JP2008211355A - Projector, program, and information storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector, or the like capable of correcting distortion in an image accurately even if the projector inclines in reference to the optical axis of projection light. <P>SOLUTION: The projector 100 includes: a projection section 190 for projecting a calibration image toward an object to be projected via a projection panel; a shape determination section 130 for determining the shape of the object to be projected, based on the imaging information from an imaging section 110; a correction target region setting section 140; and an image generation section 150 for generating an image on the projection panel. The correction target region setting section 140 determines the coordinate values of vertical and horizontal vanishing points formed by the sides of the object to be projected in the coordinate system of the projection panel, when the entire shape of the object to be projected is not determined by the shape determination section 130, and complementing an undetermined portion in the object to be projected by the shape determination section 130 based on the coordinate values, thus setting the correction target region. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a projector, a program, and an information storage medium for correcting and projecting the shape of an image.

When a projector projects an image on a screen or the like, the image may be distorted. As a technique for correcting such image distortion, for example, in Japanese Patent Application Laid-Open No. 2006-60447, a vanishing point of each side of a screen in a captured image is determined in a two-dimensional plane, and the captured image is based on the vanishing point. A method for correcting image distortion by complementing the sides of the screen has been proposed.
JP 2006-60447 A

  In Japanese Patent Laid-Open No. 2006-60447, only the horizontal tilt (yaw angle) of the projector and the vertical tilt (pitch angle) of the projector are considered, and the tilt (roll angle) of the projection light of the projector with respect to the optical axis is considered. It has not been. However, in reality, when the table on which the projector is installed is tilted, the roll angle is not 0 degree, and the technique disclosed in Japanese Patent Laid-Open No. 2006-60447 cannot correct image distortion accurately.

  An object of the present invention is to provide a projector, a program, and an information storage medium capable of accurately correcting image distortion even when the projector is tilted with respect to the optical axis of projection light. .

  In order to solve the above problems, a projector according to the present invention includes a projection unit that projects a calibration image onto a rectangular projection object via a projection panel, and the calibration image is projected onto the projection object. Based on imaging information from the imaging unit in the state or operation information from the operation unit in the state, a shape determining unit that determines at least a part of the shape of the projection target, and a shape determined by the shape determining unit A correction target area setting unit that sets a correction target area that is an area in the projection panel, and an image generation unit that generates an image in the shape of the correction target area on the projection panel. The correction target area setting unit, based on the projection target position information, corrects a correction target position related to the position of the correction target area in the imaging area. A correction target position information generation unit that generates information, a coordinate conversion unit that converts coordinate values of the correction target region in the imaging region into coordinate values in the projection panel based on the correction target position information, and the coordinate conversion An area setting unit that sets the correction target area based on the coordinate values after conversion by the unit, and the area setting unit, when the entire shape of the projection object is not determined by the shape determination unit, the coordinates Based on the coordinate values after conversion by the conversion unit, determining the coordinate values of the vanishing points in the vertical and horizontal directions formed by the sides of the projection object in the coordinate system of the projection panel, and based on the coordinate values, The correction target region is set by complementing an undetermined portion of the projection target by the shape determining unit.

  The program according to the present invention is a program readable by a computer included in a projector including a projection unit, and the computer directs the calibration image to a rectangular projection object via a projection panel. And at least a part of the projection target based on imaging information from the imaging unit in a state where the calibration image is projected onto the projection target or operation information from the operation unit in the state. A shape determination unit that determines the shape of the correction target region, a correction target region setting unit that sets a correction target region that is a region along the shape determined by the shape determination unit and is a region in the projection panel, and Functioning as an image generation unit for generating an image in the shape of the correction target area on the projection panel; An area setting unit generates a correction target position information related to the position of the correction target area in the imaging area based on the projection target position information, and the imaging area based on the correction target position information. A coordinate conversion unit that converts the coordinate value of the correction target region into a coordinate value in the projection panel, and a region setting unit that sets the correction target region based on the coordinate value converted by the coordinate conversion unit. The area setting unit includes: a projection unit configured to determine the projection object in the coordinate system of the projection panel based on the coordinate value converted by the coordinate conversion unit when the shape determination unit does not determine the entire shape of the projection target; Determining the coordinate values of the vanishing points in the vertical and horizontal directions formed by the sides, and based on the coordinate values, the shape determining unit By complementing the pending portion of the shooting object, and sets the correction target region.

  An information storage medium according to the present invention is an information storage medium storing a program readable by a computer of a projector including a projection unit, and stores the program.

  According to the present invention, the projector determines the coordinate values of the vanishing points in the vertical direction and the horizontal direction formed by the sides of the projection object in the coordinate system of the projection panel, and based on the coordinate values, the shape determination unit By complementing the undetermined portion of the projection object according to the above, it is possible to accurately correct image distortion even when the projector is inclined with respect to the optical axis of the projection light.

  Further, the imaging unit generates the imaging information indicating the captured image by capturing an area including at least a part of the calibration image projected by the projection unit and at least a part of the projection target. The shape determination unit may determine the shape of at least a part of the projection target included in the captured image based on the imaging information.

  According to this, since the projector can determine the shape of at least a part of the projection target based on the imaging information, the distortion of the image can be corrected accurately without inputting operation information.

  The region setting unit may be configured such that at least one side in the horizontal direction of the projection object and at least one side in the vertical direction of the projection object are determined by the shape determination unit as the first condition or the shape In the case where the determination unit determines the upper side and the lower side of the projection target, the projection target by the shape determination unit is calculated by calculating the rotation angle of the projector with respect to the optical axis of the projection unit as a variable. The undecided part of may be complemented.

  According to this, the projector can correct the distortion of the image accurately even when the projector is inclined with respect to the optical axis of the projection light by performing the calculation using the rotation angle of the projector as a variable.

  Further, the region setting unit does not correspond to the first condition, and when the second condition that is a case where an upper side or a lower side of the projection target is determined by the shape determination unit, By calculating the rotation angle of the projector with respect to the optical axis as 0 degree, the undetermined portion of the projection object by the shape determining unit may be complemented.

  According to this, the projector can correct the distortion of the image even when the calculation using the rotation angle of the projector as a variable cannot be performed.

  Hereinafter, an example in which the present invention is applied to a projector will be described with reference to the drawings. In addition, the Example shown below does not limit the content of the invention described in the claim at all. In addition, all the configurations shown in the following embodiments are not necessarily essential as means for solving the invention described in the claims.

(Conventional problem)
FIG. 1 is a diagram showing a conventional projected image 12. Even if the conventional projector has a horizontal: vertical ratio of about 4: 3.1 of the screen 10 which is a kind of projection object, an image having a horizontal: vertical ratio of 4: 3 is selected according to the setting. I was projecting. For this reason, as shown in FIG. 1, areas where images are not projected are generated at the upper and lower ends of the screen 10, giving the user a sense of incongruity. Further, the conventional projector corrects the image distortion according to the captured image. However, if the captured image is affected by errors due to optical distortion, noise, the resolution limit of the imaging unit, etc., the screen 10 A non-display area occurred, giving the user a sense of incongruity.

  FIG. 2 is a diagram illustrating the roll angle of the projector 20. Further, the conventional projector 20 corrects image distortion according to the vertical projection angle (pitch angle) and the horizontal projection angle (yaw angle), but the projector 20 rotates with respect to the optical axis of the projection light. Since the angle (roll angle) is not used, when the table on which the projector 20 is installed is tilted, the image distortion cannot be corrected accurately.

  FIG. 3 is a diagram showing a projection image 12 after conventional distortion correction. Further, the conventional projector 20 performs many calculations using the coordinate values of the imaging region (for example, CCD panel) of the imaging unit (for example, CCD sensor). For this reason, even when the attachment position of the imaging unit to the projector 20 is slightly deviated from the original position, the projection image 12 after the conventional distortion correction has been distorted as shown in FIG.

(First embodiment)
In order to solve these problems, the projector in this embodiment determines whether a value indicating a difference between the aspect ratio of the correction target area and the reference aspect ratio satisfies the setting condition, and the aspect ratio corresponding to the determination result. By projecting an image with, it has a function of projecting an image with an aspect ratio according to the situation. Further, the projector in the present embodiment has a function of correcting image distortion using the roll angle. Furthermore, the projector according to the present embodiment has a function of calculating the calculation related to the coordinate value of the image in the coordinate system of the projection panel.

  Next, functional blocks of projector 100 having these functions will be described. FIG. 4 is a functional block diagram of the projector 100 in the first embodiment. The projector 100 captures the calibration image projected on the screen 10 and generates imaging information indicating the captured image, a storage unit 120 that stores various data, and the screen 10 based on the imaging information. A shape determining unit 130 that determines at least a part of the shape is included.

  Further, the storage unit 120 stores image information 122 for generating an image, imaging information 124 from the imaging unit 110, reference data 126 indicating a reference aspect ratio, a determination reference value, and the like.

  The projector 100 also includes a correction target region setting unit 140 that sets a correction target region, an image generation unit 150 that generates an image in a correction target region of a liquid crystal panel that is a type of projection panel, and a projection unit that projects the image. 190, an aspect ratio calculation unit 170 that calculates the aspect ratio of the correction target area, a determination unit 172 that performs various determinations, and a vertical projection angle determination unit 180 that determines the vertical projection angle of the projector 100. It is configured.

  Further, the correction target area setting unit 140 converts the coordinate value of the imaging area into the coordinate value of the liquid crystal panel, and the correction target position information generation unit 142 that generates the correction target position information based on the information from the shape determination unit 130. The coordinate conversion unit 144 includes an area setting unit 146 that sets a correction target area based on the coordinate value.

  For example, the following hardware may be employed as hardware for implementing the functions of these units in the projector 100. For example, the imaging unit 110 is a CCD sensor, the storage unit 120 is a RAM, an HDD, the shape determination unit 130, the correction target area setting unit 140, the aspect ratio calculation unit 170, the determination unit 172 is a CPU, an image generation unit, and the like. 150 may be an image processing circuit, a liquid crystal driving circuit, the vertical projection angle determination unit 180 may be an angle sensor, and the projection unit 190 may be a liquid crystal panel, a lamp, a projection lens, or the like.

  Note that the projector 100 may read the program from the information storage medium 200 that stores the program for implementing the function of each unit and implement the function of each unit. As such an information storage medium 200, for example, a CD-ROM, DVD-ROM, ROM, RAM, HDD or the like can be applied, and the program reading method may be a contact method or a non-contact method. Good.

  Next, a projection procedure using these parts will be described. FIG. 5 is a flowchart showing a projection procedure in the first embodiment. For example, the projector 100 corrects image distortion when the projector 100 is activated or when a correction instruction is received from the user. When correcting image distortion, first, the image generation unit 150 generates a calibration image based on the image information 122, and the projection unit 190 projects the calibration image onto the screen 10 (step S1).

  The imaging unit 110 captures the calibration image projected on the screen 10, generates imaging information 124, and stores it in the storage unit 120 (step S2). In the present embodiment, the projector 100 projects and images three types of calibration images.

  6A is a diagram showing an all-white calibration image 300, FIG. 6B is a diagram showing a center white calibration image 301, and FIG. 6C is an all-black calibration image 301. It is a figure which shows the calibration image. First, the projector 100 projects a calibration image 300 of all white (the whole image is white) and captures it with automatic exposure.

  Next, in the projector 100, a central area proportional to the entire image (for example, an area that is one-ninth of the entire image and is in the center of the image) is white, and areas other than the central area are white. A black calibration image 301 is projected, and an image is captured with an exposure determined by automatic exposure when the calibration image 300 is captured. Further, the projector 100 projects a calibration image 302 of all black (the entire image is black) and captures an image with an exposure determined by automatic exposure at the time of capturing the calibration image 300.

  7A is a diagram illustrating a captured image 400 of the calibration image 300 for all white, and FIG. 7B is a diagram illustrating a captured image 401 of the calibration image 301 for central white. FIG. 6C is a diagram illustrating a captured image 402 of the all-black calibration image 302.

  For example, as shown in FIG. 7A, even if a part of the calibration image 300 protrudes outside the screen 10, the center of the calibration image 301 is shown in FIG. The area is projected on the screen 10. Thereby, the projector 100 can grasp the luminance value, shape, and the like of the all white image on the screen 10. Note that the imaging order of the three types of calibration images 300 to 302 is arbitrary.

  The shape determining unit 130 determines whether or not the above three types of imaging by the imaging unit 110 have been completed (step S3). When the imaging has been completed, the projection that indicates the position of the screen 10 in the imaging region based on the imaging information 124. Target position information is generated (step S4). Specifically, for example, the shape determination unit 130 generates a difference image between the captured image 400 and the captured image 402, and performs edge detection or the like on the difference image, so that the screen 10 and the background portion in the imaging region are detected. And the projection target position information relating to the position of the boundary line is generated. Note that the difference image is used in order to eliminate the influence of noise caused by light from a fluorescent lamp or the like appearing in the captured image 400 or the like.

  The correction target position information generation unit 142 generates correction target position information based on the projection target position information from the shape determination unit 130 (step S5). FIG. 8 is a diagram illustrating an example of the screen 10 after correction in the captured image 403. For example, the correction target position information generation unit 142 sets a region ABCD (region indicated by a broken line in FIG. 8) in which the screen 10 in the captured image 403 is enlarged by one pixel, and relates to the position of the region ABCD (for example, 4 of the region). Correction target position information (indicating coordinate values and the like in the corner imaging region) is generated.

  The coordinate conversion unit 144 converts the coordinate value in the imaging area of the area ABCD into the coordinate value in the liquid crystal panel based on the correction target position information from the correction target position information generation unit 142 (step S6). Note that this conversion specifically includes projective conversion, for example.

  The area setting unit 146 sets a correction target area based on the coordinate values after the coordinate conversion by the coordinate conversion unit 144 (step S7). Next, the setting of the correction target area will be described in more detail. FIG. 9 is a flowchart showing a correction target area setting procedure in the first embodiment.

  The region setting unit 146 determines whether the shape determining unit 130 has detected the four sides of the screen 10 in the difference image (step S11). In addition, when the four sides are not detected, the region setting unit 146 determines whether or not three sides of the screen 10 are detected (step S12).

  FIG. 10 is a schematic diagram showing the vertical vanishing point V and the horizontal vanishing point H. FIG. For example, in the example shown in FIG. 10, three sides of the upper side, the lower side, and the left side of the screen 10 are detected. When three sides are detected, the region setting unit 146 determines the other vanishing point based on either the vertical or horizontal vanishing point (step S13).

  Specifically, for example, in the example shown in FIG. 10, the region setting unit 146 sets the virtual projection plane 14 on a plane where Z = 1, and the extension line on the upper side and the extension line on the lower side of the screen 10 intersect. The coordinate value of the horizontal vanishing point H is calculated.

  The vertical vanishing point V is on the extension line of the left side, and the angle HOV formed by each vanishing point and the origin O is a right angle. Using this property, the region setting unit 146 calculates the coordinate value of the vertical vanishing point V where the extension line on the left side of the screen 10 and the extension line on the right side intersect.

  On the other hand, when the three sides are not detected, the region setting unit 146 determines whether the vertical side (left side or right side) and the horizontal side (upper side or lower side) of the screen 10 are detected (step S14). When the vertical side and the horizontal side are detected, the region setting unit 146 determines each vanishing point based on the expression in which the vertical projection angle, the horizontal projection angle, and the roll angle are variables (step S15).

  For example, if the vertical projection angle is θ, the horizontal projection angle is φ, and the roll angle is ψ, the coordinate values (X, Y) of the vanishing points on the virtual projection plane 14 are

で表される。なお、これらの式の根拠については後述する。

It is represented by The basis for these equations will be described later.

  Here, the vertical projection angle is, for example, a relative angle in the vertical direction between the screen 10 and the optical axis of the light projected by the projection unit 190, and the horizontal projection angle is, for example, the screen 10 and the projection unit. It is a relative angle in the horizontal direction with respect to the optical axis of the projection light by 190. The vertical projection angle may be a value indicating the vertical inclination of the projector 100 determined by the vertical projection angle determination unit 180.

  The area setting unit 146 can solve the above equation as simultaneous equations of φ and ψ by substituting the value indicating the vertical inclination of the projector 100 determined by the vertical projection angle determination unit 180 into θ. A vertical vanishing point and a horizontal vanishing point can be determined.

  On the other hand, when the horizontal side and the vertical side are not detected, the region setting unit 146 determines whether the upper side and the lower side of the screen 10 are detected (step S16). When the upper side and the lower side are detected, the region setting unit 146 determines each vanishing point as in step S15 (step S17). Specifically, the region setting unit 146 can determine the horizontal vanishing point from the position information of the upper side and the lower side. Similarly to step S15, the vertical vanishing point is obtained by substituting the value indicating the inclination of the projector 100 in the vertical direction determined by the vertical projection angle determination unit 180 into θ, so that the above equation is simultaneous with φ and ψ. It can be solved as an equation and the vertical vanishing point can be determined.

  On the other hand, when the upper side and the lower side are not detected, the region setting unit 146 determines whether the upper side or the lower side of the screen 10 is detected (step S18). When the upper side or the lower side is detected, the region setting unit 146 determines each vanishing point using a conventional method described in Japanese Patent Application Laid-Open No. 2006-60447 (step S19).

  When none of the above conditions is satisfied, the image generation unit 150 generates an image indicating that the image distortion cannot be corrected based on the image information 122, and the projection unit 190 projects the image ( In step S20), the projector 100 ends the distortion correction process.

  Further, when the vanishing point is determined by any one of steps S13, S15, S17, and S19, the region setting unit 146 corrects the correction target region based on the known coordinate value of the screen 10 and the coordinate value of each vanishing point. Are supplemented (step S21).

  The shape of the correction target area is determined by the above procedure. In a state where the shape of the correction target area is determined, the area setting unit 146 corrects the aspect ratio of the correction target area (step S22). Here, the aspect ratio correction procedure will be described in more detail. FIG. 11 is a flowchart showing an aspect ratio correction procedure in the first embodiment.

  The aspect ratio calculation unit 170 calculates the aspect ratio of the correction target area determined by the area setting unit 146 (step S30). The aspect ratio is a value obtained by dividing the length of the vertical side by the length of the horizontal side. For example, if the length of the horizontal side: length of the vertical side is 4: 3, the aspect ratio is 0.75.

  The determination unit 172 determines whether or not the four sides of the screen 10 have been detected by the shape determination unit 130 (step S31). When the four sides are detected, the determination unit 172 sets the condition so that the difference between the aspect ratio of the correction target area and the reference aspect ratio is within 10% (step S32).

  The reference aspect ratio is a desirable aspect ratio set by the manufacturer or user of the projector 100, for example, and is stored in the storage unit 120 as part of the reference data 126. For example, when the reference aspect ratio is 0.75, the above condition is that the aspect ratio of the correction target region is 0.675 or more and 0.825 or less.

  Further, when the four sides are not detected, the determination unit 172 sets the condition such that the difference between the aspect ratio of the correction target area and the reference aspect ratio is within 3% (step S32). For example, when the reference aspect ratio is 0.75, this condition is that the aspect ratio of the correction target region is 0.7275 or more and 0.7725 or less.

  Then, the determination unit 172 determines whether or not the aspect ratio of the correction target area calculated by the aspect ratio calculation unit 170 satisfies the set condition (step S34). When the condition is not satisfied, the determination unit 172 sets the correction target area so as to have the reference aspect ratio (step S35).

  The determination unit 172 outputs information indicating the coordinate values of the four corners of the final correction target area in the liquid crystal panel to the image generation unit 150. The image generation unit 150 generates an image in the correction target area of the liquid crystal panel based on the information and the image information 122 (step S8). The projection unit 190 projects the image (step S9).

  As described above, according to the present embodiment, the projector 100 determines whether the value indicating the difference between the aspect ratio of the correction target area and the reference aspect ratio satisfies the setting condition, and the aspect corresponding to the determination result. By projecting an image with a ratio, it is possible to project an image with an aspect ratio according to the situation.

  Further, according to the present embodiment, the projector 100 can determine the shape of at least a part of the screen 10 based on the imaging information, and thus can correct image distortion accurately without inputting operation information. An image can be projected with a desired aspect ratio.

  In addition, according to the present embodiment, the projector 100 can complement the undetermined portion of the screen 10 even when the captured image does not include the entire screen 10, so that it can be more versatile depending on the situation. An image can be projected with a certain aspect ratio.

  In addition, according to the present embodiment, the projector 100 can absorb a measurement error or the like by determining the difference in aspect ratio within a range, thereby suppressing the occurrence of a non-display area on the screen 10. can do.

  Further, according to the present embodiment, when the entire shape of the screen 10 is not determined by the shape determining unit 130, the projector 100 sets the determination range narrower than the case where the entire shape is determined. It is possible to determine more strictly when the distortion of the image is large, and it is possible to suppress the occurrence of a situation where an image is projected with an incorrect shape.

  Further, according to the present embodiment, the projector 100 sets a region that is at least one pixel larger than the shape of the screen 10 as a correction target region, thereby suppressing the occurrence of a non-display region on the screen 10. be able to.

  Further, according to the present embodiment, the projector 100 determines the coordinate values of the vanishing points in the vertical direction and the horizontal direction formed by the sides of the screen 10 in the coordinate system of the projection panel, and the shape based on the coordinate values. By complementing the undetermined portion of the screen 10 by the deciding unit 130, the projector 100 is accurate even when the projector 100 is tilted with respect to the optical axis of the projection light or when there is an attachment error of the imaging unit 110. In addition, image distortion can be corrected.

  Further, according to the present embodiment, the projector 100 performs an operation using the rotation angle of the projector 100 as a variable, thereby accurately distorting the image even when the projector 100 is inclined with respect to the optical axis of the projection light. It can be corrected. In addition, according to the present embodiment, the projector 100 calculates the rotation angle as 0 degrees, thereby reducing image distortion even when the calculation using the rotation angle of the projector 100 as a variable cannot be performed. It can be corrected.

  Further, according to the present embodiment, the projector 100 sets the correction target area based on the coordinate values on the projection panel, so that even if an error occurs in the mounting state of the imaging unit 110, image distortion is caused. Can be corrected appropriately.

(Explanation on how to find vanishing points)
Here, the method for obtaining the vanishing point will be described in more detail. If the pitch angle θ and the yaw angle φ are fixed, the correction shape is not affected even if the screen 10 rotates in the roll direction. Therefore, the projector 100 is rotated in the order of the pitch angle θ, the yaw angle φ, and the roll angle ψ. I will let you.

  A three-dimensional rotation matrix that rotates the pitch angle θ, the yaw angle φ, and the roll angle ψ is:

したがって、

Therefore,

となる（θは向きが逆なので−θの回転になっている）。

(Θ is rotated by −θ because the direction is opposite).

  This is a rotation when the projector 100 is viewed from the outside, and the projector 100 itself seems to rotate in the direction opposite to this matrix. Therefore, the coordinate transformation matrix representing the rotation of the screen 10 viewed from the projector 100 is this inverse matrix. Since the rotation matrix is a kind of orthogonal matrix, to find the inverse matrix,

を求めればよい。

You can ask for.

The vanishing point can be obtained by rotating the horizontal infinity point [1: 0: 0] and the vertical infinity point [0: 1: 0] before rotation in the transposed matrix R ′. That is, in the three-dimensional space, the vertical vanishing point and the horizontal vanishing point are orthogonal to each other. Note that the normal line of the screen 10 can be obtained by rotating the infinity point [0: 0: 1] in the depth direction. In particular,
Vertical vanishing point V = [sinψcosφ: -sinψsinφsinθ + cosψcosθ: sinψsinφcosθ + cosψsinθ] (3)
Horizontal vanishing point H = [cosψcosφ: -cosψsinφsinθ-sinψcosθ: cosψsinφcosθ-sinψsinθ] (4)
Normal of screen 10 = [-sinφ: -cosφsinθ: cosφcosθ]
It becomes.

  Here, [x: y: z] represents a point (x, y, z) in projective geometry. By dividing the three-dimensional coordinate values of the vertical vanishing point V and the horizontal vanishing point H by the Z component, the coordinate values can be expressed by the above-described equations (1) and (2).

  Further, when the horizontal vanishing point is obtained from the vertical vanishing point V and the horizontal side of the screen 10, the following calculation may be performed. As described above, the vertical vanishing point V and the horizontal vanishing point H are orthogonal to each other in the three-dimensional space. Accordingly, when the vertical vanishing point V [a: b: c] is assumed, the horizontal vanishing point H must be on a plane having V as a normal line. Since the plane equation with V as the normal is ax + by + cz = 0, if z = 1 is substituted, the horizontal vanishing point H is on the straight line ax + by + c = 0. Therefore, the horizontal vanishing point H is obtained as the intersection of the horizontal side and the straight line ax + by + c = 0.

  Further, the vertical vanishing point V can be obtained by performing the following calculation from the vertical and horizontal sides of the screen 10 and the vertical projection angle θ. First, the expression on the left side or the right side is set to Ax + By + C = 0, and the expression on the upper side or the lower side is set to Dx + Ey + F = 0.

Substituting the above formulas for the vertical vanishing point V and the horizontal vanishing point H into the vertical and horizontal sides respectively,
0 = Atanψcosφ + Bcosθ + Csinθ + (-Bsinθ + Ccosθ) tanψsinφ
0 = Dcosφ- (Ecosθ + Fsinθ) tanψ + (-Esinθ + Fcosθ) sinφ
It becomes. Since θ can be obtained from the vertical projection angle determination unit 180 and the unknowns included in these two formulas are only φ and ψ, the vertical vanishing point V can be obtained.

Further, the vertical vanishing point V can be obtained by performing the following calculation from the horizontal vanishing point H and the vertical projection angle θ. First, when Expressions (3) and (4) are rotated with respect to the X axis using θ from the vertical projection angle determination unit 180,
Vertical vanishing point V ′ = [sinψcosφ: cosψ: sinψsinφ]
Horizontal vanishing point H ′ = [cosψcosφ: -sinψ: cosψsinφ]
It becomes.

Since the horizontal vanishing point H is known, the component of H ′ rotated by θ is also obtained. Therefore, in order to obtain V ′ from the component of H ′, multiplying the component of V ′ by a constant,
Vertical vanishing point V ′ = [cosφ: cosψ / sinψ: sinφ]
= [cosψcosφ: -sinψ- (1 / -sinψ): cosψsinφ]
It becomes.

  Therefore, V ′ can be obtained from H ′ by replacing the Y component of this equation with V′y = H′y− (1 / H′y). When V ′ is obtained, the vertical vanishing point V can be obtained by rotating by −θ about the X axis.

  When the vertical vanishing point V is obtained only from θ from the vertical projection angle determination unit 180, the roll angle ψ is set to 0 degree. Substituting ψ = 0 into equation (1), the vertical vanishing point V = (0, 1 / tan θ), and the vertical vanishing point V can be obtained from θ.

(Second embodiment)
FIG. 12 is a functional block diagram of the projector 101 in the second embodiment. The projector 101 includes an operation unit 160 that inputs user operation information 128 instead of the imaging unit 110. Further, the storage unit 120 stores operation information 128 instead of the imaging information 124.

  For example, when the user performs an operation of moving the four corners of the projected image 12 to the four corners of the screen 10 using a remote controller (remote controller), the operation unit 160 inputs operation information 128 indicating the content of the operation. And stored in the storage unit 120. The shape determining unit 130 determines the shape of the screen 10 based on the operation information 128, and the correction target region setting unit 140 sets a correction target region according to the shape.

  As described above, even when the imaging information is not used, the projector 101 can correct the distortion of the image accurately as in the first embodiment.

(Other examples)
In addition, application of this invention is not limited to the Example mentioned above, A various deformation | transformation is possible. For example, the application of the present invention is not limited to image distortion correction, and may be applied to, for example, indication position detection, image brightness correction, and image color correction.

  Further, the value of the condition in step S32 is not limited to 10%, and the value of the condition in step S33 is not limited to 3%, and any numerical value can be applied. Moreover, the conditions in step S32 and step S33 may be the same conditions. In steps S32 to S34, the determination unit 172 performs determination using the difference value between the aspect ratio of the correction target area and the reference aspect ratio. However, in addition to the difference value, for example, a difference in ratio or the like is indicated. Various values can be adopted.

  In the above-described embodiment, an area that is one pixel larger than the screen 10 is applied. However, the area may coincide with the screen 10 or may be an area that is two pixels larger than the screen 10. The area may be determined from the ratio of the number of pixels of the liquid crystal panel and the number of pixels of the imaging area.

  When the projectors 100 and 101 have a zoom function, the projectors 100 and 101 may perform correction according to the zoom state. In the above-described embodiment, the difference image of the captured image is used, but the captured images 400 and 401 may be used as they are. Further, the calibration image is not limited to the calibration images 300 to 302 described above. For example, the projectors 100 and 101 may use only the calibration image 300, may use only the calibration image 301, or may use white and black checkered calibration images instead of the calibration image 301. It may be used.

  The projection object is not limited to the screen 10, and various projection objects having a rectangular projection target area such as a whiteboard, a blackboard, or a rectangular frame provided on a wall can be employed. As the projectors 100 and 101, for example, a liquid crystal projector, a CRT (Cathode Ray Tube) projector, a projector using a DMD (Digital Micromirror Device), or the like may be used. DMD is a trademark of Texas Instruments Incorporated.

It is a figure which shows the conventional projection image. It is a figure which shows the roll angle of a projector. It is a figure which shows the projection image after the conventional distortion correction. It is a functional block diagram of the projector in a 1st Example. It is a flowchart which shows the projection procedure in a 1st Example. 6A is a diagram showing an all-white calibration image, FIG. 6B is a diagram showing a center white calibration image, and FIG. 6C is an all-black calibration image. It is a figure which shows an image. FIG. 7A is a diagram showing a captured image of an all-white calibration image, FIG. 7B is a diagram showing a captured image of a center white calibration image, and FIG. FIG. 5 is a diagram illustrating a captured image of an all-black calibration image. It is a figure which shows an example of the screen after correction | amendment in a captured image. It is a flowchart which shows the correction target area | region setting procedure in a 1st Example. It is a schematic diagram which shows a vertical vanishing point and a horizontal vanishing point. It is a flowchart which shows the aspect-ratio correction | amendment procedure in a 1st Example. It is a functional block diagram of the projector in a 2nd Example.

Explanation of symbols

  10 screen, 12 projected image, 14 virtual projection plane, 20, 100, 101 projector, 110 imaging unit, 120 storage unit, 122 image information, 124 imaging information, 126 reference data, 128 operation information, 130 shape determination unit, 140 correction Target area setting unit, 142 Correction target position information generation unit, 144 Coordinate conversion unit, 146 Area setting unit, 150 Image generation unit, 160 Operation unit, 170 Aspect ratio calculation unit, 172 Determination unit, 180 Vertical projection angle determination unit, 190 Projection unit, 200 information storage medium, 300 to 302 calibration image, 400 to 403 captured image

Claims (6)

A projection unit that projects a calibration image onto a rectangular projection object via a projection panel;
A shape determination unit that determines the shape of at least a part of the projection target based on imaging information from the imaging unit in a state where the calibration image is projected onto the projection target or operation information from the operation unit in the state When,
A correction target region setting unit that sets a correction target region that is a region along the shape determined by the shape determination unit and is a region in the projection panel;
An image generator that generates an image on the projection panel in the shape of the correction target area;
Including
The correction target area setting unit includes:
A correction target position information generating unit that generates correction target position information related to the position of the correction target area in the imaging area based on the projection target position information;
Based on the correction target position information, a coordinate conversion unit that converts the coordinate value of the correction target area in the imaging area into a coordinate value in the projection panel;
An area setting unit for setting the correction target area based on coordinate values after conversion by the coordinate conversion unit;
Including
When the shape determining unit does not determine the entire shape of the projection target, the area setting unit determines the side of the projection target in the coordinate system of the projection panel based on the coordinate value converted by the coordinate conversion unit. The correction target region is set by determining the coordinate values of the vanishing points in the vertical direction and the horizontal direction to be formed and complementing the undetermined portion of the projection target by the shape determination unit based on the coordinate values A projector characterized by that. The projector according to claim 1, wherein
The imaging unit captures an area including at least a part of the calibration image projected by the projection unit and at least a part of the projection target, and generates the imaging information indicating the captured image,
The shape determining unit determines a shape of at least a part of the projection target included in the captured image based on the imaging information. The projector according to any one of claims 1 and 2,
The region setting unit is configured when at least one side in the horizontal direction of the projection object and at least one side in the vertical direction of the projection object are determined by the shape determination unit which is a first condition, or the shape determination unit If the upper and lower sides of the projection object are determined by the calculation, the rotation angle of the projector with respect to the optical axis of the projection unit is calculated as a variable, so that A projector characterized by complementing a determined part. The projector according to claim 3, wherein
The region setting unit does not correspond to the first condition, and when the second condition, which is a case where the upper side or the lower side of the projection object is determined by the shape determination unit, the optical axis of the projection unit A projector that complements an undetermined portion of the projection target by the shape determining unit by calculating a rotation angle of the projector with respect to the above. A program readable by a computer included in a projector including a projection unit,
The computer,
A projection control unit that causes the projection unit to project a calibration image onto a rectangular projection object via a projection panel;
A shape determination unit that determines the shape of at least a part of the projection target based on imaging information from the imaging unit in a state where the calibration image is projected onto the projection target or operation information from the operation unit in the state When,
A correction target region setting unit that sets a correction target region that is a region along the shape determined by the shape determination unit and is a region in the projection panel;
Function as an image generation unit for generating an image on the projection panel in the shape of the correction target area;
The correction target area setting unit includes:
A correction target position information generating unit that generates correction target position information related to the position of the correction target area in the imaging area based on the projection target position information;
Based on the correction target position information, a coordinate conversion unit that converts the coordinate value of the correction target area in the imaging area into a coordinate value in the projection panel;
An area setting unit for setting the correction target area based on coordinate values after conversion by the coordinate conversion unit;
Including
When the shape determining unit does not determine the entire shape of the projection target, the area setting unit determines the side of the projection target in the coordinate system of the projection panel based on the coordinate value converted by the coordinate conversion unit. The correction target region is set by determining the coordinate values of the vanishing points in the vertical direction and the horizontal direction to be formed and complementing the undetermined portion of the projection target by the shape determination unit based on the coordinate values The program characterized by doing. An information storage medium storing a program readable by a computer included in a projector including a projection unit,
An information storage medium storing the program according to claim 5.

Images