JP3730979B2 - Projector having tilt angle measuring device - Google Patents

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 ™ (digital light processing) technology, the miniaturization and high performance of projectors have expanded the use of projectors for the purpose of image projection. It is also attracting attention as an alternative large display device.

  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 correcting the distortion of the image. 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 excellent as a means for accurately obtaining the angle of the projector with respect to the screen, a digital camera having a two-dimensional array image sensor as its constituent device is used. Cost to use 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. Unit, a one-dimensional array CCD image 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. 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 so as to receive the reflected light from the projection plane of the high-intensity light passing through the light guide in the projector. Are arranged in a row with the vertical upper side of the projection optical axis as the center.

  The received light intensity analysis inclination angle calculation unit calculates the light that passes through the light guide unit and the straight line connecting the position of the CCD solid-state image sensor having the highest light intensity and the light guide unit based on the light intensity measurement result by the one-dimensional array CCD image sensor. The output image of the display unit is controlled by using the angle formed by the straight line parallel to the axis as the inclination angle between the projection surface on the reference plane and the plane perpendicular to the projection optical axis.

  The reference plane may be horizontal or vertical, and may have a light guide and a one-dimensional array CCD image sensor for each of horizontal and vertical.

  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 one light guide provided on the front wall, the reflected light is received by a one-dimensional array CCD image sensor arranged in a line on a reference line parallel to the reference plane inside the projector, and the received light intensity analysis inclination angle calculation unit From the light intensity measurement result of the one-dimensional array CCD image sensor, the straight line connecting the position of the CCD solid-state image sensor having the highest light intensity and the light guide part and the straight line parallel to the projection optical axis passing through the light guide part are formed. This is because the image display unit can be controlled to eliminate the distortion of the screen by using the angle as the inclination angle between the projection surface on the reference 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 a low-cost one-dimensional array CCD image sensor is used without using a high-cost digital camera having a two-dimensional array image sensor.

  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 position of the CCD solid-state imaging device on the reference line and the respective positions. It is a schematic diagram of the graph which shows the light intensity which the CCD solid-state image sensor measured, (a) is a projection optical axis and a projection. Inclination angle of 90 ° state of the surface, (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. In addition, a one-dimensional array provided in a line in the projector 10 on a reference line 29 that is a line of intersection with a plane parallel to the reference plane 28 and perpendicular to the projection optical axis 27 with the vertical upper side of the projection optical axis 27 as the center. A CCD image sensor 52 and a received light intensity analysis inclination angle calculation unit 53 are provided. The received light intensity analysis inclination angle calculation unit 53 is lightest on the reference line 29 from the light intensity measurement result of the one-dimensional array CCD image sensor 52. Strong A threshold position is specified, and an angle formed by a straight line connecting the position and the pinhole 51 and a straight line parallel to the projection optical axis 27 passing through the pinhole 51 is the projection plane 70 on the reference plane 28 and the projection optical axis 27. The output video of the display unit 22 is controlled as an inclination angle with respect to a plane perpendicular to the vertical axis.

  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, a one-dimensional array CCD image sensor 52 that receives reflected light 32 of high-intensity light from the projection surface 70 that has entered the pinhole 51, and a one-dimensional array A light reception intensity analysis inclination angle calculation unit 53 that analyzes the light intensity measured by the CCD image pickup device 52 and calculates the inclination of the projection device 20 in the vertical or horizontal direction with respect to the projection surface 70;

  The present invention can be applied regardless of whether the projector 10 is a liquid crystal projector or a DLP (registered trademark) (digital light processing) type projector, and 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 one-dimensional array CCD image sensor 52 provided on the wall surface receives the reflected light 32 from the projection surface 70 of the high-intensity projection light 31 that passes through the pinhole 51 inside the housing of the projector 10. On a reference line 29 that is an intersection line between a plane parallel to the reference plane 28 and a plane perpendicular to the projection optical axis 27, the projection optical axis 27 is provided in a line with the vertical upper side as the center.

  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, when the projection optical axis 37 is orthogonal to the projection plane 70, the light intensity of the central element of the one-dimensional array CCD image sensor 52 becomes the strongest, and the center increases as the distance from the left and right increases. It becomes weaker than the light intensity of the element. When the reference line 29 is displayed on the horizontal axis and the light intensity of the element at each position is displayed on the vertical axis, FIG. 4A is obtained. As shown in FIG. 3B, when the projection optical axis 37 intersects the projection surface 70 at the first angle α, the direction in which the projection light 31 and the main reflected light 33 coincide, that is, the projection optical axis 27. And the reflected light in the direction of (90 ° -α) is the highest, and (90 ° -α) is the inclination angle between the projection surface 70 on the reference surface 28 and the surface perpendicular to the projection optical axis 27. It is.
When the reference line 29 is displayed on the horizontal axis and the light intensity of the element at each position is displayed on the vertical axis, FIG. 4B is obtained. As shown in FIG. 3C, when the projection optical axis 37 intersects the projection surface 70 at a second angle β smaller than the first angle α, the position of the highest light intensity is shown in FIG. As shown in FIG. 2, the vertical plane including the projection optical axis 27 and the reflected light in the direction of (90 ° -β) are the highest, and this (90 ° -β) is the projection plane on the reference plane. 70 is an inclination angle between the surface 70 and a plane perpendicular to the projection optical axis 27.

  The received light intensity analysis inclination angle calculation unit 53 obtains the position on the horizontal axis of the maximum value 82 from the light intensity measurement result of the one-dimensional array CCD image sensor 52. As described above, the reflected light 32 passing through the pinhole 51 coincides with the projection light 31, that is, the reflected light 32 becomes maximum when the projection light 31 and the projection surface 70 are orthogonal to each other. Here, since the reflected light 32 connecting the position of the element having the highest light intensity of the one-dimensional array CCD image pickup element 52 and the pinhole 51, that is, the projection light 31 and the projection surface 70 are orthogonal to each other, An angle formed by a straight line connecting the position of the maximum value 82 and the pinhole 51 and a straight line passing through the pinhole 51 and parallel to the projection optical axis 27 is perpendicular to the projection plane 70 on the reference plane 28 and the projection optical axis 27. The output image of the display unit 22 is controlled as an inclination angle with respect to a smooth surface.

  FIG. 5 is a schematic flowchart showing a process of correcting the output image of the display unit 22 from the light intensity of the one-dimensional array CCD image sensor 52. The received light intensity analysis inclination angle calculation unit 53 analyzes the position of the highest light intensity from the light intensity distribution of the one-dimensional array CCD image sensor 52 (step S1), and based on this, the calculation of the projection device 20 is performed by calculation or table reference. An inclination angle between the projection optical axis 27 and the projection surface 70 is generated (step S2). Upon receiving the generated inclination angle, the image control unit 23 generates an LSI control parameter (step S3), and controls the projector image processing LSI. As a result (step S4), the input video 24 is modified to become an 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, it has been described by measuring the tilt angle in the horizontal direction, but the vertical direction is obtained by rotating the positions of the pinhole 51 and the one-dimensional array CCD image sensor 52 by 90 ° about the projection optical axis 27. It is possible to measure the inclination 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 one-dimensional array CCD image sensor 52 when the convex lens 56 is used as the light guide. Even when the convex lens 56 is used, the reflected light 32 from the projection surface 70 is input to the one-dimensional array CCD image 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 is horizontal depending on the light intensity measured by the one-dimensional array CCD image sensor 52. In addition to calculating the tilt angle in the direction, the tilt angle in the vertical direction detected by the vertical tilt sensor 54 is output to the image control unit 23, and the image control unit 23 takes into account the tilt in the horizontal and vertical directions. Generate control parameters. 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 one-dimensional array CCD image sensor 52 that were only used for measuring the tilt angle in the horizontal direction in the first embodiment, the pinhole 51 for measuring the tilt angle in the vertical direction. Since the configuration and the operation are the same as those in the first embodiment except that each has a one-dimensional array CCD image pickup device 52 and is connected to the received light intensity analysis inclination angle calculation unit 53, the same components have the same reference numerals. The description of the same part is omitted.

  The light intensity measured by the one-dimensional array CCD image sensor 52 ′ for measuring the tilt angle in the vertical direction is also input to the received light intensity analysis tilt angle calculator 53, and the received light intensity analysis tilt angle calculator 53 receives the one-dimensional array CCD image sensor 54. The horizontal tilt angle is calculated from the light intensity measured in Step 1, and the vertical tilt angle is calculated from the light intensity measured by the one-dimensional array CCD image pickup device 54 ′, so that the horizontal tilt angle and the vertical tilt angle are calculated. The inclination angle is combined and output to the image control unit 23, and the image control unit 23 generates LSI control parameters in consideration of the 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.

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 of the graph which shows the position of the CCD solid-state image sensor on a reference line, and the light intensity which each CCD solid-state image sensor measured. (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 of a one-dimensional arrangement | sequence CCD image pick-up element. It is a schematic diagram which shows the light-incidence state to the one-dimensional arrangement | sequence CCD image 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, 52 ′ One-dimensional array CCD image sensor 53 Light reception intensity analysis tilt angle calculation unit 54 Vertical direction tilt sensor 56 Convex lens 60 CPU
70 Projection surface 81 Light intensity 82 Maximum value S1-S4 step

Claims (9)

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. A one-dimensional array CCD image sensor and a received light intensity analysis inclination angle calculation unit,
The light guide 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 from which the tilt angle is required.
The one-dimensionally arrayed CCD image sensor includes a plane parallel to the reference plane and the projection light so as to receive the reflected light from the projection plane of the high-intensity light passing through the light guide unit inside the projector. Provided on a reference line, which is a line of intersection with a surface perpendicular to the axis, in a line with the vertical upper side of the projection optical axis as the center,
The received light intensity analysis inclination angle calculation unit calculates the light guide from the light intensity measurement result by the one-dimensional array CCD image sensor and a straight line connecting the position of the CCD solid image sensor having the highest light intensity and the light guide. Controlling an output image of the display unit with an angle formed by a straight line parallel to the projection optical axis passing as an inclination angle between the projection plane on the reference plane and a plane perpendicular to the projection optical axis. A projector having a characteristic tilt angle measuring device.   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 angle measuring device according to claim 2, wherein an output image of the display unit is controlled by combining an upper tilt angle and a tilt angle on a horizontal plane calculated using the one-dimensional array CCD image sensor. projector.   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. 2. 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 one-dimensional array CCD image pickup device 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.

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