JP5445745B2 - Projector, program, information storage medium, and trapezoidal distortion correction method - Google Patents

Description

  The present invention relates to a projector, a program, an information storage medium, and a trapezoidal distortion correction method.

  As a method in which the projector performs trapezoidal distortion correction (also called keystone correction, keystone correction, etc.), for example, as described in JP-A-2005-347790, projection is performed by imaging using an image sensor. A method of acquiring and correcting information on the boundary line around the object has been proposed.

JP 2005-347790 A

  However, in the method of acquiring information about the boundary line around the projection object, the projector may not be able to accurately correct the trapezoidal distortion if the edge of the desk in front of the projector is identified as the boundary line. This is because the edge of the desk may not be parallel to the screen rectangle.

  Further, for example, when the projector identifies the lower side of the screen as a boundary line, it may not be possible to correct the trapezoidal distortion accurately. This is because the bottom side of the screen is almost the same height as the projector, and it is difficult to detect the screen tilt during imaging when the screen is tilted with the vertical direction as the rotation axis. This is because sufficient accuracy cannot be obtained.

  Some aspects according to the present invention provide a projector, a program, an information storage medium, and a trapezoidal distortion correction method capable of performing more accurate trapezoidal distortion correction by solving the above problems.

  A projector that is one aspect of the present invention includes an imaging unit that captures a projection target and generates a captured image, and an information generation unit that generates coordinate information of a boundary line of the projection target included in the captured image A correction target area is set by executing a complementing process that complements a deficient portion according to the shape of the boundary line using coordinate information of a boundary line other than the lower side of the projection target, and the correction target area And a trapezoidal distortion correction unit that performs trapezoidal distortion correction.

  According to another aspect of the present invention, a projector includes an imaging unit that captures a projection target and generates a captured image, and information that generates coordinate information of a boundary line of the projection target included in the captured image. Based on the coordinate information of at least one boundary line excluding the lower boundary line among the boundary lines for which the coordinate information has been generated by the generation unit and the information generation unit, is defined by the at least one boundary line And a trapezoidal distortion correction unit that sets a correction target area by executing a complementing process that complements the deficient part according to the shape, and performs trapezoidal distortion correction based on the correction target area.

  In addition, a program that is one aspect of the present invention causes a computer included in a projector to cause an imaging device to capture an image of a projection target and generate a captured image, and to detect a boundary line of the projection target included in the captured image. Correction is performed by generating coordinate information and executing a complementing process for complementing the deficient portion according to the shape of the boundary line using the coordinate information of the boundary line other than the lower side of the projection target based on the coordinate information A target area is set, and keystone distortion correction is performed based on the correction target area.

  An information storage medium according to one aspect of the present invention is an information storage medium that stores a program readable by a computer included in a projector, and stores the program.

  Further, according to the trapezoidal distortion correction method which is one of the aspects of the present invention, the projector causes the imaging device to capture the projection target to generate a captured image, and the boundary line of the projection target included in the captured image is detected. Correction is performed by generating coordinate information and executing a complementing process for complementing the deficient portion according to the shape of the boundary line using the coordinate information of the boundary line other than the lower side of the projection target based on the coordinate information A target area is set, and keystone distortion correction is performed based on the correction target area.

  According to the present invention, since the projector can eliminate erroneous detection of the edge of the desk or the like by not using the coordinate information of the lower boundary line of the projection target included in the captured image, the trapezoid more accurately. Distortion correction can be performed.

  The projector includes a projection unit that projects a calibration image for correcting trapezoidal distortion, and the information generation unit includes the calibration image in an image formation region of the projection unit or a virtual region corresponding to the image formation region. Position information indicating the correspondence between the positions of a plurality of points in the captured image and the positions of the plurality of points in the captured image, and based on the position information, coordinates of the image forming region or the virtual region and the captured image The keystone distortion correction unit generates conversion information indicating a conversion equation with coordinates, and the trapezoidal distortion correction unit sets the infinity point related to the boundary line as the coordinates of the image forming region or the virtual region based on the coordinate information and the conversion information. You may perform the said complementation process by calculating the coordinate of the vanishing point projected on the system.

  According to this, the projector can perform trapezoidal distortion correction more accurately by performing coordinate conversion and the like.

  In addition, the projector includes a determination unit that determines, based on the conversion information, whether all the boundaries of the projection target are within the range of the image formation region or the virtual region, and the complementary trapezoidal distortion correction unit If the entire boundary line of the projection object is within the range, an area along the shape of the boundary line is set as the correction target area, and the entire boundary line of the projection object is not within the range. In this case, the correction target area may be set by executing the complementing process.

  According to this, the projector can perform the trapezoidal distortion correction more accurately by performing the setting according to whether or not the entire boundary line of the projection target is within the displayable range.

It is a functional block diagram of the projector in a 1st Example. It is a flowchart which shows the trapezoid distortion correction | amendment procedure in a 1st Example. It is a figure which shows an example of the calibration image in a 1st Example. It is a flowchart which shows the correction target area | region setting procedure in a 1st Example. It is a schematic diagram which shows the vanishing point in the three-dimensional space in a 1st Example. It is a schematic diagram which shows an example of the vanishing point in the coordinate system of the virtual area in a 1st Example. It is a schematic diagram which shows another example of the vanishing point in the coordinate system of the virtual area in a 1st Example.

  Embodiments in which the present invention is applied to a projector will be described below 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.

(First embodiment)
FIG. 1 is a functional block diagram of a projector 100 according to the first embodiment. The projector 100 includes an imaging unit 110 that captures a calibration image or the like to generate a captured image, an image input unit 120 that inputs image information (for example, an RGB signal) from a PC (Personal Computer) or the like, coordinate information, and the like. Information generation unit 130 for generating image, determination unit 140 for making various determinations, image generation unit 150 for generating an image based on image information and the like, and projection unit 190 for projecting an image. The image generation unit 150 also has a function as a trapezoidal distortion correction unit that performs keystone distortion correction.

  The projector 100 may function as each of these units using the following hardware. For example, in the projector 100, the imaging unit 110 is a CCD camera, the image input unit 120 is an image signal input port, a converter, the information generation unit 130, the determination unit 140 is a CPU, the image generation unit 150 is an image processing circuit, or the like. The unit 190 may use a lamp, a liquid crystal panel, a liquid crystal driving circuit, a projection lens, or the like.

  The computer included in the projector 100 may function as the information generation unit 130 by reading a program stored in the information storage medium 200. As such an information storage medium 200, for example, a CD-ROM, DVD-ROM, ROM, RAM, HDD, or the like can be applied.

  Next, a trapezoidal distortion correction procedure using these units will be described. FIG. 2 is a flowchart showing the trapezoidal distortion correction procedure in the first embodiment.

  The imaging unit 110 captures a screen, which is a type of projection target, in a state where no image is projected or a black image is projected, and generates a first captured image (step S1). The information generation unit 130 generates coordinate information indicating the coordinates of the boundary line of the screen in the captured image based on the first captured image (step S2).

  Note that the screen may have, for example, a rectangular white area and a black area provided around the white area. In this case, the white area is an area where the projected image can be displayed, and the boundary between the white area and the black area corresponds to the boundary line. The coordinate information may be, for example, information indicating the coordinates of the end points of each boundary line, information indicating the coordinates of at least one point on each boundary line, and the inclination of each boundary line, and the like.

  The image generation unit 150 generates a calibration image for trapezoidal distortion correction. The projection unit 190 projects the calibration image. The imaging unit 110 captures the calibration image projected on the screen and generates a second captured image (step S3).

  FIG. 3 is a diagram illustrating an example of the calibration image 300 in the first embodiment. The calibration image 300 includes a pattern image having a shape in which four rectangles are arranged in two rows and two columns. That is, the pattern image is formed in a state in which three straight lines arranged in parallel in the vertical direction and at equal intervals and three straight lines arranged in parallel in the horizontal direction at equal intervals are orthogonal to each other. Nine intersections (reference points). In addition, this space | interval may be 200 pixels or more, for example, when a liquid crystal panel is 1024x768 pixels. As described above, the projector 100 can suppress interference with an adjacent line when measuring a luminance value or the like by keeping an interval between lines forming the pattern.

  Further, the straight line included in the pattern image has a gradation that is brightest at the center of the line and darkest at the outer edge of the line. For example, in the calibration image 300 shown in FIG. 3, a white region is provided at the center of the line, a light gray region is provided so as to sandwich the white region, and a dark region is provided so as to sandwich the light gray region. A gray area is provided.

  The width of each region may be 4 pixels or more, for example. Further, the background of the pattern image is a region (for example, a region of white, black, etc.) having a gradation different from the region of the outer edge portion of the pattern image (dark gray region in this embodiment). When the background of the pattern image has a darker gradation (for example, black) than the region of the outer edge of the pattern image, the calibration image 300 has four different gradations in total including the pattern image and the background. Further, the calibration image 300 may have three different gradations including the pattern image and the background image as a whole, from the pattern image formed from the white region and the light gray region and the dark gray region. It may be an image including a background image to be formed. In other words, the calibration image 300 includes a first area having a first gradation (white area) and a second area having a second gradation darker than the first gradation (dark gray area). ) And a third region (light gray) provided between the first region and the third region, which has a third gradation that is darker than the first gradation and brighter than the second gradation. The image may include an area).

  The information generation unit 130 generates position information indicating the correspondence between the positions of a plurality of reference points (in the imaging coordinate system) in the second captured image and the positions of the reference points in the projection coordinate system (step S4). Further, the information generation unit 130 generates conversion information indicating a conversion formula between the coordinates of the projection coordinate system and the coordinates of the imaging coordinate system based on the position information (step S5).

  This conversion formula is a conversion formula such as projective conversion. The projection coordinate system is, for example, a coordinate system of an image forming area of a liquid crystal panel or a virtual area coordinate system having the same shape as the image forming area described later.

  In addition, the information generation unit 130 performs parabolic approximation calculation, centroid calculation, and the like using the luminance information of the second captured image and the like, and the white reference points that are the nine reference points included in the second captured image are displayed. The coordinates of the area may be determined. This coordinate is, for example, a two-dimensional coordinate in the imaging region (imaging coordinate system) of the imaging unit 110.

  The determination unit 140 determines the position of the boundary line in the projection coordinate system with the principal point of the projection lens as the origin based on the coordinate information of the boundary line of the screen and the conversion information, and all four boundary lines are the projector 100. To determine whether the image is within a displayable range (step S6).

  When the entire boundary line is within a range in which an image can be displayed by the projector 100, the image generation unit 150 displays the image after the trapezoidal distortion correction in the image forming area of the liquid crystal panel based on the coordinate information and the conversion information. A correction target area indicating the area is set. The image generation unit 150 performs trapezoidal distortion correction on the input image information based on the set correction target area (step S7).

  On the other hand, when at least a part of the boundary line is outside the range in which an image can be displayed by the projector 100, the information generation unit 130 determines the two-dimensional coordinates of the reference point in the second captured image based on the conversion information or the like. Is converted into the three-dimensional coordinates of the projection coordinate system (step S8). Further, the information generation unit 130 generates projection angle information indicating a projection angle that is a tilt of the screen with respect to the projector 100 based on the three-dimensional coordinates (step S9). More specifically, for example, the information generation unit 130 uses the at least three three-dimensional coordinates among the nine reference points of the nine reference points, and the relative vertical direction of the projection light and the screen 10 and You may generate | occur | produce the projection angle information which shows the inclination of a horizontal direction.

  In this case, the image generation unit 150 sets a correction target area based on the projection angle information and the coordinate information (step S10), and performs trapezoidal distortion correction (step S11).

  Here, the procedure for setting the correction target area in step S10 will be described in more detail. FIG. 4 is a flowchart showing a correction target area setting procedure in the first embodiment.

  The determination unit 140 determines which boundary line information of all the boundary lines has been detected based on the coordinate information or the like. More specifically, for example, the determination unit 140 determines whether or not the upper boundary line (upper side), the left boundary line (left side), and the right boundary line (right side) among all the boundary lines have been detected ( Step S21). Note that the determination unit 140 determines the relationship between the position of the boundary line and the position of the reference point based on, for example, coordinate information (for example, the upper side if the position of the boundary line is above the position of the uppermost reference point). By determining the connection relation of the boundary lines, it is possible to determine which side each boundary line corresponds to.

  When the upper side, the left side, and the right side can be detected, the image generation unit 150 determines a vertical vanishing point from the infinity point on the left side or the right side, and determines a horizontal vanishing point from the infinity point on the upper side (step S22).

  FIG. 5 is a schematic diagram showing vanishing points in the three-dimensional space in the first embodiment. For example, as shown in FIG. 5, an infinite point Hi exists on the extended line of the upper side (solid line part in the screen 10 of FIG. 5) in the screen 10. Further, an infinite point Vi exists on the extension line of the left side and the right side. There is also an infinite point Vi on an extension of a straight line perpendicular to the upper side.

  Actually, the infinity point is located at infinity, but FIG. 5 schematically shows the infinity point for easy understanding. In this embodiment, a method of determining each vanishing point using the right infinity point Hi and the upper infinity point Vi is employed, but the left infinity point and the lower infinity point are employed. You may employ | adopt the system which determines each vanishing point using. Regardless of which method is used, the position of each vanishing point does not change. In practice, the liquid crystal panel is on the near side (−Z direction) with respect to the principal point O of the projection lens. However, for the sake of simplicity, for example, the virtual panel is parallel to the image forming area of the liquid crystal panel and has the same shape. It is assumed that the region 20 is arranged in parallel with the XY plane at Z = 1.

  By projecting these infinite points onto the plane of the virtual region 20, the vertical vanishing point Vp and the horizontal vanishing point Hp in the coordinate system (projection coordinate system) of the virtual region 20 can be determined.

  If the determination result of step S21 is false, the determination unit 140 determines whether the left side and the right side of all the boundary lines have been detected (step S23). When the left side and the right side can be detected, the image generation unit 150 determines the vertical vanishing point from the infinity point of the detection side (left side and right side), and determines the horizontal vanishing point from the infinity point of the straight line perpendicular to the detection side. (Step S24).

  Moreover, the determination part 140 determines whether the left side or right side was detected among all the boundary lines, when the determination result of step S23 is false (step S25), and when the determination result is true, the upper side is determined. It is determined whether or not it has been detected (step S26).

  When the determination result of step S26 is true, that is, when the left side or the right side and the upper side can be detected, the image generation unit 150 determines the vertical vanishing point from the infinity point on the left side or the right side, and the infinity point on the upper side The horizontal vanishing point is determined from (step S27).

  On the other hand, when the determination result in step S26 is false, that is, when only the left side or the right side can be detected, the image generation unit 150 determines the vertical vanishing point from the infinity point of the detection side (left side or right side) and detects it. A horizontal vanishing point is determined from the infinity point of a straight line perpendicular to the side (step S24).

  Moreover, when the determination result of step S25 is false, the determination part 140 determines whether the upper side was detected among all the boundary lines (step S28). If the upper side can be detected, the image generation unit 150 determines the vertical vanishing point from the infinity point of the straight line perpendicular to the upper side, and determines the horizontal vanishing point from the infinity point of the upper side (step S29).

  When each vanishing point is determined (in the case of any of steps S22, S24, S27, and S29), the image generation unit 150 lacks a line segment on the straight line passing through the vanishing point based on the coordinates of each vanishing point. The correction target area in the liquid crystal panel is set by complementing as the boundary line that is being performed (step S30).

  FIG. 6 is a schematic diagram illustrating an example of a vanishing point in the coordinate system of the virtual region 20 in the first embodiment. FIG. 7 is a schematic diagram illustrating another example of the vanishing point in the coordinate system of the virtual region 20 in the first embodiment.

  For example, as illustrated in FIG. 6, when only one boundary line can be detected, the image generation unit 150 sets a straight line passing through each vanishing point using the coordinates of the boundary line and the coordinates of each vanishing point. By executing a complementing process that compensates for the missing edge, the coordinates of the four corners of the target area ABCD in the virtual area 20 are determined so as to satisfy a predetermined condition, and correction target areas in the liquid crystal panel are set.

  The target area ABCD is an area on the virtual area 20 corresponding to the correction target area in the liquid crystal panel. The predetermined condition includes, for example, a condition that the corrected image satisfies a predetermined aspect ratio (for example, 4: 3, 16: 9), a condition that the liquid crystal panel is used to the maximum.

  Further, for example, as illustrated in FIG. 7, when two or more boundary lines can be detected, the image generation unit 150 uses the coordinates of each boundary line and the coordinates of each vanishing point to pass through each vanishing point. The target area ABCD is determined by executing a complementing process that compensates for the missing side by setting a straight line to be corrected, and a correction target area in the liquid crystal panel is set. The image generation unit 150 changes the shape of the boundary line based only on the coordinate information of the boundary line generated by the information generation unit 130 among the upper boundary line, the left boundary line, and the right boundary line of the screen. Corresponding correction target areas are set.

  If none of the upper side, the left side, and the right side can be detected, the image generation unit 150 sets a correction target area in the liquid crystal panel based on the projection angle information (step S31). More specifically, for example, the image generation unit 150 sets the correction target area according to the projection angle using data in which the vertical and horizontal projection angles are associated with the coordinates of the correction target area. May be. In this embodiment, the projector 100 does not use information on the lower side.

  As described above, according to the present embodiment, the projector 100 does not use the coordinate information of the lower boundary line of the screen 10 included in the captured image, so that erroneous detection of the edges of the desk or the lower side of the captured image is performed. As a result, it is possible to eliminate a decrease in measurement accuracy due to the fact that the tilt of the angle cannot be obtained, so that trapezoidal distortion correction can be performed more accurately.

  Further, according to the present embodiment, the projector 100 can perform the trapezoidal distortion correction more accurately by performing the setting according to whether or not all the boundary lines are within the displayable range.

  Further, the projector 100 can accurately determine the coordinates and the like of the reference point even when the focus adjustment is not properly performed by using the gradation pattern image as the calibration image 300.

(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 projection object is not limited to a screen, and may be a blackboard, a white board, a wall, a pillar, a desk, or the like, and a plurality of objects whose lower side is the edge of the desk and the remaining three sides are the screen. It may be composed of an object.

  The calibration image 300 is not limited to the above-described embodiment. For example, the pattern image of the calibration image 300 may be an image in a state where each straight line protrudes from the outer peripheral line of the pattern image shown in FIG. 3 (for example, # when the pattern image is a square).

  The pattern image described above has three gradations, but may have four or more gradations. Further, in the above-described pattern image, regions having the same gradation are arranged on both sides of the white region, but regions having different gradations may be arranged only on one side. For example, the pattern image may be a linear image having a dark gray area on the left, a light gray area on the center, and a white area on the right.

  Moreover, the information generation part 130 does not need to generate | occur | produce position information and conversion information. For example, when the projection lens and the imaging lens are substantially at the same position, the projector 100 may execute the above-described processing using the two-dimensional coordinates in the imaging coordinate system as they are.

  Further, the projector 100 generates coordinate information of the screen boundary line by capturing an image in a non-projection state, but the calibration image for correcting the trapezoidal distortion is an image that can also detect the screen boundary line. Alternatively, coordinate information of the boundary line of the screen may be generated based on the captured image of the calibration image.

  In addition, when the projector 100 is installed in a ceiling-mounted state, for example, the imaging unit 110 is also turned upside down, so the upper side of the projection target in the actual three-dimensional space (the lower side in the coordinate system of the captured image) The trapezoidal distortion correction described above may be performed without using the coordinate information of the side.

  Further, the projector 100 is not limited to a liquid crystal projector (transmission type, reflection type such as LCOS), and may be a projector using DMD (Digital Micromirror Device), for example. DMD is a trademark of Texas Instruments Incorporated. Further, the function of the projector 100 may be distributed to a plurality of devices (for example, a PC and a projector, an external camera and a projector, etc.).

  10 screens, 20 virtual areas, 100 projectors, 110 imaging units, 120 image input units, 130 information generation units, 140 determination units, 150 image generation units (trapezoidal distortion correction units), 190 projection units, 200 information storage media, 300 calibration Image

Claims (13)

An imaging unit that images a projection target and generates a captured image;
An information generating unit that generates coordinate information of a boundary line of the projection target included in the captured image;
A correction target area is set by executing a complementing process that complements a deficient portion according to the shape of the boundary line using coordinate information of a boundary line other than the lower side of the projection target, and based on the correction target area A trapezoidal distortion correction unit for correcting the keystone distortion;
Only including,
The trapezoidal distortion correction unit is
Performing the complementing process without using coordinate information of the lower boundary line of the projection object generated by the information generation unit;
projector. An imaging unit that images a projection target and generates a captured image;
An information generating unit that generates coordinate information of a boundary line of the projection target included in the captured image;
Based on the coordinate information of at least one boundary line excluding the lower boundary line among the boundary lines for which the coordinate information is generated by the information generation unit, according to the shape defined by the at least one boundary line A trapezoidal distortion correction unit that sets a correction target area by executing a complementing process that complements the deficient part, and performs trapezoidal distortion correction based on the correction target area;
Only including,
The trapezoidal distortion correction unit is
Performing the complementing process without using coordinate information of the lower boundary line of the projection object generated by the information generation unit;
projector. The projector according to claim 1,
The trapezoidal distortion correction unit is
Performing the complementing process using coordinate information of at least one of the right boundary line and the left boundary line of the projection object;
projector. The projector according to claim 1,
The trapezoidal distortion correction unit is
Performing the complementing process using the coordinate information of the right boundary line or the left boundary line of the projection object and the coordinate information of the upper boundary line;
projector. In the projector in any one of Claims 1-4 ,
Including a projection unit for projecting a calibration image for correcting keystone distortion,
The information generator is
Generating position information indicating correspondence between positions of the plurality of points in the calibration image in the image forming area of the projection unit or a virtual area corresponding to the image forming area and the positions of the plurality of points in the captured image; ,
Based on the position information, generating conversion information indicating a conversion formula between the coordinates of the image forming region or the virtual region and the coordinates of the captured image,
Based on the coordinate information and the conversion information, the trapezoidal distortion correction unit calculates the coordinates of the vanishing point obtained by projecting the infinity point related to the boundary line to the coordinate system of the image forming region or the virtual region. , Execute the complementing process,
projector. The projector according to claim 5 , wherein
Based on the conversion information, including a determination unit that determines whether all the boundaries of the projection object are within the range of the image formation region or the virtual region,
Before Symbol table Katachiyugami correction unit, when the entire perimeter of the projection target is in the range sets the area along the shape of the boundary line as the correction target region, all the boundaries of the projection target If the line is not within the range, the correction target area is set by executing the complement process,
projector. To computer which projector has,
Causing the imaging device to capture an image of the projection target and generate a captured image;
Generating coordinate information of a boundary line of the projection object included in the captured image;
Based on the coordinate information, the correction target region is set by executing a complementing process that complements the deficient portion according to the shape of the boundary line using the coordinate information of the boundary line other than the lower side of the projection target,
Based on the correction target area, trapezoidal distortion correction is performed ,
A program for executing the complementing process without using coordinate information of the generated lower boundary line of the projection object . An information storage medium storing a program readable by a computer of a projector,
An information storage medium storing the program according to claim 7 . The projector
Causing the imaging device to capture an image of the projection target and generate a captured image;
Generating coordinate information of a boundary line of the projection object included in the captured image;
Based on the coordinate information, the correction target region is set by executing a complementing process that complements the deficient portion according to the shape of the boundary line using the coordinate information of the boundary line other than the lower side of the projection target,
Based on the correction target region, have rows trapezoidal distortion correction,
A trapezoidal distortion correction method for executing the complementing process without using coordinate information of a generated lower boundary line of the projection object . An imaging unit that images a projection target and generates a captured image;
A determination unit for determining whether or not a boundary line of the projection object is within a predetermined range;
An information generating unit that generates coordinate information of a boundary line of the projection target included in the captured image;
Using said coordinate information of the boundary boundary lines of projection target sets the correction target region by performing the complementary processing to supplement the insufficient portion in accordance with the shape of the boundary line, on the basis of the correction target region, trapezoidal distortion correction A trapezoidal distortion correction unit for performing
Only including,
The determination unit causes the lower boundary line of the projection object and one or two sides of the upper, right, and left boundary lines of the projection object to be within the predetermined range. Is determined,
The trapezoidal distortion correction unit uses coordinate information of one or two of the boundary lines on the upper side, the right side, and the left side of the projection target determined to be within the predetermined range. Complementing the deficient part according to the shape of the boundary line,
projector. The projector according to claim 10 .
Prior Symbol table Katachiyugami correction unit, Ru set Teisu the area along the shape of the boundary line as the correction target region if the entire perimeter of the projection target is determined to be within the predetermined range ,
projector. The projector according to claim 11 ,
Including a projection unit for projecting a calibration image for correcting keystone distortion,
The information generator is
Generating position information indicating correspondence between positions of the plurality of points in the calibration image in the image forming area of the projection unit or a virtual area corresponding to the image forming area and the positions of the plurality of points in the captured image; ,
Based on the position information, generating conversion information indicating a conversion formula between the coordinates of the image forming region or the virtual region and the coordinates of the captured image,
Based on the coordinate information and the conversion information, the trapezoidal distortion correction unit calculates the coordinates of the vanishing point obtained by projecting the infinity point related to the boundary line to the coordinate system of the image forming region or the virtual region. , Execute the complementing process,
projector. The projector
Causing the imaging device to capture an image of the projection target and generate a captured image;
Determining whether a boundary line of the projection object is within a predetermined range;
Generating coordinate information of a boundary line of the projection object included in the captured image;
Wherein based on the coordinate information, set the correction target region by performing the complementary processing to supplement the insufficient portion in accordance with the shape of the boundary line with the coordinate information of the boundary boundary lines of the projection target,
Based on the correction target region, have rows trapezoidal distortion correction,
In the determination, when a lower boundary line of the projection object and one or two sides of the upper, right, and left boundary lines of the projection object are within the predetermined range. If determined,
In the trapezoidal distortion correction, the coordinate information of one or two of the boundary lines on the upper side, the right side, and the left side of the projection object determined to be within the predetermined range is used. Complement the missing part according to the shape of the boundary line,
Trapezoidal distortion correction method.

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