1 to 5, wherein the output unit having the high-luminance light output function includes an image control unit, a DMD (digital micromirror device) display unit, a color wheel, and a light source. A projector having a measuring device.   The projector which has a tilt angle measuring apparatus of any one of Claim 1 to 7 whose said light guide part is a pinhole provided in the wall surface of a projection apparatus.   The projector which has a tilt angle measuring apparatus of any one of Claim 1-7 whose said light guide part is an optical lens provided in the wall surface of the projection apparatus.   The projector having the tilt angle measuring device according to any one of claims 1 to 9, wherein the light intensity measurement sensor and the ambient environment lightness measurement sensor are phototransistors.

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