JP2006243149A - Projector, and projection image distortion correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector capable of displaying a correct correction angle for the projector by detecting the inclination angle of a projection screen to the projection optical axis of the projector. <P>SOLUTION: The projector comprises: a transmission time information receiving section 30 for calculating a distance between a transmitter and a first ultrasonic wave receiving section 31 and a distance between the transmitter and a second ultrasonic wave receiving section 32 based upon a ultrasonic wave transmitted by the transmitter indicating a position on the projection screen 80 and time at which an infrared ray is received, and for storing the distances as distance information; an angle correction information calculating section 50 which, based upon the distance information obtained by the transmission time information receiving section 30 via the transmitter, calculates the vertical and horizontal inclination angle of the projection screen 80 relative to the projection optical axis 85 of the projector for a plurality of reference points projected to the projection screen 80 as test patterns so as to be disposed in predetermined positions on a vertical center line and horizontal center line on the projection screen; and a correction angle display section 53 for displaying an inclination angle and a correction angle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projector and a projection image distortion correction method, and more particularly to a projector with a transmitter information receiving unit and a projection image distortion correction method capable of displaying an inclination relationship between a projection surface and a projector on the projection surface.

  In recent years, projectors have become shorter in focus, and the number of projectors that can greatly reduce the projection display distance has increased. Recently, a mirror-type projector equipped with a projection mirror in a housing with an aperture structure that can be made even shorter. The development of projectors has progressed, and an ultra-short focus type mirror projector having a projection screen type 60 and a projection distance of about 26 cm has been developed.

  The image projected by the short focus type projector is projected without distortion when the projection surface and the projection optical axis of the projection mirror of the projector are at a predetermined angle, but the relative relationship between the projector and the screen is projected. If a slight difference occurs, since the distance between the projector and the screen is short, the ratio of the distortion with respect to the distance becomes large, and a very large distortion is likely to occur in the projected image. In the case of a mirror projector, the distortion is adjusted by manually adjusting the vertical and horizontal angles of the projector itself, but there is a problem that it takes time and accurate adjustment is not easy. This is set so that a distortion-free image is projected when the vertical inclination angle of the projector and the screen is a predetermined inclination angle, so that the projection optical axis of the projector and the screen are at a predetermined angle. This is because the image projected from the projector will be distorted if it is not orthogonal in the left-right direction. On the other hand, it is difficult for the user to recognize the degree of tilt and the necessary correction amount. It has an influence.

Conventionally, Patent Document 1 discloses a correction method using a mechanism of a mechanical tilt sensor in order to improve the adjustment labor during such installation. Furthermore, a method of electrically detecting and correcting the tilt of the projector itself has been studied.
JP 2003-324669 A

  In the method disclosed in Patent Document 1, it is necessary to provide a space for mounting the tilt sensor inside the projector, and the method of electrically detecting and correcting the tilt of the projector itself is for solving the problem of the projector itself. The tilt relationship between the projector and the screen could not be grasped.

  An object of the present invention is to provide a projector capable of displaying a correct projector correction angle by detecting an inclination angle between a projection screen and a projection optical axis of the projector without providing a tilt detection mechanism of the projector itself.

The projector with a transmitter information receiving unit of the present invention,
A projector having a first wave receiving unit and a second wave receiving unit, which are used in combination with an electromagnetic wave light emitting unit and a wave transmitting unit, and are disposed apart from each other. Transmitting time information receiving unit that calculates the distance between the transmitter and the first wave receiving unit and the transmitter and the second wave receiving unit based on the wave and electromagnetic wave reception times transmitted by the transmitter and stores them as distance information And an angle correction information calculating unit that calculates an inclination angle of the projection surface with respect to the optical axis of the projector from each distance information acquired by the transmission time information receiving unit via a transmitter for a plurality of reference points on the projection surface; Have

  A plurality of reference points projected on the projection surface as a test pattern so that a plurality of reference points on the projection surface are at a predetermined position on a center line in a predetermined direction of the projection surface, and via a transmitter An inclination angle in a predetermined direction with respect to the optical axis of the projector on the projection surface may be calculated from each distance information acquired by the transmission time information receiving unit, and becomes a predetermined position on the center line in the predetermined direction on the projection surface. A plurality of reference points projected toward the projection surface as a test pattern so that a plurality of reference points projected toward the projection surface as a test pattern are at predetermined positions above and below the vertical center line of the projection surface From the respective distance information acquired by the transmission time information receiving unit via the transmitter, the vertical inclination angle of the projection surface with respect to the optical axis of the projector may be calculated. Test so that a plurality of reference points projected toward the projection surface as a test pattern so as to be in a predetermined position on the center line in a predetermined direction are at predetermined positions on the left and right of the horizontal center line of the projection surface. It is a plurality of reference points projected toward the projection surface as a pattern, and from each distance information acquired by the transmission time information receiving unit via the transmitter, the inclination angle in the horizontal direction with respect to the optical axis of the projector on the projection surface is calculated. It may be calculated.

  A plurality of reference points projected toward the projection surface as a test pattern so as to be in a predetermined position on the center line of the projection surface in the predetermined direction are on the center line of the projection surface in the first direction and in the second direction. From the respective distance information acquired by the transmission time information receiving unit via the transmitter, the projection surface is a plurality of reference points projected toward the projection surface as a test pattern so as to be at a predetermined position on the center line of the projection plane. The inclination angle of the first direction and the second direction with respect to the optical axis of the projector may be calculated, the first direction of the projection surface being the vertical direction of the projection surface, and the second direction being the horizontal direction. From the distance information acquired by the transmission time information receiving unit via the transmitter, the projection surface projection is obtained for a plurality of reference points projected toward the projection surface as a test pattern so as to be in a predetermined position. It may calculate the vertical direction and the inclination angle in the horizontal direction with respect to the optical axis of the motor.

  The angle correction information calculation unit may further calculate a correction value for correcting the tilt angle of the projection surface in the vertical direction or the horizontal direction with respect to the optical axis of the projector, or both of them to a predetermined angle. The tilt angle and / or the correction value of both in the vertical direction and / or the horizontal direction with respect to the image may be displayed on the screen on the projection surface, or may be displayed on the display unit of the projector.

  The electromagnetic wave is an infrared ray, the wave is an ultrasonic wave, and the transmission time information receiving unit is a first ultrasonic receiving unit and a second ultrasonic receiving unit that receive ultrasonic waves generated by the ultrasonic transmitting unit of the transmitter. And an infrared light receiving unit that receives infrared light generated by the infrared light emitting unit of the transmitter, and the difference between the light reception time of the infrared light receiving unit and the reception time of the first ultrasonic receiving unit and the second ultrasonic receiving unit, The ultrasonic wave arrival times from the ultrasonic wave transmitter of the transmitter to the first ultrasonic wave receiver and the second ultrasonic wave receiver are calculated, and the ultrasonic wave transmitter and the first ultrasonic wave are calculated from the ultrasonic wave arrival times. An angle correction information calculation unit having a time difference analysis distance calculation unit for calculating the distance to the reception unit and the second ultrasonic reception unit, and a transmitter distance information storage unit for storing the calculated distance information in a predetermined order Is a point-shaped test pad that serves as multiple reference points. A test pattern generator for projecting an image, a reference point projected at predetermined positions on the right and left of the vertical center line and on the left and right of the horizontal center line of the projection plane stored in the transmitter distance information storage unit Projected from the distance information between the first ultrasonic receiving unit and the second ultrasonic receiving unit, the distance information between the first ultrasonic receiving unit and the second ultrasonic receiving unit, and the projection angle information of the reference point An inclination angle calculation unit that calculates vertical and horizontal inclination angles with respect to the optical axis of the projector on the surface, and a vertical and horizontal inclination angle with respect to the optical axis of the projector calculated by the angle correction information calculation unit The angle correction information calculation unit may further correct the vertical and horizontal tilt angles of the projection surface with respect to the optical axis of the projector to a predetermined angle. The correction value may be calculated.

The projected image distortion correction method of the present invention includes:
Projecting a test pattern having a plurality of reference points from a projector onto a projection surface;
A step of sequentially pointing a reference point projected on the projection surface with a transmitter including an ultrasonic wave transmitting unit and an infrared light emitting unit and performing transmission, and two times of reception of infrared rays received by the infrared receiving unit of the transmission time information receiving unit Calculating and storing the distance between each of the plurality of reference points and the two ultrasonic receivers, and the reference projected on the projection surface, with the reception time of the ultrasonic waves received by the ultrasonic receiver Projector on the projection surface from the distance information between each of the points and the two ultrasonic receivers, the distance information between the first ultrasonic receiver and the second ultrasonic receiver, and the projection angle information of the reference point Calculating the tilt angle with respect to the optical axis of the projector, and displaying the tilt angle with respect to the optical axis of the projector on the screen on the projection surface as projection image distortion correction data.

  Also, a step of projecting point-like test patterns serving as a plurality of reference points on the projection surface from the projector so as to be at predetermined positions on the center line in the first direction and on the center line in the second direction. And a step of sequentially pointing a reference point projected on the projection surface with a transmitter including an ultrasonic wave transmitting unit and an infrared light emitting unit, and performing transmission, and an infrared reception time received by the infrared receiving unit of the transmission time information receiving unit, Calculating and storing the distance between each of the plurality of reference points and the two ultrasonic receiving units based on the reception times of the ultrasonic waves received by the two ultrasonic receiving units; Distance information between each of the reference points projected on the center line in the first direction and on the center line in the second direction and the two ultrasonic receiving units, and the first ultrasonic receiving unit and the second ultrasonic receiving unit Distance between clubs Calculating a first direction of the projection surface relative to the optical axis of the projector and an inclination angle of the second direction from the projection angle information of the reference point, and a first direction and a second direction relative to the optical axis of the projector And a step of displaying the inclination angle of the direction on the screen on the projection surface as projection image distortion correction data.

  A step of projecting a point-shaped test pattern serving as a plurality of reference points so as to be in a predetermined position on the projection surface from above and below the vertical center line of the projection surface and on the left and right of the horizontal center line; A step of sequentially pointing a reference point projected on the projection surface with a transmitter including an ultrasonic wave transmitting unit and an infrared light emitting unit and performing transmission, and two times of reception of infrared rays received by the infrared receiving unit of the transmission time information receiving unit Calculating and storing the distance between each of the plurality of reference points and the two ultrasonic wave receiving units with the ultrasonic wave receiving time received by the ultrasonic wave receiving unit, and the vertical center line of the projection surface Distance information between each of the reference points projected on the upper and lower sides and the left and right of the horizontal center line and the two ultrasonic receiving units, and the distance between the first ultrasonic receiving unit and the second ultrasonic receiving unit Affection Calculating the vertical and horizontal tilt angles of the projection plane with respect to the optical axis of the projector from the projection angle information of the reference point, and the vertical and horizontal tilt angles with respect to the optical axis of the projector. And displaying the distortion correction data on a screen on the projection surface.

  Using a transmitter having an infrared light emitting unit and an ultrasonic wave transmitting unit, a plurality of reference points of the projected image are indicated, and the distance between each indicated reference point and the receiving unit incorporated in the projector is determined by infrared rays. And the ultrasonic time difference, the inclination between the projector and the screen is detected, and the inclination angle and the necessary correction amount are displayed on the screen.

  The present invention uses a projector with a transmitter information receiver in combination with a transmitter including an ultrasonic transmitter that transmits ultrasonic waves and an infrared light emitter that emits infrared rays. Since the tilt angle in the vertical direction and the horizontal direction can be acquired and the tilt angle and the necessary correction amount are displayed, there is an effect that the installation angle of the projector can be easily adjusted to the correct angle.

  The present invention detects an inclination between a projector and a projection surface using an image having a projected reference point and a pointing stick with a transmitter, and indicates the user to easily adjust the installation conditions of the projector and the projection surface. It is characterized by doing.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing a relationship between a projector with a transmitter information receiving unit, a pointer with a transmitter, and a projection surface according to an embodiment of the present invention, and FIG. 2 is a transmitter according to the embodiment of the present invention. It is a typical block block diagram of a projector with an information receiver. In the following description, the projector with the transmitter information receiving unit 10 may be abbreviated as the projector 10 in some cases.

  Configurations and functions of projector 10 with transmitter information receiver, transmitter pointer 70 and projection surface 80 according to the embodiment of the present invention will be described with reference to FIGS. The pointing rod 70 with a transmitter has the same configuration as an electronic pen often used for an electronic blackboard, an infrared light emitting unit 72 that emits infrared light as a trigger pulse, and an ultrasonic transmission unit 71 that transmits ultrasonic waves for position detection. Is a pointer provided in the vicinity of the tip of the transmitter. Here, sound waves having a frequency higher than 15 kHz are called ultrasonic waves, and light having a wavelength longer than 0.74 μm is called infrared rays. In this embodiment, it will be described as a pointing stick with a transmitter, but there is no problem even with an electronic pen with a short length, and various types of devices can be used as long as the transmitter has an infrared light emitting unit and an ultrasonic transmission unit. Possible forms. It is desirable that the transmitter having the ultrasonic transmission unit is provided in the vicinity of a portion indicating the projection surface.

  The ultrasonic transmitter 71 and the infrared light emitter 72 of the transmitter generate an ultrasonic signal and an infrared pulse only once in a cycle in synchronization. Here, the ultrasonic transmitter 71 and the infrared light emitter 72 are turned on and off by the operation of the switch 76 at the hand of the pointing rod 70 with a transmitter, but may be performed by pressing the tip portion against the projection surface. Good.

  The projector with a transmitter information receiving unit 10 includes a transmission time information receiving unit 30, an angle correction information calculating unit 50, an image control unit 21, a light beam modulating unit 22, an optical system 23, and a projection unit 24. It has the projection part 20 which projects information outside, and the central control apparatus 60 which controls each part. Although an ultra-short focus mirror type projector will be described here as an example, it can be effectively applied to a short focus lens projection type projector having a lens shift mechanism.

  The transmission time information reception unit 30 includes a first ultrasonic reception unit 31, a second ultrasonic reception unit 32, an infrared light reception unit 33, a time difference analysis distance calculation unit 41, and a transmitter distance information storage unit 42. Have.

  The first ultrasonic receiving unit 31 and the second ultrasonic receiving unit 32 are disposed in the direction perpendicular to the vertical plane including the projection optical axis 85 and are separated from each other in the horizontal direction. The ultrasonic signals 73 and 74 generated by the ultrasonic transmission unit 71 of 70 are respectively received. Such an arrangement is desirable for calculating the tilt angle, but even a different arrangement can be corrected. The infrared light receiving unit 33 receives the infrared pulse 75 generated in the infrared light emitting unit 72 of the pointing rod 70 with the transmitter disposed near the first ultrasonic receiving unit 31 and the second ultrasonic receiving unit 32. To do. The infrared light receiving unit 33 does not cause a large error in the light receiving time even if it is provided at a remote location.

  The ultrasonic transmitting unit 71 and the infrared light emitting unit 72 of the pointing rod 70 with a transmitter generate an ultrasonic signal and an infrared pulse only once in a cycle in synchronization, and the infrared light emission time and the light reception time are almost the same. Therefore, the difference between the reception time of the infrared light reception unit 33 and the reception time of the first ultrasonic reception unit 31 and the reception time of the reception time of the infrared reception unit 33 and the reception time of the second ultrasonic reception unit 32 are different. From the ultrasonic transmitter 71 of the transmitter-attached pointer 70 to the first ultrasonic receiver 31 and the ultrasonic arrival times from the ultrasonic transmitter 71 to the second ultrasonic receiver 32 are calculated. The time difference analysis distance calculation unit 41 converts the distance from the ultrasonic transmission unit 71 to the first ultrasonic reception unit 31 and from the ultrasonic transmission unit 71 to the second ultrasonic reception unit 32 by converting using the speed of sound. It can be calculated.

  The calculated distance information is stored in the transmitter distance information storage unit 42 in a predetermined order, for example, in the order received, for future reading.

  The angle correction information calculation unit 50 includes a test pattern generation unit 51, an inclination angle calculation unit 52, and a correction angle display unit 53.

  The test pattern generation unit 51 generates a point-shaped test pattern serving as a reference point in the horizontal direction with a predetermined projection angle and two points at the top and bottom across the center point of the image projected on the projection surface 80. Two points are projected from the projection unit 20 as an image onto the projection surface 80 at a predetermined projection angle. If only the vertical inclination angle is detected, only the vertical test pattern is required, and if only the horizontal inclination angle is detected, only the horizontal test pattern is required. The tilt angle can be easily calculated by setting the vertical direction and the horizontal direction, but the tilt angle can be calculated even in any direction.

  Each reference point and the first ultrasonic receiving unit 31 and the second ultrasonic receiving unit of the transmission time information receiving unit 30 are indicated and transmitted by the transmitting unit of the transmitter-attached pointing rod 70 in a predetermined order. 32 is acquired, the distance is calculated by the time difference analysis distance calculation unit 41, and stored in the transmitter distance information storage unit 42.

  In the inclination angle calculation unit 52, the distance information of the reference point is acquired from the transmitter distance information stored in the transmitter distance information storage unit 42, and the projection optical axis of the projector 10 is obtained by a predetermined calculation formula or a lookup table. The vertical and horizontal tilt angles of the projection surface 80 with respect to 85 and the necessary correction values are calculated and output to the correction angle display unit 53.

  The correction angle display unit 53 inputs the vertical and horizontal inclination angles of the projection surface 80 with respect to the projection optical axis 85 of the projector 10 and the necessary correction values from the projection unit 20 via the image control unit 21 to the projection surface. 80 is displayed as an image.

  Next, the operation of the embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a schematic diagram showing the positional relationship between the distortion of the image and the reference point due to the inclination relationship between the projector and the projection surface. FIG. 3A shows a case where the projection surface is set at a predetermined angle, and FIG. When inclined in the direction, (c) shows the case where the projection surface is inclined in the vertical direction. In each, the lower left is a front view, the upper left is a top view, and the right is a side view. When the projector 10 and the projection surface 80 are installed so as to have a predetermined angular relationship, the outline of the projection image is not distorted as shown in FIG. 3 is not set at a predetermined angle, the image 82 is distorted in the contour of the projected image as shown in FIGS. 3B and 3C, and the reference point 200 moves.

  FIG. 4 is an explanatory diagram when two right and left reference points are projected on the projection screen from the projector so as to be at the same angle from the projection optical axis, and (a) is formed by the projection plane and the projection optical axis. It is a front view of the reference point on the image plane when the angle is the same in the horizontal direction, and (b) is the reference point on the image plane when the angle between the projection plane and the projection optical axis is the same in the horizontal direction. FIG. 6 is a top view showing a movement state of a reference point on an image plane when left and right are different. When the angle between the projection surface 80 and the projection optical axis 85 is the same in the horizontal direction, the left and right reference points 201 and 202 on the projection surface 80 are the same distance on the left and right with respect to the vertical center line. When the angle formed with the projection optical axis 85 differs between the left and right in the horizontal direction, the reference point 202 moves to the position of the reference point 204.

  When each reference point 200 of the projected image is pointed by the pointing rod 70 with the transmitter, the reference point 200, the first ultrasonic receiving unit 31 and the second ultrasonic receiving unit 32 are used with the projector 10 with the transmitter information receiving unit. The distance information between the projector 10 and the projection surface 80 can be calculated based on the distance information.

  The principle of distance information acquisition and the method of calculating the tilt angle between the projector 10 and the projection surface 80 will be described. FIG. 5 is a schematic diagram showing the relationship between transmission and reception of infrared rays and ultrasonic waves between a pointer with a transmitter and a projector with a transmitter information receiving unit, and FIG. 6 is a diagram of a projector according to an embodiment of the present invention. It is a typical block block diagram of a time difference analysis distance calculation part and a transmitter distance information storage part.

  When the transmitter is applied to the indicated position and the switch 76 is turned on, as shown in FIG. A sound wave signal 702 is transmitted. The infrared light receiving unit 33 of the projector with the transmitter information receiving unit 10 receives the infrared trigger pulse 701 as the infrared trigger pulse 331, and the first ultrasonic receiving unit 31 and the second ultrasonic receiving unit 32 receive the ultrasonic signal 702. Are received as ultrasonic signals 311 and 321, respectively.

There is almost no time delay between the light receiving time t ₀ of the infrared trigger pulse 331 received by the infrared light receiving unit 33 and the light emitting time of the infrared trigger pulse 701 emitted from the infrared light emitting unit 72 of the pointing rod 70 with a transmitter. However, the reception time t ₁ of the ultrasonic signal 311 is received by the first ultrasonic wave receiver 31, the reception time t ₂ of the ultrasonic signal 321 is received by the second ultrasonic wave receiving unit 32, ultrasonic A delay corresponding to the time obtained by dividing the distance by the speed of sound (about 340 m / s) occurs from the time when the ultrasonic wave signal 702 is transmitted from the sound wave transmitting unit 71. By obtaining T ₁ and T ₂ , which are the differences between the times t ₁ and t ₂ and t ₀ , information on the required times can be obtained. In the actual measurement of the reception time, there is a possibility that an error may occur in the measurement of the first wave. Therefore, the reception times after the second wave may be measured to obtain t ₁ and t ₂ by calculation.

  Next, the configuration and operation of the time difference analysis distance calculation unit 41 and the transmitter distance information storage unit 42 of the transmission time information reception unit 30 will be described. As described above, since the ultrasonic transmission unit 71 and the infrared light emitting unit 72 generate the ultrasonic signal and the infrared pulse only once in one cycle, the light reception time of the infrared pulse is substantially the same as the emission time of the ultrasonic signal, The difference between the reception time of the ultrasonic signal and the reception time of the infrared pulse is the arrival time of the ultrasonic wave, and the distance between the ultrasonic transmission unit 71 and the ultrasonic reception units 31 and 32 can be calculated using the speed of sound.

As illustrated in FIG. 6, the time difference analysis distance calculation unit 41 includes an infrared light reception time (t ₀ ) acquisition unit 411, a first ultrasonic reception time (t ₁ ) acquisition unit 412, and a second ultrasonic reception time (t ₂ ) Acquisition unit 413, first ultrasonic arrival time (t ₁ -t ₀ = T ₁ ) calculation unit 414, second ultrasonic arrival time (t ₂ -t ₀ = T ₂ ) calculation unit 415, T ₁ A distance conversion unit (= L ₁ ) 416, a T ₂ distance conversion unit (= L ₂ ) 417, and L ₁ and L ₂ distance notification units 418 are included. The transmitter distance information storage unit 42 includes a first ultrasonic reception unit-second ultrasonic reception unit distance L ₀ storage unit 421, and L ₁ and L ₂ distance storage units 422. The first ultrasonic wave receiver - the second ultrasonic wave receiver distance L ₀ storage unit 421, the distance L ₀ between the advance and the first ultrasonic wave receiver 31 and the second ultrasonic wave receiver 32 stored in L _1, L ₂ distance storage unit 422 L ₁ is calculated by the time difference analysis position calculating unit 41 to, L ₂ distance predetermined order, for example, stored in the calculating order, following angle storage order as an index It is extracted by the correction information calculation unit 50. The projection angle of each reference point may be stored in advance in the transmitter distance information storage unit, and may be read out and used for calculation by the tilt angle calculation unit 52 as necessary.

The infrared light reception time (t ₀ ) acquisition unit 411 acquires the light reception time t ₀ at the infrared light reception unit 33 of the infrared pulse 75 emitted simultaneously with the ultrasonic wave transmission unit 71 from the infrared light emission unit 72 of the pointing rod with transmitter 70. To do. The first ultrasonic wave reception time (t ₁ ) acquisition unit 412 and the second ultrasonic wave reception time (t ₂ ) acquisition unit 413 are respectively connected to the infrared light emission unit 72 from the ultrasonic wave transmission unit 71 of the pointing rod 70 with a transmitter. The reception times t ₁ and t ₂ at the _first ultrasonic receiving unit 31 and the second ultrasonic receiving unit 32 of the ultrasonic signals 73 and 74 transmitted simultaneously are acquired. The first ultrasonic wave arrival time (t ₁ −t ₀ = T ₁ ) calculation unit 414 calculates the time difference T ₁ between the reception time t _{1 of the first} ultrasonic reception unit 31 and the light reception time t ₀ of the infrared light receiving unit 33. Is calculated. The second ultrasonic arrival time (t ₂ −t ₀ = T ₂ ) calculation unit 415 calculates the time difference T ₂ between the reception time t _{2 of the second} ultrasonic reception unit 32 and the light reception time t ₀ of the infrared light receiving unit 33. Is calculated.

The T ₁ distance conversion unit (= L ₁ ) 416 uses the sound speed data to set the time difference T ₁ to the distance L ₁ between the ultrasonic transmission unit 71 of the pointing rod 70 with the transmitter and the first ultrasonic reception unit 31. Convert. The T ₂ distance conversion unit (= L ₂ ) 417 uses the sound speed data to set the time difference T ₂ to the distance L ₂ between the ultrasonic transmission unit 71 and the second ultrasonic reception unit 32 of the pointing rod with transmitter 70. In conversion, the L ₁ and L ₂ distance notification unit 418 stores the acquired distances L ₁ and L ₂ in the L ₁ and L ₂ distance storage unit 422 of the transmitter distance information storage unit 42.

In the inclination angle calculation unit 52 of the angle correction information calculation unit 50, a plurality of reference points on the projection surface 80 stored in the L ₁ and L ₂ distance storage unit 422 of the transmitter distance information storage unit 42 and the first super The distance information to the sound wave reception unit 31 and the second ultrasonic wave reception unit 32 and the first ultrasonic wave reception unit-second ultrasonic wave reception unit distance L ₀ storage unit 421 of the transmitter distance information storage unit 42 are stored. The tilt angle between the projector 10 and the projection surface 80 can be calculated from the first ultrasonic receiving unit-second ultrasonic receiving unit distance L ₀ and the projection angle of each predetermined reference point. .

7A and 7B are schematic diagrams for explaining a method of calculating the tilt angle in the left-right direction between the projector and the projection surface, where FIG. 7A is a side view and FIG. 7B is a top view. Both the first reference point 341 and the second reference point 342 on the screen are projected from the projector 10 onto the projection surface 80 having an elevation angle α and a left and right opening angle β, and a horizontal inclination angle θ. . When the transmitter of the pointing rod 70 with the transmitter transmits the first reference point 341 and the second reference point 342 sequentially, the time difference analysis distance calculation unit 41 starts the first ultrasonic reception unit from the first reference point 341. distance l ₁₁ to 31, the first from the reference point 341 the second ultrasonic receiver 32 to the distance l _12, and the second distance l ₂₁ from the reference point 342 to the first ultrasonic wave receiver 31, A distance l ₂₂ from the second reference point 342 to the second ultrasonic receiving unit 32 can be acquired and stored in the transmitter distance information storage unit 42 in a predetermined order.

Assuming that the first ultrasonic receiver 31 and the second ultrasonic receiver 32 are arranged equidistant from the center point C of the projection, the first reference point 341 on the screen from the center point C of the projection. And the distance l ₁₀ and the distance l _{20 to} the second reference point 342 are respectively
l ₁₀ = (l ₁₁ + l ₁₂ ) / 2
l ₂₀ = (l ₂₁ + l ₂₂ ) / 2
It becomes. Projected lengths l ₁₀ ′ and l ₂₀ ′ on the horizontal plane of l ₁₀ and l ₂₀ shown in FIG.
l ₁₀ '= l ₁₀ × cos α
l ₂₀ '= l ₂₀ × cos α
It becomes. The inclination angle θ of the projection surface 80 can be calculated if a and b in FIG.

a = a ₁ −a ₂ = l ₁₀ ′ × cos β−l ₂₀ ′ × cos β
= (L ₁₀ '-l ₂₀ ') × cos β
b = b ₁ + b ₂ = l ₁₀ '× sin β + l ₂₀ ' × sin β
= (L ₁₀ '+ l ₂₀ ') × sin β
Therefore,
tan θ = a / b
= {(L ₁₀ '-l ₂₀ ') × cos β} / {(l ₁₀ '+ l ₂₀ ') × sin β}
θ = tan ⁻¹ {(l ₁₀ ′ −l ₂₀ ′) × cos β} / {(l ₁₀ ′ + l ₂₀ ′) × sin β}
As a result, the inclination angle θ in the left-right direction of the projection surface is determined by the distance l ₁₁ from the first reference point 341 to the first ultrasonic receiver 31 and the second ultrasonic receiver 32 from the first reference point 341. a distance l ₂₂ from a distance l ₁₂ and the second reference point 342, to the first distance l ₂₁ to ultrasonic receiver 31, the second reference point 342 to the second ultrasonic wave receiver 32, The predetermined reference points 341 and 342 are obtained from the projection elevation angle α from the projector 10 and the left and right projection opening angles β.

In this equation, if (l ₁₀ ′ −l ₂₀ ′), that is, the distance between the two reference points 341, 312 and the two ultrasonic receivers 31, 32 is the same, (l ₁₀ ′ −l ₂₀ ′) = 0 and θ = 0, and it can be seen that the projection surface 80 is installed at the same left and right angles with respect to the projection optical axis 85 of the projector 10, that is, 90 °.

Next, a method for calculating the vertical inclination angle of the projection surface 80 will be described. FIG. 8 is a schematic diagram for explaining a method of calculating the vertical tilt angle between the projector and the projection surface. FIG. 8A is a perspective view showing the relationship between the reference point on the projection surface and the ultrasonic wave receiver. FIG. 4B is a side view. The first ultrasonic receiver 31 and the second ultrasonic receiver 32 are at the same distance L _0/2 from the center point C across the center point C, and the third reference point 343 and the fourth reference point A point 344 is projected at elevation angles γ and δ in directions orthogonal to a line connecting the first ultrasonic receiving unit 31 and the second ultrasonic receiving unit 32, respectively. The reference point and the first ultrasonic receiving unit The distance between 31 and the second ultrasonic wave receiving unit 32 is the same, l ₃₁ and l ₄₁ . Accordingly, the distances l ₃₀ and l ₄₀ between the third reference point 343, the fourth reference point 344 and the center point.
Is
l ₃₀ = {l ₃₁ ² − (L _0/2 ) ² } ^1/2
l ₄₀ = {l ₄₁ ² − (L _0/2 ) ² } ^1/2
It becomes.

In FIG. 8B,
l ₃₀ '= l ₃₀ × cos γ
l ₃₀ ”= l ₃₀ × sin γ
l ₄₀ '= l ₄₀ × cos δ
l ₄₀ ”= l ₄₀ × sin δ
l _H = l ₄₀ '−l ₃₀ '
l _V = l ₃₀ “−l ₄₀ ”
And
tan θ ′ = l _H / l _V
Therefore, the inclination angle θ ′ is
θ ′ = tan ⁻¹ (l _H / l _V )
It becomes.

Thus, the vertical inclination angle θ ′ of the projection surface is determined by the distance l ₃₁ from the third reference point 343 to the first ultrasonic receiver ₃₁ and the first ultrasonic reception from the fourth reference point 344. a distance l ₄₁ to section 31, from the center point C that is set in advance the first distance L _0/2 to the ultrasonic receiver 31, the projection angle of elevation from the projector 10 of the reference point 343 gamma, the reference point 344 It is obtained from the projection elevation angle δ from the projector 10. When the projection point of the reference point is at a position different from the intermediate point between the first ultrasonic receiving unit 31 and the second ultrasonic receiving unit 32, the difference needs to be corrected.

  The tilt angle θ in the horizontal direction of the projection surface and the tilt angle θ ′ in the vertical direction of the projection surface may be calculated by the above-described calculation formula, or may be obtained by a preset lookup table.

  By displaying the inclination angle information and the correction angle information for correcting to the normal angle calculated from the current inclination angle from the correction angle display unit 53 via the image control unit 21 on the screen, the user can Can recognize the current tilt angle and the necessary correction amount, and the user can easily correct the setting state of the projector 10 to the correct state. Although the current inclination angle and the necessary correction amount have been described as being displayed on the screen, they may be displayed on the main body of the projector 10 or may be displayed on both the screen and the main body of the projector 10.

  So far, the horizontal and vertical reference points have been described as two points, respectively, but the accuracy of tilt angle detection between the projector and the screen is improved by increasing the horizontal and vertical reference points.

  The present invention is not limited to a projector, and can be applied as an application for acquiring and indicating to a user tilt information between an object and a device having a transmitter information receiving unit using a transmitter stick. This is particularly effective for a short focus type projector and an ultra short focus type projector having an electronic blackboard function that easily causes distortion in a projected image.

  In the above-described embodiment, infrared rays are used as trigger pulses and ultrasonic waves are used for position detection. Since the human eye has low sensitivity to infrared rays, it is desirable to use infrared rays as a trigger pulse, but electromagnetic waves other than infrared rays can also be used. For example, an electromagnetic wave having a wavelength of 0.40 μm or more has little influence on the human body. In addition, since the human ear has low sensitivity to ultrasonic waves, it is desirable to use ultrasonic waves for position detection, but waves other than ultrasonic waves can also be used. For example, even a sound wave having a frequency of 15 kHz or less can be used without any problem as long as the sound volume is not felt by the user.

It is a typical perspective view which shows the relationship between the projector with a transmitter information receiving part of embodiment of this invention, a pointer with a transmitter, and a projection surface. It is a typical block block diagram of the projector with a transmitter information receiving part of an embodiment of the invention. It is a schematic diagram which shows the distortion of the image by the inclination relationship of a projector and a projection surface, and the positional relationship of a reference point, When (a) is installed in the predetermined | prescribed angle, (b) is a projection surface inclined in the left-right direction. (C) shows the case where the projection surface is inclined in the vertical direction. It is explanatory drawing at the time of projecting the reference point of two right and left so that it may become the same angle from a projection optical axis with respect to a projection screen from a projector, (a) is an angle made by a projection surface and a projection optical axis horizontal. It is a front view of the reference point on the image plane when the left and right are the same in the direction, and (b) is a case where the angle between the projection surface and the projection optical axis is different from the reference point on the image plane when the horizontal direction is the same It is a top view which shows the movement state of the reference point in the image plane. It is a schematic diagram which shows the relationship between transmission and reception of infrared rays and ultrasonic waves between a pointing rod with a transmitter and a projector with a transmitter information receiver. It is a typical block block diagram of the time difference analysis distance calculation part and transmitter distance information storage part of the projector of an embodiment of the invention. It is a schematic diagram for demonstrating the calculation method of the inclination angle of the left-right direction between a projector and a projection surface, (a) is a side view, (b) is a top view. It is a schematic diagram for demonstrating the calculation method of the inclination angle of the up-down direction between a projector and a projection surface, (a) is a perspective view which shows the relationship between the reference point on a projection surface, and an ultrasonic receiving part. b) is a side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Projector with transmitter information receiving part 20 Projection part 21 Image control part 22 Light flux modulation part 23 Optical system 24 Projection part 30 Transmission time information reception part 31 1st ultrasonic reception part 32 2nd ultrasonic reception part 33 Infrared reception Unit 41 Time difference analysis distance calculation unit 42 Transmitter distance information storage unit 50 Angle correction information calculation unit 51 Test pattern generation unit 52 Inclination angle calculation unit 53 Correction angle display unit 60 Central controller 70 Pointer with transmitter 71 Ultrasonic transmission unit 72 Infrared light emitting unit 73, 74 Ultrasonic signal 75 Infrared pulse 76 Switch 80 Projection surface 81 Inclined projection surface 82 Image 83 Vertical direction center line 84 Horizontal direction center line 85 Projection optical axis 200, 201, 202, 203, 204 Reference point 311, 321, 702 Ultrasonic signal 331, 701 Infrared pulse 341 First reference point 42 a second reference point 343 the third reference point 344 a fourth reference point 411 infrared receiving time (t ₀₎ acquiring unit 412 first ultrasonic reception time (t ₁₎ acquiring unit 413 the second ultrasonic wave receiving time (T ₂ ) Acquisition unit 414 First ultrasonic wave arrival time (t ₁ -t ₀ = T ₁ ) calculation unit 415 Second ultrasonic wave arrival time (t ₂ -t ₀ = T ₂ ) calculation unit 416 T ₁ distance Conversion part (= L ₁ )
417 T ₂ distance conversion part (= L ₂ )
418 L ₁ , L ₂ distance notifying unit 421 First ultrasonic receiving unit-second ultrasonic receiving unit L ₀ storage unit 422 L ₁ , L ₂ distance storage unit

Claims (15)

A projector having a first wave receiving unit and a second wave receiving unit which are used in combination with a transmitter including an electromagnetic wave light emitting unit and a wave transmitting unit, and are disposed apart from each other.
Based on the wave transmitted by the transmitter and the reception time of the electromagnetic wave, the distance between the transmitter and the first wave receiver and the distance between the transmitter and the second wave receiver is calculated as distance information. An outgoing time information receiver to store;
Angle correction information for calculating an inclination angle of the projection surface with respect to the optical axis of the projector from each distance information acquired by the transmission time information receiving unit via the transmitter for a plurality of reference points on the projection surface. A projector having a calculation unit.   The plurality of reference points projected on the projection surface as a test pattern so that the plurality of reference points on the projection surface are at a predetermined position on a center line in a predetermined direction of the projection surface, and the transmission The projector according to claim 1, wherein an inclination angle of the projection surface in a predetermined direction with respect to the optical axis of the projector is calculated from each distance information acquired by the transmission time information receiving unit via a device.   A plurality of reference points projected toward the projection surface as test patterns so as to be in a predetermined position on a center line in a predetermined direction of the projection surface are defined as predetermined positions above and below the vertical center line of the projection surface. A plurality of reference points projected toward the projection plane as test patterns, and from the distance information acquired by the transmission time information receiving unit via the transmitter, the projector on the projection plane The projector according to claim 2, wherein an inclination angle in a vertical direction with respect to the optical axis is calculated.   A plurality of reference points projected toward the projection surface as test patterns so as to be in a predetermined position on a center line in a predetermined direction of the projection surface are defined as predetermined positions on the left and right of the horizontal center line of the projection surface. A plurality of reference points projected toward the projection plane as test patterns, and from the distance information acquired by the transmission time information receiving unit via the transmitter, the projector on the projection plane The projector according to claim 2, wherein an inclination angle in a horizontal direction with respect to the optical axis is calculated.   A plurality of reference points projected toward the projection surface as test patterns so as to be in a predetermined position on the center line in the predetermined direction of the projection surface are on the center line in the first direction of the projection surface, and second Are a plurality of reference points projected toward the projection plane as test patterns so as to be in a predetermined position on the center line in the direction of the direction, and each of the transmission time information receiving units acquired via the transmitter The projector according to claim 2, wherein an inclination angle of the first direction and the second direction with respect to the optical axis of the projector on the projection surface is calculated from distance information.   A plurality of reference points projected toward the projection surface as a test pattern so that the first direction of the projection surface is the vertical direction of the projection surface, the second direction is the horizontal direction, and a predetermined position is obtained. The vertical and horizontal inclination angles of the projection surface with respect to the optical axis of the projector are calculated from the distance information acquired by the transmission time information receiving unit via the transmitter. The projector described.   The angle correction information calculation unit further calculates a correction value for correcting a vertical angle or a horizontal direction of the projection plane with respect to the optical axis of the projector or both of them to a predetermined angle. Item 7. The projector according to any one of Items 6 above.   The vertical angle and / or horizontal direction with respect to the optical axis of the projector calculated by the angle correction information calculation unit, or both of the inclination angles and / or correction values are displayed on the screen on the projection surface. The projector according to any one of claims 1 to 7.   The vertical angle and / or horizontal direction with respect to the optical axis of the projector calculated by the angle correction information calculation unit, or both of the inclination angles and / or correction values are displayed on the display unit of the projector. The projector according to claim 7.   The projector according to any one of claims 1 to 9, wherein the electromagnetic wave is an infrared ray, and the wave is an ultrasonic wave. The outgoing time information receiving unit
A first ultrasonic receiver and a second ultrasonic receiver for receiving ultrasonic waves generated by the ultrasonic transmitter of the transmitter;
An infrared receiver that receives infrared rays generated by the infrared emitter of the transmitter;
From the difference between the light reception time of the infrared light receiving unit and the reception times of the first ultrasonic wave reception unit and the second ultrasonic wave reception unit, the first ultrasonic wave reception from the ultrasonic wave transmission unit of the transmitter And an ultrasonic arrival time to the second ultrasonic reception unit, respectively, and the ultrasonic transmission unit, the first ultrasonic reception unit, and the second ultrasonic reception unit from the ultrasonic arrival time A time difference analysis distance calculation unit for calculating the distance to each of
A transmitter distance information storage unit that stores the calculated distance information in a predetermined order;
The angle correction information calculation unit
A test pattern generator for projecting a point-shaped test pattern serving as a plurality of reference points;
The reference point and the first ultrasonic receiving unit projected at predetermined positions on the projection plane stored in the transmitter distance information storage unit above and below the vertical center line and on the left and right of the horizontal center line, and From the distance information with respect to the second ultrasonic receiver, the distance information between the first ultrasonic receiver and the second ultrasonic receiver, and the projection angle information of the reference point, An inclination angle calculation unit for calculating an inclination angle in a vertical direction and a horizontal direction with respect to the optical axis of the projector;
11. The projector according to claim 10, further comprising: a correction angle display unit that displays on the screen on the projection surface the tilt angles in the vertical direction and the horizontal direction with respect to the optical axis of the projector calculated by the angle correction information calculation unit. .   The projector according to claim 11, wherein the angle correction information calculation unit further calculates a correction value for correcting the vertical and horizontal tilt angles of the projection plane with respect to the optical axis of the projector to a predetermined angle. Projecting a test pattern having a plurality of reference points from a projector onto a projection surface;
A step of sequentially indicating the reference point projected on the projection surface with a transmitter including an ultrasonic wave transmitting unit and an infrared light emitting unit, and performing transmission;
Each of the plurality of reference points and the two super-points are determined by the infrared reception time received by the infrared reception unit of the transmission time information reception unit and the ultrasonic reception time received by the two ultrasonic reception units. Calculating and storing a distance from the sound wave receiving unit, respectively;
Distance information between each of the reference points projected on the projection surface and the two ultrasonic receiving units, distance information between the first ultrasonic receiving unit and the second ultrasonic receiving unit, and Calculating an inclination angle of the projection surface with respect to the optical axis of the projector from the projection angle information of a reference point;
And a step of displaying an inclination angle with respect to the optical axis of the projector on the screen on the projection plane as projection image distortion correction data. Projecting a point-like test pattern serving as a plurality of reference points on the projection surface from the projector so as to be in a predetermined position on the center line in the first direction and on the center line in the second direction;
A step of sequentially indicating the reference point projected on the projection surface with a transmitter including an ultrasonic wave transmitting unit and an infrared light emitting unit, and performing transmission;
Each of the plurality of reference points and the two super-points are determined by the infrared reception time received by the infrared reception unit of the transmission time information reception unit and the ultrasonic reception time received by the two ultrasonic reception units. Calculating and storing a distance from the sound wave receiving unit, respectively;
Distance information between each of the reference points projected on the center line in the first direction and the center line in the second direction of the projection surface and the two ultrasound receivers, and the first ultrasound reception The first and second tilt angles of the projection plane with respect to the optical axis of the projector are calculated from the distance information between the projection section and the second ultrasonic receiving section and the projection angle information of the reference point. And steps to
The projection image distortion according to claim 13, further comprising a step of displaying the tilt angles in the first direction and the second direction with respect to the optical axis of the projector as projection image distortion correction data on the screen on the projection surface. Correction method. Projecting a point-shaped test pattern serving as a plurality of reference points so as to be at predetermined positions on the projection surface from above and below the vertical center line of the projection surface and on the left and right of the horizontal center line;
A step of sequentially indicating the reference point projected on the projection surface with a transmitter including an ultrasonic wave transmitting unit and an infrared light emitting unit, and performing transmission;
Each of the plurality of reference points and the two super-points are determined by the infrared reception time received by the infrared reception unit of the transmission time information reception unit and the ultrasonic reception time received by the two ultrasonic reception units. Calculating and storing a distance from the sound wave receiving unit, respectively;
Distance information between each of the reference points projected above and below the vertical center line of the projection surface and to the left and right of the horizontal center line and the two ultrasonic receivers, the first ultrasonic receiver, Calculating the vertical and horizontal inclination angles of the projection surface with respect to the optical axis of the projector from the distance information between the second ultrasonic receivers and the projection angle information of the reference point;
The projection image distortion correction method according to claim 14, further comprising: displaying tilt angles in a vertical direction and a horizontal direction with respect to the optical axis of the projector as projection image distortion correction data on the screen on the projection surface.

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