JP3730982B2 - projector - Google Patents

Description

The present invention relates to a projector, relates to a projector for outputting a tilt angle information of the projection optical axis and the projection plane of the projection apparatus a projector used in particular computer.

  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 the purpose of image projection. It attracts attention not only as a display device for video information provided but also as a large display device in the home instead of a display television.

  However, unlike a display-type television, the projector has a problem in that the image plane is a screen or a wall, so that a trapezoidal distortion is generated in the image due to the relative relationship between the projection optical axis of the projector and the projection plane. In order to deal with this problem, the liquid crystal projector has an installation angle detection means and a distance detection means for detecting the distance between the liquid crystal projector and the projection target, and the angle of the liquid crystal display unit is determined by the angle calculated from both detection results. A method of adjusting is disclosed (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 an image without distortion 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).

  Also, a front projection touch panel comprising a large touch panel on which an image is projected, a projector, and a personal computer having a distortion correction conversion processing function for correcting distortion of the projected image caused by the relative positional relationship between the large touch panel and the projector. A system is disclosed (see Patent Document 4).

  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. In addition, the method described in Patent Document 4 needs to use a large touch panel, and cannot use a normal screen or wall as a projection surface.

  Further, barrel-type and pin-cushion type distortion aberrations caused by the zooming focal length are also corrected.

The inventor of the present invention can accurately measure the vertical and horizontal tilt angles of the screen with respect to the projection optical axis of a 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 excellent 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.
Japanese Patent Laid-Open No. 9-281597 Japanese Patent Application Laid-Open No. 2001-169211 JP 2003-5278 A Japanese Patent Laid-Open No. 10-21007

  Some projectors are used to shoot materials placed on the platen and project them from the projector onto the screen. Recently, the projector is connected to a personal computer to record video information created and recorded by the personal computer. Projecting on a screen is widely performed.

  In this case as well, it is desirable to correct the trapezoidal distortion of the image on the projection surface. However, unlike large display devices that require large image reproducibility and clarity, and display devices that replace televisions in the home, trapezoidal images are required. Providing an expensive function for correcting the distortion has a problem of economy and has a resistance.

It is an object of the present invention to correct a trapezoidal distortion at a low cost by cooperating with a computer having a distortion correcting means, by a tilt angle in a vertical direction and / or a horizontal direction of a screen with respect to a projection optical axis measured by a projector. It is to provide a projector that can be.

The projector of the present invention
A projector that projects an image from a personal computer that corrects trapezoidal distortion based on tilt angle information about a tilt angle in a vertical direction and a horizontal direction between a projection surface and a projection optical axis from a projection device onto the projection surface. A tilt angle measuring device that acquires tilt angle information about the vertical and horizontal tilt angles of the surface and the projection optical axis, the tilt angle measuring device includes a vertical tilt sensor and a tilt angle calculating unit; The vertical tilt sensor measures the tilt angle of the projection device with respect to the direction of gravity, and the tilt angle calculation unit outputs the tilt angle in the vertical direction between the projection surface and the projection optical axis of the projection device to the personal computer as tilt angle information , Furthermore, the projection device of the projector 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 a light receiving intensity analysis inclination angle calculating section and two light intensity measuring sensor provided in the interior of one of the light guide section and a projector provided on the wall surface of projector as the inclination angle calculation unit, the light guide portion The light intensity measurement sensor is provided inside 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 a horizontal 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, 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, On the other hand, the light intensity analysis inclination angle calculation unit is arranged at the same interval on the left and right with the vertical upper part of the projection optical axis as the center, and from the light intensity measurement results of the two light intensity measurement sensors, The difference between and get preset From the correlation between the inclination angle between the projection surface on the reference plane and the plane perpendicular to the projection optical axis corresponding to the light intensity of each of the two light intensity measurement sensors and the difference between the left and right light intensities, seeking inclination angle of the projection surface and the plane perpendicular to the projection optical axis on the surface, you output to a personal computer as the inclination angle information in conjunction with the vertical tilt angle.

  The present invention has an effect that the trapezoidal distortion of the image projected from the projector on the projection surface can be corrected at low cost.

  The projector has a tilt angle measuring device that can measure the tilt angle in the vertical direction and the horizontal direction of the screen with respect to the projection optical axis of the projector at a low cost, and the computer that outputs video information to the projector Based on the horizontal tilt angle, the video output software has a distortion correction means that corrects the distortion of the video information to be output. The video information distortion is corrected by the tilt angle information input from the projector and output to the projector. This is because it is not necessary to provide an expensive video processing LSI in the projector.

  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 system according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a projector having an inclination angle measuring device according to an embodiment of the present invention. (B) is a side view, (c) is a top view, and FIG. 3 is a schematic diagram showing a state of reflected light of uniform high-intensity light projected from the projection device onto the projection surface. (A) is projection light. When the tilt angle between the axis and the projection surface is 90 °, (b) is the first tilt angle α, (c) is the second tilt angle β smaller than the first tilt angle, (d ) Is the distribution of light intensity depending on the incident angle of the light beam on the projection surface and the reflection angle of the reflected light beam. FIG. 4 shows the position of the light intensity measurement sensor with the horizontal axis as the reference line and the vertical axis of the light intensity measurement sensor. It is a schematic diagram which shows the right and left light intensity difference when it is set as the measured light intensity, (a) is a projection optical axis and projection. Inclination angle of 90 ° state between, (b) in the case of the first inclination angle, (c) is the case of the second inclination angle.

  Here, the reference plane 28 is a plane including the projection optical axis 27 and extending in the horizontal direction from the projection optical axis 27, and the horizontal inclination angle is the inclination between the projection plane 70 and the projection optical axis 27 on the reference plane 28. The inclination angle in the vertical direction is an inclination angle between the projection surface 70 and the projection optical axis 27 on a plane perpendicular to the reference plane 28 including the projection optical axis 27.

  Although the light guide unit is described as a pinhole here, it may be an optical lens as described later.

The projector system 1 according to the present invention includes a projector 10 and a personal computer 40. In this embodiment, in order to facilitate explanation and understanding, the projector according to the present invention and a personal computer that corrects distortion of video information based on tilt angle information input from the projector and outputs the information to the projector will be referred to as a projector system. To do.

  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 output unit 23 that outputs an image to the display unit 22, and the tilt angle measuring device 30. And a central processing unit 60.

  The projection apparatus 20 receives the distortion corrected video information 49 output from the image control unit 47 of the personal computer 40 via the output unit 44 by the image output unit 23, and outputs the output video from the display unit 22 via the projection lens 21. And projected onto the projection surface 70. Further, the projection device 20 has a high-luminance light output function for projecting the uniform and high-luminance projection light 31 from the projection lens 21 to the projection surface 70 as an image when the tilt angle is measured, The tilt angle measuring device 30 includes a pinhole 51 provided on the front wall surface of the projector 10 and two right and left lights that receive reflected light 32 of the high-intensity projection light 31 from the projection surface 70 that has entered the pinhole 51. The intensity measurement sensor 52 (52R, 52L), the vertical direction inclination sensor 54, the vertical inclination measured by the vertical direction inclination sensor 54, and the light intensity measured by the two light intensity measurement sensors 52 are obtained. A light reception intensity analysis inclination angle calculation unit 53 that calculates a horizontal inclination of the projection device 20 with respect to the projection plane 70 by analyzing the difference in light intensity, and the light reception intensity analysis inclination angle calculation unit 53 calculates And outputs to the PC 40 the inclination angle information as the inclination angle information 48.

  As shown in FIG. 2, the pinhole 51 is provided on the front surface of the projector 10 at a predetermined distance from the reference plane vertically above the projection optical axis 27, and the light intensity measurement sensors 52 (52R, 52L) are pinholes 51. A line parallel to the reference plane 28 inside the projector 10 and a plane perpendicular to the projection optical axis 27 so as to receive the reflected light 32 of the high-intensity projection light 31 from the projection plane 70 passing through On a certain reference line 29, they are arranged at the same interval on the right and left with respect to the reference plane 28 with the vertical upper side of the projection optical axis 27 as the center. For example, a phototransistor is used as the light intensity measurement sensor 52.

  The vertical inclination sensor 54 is an inclination sensor (G sensor) using an acceleration detection element that is also used for centering the machine. The vertical inclination sensor 54 accurately measures the inclination angle with respect to the direction of gravity as numerical data. Output.

  The received light intensity analysis inclination angle calculation unit 53 acquires the inclination angle in the vertical direction detected by the vertical direction inclination sensor 54, and from the light intensity measurement results of the two light intensity measurement sensors 52 (52R, 52L), The light intensity and the difference between the left and right light intensities are obtained, and the horizontal direction corresponding to the light intensity of each of the two preset light intensity measurement sensors 52 (52R, 52L) and the difference between the left and right light intensities The horizontal inclination angle is obtained from the correlation with the inclination angle.

  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.

  The personal computer 40 includes an input unit 41, a data processing unit 42, a storage unit 43, and an output unit 44. The data processing unit 42 includes a central processing unit 45 that controls the overall operation, an input from the input unit 41 and a storage unit 43. The image generation unit 46 that generates an input video from the storage data stored in the image data, and the projection surface based on the tilt angle information 48 that is input from the received light intensity analysis tilt angle calculation unit 53 of the projector 10 for the input video generated by the image generation unit 46 An image control unit 47 that performs control so that the image is not distorted when projected onto the image 70, and the output video generated by the image control unit 47 is output to the image output unit 23 of the projector 10 as distortion-corrected video information 49. Is done.

  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, ½ of this angle is an inclination angle between the plane perpendicular to the optical axis 27 on the reference plane 28 and the projection plane 70. It becomes.

  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 intensities of the measurement sensors 52L and 52R have 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, from this difference, the difference between the light intensity of each of the two light intensity measurement sensors 52 (52R, 52L) and the left and right light intensity, which is calculated based on a predetermined calculation formula set in advance or created from the experimental result, Is perpendicular to the projection surface 70 on the reference plane 28 and the projection optical axis 27 from the table showing the correlation between the tilt angle between the projection plane 70 on the reference plane 28 and the plane perpendicular to the projection optical axis 27. The angle of inclination with a smooth 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. For this reason, it is desirable to perform correction by mounting an ambient lightness measurement sensor for obtaining the brightness of the surrounding environment separately from the light intensity measurement sensor 52, but the accuracy is somewhat lowered when low cost is required. There is no particular problem even if correction by the ambient lightness measurement sensor is not performed.

FIG. 5 shows a process of correcting the output image of the display unit 22 from the horizontal direction inclination angle generated from the light intensity difference 81 between the two light intensity measurement sensors 52 and the vertical direction inclination angle detected by the vertical direction inclination sensor 54. It is a typical flowchart. The received light intensity analysis inclination angle calculator 53 generates two light intensity differences from the light intensities of the two light intensity measurement sensors 52 (step S1), and calculates the projection apparatus by calculating from the two light intensity differences or referring to a table. The horizontal tilt angle between the 20 optical axes 27 and the projection surface 70 is generated (step S2), the vertical tilt angle is obtained from the vertical tilt sensor 54 (step S3), and the horizontal tilt angle and the vertical tilt angle are obtained. Are transmitted to the personal computer 40 as the tilt angle information 48, the image control unit 47 of the personal computer 40 generates video control parameters (step S4), corrects the input video 24 generated by the image generation unit 46 (step S5), The input video 24 is corrected to become an output video 25, and the output video 25 is transmitted to the image output unit 23 of the projector 10 as distortion corrected video information 49. It is sent to the display unit 22 of the al projecting device 20. When the output video 25 is projected onto the projection surface 70, it becomes a video similar to the input video 24. This method is desirably projection surface 70 is illuminated with uniform brightness, because it tends to be irradiated actually more central bright, the angle by that amount of correction even calculation step S 2, including It is preferable to calculate the angle using a table rather than the calculation.

  In the description so far, the input image is corrected using the horizontal and vertical inclinations. However, since the trapezoidal distortion due to the influence of the vertical inclination is generally larger, it is measured by the vertical inclination sensor 54. Even if the input image 24 is corrected only by the inclination in the vertical direction, a substantial part of the trapezoidal distortion can be corrected, and the cost is reduced accordingly.

  In this embodiment, the inclination angle measurement has been described in the form of receiving the reflected light 32 of the high-intensity projection light 31 from the projection surface 70 by the vertical direction inclination sensor 54 and the two light intensity measurement sensors. The invention is not limited, and the object of the present invention can be achieved if the tilt angle can be measured at low cost. For example, the reflected light of the projection light projected on the projection surface from the left and right light emitting elements inside the projector with one projection lens. The light is received by two one-dimensional array image sensors arranged vertically above the light emitting element via one light receiving lens provided above the light projecting lens, and the relationship between the left and right light receiving positions. Even if the horizontal slope is calculated from the above, the cost is increased but it can be applied.

  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.

1 is a schematic block diagram of a projector system according to an embodiment of the present invention. It is a schematic diagram of a projector having an inclination angle measuring device of an 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 horizontal direction inclination angle produced | generated from the light intensity difference of two light intensity measurement sensors, and the vertical direction inclination angle detected with the vertical direction inclination sensor. 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projector system 10 Projector 20 Projector 21 Projection lens 22 Display part 23 Image output part 24 Input image 25 Output image 27 Projection optical axis 28 Reference surface 29 Reference line 30 Inclination angle measuring device 31 Projection light 32 Reflection light 33 Main reflection light 40 PC 41 Input unit 42 Data processing unit 43 Storage unit 44 Output unit 45, 60 Central processing unit 46 Image generation unit 47 Image control unit 48 Inclination angle information 49 Distortion corrected video information 51 Pinhole 52, 52L, 52R Light intensity measurement sensor 53 Light reception intensity analysis inclination angle calculation unit 54 Vertical direction inclination sensor 56 Convex lens 70 Projection surface 81 Light intensity difference S1 to S5 Steps

Claims (6)

A projector that inputs an image from a personal computer that corrects trapezoidal distortion based on tilt angle information about a tilt angle in a vertical direction and a horizontal direction between a projection surface and a projection optical axis, and projects the image from a projection device onto the projection surface. ,
The projector has a tilt angle measuring device that acquires tilt angle information about a tilt angle in a vertical direction and a horizontal direction between the projection surface and the projection optical axis,
The tilt angle measuring device includes a vertical tilt sensor and a tilt angle calculating unit, the vertical tilt sensor measures a tilt angle of the projection device with respect to the direction of gravity, and the tilt angle calculating unit includes the projection surface and the projection surface. Output the tilt angle in the direction perpendicular to the projection optical axis of the projector as tilt angle information to the personal computer,
Further, the projection device of the projector 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 provided on the wall surface of the projector. One light guide provided, two light intensity measurement sensors provided inside the projector, and a received light intensity analysis inclination angle calculator as the inclination angle calculator;
The light guide unit is provided on a front wall surface of the projector at a predetermined interval in a vertical direction from the projection optical axis with respect to a reference plane including the projection optical axis in which the inclination angle in the horizontal direction is obtained,
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 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 sets the two predetermined light intensity values. From the correlation between the angle of inclination of the projection plane on the reference plane and the plane perpendicular to the projection optical axis corresponding to the light intensity of each light intensity measurement sensor and the difference between the left and right light intensity, the reference A projector that obtains an inclination angle between the projection plane on a plane and a plane perpendicular to the projection optical axis, and outputs it to the personal computer as inclination angle information together with the vertical inclination angle . The projector according to claim 1 , wherein the light guide is a pinhole provided on a wall surface of the projector. The projector according to claim 1 , wherein the light guide is an optical lens provided on a wall surface of the projector. The projector according to claim 1 , wherein the light intensity measurement sensor is a phototransistor . The projector according to any one of claims 1 to 4 , wherein the projection device includes a liquid crystal display unit . The projector according to any one of claims 1 to 4 , wherein the projection device includes a DMD (digital micromirror device) display unit, a color wheel, and a light source .

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