JP3914938B2 - Projector keystone distortion correction device and projector including the keystone distortion correction device - Google Patents

Description

  The present invention relates to a projector, and more particularly, to a trapezoidal distortion correction device for calculating an inclination angle between a projection optical axis of a projection device and a projection surface from a crossing line between a wall surface serving as a captured projection surface and a surface intersecting the wall surface. The present invention relates to a projector.

  With the rapid development of liquid crystal technology and DLP ™ (digital light processing) technology, the miniaturization and high performance of projectors has expanded the use of projectors for video projection, making it a display-type television at home. It is also attracting attention as an alternative large display device.

  However, unlike a display-type television, the projector has a problem that the image is distorted due to the relative relationship between the projection optical axis of the projector and the projection surface because the image surface is a screen or a wall. Patent Document 1 has a liquid crystal projector 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 adjusted by the angle calculated from both detection results. A method is disclosed. In this case, it is necessary to mechanically adjust the angle of the liquid crystal display unit. In Patent Document 2, the light spot of a laser pointer capable of angle control is projected onto a curved screen. On the other hand, a point image for measurement is generated, projected from the projector onto the screen, and photographed with a camera. Measure the position of the image and move the point image. When the two points coincide, replace the pixel coordinates on the frame memory of the point image with the coordinates on the input image of the light point and set in the coordinate conversion parameter memory. A distortion correction method is disclosed. In this case, it is necessary to control the angle of the laser pointer, and the structure becomes complicated.

On the other hand, a technique for projecting an image without distortion onto the screen by converting the coordinates of the frame memory of the projector when the vertical and horizontal inclinations of the screen with respect to the projection optical axis of the projector are known has been put into practical use. For this reason, 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. There is also a liquid crystal projector having a tilt angle measuring device that can accurately measure the tilt angles in the vertical and horizontal directions with respect to the projection optical axis of the liquid crystal projector of the screen for image distortion correction using a digital camera having a laser pointer and an image sensor. It has been studied and is an excellent means for accurately obtaining the angle of the projector with respect to the screen. However, it is necessary to use a digital camera having a laser pointer and a two-dimensional array image sensor as its constituent devices.

  The object of the present invention is to determine the inclination angle of the projection surface with respect to the projection optical axis of the projector for image distortion correction, based on the captured image of the intersection line between the wall surface of the projection surface and the surface intersecting with it. An object of the present invention is to provide a projector having a trapezoidal distortion correction device that calculates by calculation using the three-dimensional coordinates of an intersection with a range frame line.

The trapezoidal distortion correction apparatus for a projector according to the present invention is:
A solid-state imaging device having an imaging surface of a predetermined imaging range including a projection image by a projector, and a cross line between a plane that is a projection surface and a plane that intersects the plane is detected from the captured image in the solid-state imaging device, and the intersection line Is calculated based on the position information of the intersection point between the projection line and the frame defining the imaging range, and the projection apparatus displays the calculated inclination angle according to the inclination angle. And a captured image analysis tilt angle calculation unit that outputs to the image control unit of the projector that corrects trapezoidal distortion in the image of the projection surface by controlling the output video of the unit.

  The detection of the intersecting line between the plane that is the projection plane from the captured image of the solid-state imaging device and the plane that intersects the plane is performed by two or more of the vertical direction and the horizontal direction projected from the projection device onto the projection plane The position information of the refraction point appearing on the imaging surface of the reflected light of the straight test pattern is obtained, the straight line connecting the refraction points is calculated, and the plane that becomes the projection plane and the plane that intersects the plane It may be an intersection line.

  The intersecting line between the plane on the projection plane and the plane intersecting with the plane is the two intersecting lines in the horizontal direction between the wall surface serving as the projection plane and the ceiling and floor surface intersecting with the wall surface. The analysis inclination angle calculation unit uses the center of the imaging lens that projects an image on the solid-state imaging device as the origin, the optical axis of the imaging lens as the Z axis, and the intersection line between the vertical plane including the Z axis and the imaging plane as the Y axis By applying a three-dimensional coordinate rotation formula to the three-dimensional coordinates that are position information of the intersection of the left and right frame lines and the intersection line calculated with the intersection line between the horizontal plane including the Z axis and the imaging plane as the X axis, You may calculate the inclination angle of the horizontal and vertical direction of the optical axis of a projector of a projector, and a projection surface.

  In that case, the captured image analysis inclination angle calculation unit calculates the horizontal direction and the X axis centered on the Y axis based on the calculated three-dimensional coordinates of X, Y, and Z of the left and right frame lines and the intersection of the intersection lines. Based on the rotation angle, the vertical distance from the origin to the imaging surface, and the angle of view of the imaging lens with respect to the imaging surface, assuming that the vertical rotation around the center is assumed The horizontal rotation angle about the Y axis is used as the optical axis and the projection plane when it is determined that the two intersecting lines are parallel from the X, Y, and Z coordinates of the obtained four intersections. And the vertical inclination angle between the optical axis and the projection surface may be calculated from the vertical rotation angle about the X axis.

A projector equipped with the trapezoidal distortion correction device of the present invention,
A trapezoidal distortion correction device for a projector as described above, and an image control unit that corrects trapezoidal distortion in an image on a projection surface by controlling an output image of a display unit of the projection device according to an inclination angle calculated by the trapezoidal distortion correction device. Have.

  The present invention calculates based on the captured image of the intersection line between the wall surface of the projection surface and the surface intersecting with it using the three-dimensional coordinates that are the position information of the intersection of the two intersection lines and the frame line of the imaging range. Since the angle of inclination of the projection surface with respect to the projection optical axis of the projector is calculated by the above, if a captured image of the intersection line between the wall surface of the projection surface and the surface intersecting with it can be acquired, the trapezoidal distortion of the image can be corrected with a simple mechanism. There is an effect.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram of a projector including a projector keystone distortion correction apparatus according to a first embodiment of the present invention, and FIG. 2 is a keystone distortion correction apparatus according to the first embodiment of the present invention. 1A is a front view, FIG. 2B is a side view, and FIG. 2C is a top view.

  The projector 10 includes a projection device 20 having a projection lens 21 and a display unit 22, an image control unit 23 that controls the image of the display unit 22, a trapezoidal distortion correction device 30, and a central processing unit 60 that controls the overall operation. With. The image control unit 23 controls the output image of the display unit 22 according to the tilt angle calculated by the trapezoidal distortion correction device 30, thereby correcting the image distortion on the projection surface 70. Image distortion correction is automatically performed by the central processing unit 60 in a predetermined procedure.

  The trapezoidal distortion correction device 30 is provided on the front surface of the projector 10 and has an imaging lens 51 having an optical axis in a predetermined direction, and receives light passing through the imaging lens 51 and outputs desired position information of the captured image. A solid-state imaging device 53 provided inside the projector 10 so as to be perpendicular to the optical axis of the imaging lens 51 and provided with a frame line around the imaging surface in a predetermined shape; and a solid-state imaging device And a captured image analysis tilt angle calculation unit 54 that calculates the tilt angle of the projector 10 from the analysis of the position information of the image at 53.

  In the present invention, the projection of the projector 10 is performed based on positional information on the screen of the solid-state imaging device 53 of at least two intersecting lines in the horizontal direction between the wall surface serving as the projection surface 70 and the ceiling or floor surface intersecting the wall surface. The tilt angle in the horizontal direction and the vertical direction between the projection optical axis 27 and the projection surface 70 of the apparatus 20 is calculated. Further, based on the positional information on the screen of the solid-state imaging device 53 of at least two intersecting lines in the vertical direction between the wall surface serving as the projection surface 70 and the wall surface intersecting with the wall surface, the projection light of the projection device 20 of the projector 10 is projected. The present invention can also be applied to calculating the inclination angle between the shaft 27 and the projection surface 70.

  There are two methods for acquiring the position information of the intersecting line of the wall surface on the screen of the solid-state image sensor 53. In the first method, for example, a change line of illuminance on the imaging screen of total reflection light that has passed through the imaging lens 51 and input to the solid-state imaging element 53 from a reflection surface including the projection surface 70 on the front side of the projector 10 is a boundary line. Get as. In this case, in order to obtain a clear boundary line, it is often necessary to perform an operation such as appropriately performing a filter process.

The second method is a method in the case where the projection range is sufficiently large and covers the ceiling or floor. Two or more straight lines in either the vertical direction or the horizontal direction are projected on the front surface including the projection surface 70 from the projection device 20. A test pattern is projected, the refraction point appearing on the imaging screen of the reflected light from the test pattern is obtained, a straight line connecting the refraction points is calculated, and the straight line intersects the plane that becomes the projection surface and the plane The intersection line with the surface,
FIG. 3 is a schematic diagram showing a state in which a plurality of vertical test patterns are projected from the projector onto the wall surface and ceiling, (a) is a side view, (b) is a rear view, and FIG. 4 is a test pattern change. (A) is a projected test pattern, (b) is a test pattern incident on a solid-state image sensor, and FIG. 5 explains a method for detecting a crossing line on a wall surface from the incident test pattern. (A) is the state of the assumed intersection line, (b) is a schematic diagram explaining the principle which detects the intersection line of a wall surface from the incident test pattern.

  When a plurality of vertical test patterns 90 shown in FIG. 4A are projected onto a wall surface 75 that becomes the projection surface 70 and a ceiling 76 that intersects the wall surface 75 as shown in FIG. 20 is inclined with respect to the projection optical axis 27, so that an image of the test pattern 90 refracted from the wall surface 75 to the ceiling 76 is generated, and the reflected light passes through the imaging lens 51 of the projector 10 and passes through the imaging element 51 of the projector 10. It enters the imaging screen 80 as a test pattern image 91 shown in FIG. The test pattern image 91 has a straight intersection 99 as shown in the figure.

  An intersection line 92 shown by a one-point difference line in FIG. 5A is obtained by connecting the intersection points 99 of the plurality of straight lines. Although five test patterns 90 are shown in the figure, the intersection line 92 can be calculated even if there are two test patterns 90. As shown in FIG. 5 (b), the straight line intersection 99 is obtained by obtaining the coordinates of the two detection points 93 and 94 on the upper side of the test pattern image 91 from the pixel positions of the detection points 93 and 94. A straight line 95 is obtained by a linear equation, the coordinates of two detection points 96 and 97 on the lower side of the test pattern image 91 are obtained from the pixel positions of the detection points 96 and 97, and a straight line 98 is obtained by a second linear equation. A straight line intersection 99 may be obtained as the intersection of the first linear equation and the second linear equation. When two intersection points 99 of the straight line are obtained, the third linear equation of the intersection line 92 can be obtained from the respective coordinates. If there are a plurality of straight line intersections 99, the third straight line equation may be obtained from each coordinate using the least square method.

  Since the calculation of the first and second linear equations of the test pattern image 91 is performed based on two or more coordinates of the captured test pattern image 91, the test pattern 90 is not a continuous straight line, but a plurality of bright spots. May be obtained from the coordinates of the imaged bright spots, and in that case, if there are two bright spots, a linear equation that passes through two points, and if there are more than two, the minimum two An approximation method such as multiplication can be used.

  Here, in order to simplify the description, the method of obtaining one intersection line has been described. However, when obtaining two intersection lines, upper and lower, the intersection line between the wall surface 75 and the ceiling and the floor surface enters the projection range. The test pattern 90 is projected to obtain intersections 99 of two straight lines at the top and bottom, and intersecting lines 92 are obtained for the respective intersections 99.

  When two intersecting line images in the same direction or the calculated intersecting line 92 is obtained from the image capturing screen 80 of the solid-state image sensor 53, the captured image analysis inclination angle calculating unit 54 determines the obtained intersecting line 92 and the image capturing surface. The position of the intersection with the frame line 82 of the imaging range 81 is acquired as a three-dimensional coordinate, and is projected from the distance between the known imaging lens 51 and the imaging surface and the angle of view of the imaging lens 51 with respect to the frame line 82 of the imaging range 81. An inclination angle formed by the wall surface to be the surface 70 and a surface perpendicular to the optical axis of the imaging lens 51 is calculated.

  In the present invention, the inclination angle between the wall surface and the projector 10 is calculated using two intersecting lines in the same direction between the wall surface and the ceiling and the floor surface, or two intersecting lines in the same direction between the wall surface and the left and right wall surfaces. However, the case where two intersecting lines in the same direction of the wall surface, the ceiling, and the floor surface are used will be mainly described. If two intersecting lines in the same direction between the wall surface and the left and right wall surfaces are used, it may be considered that they are rotated by 90 degrees.

  FIG. 6 is a schematic diagram of a captured image of an individual image sensor when a wall, a ceiling, and a floor surface are imaged within an imaging range, and FIG. 7 is for calculating an intersection of an intersection line and a frame line of an imaging screen. FIG. 8 is a schematic diagram for explaining the initial setting of the coordinates of FIG. 8. FIG. 8 is a schematic diagram showing the coordinates of the intersection of the intersection line in the initial mapping on the virtual screen described later and the frame line of the imaging screen. FIG. 10 is a schematic diagram showing the coordinates of the intersection point of the intersection line on the virtual screen after the rotation around the y axis and the frame line of the imaging screen, and FIG. 10 further shows the coordinates on the virtual screen after the rotation around the x axis. It is a schematic diagram which shows the coordinate of the intersection of an intersection line and the frame line of an imaging screen.

  FIG. 6 shows an image obtained by the individual image sensor 53 when the projector 10 equipped with the individual image sensor 53 is projected obliquely. In the display area 71 of the projection image projected from the projection device 20 onto the projection surface 70 on the individual imaging element 53, the distance between the individual imaging element 53 and the projection lens 21 is the projection distance (the distance between the projector 10 and the projection plane 70). If it is small enough compared to), it becomes almost rectangular. Since the image projected from the projector 10 is usually projected with a launch angle upward in the vertical direction with respect to the center line of the projection lens, the display area 71 is above (actually below) the center point 72 of the imaging screen 80 in the figure. Are displayed away. A range wider than the display area 71 of the projected image is imaged on the imaging screen 80 of the individual imaging element 53, and an intersection line 78 between the wall surface 75 and the ceiling 76 and an intersection line 79 between the wall surface 75 and the floor surface 77 are also imaged. ing. The imaging screen 80 shows the entire imaging range by the individual imaging element 53 and is surrounded by a frame line 82. Here, an intersection line 78 between the ceiling 76 and the wall surface 75 and an intersection line 79 between the floor surface 77 and the wall surface 75 are shown.

  FIG. 6 shows an image on the individual imaging device 53, which can be considered as a mapping onto a plane (hereinafter referred to as a virtual screen 74) perpendicular to a line connecting the center of the imaging lens 51 and the center 72 of the captured image 80. it can. The captured image of FIG. 6 is assumed on the assumption that the intersection line 78 between the ceiling 76 and the wall surface 75 and the intersection line 79 between the floor surface 77 and the wall surface 75 are parallel to the wall surface 75 when viewed from the vertical direction. A method of obtaining horizontal and vertical angles between the projector 10 and the wall surface 75 by calculation based on the mapping on the virtual screen 74 and correcting the distortion of the image based on the angles will be described.

  First, three-dimensional coordinates are determined for the mapping on the virtual screen 74 as shown in FIG. The imaging lens center 52 in FIG. 7 is the origin at the time of three-dimensional coordinate rotation calculation. The extension direction of the line connecting the imaging lens center 52 and the center point 73 of the mapping on the virtual screen 74 is the z axis, the vertical direction of the mapping of the virtual screen 74 is the y axis, and the counterclockwise rotation angle around the y axis is θ, The horizontal direction of the mapping on the virtual screen 74 is taken as the x axis, and the counterclockwise rotation angle around the x axis is taken as ψ. The imaging range 80 of the individual imaging element 53 in FIG. 6 is not necessarily limited to the physical limit of the individual imaging element 53, and is determined as a rectangle having an appropriate size in consideration of the resolution of the individual imaging element 53, measurement errors, and the like. be able to.

  FIG. 8 shows intersections A, B, C, and D of the intersection line 78 and the intersection line 79 obtained from the image captured in FIG. 6 and the frame line 82 of the imaging range. Since FIG. 8 is an image on the individual imaging device 53, the coordinates of these four intersections on the xy plane can be obtained. Further, since the angle of view of the imaging lens 51 is known, the distance from the imaging lens center 52 to the virtual screen 74 and the coordinates of these four intersections are in a proportional relationship. Of course, the definition of the intersecting lines 78 and 79 is not limited to two points at both ends, but may be a plurality of points or may be defined by a linear equation.

  Next, in order to reversely calculate the distortion caused by the inclination of the projector 10, a coordinate rotation calculation is performed on the four selected coordinates. Here, it is assumed that the projector 10 is placed on a horizontal base (that is, there is no rotation around the z axis). The counterclockwise angle around the y axis is θ, the counterclockwise angle around the new x axis after rotation around the y axis is ψ, and any point (X, Y, Z on the virtual screen of the individual image sensor 53 ) If the coordinates after the coordinate rotation are (x, y, z), the following equation is established.

That is,
x = X cos θ + Y sin θ sin φ + Z sin θ cos φ
y = Ycosψ−Zsinψ
z = −X sin θ + Y cos θ sin ψ + Z cos θ cos ψ
It becomes. If the distance from the imaging lens center 52 to the virtual screen 74 is Z0, the original coordinates of the four points are A (X1, Y1, Z0), B (X2, Y2, Z0), C (X3, Y3, Z0). , D (X4, Y4, Z0). By substituting these into the above equation, coordinates A (x1, y1, z1), B (x2, y2, z2), C (x3, y3, z3), D (x4, y4, z4) can be determined. Further, by normalizing z1 to z4 to Z0, the image after the coordinate rotation can be represented as a mapping on the virtual screen 74. Assuming that the coordinates normalized by Z0 are (Nx, Ny),
Nx = x / z × Z0 Ny = y / z × Z0
It becomes.

  Next, a procedure for obtaining θ and ψ in which the intersecting lines 78 and 79 obtained in FIG. 6 become parallel by coordinate rotation will be described. The direction of rotation about the y-axis is determined from the spread of the two intersecting lines in FIG. Judgment is made by comparing the difference in y-coordinate between points B and D with the difference in y-coordinate between points A and C. In the state of FIG. 8, since Y4-Y2> Y3-Y1, the two intersecting lines spread to the right. This means that the position of the individual imaging element 53 (that is, the position of the projector) is on the lower left side with respect to the front wall. In this case, the rotation direction around the y axis is clockwise, and the rotation direction around the x axis is clockwise.

First, rotation about the y-axis is performed. The coordinates on the virtual screen plane of the four intersections A ′, B ′, C ′, and D ′ normalized by Z0 after the coordinate rotation and converted into the mapping to the virtual screen 74 are (Nx1, Ny1), (Nx2, Ny2), respectively. ), (Nx3, Ny3), (Nx4, Ny4). here,
Δy1 = | (Ny3-Ny1) − (Ny4-Ny2) |
Then, θ is changed so that Δy1 is minimized. In the case of FIG. 8, since the rotation direction is clockwise, the rotation angle is reduced from zero. When Δy1 becomes minimum, a new rotation around the x-axis is performed by rotating the y-axis. FIG. 9 shows the mapping onto the virtual screen 74 when Δy1 is minimized. here,
Δy2 = | Ny1-Ny2 |
Δy3 = | Ny3-Ny4 |
And ψ is reduced from zero until | Δy2−Δy3 | becomes minimum. FIG. 10 shows mappings A ″, B ″, C ″, and D ″ of the four intersections onto the virtual screen 74 when | Δy2−Δy3 | becomes the minimum. It can be seen that the two line segments CD and AB are substantially parallel to the ground surface. The angles θ and ψ obtained by the above procedure are angles when the front wall is viewed from the imaging lens center 52, and the distance between the individual imaging element 53 and the projection lens 21 of the projector 10 is the projector 10 and the wall. If the angle θ and ψ are sufficiently shorter than the distance to the projector, it can be considered that there is a strong correlation between the tilt angle of the projector. In particular, θ, which is the rotation angle around the y-axis, becomes the tilt angle of the projector 10 as it is when the solid-state image sensor 53 is mounted perpendicular to the projection optical axis 27 of the projection lens 21 of the projector 10.

  In the process of the above calculation, since the x coordinate of the mapping to the virtual screen 74 is not involved in the calculation, the individual image pickup device 53 is attached to be inclined upward with respect to the projection optical axis 27 of the projection lens 21 of the projector 10. This means that the attitude of the projector can be obtained even if it is. For example, when the individual image pickup device 53 is inclined by α with respect to the projection optical axis 27 of the projector 10, θ−α obtained by subtracting the launch angle α of the individual image pickup device 53 from θ obtained by the above procedure is the inclination of the projector itself. Represents.

  Because the tilt angle from the imaging lens center 52 to the wall and the tilt angle to the wall of the projector itself are considered to be approximately equal, it is caused by projecting obliquely based on θ and ψ, the launch angle α of the projector, and the projection magnification of the lens Distortion can be corrected. It may be obtained directly from the above-mentioned parameters, or a two-dimensional lookup table having θ and ψ as variables may be created and parameters necessary for distortion correction may be referred to.

  Similarly, when two perpendicular intersecting lines can be detected, θ and ψ can be obtained by performing the same operation on the x coordinate of the mapping in the above procedure.

  The image control unit 23 controls the output video of the display unit 22 based on the tilt angle so as to correct the distortion.

  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.

  In FIG. 11, when the intersection line is calculated by the second method, the intersection line position information is acquired as the three-dimensional coordinates from the incident position information of the reflected light of the solid-state imaging device 53, and the inclination angle is calculated by rotating the coordinates. 5 is a schematic flowchart showing a process of correcting an output video of the display unit 22.

  The captured image analysis inclination angle calculation unit 54 acquires the incident position of the reflected light of the two or more linear test patterns in the same direction on the projection surface 70 in the solid-state image sensor 53 (step S11), and refracts each test pattern image. A point (intersection 99 of the straight line) is calculated (step S12), a straight line connecting the refraction points is calculated as the intersection line 92 of the wall surface (step S13), and the position of the intersection of the intersection line 92 and the frame line 82 of the imaging screen 80 is calculated. Information is acquired as three-dimensional coordinates (step S14), and coordinate rotation is performed around the x-axis and the y-axis (step S15), and the rotation direction around the y-axis is determined from the spread of two intersecting lines ( Step S16) Rotates around the y axis so that the distance between the intersections in the y-axis direction is the same on the left and right (step S17), so that the coordinates in the y-axis direction between the intersections in the horizontal direction coincide. Rotates about the axis (step S18), and calculates the inclination angle between a surface perpendicular from the rotation angle ψ to the wall surface and the optical axis around the rotation angle θ and the x-axis around the y-axis (step S19).

  In response to the tilt angle generated in step S19, the image control unit 23 generates an LSI control parameter (step S21), and controls the projector image processing LSI (step S22), whereby the input video 24 is corrected and the display unit is displayed. 22 becomes an output image 25. When the output video 25 is projected onto the projection surface 70, it becomes a video similar to the input video 24.

1 is a schematic block configuration diagram of a projector provided with a trapezoidal distortion correction device for a projector according to a first embodiment of the present invention. 1 is a schematic diagram of a projector including a trapezoidal distortion correction 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 which projected the several test pattern of the perpendicular direction on the wall surface and ceiling from the projector. (A) is a side view. (B) is a rear view. It is a schematic diagram which shows the change of a test pattern. (A) is a projected test pattern. (B) is a test pattern incident on the solid-state imaging device. It is a schematic diagram for demonstrating the method to detect the crossing line of a wall surface from the incident test pattern. (A) is the state of the assumed intersection line. (B) is a schematic diagram explaining the principle which detects the crossing line of a wall surface from the incident test pattern. It is a schematic diagram of the picked-up image of an individual image pick-up element when a wall, a ceiling, and a floor surface are imaged within the imaging range. It is a schematic diagram for demonstrating the initial setting of the coordinate for the calculation of the intersection of an intersection line and the frame line of an imaging screen. It is a schematic diagram which shows the coordinate of the intersection of the intersection line in the initial mapping on a virtual screen, and the frame line of an imaging screen. It is a schematic diagram which shows the coordinate of the intersection of the intersection line on the virtual screen after implementing rotation around a y-axis, and the frame line of an imaging screen. Furthermore, it is a schematic diagram which shows the coordinate of the intersection of the intersection line on the virtual screen after implementing rotation around x-axis, and the frame line of an imaging screen. When the intersection line is calculated by the second method, the intersection line position information is acquired as the three-dimensional coordinates from the incident position information of the reflected light of the solid-state imaging device, and the tilt angle is calculated by rotating the coordinates to output the display unit. It is a typical flowchart which shows the process which corrects an image | video.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Projector 20 Projector 21 Projection lens 22 Display part 23 Image control part 24 Input image 25 Output image 27 Projection optical axis 30 Trapezoid distortion correction apparatus 51 Imaging lens 52 Imaging lens center 53 Individual image sensor 54 Captured image analysis inclination angle calculation part 60 Central processing unit 70 Projection surface 71 Projected image display area 72, 73 Center point 74 Virtual screen 75 Wall surface 76 Ceiling 77 Floor surface 78, 79, 92 Cross line 80 Imaging screen 82 Frame 90 Test pattern 91 Test pattern image 93, 94 , 96, 97 Detection point 95, 98 Straight line by equation 99 Straight line intersection S11-S19, S21, S22 Steps

Claims (5)

A keystone distortion correction apparatus for a projector provided in a projector for projecting an image,
A solid-state imaging device having an imaging surface of a predetermined imaging range including an image projected by the projector;
An intersection line between a plane serving as a projection plane and a plane intersecting the plane is detected from a captured image in the solid-state imaging device, and based on position information of an intersection between the intersection line and a frame line defining the imaging range. The tilt angle between the optical axis of the projector of the projector and the projection plane is calculated, and the calculated tilt angle is controlled by controlling the output image of the display unit of the projector according to the tilt angle. A trapezoidal distortion correction apparatus for a projector, comprising: a captured image analysis tilt angle calculation unit that outputs to a projector image control unit that corrects a trapezoidal distortion in an image.   The detection of the intersecting line between the plane that is the projection plane and the plane that intersects the plane from the captured image of the solid-state imaging element is either the vertical direction or the horizontal direction that is projected from the projection device onto the projection plane. The position information of the refraction point of the reflected light that appears on the imaging surface of the two or more straight line test patterns is obtained, a straight line connecting the refraction points is calculated, the straight line is defined as a plane that becomes the projection surface, and the straight line The trapezoidal distortion correction apparatus for a projector according to claim 1, wherein the trapezoidal distortion correction apparatus is a crossing line with a plane that intersects the plane.   The intersecting line between the plane on the projection surface and the plane intersecting the plane is two intersecting lines in the horizontal direction between the wall surface serving as the projection surface and the ceiling and floor surface intersecting the wall surface, The captured image analysis tilt angle calculation unit uses the center of the imaging lens that projects an image on the solid-state imaging device as the origin, the optical axis of the imaging lens as the Z axis, and a vertical plane including the Z axis and the imaging plane 3 with respect to the three-dimensional coordinates that are the position information of the intersection of the left and right frame lines and the intersection line calculated with the intersection line as the Y axis and the intersection line between the horizontal plane including the Z axis and the imaging surface as the X axis. 3. The keystone distortion correction of a projector according to claim 1, wherein a tilt angle in a horizontal direction and a vertical direction between an optical axis of the projection device of the projector and the projection plane is calculated by applying a coordinate rotation type of the projector. apparatus.   The captured image analysis inclination angle calculation unit calculates a horizontal direction and an X axis centered on the Y axis based on the calculated three-dimensional coordinates of X, Y, and Z of the left and right frame lines and the intersection line. The change information of the coordinates of the intersection of the intersection when it is assumed that the center is rotated in the vertical direction, the rotation angle, the vertical distance from the origin to the imaging surface, and the imaging lens with respect to the imaging surface The horizontal rotation angle about the Y axis when it is determined that the two intersection lines are parallel based on the X, Y, and Z coordinates of the four intersections obtained based on the angle of view. Is determined as a horizontal inclination angle between the optical axis and the projection plane, and a vertical inclination angle between the optical axis and the projection plane is calculated from a vertical rotation angle about the X axis. Item 4. A trapezoidal distortion correction apparatus for a projector according to Item 3.   5. The projector trapezoidal distortion correction device according to claim 1 and a projection surface by controlling an output image of a display unit of the projection device according to an inclination angle calculated by the trapezoidal distortion correction device. A projector including a trapezoidal distortion correction device, and an image control unit that corrects a trapezoidal distortion in the image.

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