JP2008306644A - Image process for projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for causing a rectangular image having a correct aspect ratio to be easily displayed on a projection screen even when the projector does not provide a sensor for detecting a zoom position. <P>SOLUTION: In an image processing device, an image forming unit comprises an image forming area setting unit for setting an image forming area in which a significant image is formed, and a correction executing unit for producing corrected image data which indicate already corrected image to be formed in the image forming area after correcting objected image data which indicate objected image. The image forming area setting unit comprises an adjusting area determining unit for determining an adjusting area of an aspect ratio of an image to be displayed on a projection screen using projection angle information relating to a projection angle of a projector to be provided by a user, and an image forming area determining unit for determining the image forming area using projection angle information and an adjustment value within an adjustment area. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to image processing for a projector, and more particularly to a technique for correcting distortion of an image displayed on a projection surface.

  A projector normally displays an image on a projection plane by tilt projection. When tilt projection is performed, the image displayed on the projection surface is distorted. For this reason, the projector forms a distorted image (corrected image) on an image forming unit such as a liquid crystal panel, whereby an image without distortion on the projection surface, that is, a rectangular image (correct image) having a correct aspect ratio. ) Is displayed. Note that tilt projection means a projection method when the optical axes of the projector do not intersect perpendicularly to the projection plane.

  The projector usually includes a projection optical system that can adjust the zoom position, and a sensor that detects an actual zoom position of the projection optical system. Then, the projector forms a corrected image in the image forming unit based on the detection result of the sensor.

JP 2002-189442 A JP 2005-227661 A

  In order to reduce the size of the projector, it is preferable that the projector does not include a sensor for detecting the zoom position. However, when the projector does not include the sensor, it is difficult to form an appropriate corrected image on the image forming unit, and as a result, it is difficult to display a normal image on the projection plane. Specifically, the aspect ratio of the rectangular image displayed on the projection plane is deviated from the correct aspect ratio.

  The present invention has been made to solve the above-described problems in the prior art, and even when the projector does not include a sensor for detecting the zoom position, a rectangular image having a correct aspect ratio on the projection surface is provided. An object is to display an image easily.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 For a projector including an image forming unit that emits light that represents an image, and a projection optical system that projects the light emitted from the image forming unit onto a projection surface and can adjust the zoom position Image processing apparatus,
An image forming region setting unit for setting an image forming region in which a significant image is to be formed in the image forming unit;
A correction execution unit that corrects target image data representing a target image and generates corrected image data representing a corrected image to be formed in the image forming region;
With
The image forming area setting unit
An adjustment range determination unit that determines an adjustment range of an aspect ratio of an image displayed on the projection plane, using projection angle information relating to the projection angle of the projector given by a user;
An image forming area determining unit that determines the image forming area using the projection angle information and an adjustment value within the adjustment range;
An image processing apparatus comprising:

  In this image processing apparatus, since the adjustment range of the aspect ratio of the image displayed on the projection surface is determined using the projection angle information, an appropriate adjustment range can be set. Since the image forming area is determined using an adjustment value within an appropriate adjustment range, a rectangular image having a correct aspect ratio can be easily displayed on the projection surface.

  Note that the zoom position of the projection optical system means the arrangement of the projection optical system in a direction parallel to the central axis of the projection optical system.

Application Example 2 An image processing apparatus according to Application Example 1,
The adjustment range determination unit further includes tele-end information relating to the magnification of the projection optical system when the zoom position of the projection optical system is at the tele end, and the zoom position of the projection optical system at the wide end. An image processing apparatus that determines the adjustment range using wide end information related to a magnification of the projection optical system.

[Application Example 3] The image processing apparatus according to Application Example 1 or 2,
The projection angle information includes a first rotation angle of the projector about a first axis that is orthogonal to a normal line of the projection plane and parallel to a lateral side of an image to be projected on the projection plane. A second rotation angle of the projector about a second axis perpendicular to the normal of the projection plane and parallel to a vertical side of the image to be projected on the projection plane; An image processing apparatus that is information indicating a large rotation angle.

  By doing so, it is possible to easily determine the adjustment range as compared to the case where the adjustment range is determined using information indicating the first rotation angle and information indicating the second rotation angle individually. Become.

Application Example 4 An image processing apparatus according to Application Example 2,
The projection angle information is
First angle information indicating a first rotation angle of the projector about a first axis that is orthogonal to the normal line of the projection plane and parallel to a lateral side of an image to be projected on the projection plane When,
A second rotation angle of the projector about a second axis that is perpendicular to the normal of the projection plane and parallel to a vertical side of the image to be projected on the projection plane; Angle information,
Including
The adjustment range determination unit
A larger one of the first value obtained using the first angle information and the wide end information and the second value obtained using the second angle information and the tele end information. Set the value to the maximum value of the adjustment range,
The smaller of the third value obtained using the first angle information and the tele end information, and the fourth value obtained using the second angle information and the wide end information An image processing apparatus that sets a value to a minimum value of the adjustment range.

  As described above, the first aspect information indicating the first rotation angle and the second angle information indicating the second rotation angle are separately used, and the adjustment range of the aspect ratio is minimized. Can be set in the range.

Application Example 5 An image processing apparatus according to Application Example 2,
The projection angle information includes a first rotation angle of the projector about a first axis that is orthogonal to a normal line of the projection plane and parallel to a lateral side of an image to be projected on the projection plane. Including information to indicate,
The adjustment range determination unit
Using the projection angle information and the wide end information, determine the maximum value of the adjustment range,
An image processing apparatus that determines a minimum value of the adjustment range using the projection angle information and the tele end information.

  By doing this, it is possible to determine the adjustment range of the aspect ratio according to the information indicating the first rotation angle.

Application Example 6 An image processing apparatus according to Application Example 2,
The projection angle information includes a second rotation angle of the projector about a second axis that is orthogonal to a normal line of the projection plane and parallel to a vertical side of an image to be projected on the projection plane. Including information to indicate,
The adjustment range determination unit
Using the projection angle information and the tele end information, determine the maximum value of the adjustment range,
An image processing apparatus that determines a minimum value of the adjustment range using the projection angle information and the wide end information.

  By doing this, it is possible to determine the adjustment range of the aspect ratio according to the information indicating the second rotation angle.

[Application Example 7] The image processing apparatus according to any one of Application Examples 2 to 6,
The image processing apparatus, wherein the adjustment range determination unit further determines the adjustment range using reference information regarding the magnification of the projection optical system corresponding to a reference zoom position of the projection optical system.

  In this way, the adjustment range of the aspect ratio can be determined using the reference information.

Application Example 8 An image processing apparatus according to Application Example 7,
The image processing apparatus, wherein the reference information is given by the user.

  By doing this, it is possible to determine the adjustment range of the aspect ratio using the reference information set by the user.

[Application Example 9] The image processing apparatus according to any one of Application Examples 1 to 6,
The image processing area determining unit further determines the image forming area using reference information regarding the magnification of the projection optical system corresponding to a reference zoom position of the projection optical system.

  In this way, it is possible to set the image forming area using the reference information.

[Application Example 10] The image processing apparatus according to any one of Application Examples 1 to 9,
The image formation region determination unit preliminarily determines the image formation region without using the adjustment value, and changes the preliminary image formation region using the adjustment value to change the image formation region. An image processing apparatus to determine.

Application Example 11 A projector,
The image forming unit;
The projection optical system;
The image processing apparatus according to any one of Application Examples 1 to 10,
A projector comprising:

  Note that the projection optical system of the projector may be exchangeable with other projection optical systems.

  The present invention relates to an image processing apparatus and method, a projector including the image processing apparatus and an image processing method therefor, a computer program for realizing the functions of these methods or apparatuses, a recording medium on which the computer program is recorded, The present invention can be realized in various forms such as a data signal embodied in a carrier wave including the computer program.

Next, embodiments of the present invention will be described in the following order based on examples.
A. First embodiment:
A-1. Assumptions:
A-1-1. Relationship between projector and screen:
A-1-2. Images to be formed on the LCD panel:
A-2. Problems with distortion correction processing:
A-3. Projector configuration:
A-4. Distortion correction processing:
A-4-1. Specific processing in step S120:
A-4-2. Specific processing in step S140:
A-4-3. Specific processing in step S160:
A-5. Modification of the first embodiment:
B. Second embodiment:
B-1. Modification of the second embodiment:
C. Third embodiment:

A. First embodiment:
In the following, prerequisite items will be described prior to specific description of the configuration and operation of the projector of the present embodiment.

A-1. Assumptions:
A-1-1. Relationship between projector and screen:
FIG. 1 is an explanatory diagram showing the relationship between the projector PJ and the screen SC. As will be described later, the projector PJ includes a liquid crystal panel (hereinafter also simply referred to as “panel”) and a projection optical system.

  FIG. 1 shows the xyz coordinate system. The xyz coordinate system is a coordinate system based on the screen SC. The z axis is parallel to the normal of the screen SC. The x axis is orthogonal to the z axis and parallel to the horizontal direction. In other words, the x-axis is an axis parallel to the lateral side of the rectangular image to be projected on the screen SC. The y-axis is orthogonal to the z-axis and is parallel to the vertical direction. In other words, the y-axis is an axis parallel to the vertical side of the rectangular image to be projected on the screen SC. The origin of the xyz coordinate system is set to the principal point of the projection optical system. In FIG. 1, the coordinate axes are represented by a left-handed system.

  In the figure, the rotation angle (pitch angle) of the projector PJ around the x axis is θ. When the projector PJ faces upward, the rotation angle θ is a positive value. In the drawing, the rotation angle (yaw angle) of the projector PJ around the y-axis is φ. When the projector PJ turns to the right, the rotation angle φ is a positive value.

  When at least one of the two rotation angles (hereinafter referred to as “projection angles”) θ and φ of the projector PJ is a significant value (a non-zero value), in other words, the optical axis of the projector PJ (ie, projection) When the optical system central axis) and the screen SC normal (z-axis) do not match, tilt projection is realized.

  When tilt projection is realized, if an image without distortion is formed on the panel, the image displayed on the screen is distorted. Conversely, when a distorted image (corrected image) is formed on the panel, an image without distortion, that is, a rectangular image (correct image) having a correct aspect ratio can be displayed on the screen.

  FIG. 2 is an explanatory diagram showing a relationship between coordinates (x, y) on the screen and coordinates (X, Y) on the liquid crystal panel.

  The coordinates (x, y) on the screen SC indicate the coordinates of the intersection of a straight line passing through the origin of the xyz coordinate system and a point on the screen SC and a plane where z = 1. In other words, the coordinates (x, y) on the screen SC indicate the coordinates when the screen SC is assumed to be a plane with z = 1.

  The coordinates (X, Y) on the panel are coordinates based on the panel. In the figure, the X axis is parallel to the horizontal side (long side) of the panel, and the Y axis is the vertical direction of the panel. It is parallel to the side (short side). The intersection of the X axis and the Y axis is the intersection of the panel and the optical axis of the projector PJ (that is, the central axis of the projection optical system). In FIG. 2, the intersection of the X axis and the Y axis is offset from the center of the panel. This is because the central axis of the projection optical system is offset from the normal line of the panel passing through the center of the panel.

  The relationship between the coordinates (x, y) and the coordinates (X, Y) can be expressed by coordinate transformation called “projective transformation”. This relationship is expressed by the following formula (1). Moreover, this relationship is represented by Formula (2) using Formula (1).

  Note that (x, y, 1) in equation (1) is the coordinates on the screen in the xyz coordinate system before the matrix of equation (1) is applied, and (x ′, y ′, z ′) is , The coordinates on the panel in the xyz coordinate system after the matrix of equation (1) is applied.

  The matrix of Equation (1) can be expressed as a product of rotation matrices. Specifically, in order to convert the coordinates (x ′, y ′, z ′) on the panel into the coordinates (x, y, 1) on the screen in the xyz coordinate system, the coordinates on the panel are set to x. After rotating by θ around the axis, it may be rotated by φ around the y axis. Conversely, in order to convert coordinates (x, y, 1) on the screen into coordinates (x ′, y ′, z ′) on the panel in the xyz coordinate system, the coordinates on the screen are centered on the y axis. After rotating by −φ, the rotation may be made by −θ around the x axis. Therefore, the transformation matrix is expressed as in Equation (3). In Equation (3), the rotation matrix Rx indicates rotation about the x axis, and the rotation matrix Ry indicates rotation about the y axis. As described above, in FIG. 1, the coordinate axis is represented by the left-handed system. Therefore, in equation (3), the parameter of the rotation matrix Rx is represented by “θ” instead of “−θ” in order to match the coordinate axis of the right-handed system.

  From the equation (3), the values of the respective coefficients A, B, C... Of the matrix of the equation (1) are obtained.

A-1-2. Images to be formed on the LCD panel:
FIG. 3 is an explanatory diagram showing an example of an image to be formed on the liquid crystal panel. As shown in FIGS. 3A to 3D, an image corresponding to two projection angles θ and φ is formed on the panel, so that the screen SC has a correct aspect ratio (1: m). A rectangular image (normal image) is displayed. Here, the correct aspect ratio means the aspect ratio of the panel, in other words, the aspect ratio of the image to be displayed, and the value of m is, for example, 3/4, 9/16.

  FIG. 3A shows an image to be formed on the panel when the two projection angles θ and φ are both zero. FIG. 3B shows an image to be formed on the panel when the projection angle θ is a significant value and the projection angle φ is zero. FIG. 3C shows an image formed on the panel when the projection angle θ is zero and the projection angle φ is a significant value. FIG. 3D shows an image to be formed on the panel when the two projection angles θ and φ are both significant values.

  As shown in FIG. 3A, when both of the two projection angles θ and φ are zero, when a rectangular image having the correct aspect ratio (1: m) is formed on the panel, the screen A rectangular image (correct image) having a correct aspect ratio (1: m) is also displayed on the SC. On the other hand, as shown in FIGS. 3B to 3D, when at least one of the two projection angles θ and φ is a significant value, a distorted image (corrected image) is formed on the panel. Then, a rectangular image (normal image) having a correct aspect ratio (1: m) is displayed on the screen SC.

  3A to 3D, the image on the panel is formed in an image forming area WF having a quadrangle (substantially trapezoidal shape). Two opposing sides of the image forming area WF pass through the first vanishing point Vv, and the opposing upper and lower sides pass through the second vanishing point Vh. In addition, the diagonal line of the image forming area WF passes through the third vanishing point Vm. In FIG. 3A, the three vanishing points Vv, Vh, Vm are not shown because they exist at infinity. Similarly, in FIG. 3B, the second vanishing point Vh exists at infinity, and in FIG. 3C, the first vanishing point Vv exists at infinity.

Three vanishing points Vv, Vh, and Vm on the panel are points at which an infinite point on the screen SC is projected onto the panel. Consider an infinite point that exists on a straight line having a direction vector (a, b) passing through a point (x ₀ , y ₀ ) on the screen SC. This straight line is expressed as x = a · t + x ₀ , y = b · t + y ₀ using the parameter t. The point on the screen when the parameter t is ± ∞ is the infinity point. The coordinates of the vanishing point on the panel corresponding to the infinite point (x (= a · t + x ₀ ), y (= b · t + y ₀ )) on the screen SC are expressed by the equation (4) using the equation (2). It is represented by

  Using equation (4), the above three vanishing points Vv, Vh, Vm can be obtained. The first vanishing point (hereinafter also referred to as “vertical vanishing point”) Vv on the panel corresponding to the infinity point in the vertical (vertical) direction on the screen SC (that is, (a, b) = (0, 1)). The coordinates are expressed by equation (5). Further, the coordinates of the second vanishing point (hereinafter also referred to as “horizontal vanishing point”) Vh on the panel corresponding to the infinity point in the horizontal direction on the screen SC (that is, (a, b) = (1, 0)). Is represented by Formula (6). Of the third vanishing point Vm (hereinafter also referred to as “diagonal vanishing point”) on the panel corresponding to the point of infinity in the direction of the inclination m on the screen SC (that is, (a, b) = (1, m)). The coordinates are expressed by equation (7). Note that a diagonal line of a rectangular image (normal image) having a correct aspect ratio (1: m) displayed on the screen SC has an inclination m.

  As can be seen from the above description, an arbitrary straight line passing through the vertical vanishing point Vv on the panel corresponds to a straight line along the vertical (vertical) direction on the screen SC, and an arbitrary straight line passing through the horizontal vanishing point Vh on the panel. The straight line corresponds to a straight line along the horizontal direction on the screen SC. An arbitrary straight line passing through the diagonal vanishing point Vm on the panel corresponds to a straight line having an inclination m on the screen SC.

  Therefore, on the panel, an arbitrary first square area surrounded by any two straight lines passing through the vertical vanishing point Vv and any two straight lines passing through the horizontal vanishing point Vh is a rectangular area on the screen SC. Corresponds to the region. In addition, among the arbitrary first type quadrangular areas described above, an arbitrary second quadrangular area whose diagonal passes through the diagonal vanishing point Vm is a rectangular area having an aspect ratio of 1: m on the screen SC. Correspond.

  Therefore, in this embodiment, a corrected image is formed in the second quadrangular area on the panel, thereby displaying a rectangular image (normal image) having a correct aspect ratio (1: m) on the screen SC. ing. However, it is possible to draw a plurality of types of second rectangular regions on the panel. For this reason, in the present embodiment, a specific second rectangular area having the largest area among the arbitrary second rectangular areas that can be drawn on the panel is used as the image forming area WF. .

  3A to 3D, the image forming area WF is formed in a rectangular reference area WP corresponding to the panel. The reference area WP is an area that does not depend on the projection angles θ and φ. Consider a case in which two projection angles θ and φ are zero and a rectangular image (correct image) having a correct aspect ratio is displayed on the screen SC. At this time, since the matrix of Expression (1) is a unit matrix, (X, Y) = (x, y) is established. That is, the coordinates of the four corners of the reference area WP are, in the above case, four straight lines passing through the origin of the xyz coordinate system (FIG. 1) and the four corner points of the normal image displayed on the screen SC, and z = 1. And the coordinates of the four intersections. Further, the size of the reference area WP matches the size of the area surrounded by the above four intersections. In other words, the coordinates of the four corners of the reference area WP coincide with the coordinates of the four corner points of the positive image displayed on the screen SC when the screen SC is assumed to be a plane with z = 1 in the above case. To do. In addition, the size of the reference area WP matches the size of the normal image displayed on the screen SC when the screen SC is assumed to be a plane with z = 1.

A-2. Problems with distortion correction processing:
By the way, when the zoom position (view angle) of the projection optical system can be adjusted, the size of the normal image displayed on the screen changes according to the actual zoom position (view angle) of the projection optical system. . As described above, the reference area WP is an area determined based on the coordinates of the four corner points of the normal image displayed on the screen. Therefore, the size of the reference region WP is preferably determined according to the actual zoom position (view angle) of the projection optical system.

  For this reason, when the projector includes a projection optical system capable of adjusting the zoom position (view angle), the projector preferably includes a sensor for detecting an actual zoom position of the projection optical system.

  However, as will be described later, in this embodiment, the projector PJ includes a projection optical system capable of adjusting the zoom position (view angle), but a sensor for detecting the actual zoom position of the projection optical system is provided. Not prepared. For this reason, in this embodiment, the image forming area is determined using the fixed reference area WP regardless of the actual zoom position (view angle) of the projection optical system. The fixed reference area WP is an area corresponding to a zoom position (view angle) that is a reference of the projection optical system.

  In FIG. 3 described above, when the reference zoom position (reference angle of view) of the projection optical system corresponding to the fixed reference area WP matches the actual zoom position (view angle) of the projection optical system, it is displayed on the panel. An example of a corrected image to be formed is shown.

  If the reference zoom position (reference angle of view) of the projection optical system corresponding to a certain reference area WP does not match the actual zoom position (view angle) of the projection optical system, an appropriate corrected image is formed on the panel. As a result, the aspect ratio of the image displayed on the screen deviates from the correct aspect ratio. Below, the problem of this distortion correction process is demonstrated.

  In this embodiment, the projector PJ does not include a sensor that detects the projection angles θ and φ. Therefore, in this embodiment, the user inputs the projection angle parameters θp and φp related to the projection angles θ and φ of the projector PJ to the projector PJ. Note that the values of the projection angle parameters θp and φp can be set regardless of the actual projection angles θ and φ. The projector PJ determines the coordinates of the three vanishing points Vv, Vh, Vm on the panel using the values of the projection angle parameters θp, φp, and uses the three vanishing points Vv, Vh, Vm and the reference area WP. Use to set the image forming area WF. Then, the projector PJ forms a corrected image in the image forming area WF on the panel, and as a result, the image is displayed on the screen.

  In the first stage (initial state), it is assumed that the actual projection angles θ and φ of the projector PJ are zero, and the actual zoom position (view angle) of the projection optical system is arbitrary. Further, it is assumed that the projection angle parameters θp and φp are initial values (zero). At this time, a rectangular image (correct image) having a correct aspect ratio (1: m) is displayed on the screen SC.

  In the second stage, the user changes the height of the leg provided on the projector PJ or changes the horizontal direction of the projector in order to display an image at the target position on the screen SC. As a result, the actual projection angles θ and φ of the projector PJ are changed. Further, the user changes the actual zoom position of the projector PJ in order to display an image having a target size on the screen SC. At this time, since the projection angle parameters θp and φp remain at the initial values (zero), a distorted image is displayed on the screen SC.

  In the third stage, the user inputs the values of the projection angle parameters θp and φp so that a rectangular image is displayed on the screen SC while checking the image displayed on the screen SC. As a result, a rectangular image is displayed on the screen.

  FIG. 4 is an explanatory diagram showing the relationship between the actual zoom position of the projection optical system and the rectangular image displayed on the screen SC. In FIG. 4, for convenience of explanation, it is assumed that the actual projection angle θ is a significant value and the actual projection angle φ is zero. In FIG. 4, it is assumed that the value of the projection angle parameter φp is set to zero.

  In this case, in the second stage, a trapezoidal image with two side edges (left and right sides) inclined is displayed on the screen SC. In the third stage, when the value of the projection angle parameter θp is adjusted, the inclinations of the two side edges (left and right sides) of the trapezoidal image displayed on the screen SC are changed. For this reason, in the third stage, a rectangular image is displayed on the screen SC regardless of the actual zoom position (field angle) of the projection optical system.

  4A-1 assumes a case where the actual zoom position (view angle) of the projection optical system matches the reference zoom position (reference view angle) corresponding to the reference area WP. In this case, when the value of the projection angle parameter θp coincides with the actual projection angle θ, the screen SC has a correct aspect ratio (1: m) as shown in FIG. 4A-2. A rectangular image (normal image) is displayed.

  In FIG. 4 (B-1), the actual zoom position of the projection optical system is set to the tele side with respect to the position of FIG. 4 (A-1), and the actual zoom position (view angle) of the projection optical system is It is assumed that the reference zoom position (reference angle of view) corresponding to the reference area WP does not coincide. In this case, a rectangular image is not displayed on the screen SC even if the value of the projection angle parameter θp matches the actual projection angle θ. Conversely, when the value of the projection angle parameter θp is different from the actual projection angle θ, a rectangular image can be displayed on the screen SC as shown in FIG. 4B-2. However, in FIG. 4B-2, the aspect ratio of the rectangular image is 1: m ′. Note that m ′ is larger than m.

  In FIG. 4C-1, the actual zoom position of the projection optical system is set to be wider than the position of FIG. 4A-1, and the actual zoom position (view angle) of the projection optical system is It is assumed that the reference zoom position (reference angle of view) corresponding to the reference area WP does not coincide. In this case as well, even if the value of the projection angle parameter θp matches the actual projection angle θ, a rectangular image is not displayed on the screen SC. Conversely, when the value of the projection angle parameter θp is different from the actual projection angle θ, a rectangular image can be displayed on the screen SC as shown in FIG. 4C-2. However, in FIG. 4C-2, the aspect ratio of the rectangular image is 1: m ″. Note that m ″ is smaller than m.

  As described above, when the actual zoom position (view angle) of the projection optical system does not match the reference zoom position (reference view angle) corresponding to the reference area WP, the value of the projection angle parameter θp is the actual value. Even if it coincides with the projection angle θ, a rectangular image is not displayed on the screen. When the value of the projection angle parameter θp is different from the actual projection angle θ, a rectangular image having an incorrect aspect ratio can be displayed on the screen.

  As can be seen from this phenomenon, the size of the reference area WP is preferably adjusted in consideration of the actual zoom position (view angle) of the projection optical system. However, even if the size of the reference area WP can be adjusted by the user, it is difficult to display a normal image on the screen. For example, as shown in FIGS. 4B-1 and 4C-1, when the user adjusts the size of the reference region WP in a state where a rectangular image having an incorrect aspect ratio is displayed on the screen. Is assumed. When the size of the reference area WP is adjusted, the rectangular image on the screen is distorted. Therefore, the user adjusts the value of the projection angle parameter θp again so that a rectangular image is displayed on the screen. Then, when a rectangular image having an incorrect aspect ratio is displayed again on the screen, the user adjusts the size of the reference area WP again. Thus, even if the size of the reference area WP can be adjusted by the user, it is difficult to display a normal image on the screen. For this reason, in this embodiment, a constant reference area WP is used regardless of the actual zoom position (view angle) of the projection optical system.

  In this embodiment, it is easy to shift the aspect ratio of the rectangular image due to the difference between the reference zoom position (reference field angle) corresponding to the reference area WP and the actual zoom position (view angle) of the projection optical system. It is devised so that it can be resolved.

A-3. Projector configuration:
FIG. 5 is a block diagram schematically showing the configuration of the projector PJ. The projector PJ includes an illumination optical system 100, a liquid crystal panel 200, a projection optical system 300, and a control circuit 400 that controls the entire projector PJ. The projector PJ is further provided with an operation unit (not shown). The operation unit includes buttons provided on the projector PJ main body, a remote controller, and the like. The user can perform various settings regarding the projector PJ by operating the operation unit.

  The liquid crystal panel 200 modulates the light emitted from the illumination optical system 100 using the image data provided from the control circuit 400, and emits light representing an image.

  The projection optical system 300 projects the light emitted from the liquid crystal panel 200 onto the screen SC, and as a result, an image is displayed on the screen SC.

  In this embodiment, the projection optical system 300 includes an adjustment mechanism for adjusting the zoom position. Specifically, the adjustment mechanism moves the position of the lens included in the projection optical system 300 in a direction parallel to the optical axis of the projector PJ (the central axis of the projection optical system 300). Adjust the zoom position. In this embodiment, the adjustment mechanism is manually operated by the user turning the zoom ring provided in the projection optical system 300.

  The control circuit 400 includes a CPU and a memory, and a computer program that functions as the image processing unit 410 is stored in the memory. The function of the image processing unit 410 is realized by the CPU executing a computer program. The computer program is provided in a form recorded on a computer-readable recording medium such as a CD-ROM.

  The image processing unit 410 includes a setting screen composition unit 420, an image formation region setting unit 430, and a correction execution unit 440, and performs image processing on original image data IM1 representing an original image given from the outside. Then, processed image data IM2 representing the processed image is supplied to the panel 200. The image processing includes distortion correction processing for correcting distortion of an image displayed on the screen SC.

  The setting screen composition unit 420 displays a setting screen on the screen SC. Specifically, the setting screen composition unit 420 prepares setting screen data representing the setting screen when the user instructs to display the setting screen by operating the operation unit. Then, the setting screen composition unit 420 synthesizes the original image data IM1 and the setting screen data, and generates composite image data representing a composite image in which the setting screen is superimposed on the original image. Note that the user can set various items related to image processing via the setting screen. For example, the user can input values of various parameters for distortion correction processing via the setting screen.

  The image forming area setting unit 430 includes a projection angle parameter value acquiring unit 432, an adjustment range determining unit 434, an adjustment parameter value acquiring unit 436, and an image forming region determining unit 438. An image forming area in which a significant image is to be formed is set in the effective display area.

  The projection angle parameter value acquisition unit 432 acquires the values of the projection angle parameters θp and φp. The values of the projection angle parameters θp and φp are given by the user via the setting screen. As described above, the projection angle parameters θp and φp are parameters related to the projection angles θ and φ of the projector PJ, and the values of the projection angle parameters θp and φp can be set regardless of the actual projection angles θ and φ. is there.

  The adjustment range determination unit 434 sets an adjustment range for adjusting the aspect ratio of the rectangular image displayed on the screen SC. The adjustment range is determined using the values of the projection angle parameters θp and φp.

  The adjustment parameter value acquisition unit 436 acquires the value of the adjustment parameter Rp. The adjustment parameter Rp is a parameter for adjusting the aspect ratio of the image displayed on the screen SC. The value of the adjustment parameter Rp is a value within the adjustment range, and is given by the user via the setting screen.

  The image forming area determination unit 438 determines an image forming area using the values of the projection angle parameters θp and φp and the value of the adjustment parameter Rp. More specifically, the image forming area determination unit 438 first determines the image forming area preliminarily using the values of the projection angle parameters θp and φp without using the value of the adjustment parameter Rp. Next, the image forming area determination unit 438 changes the preliminary image forming area using the value of the adjustment parameter Rp. As a result, a target image forming area for displaying a normal image on the screen SC is determined.

  The correction execution unit 440 corrects the target image data representing the display target image so that a distorted image (corrected image) is formed in the image formation region set by the image formation region setting unit 430, and performs correction. Generated image data (processed image data) IM2. In the case where the composite image data is generated by the setting screen composition unit 420, the target image data is composite image data including the original image data IM1, and the composite image data is not generated by the setting screen composition unit 420. The target image data is the original image data IM1. By forming a corrected image on the panel 200 according to the corrected image data IM2, a normal image is displayed on the screen SC.

  In this embodiment, the projector PJ is provided with a sensor for detecting the actual projection angles θ and φ of the projector PJ and a sensor for detecting the actual zoom position of the projection optical system 300. Not.

  The values of the projection angle parameters θp and φp in this embodiment correspond to the projection angle information in the present invention. Further, the value of the adjustment parameter Rp corresponds to the adjustment value in the present invention.

A-4. Distortion correction processing:
FIG. 6 is a flowchart showing the procedure of the distortion correction process. The processing in FIG. 6 is executed by the image processing unit 410. Note that the processing of FIG. 6 is executed after the processing of the first stage and the second stage is completed. Specifically, when the user operates the operation unit to instruct the image processing unit 410 to display a setting screen for distortion correction processing, the image processing unit 410 starts the distortion correction processing in FIG.

  At this time, the setting screen composition unit 420 generates setting screen data representing the setting screen, and generates composite image data using the setting screen data and the original image data. Immediately after the processing of FIG. 6 is started, the image forming area setting unit 430 sets a rectangular image forming area using initial values (zero) of the projection angle parameters θp and φp. Then, the correction execution unit 440 corrects the target image data (synthesized image data) so that the target image (synthesized image) is formed in the rectangular image forming region, and generates corrected image data IM2. . As a result, a composite image in which the setting screen is included in the original image is displayed on the screen SC.

  FIG. 7 is an explanatory diagram illustrating an example of the setting screen SS. As illustrated, the setting screen SS includes a first setting area SF1 for setting the value of the projection angle parameter φp, a second setting area SF2 for setting the value of the projection angle parameter θp, and an aspect ratio. And a third setting area SF3 for setting the value of the adjustment parameter Rp. Each setting area SF1 to SF3 includes a bar and a slider, and parameter values are set according to the position of the slider.

  When the user operates the operation unit to select the first setting area SF1, the projection angle parameter φp can be set. When the second setting area SF2 is selected, the projection angle parameter The value of θp can be set. In addition, when the third setting area SF3 is selected, the value of the adjustment parameter Rp can be set. When the image is displayed on the screen SC in a distorted state, the setting screen SS is also displayed in a distorted state.

  In step S110 (FIG. 6), the projection angle parameter value acquisition unit 432 acquires the values of the projection angle parameters θp and φp given by the user. Specifically, when the user moves the slider provided in the first setting area SF1 by operating the operation unit, the projection angle parameter value acquisition unit 432 causes the projection angle parameter according to the position of the slider to be moved. Get the value of φp. Similarly, when the user moves the slider provided in the second setting area SF2 by operating the operation unit, the projection angle parameter value acquisition unit 432 sets the projection angle parameter θp according to the position of the slider. Get the value.

  In step S120, the image forming area determination unit 438 determines the image forming area in the panel 200 using the values of the projection angle parameters θp and φp obtained in step S110. The process of step S120 will be further described later.

  In step S130, the correction execution unit 440 corrects the target image data to generate corrected image data so that a corrected image is formed in the image forming area in the panel 200 determined in step S120. As a result, an image corresponding to the values of the projection angle parameters θp and φp given by the user is displayed on the screen SC.

  The corrected image data is generated as follows. Specifically, the pixel in the target image corresponding to the target pixel in the image forming area is specified, and the tone value of the target pixel is determined using the tone value of the specified pixel. The relationship between the coordinates of the pixel of interest in the image forming area and the coordinates of the corresponding pixel in the target image is expressed using the following equation (8). The coefficients a to h are obtained by substituting the coordinates of the four corner points of the image forming area for X and Y, and by substituting the coordinates of the four corner points of the target image for S and T. Obtained by solving the equation).

  Note that the processes of steps S110 to S130 are actually repeatedly performed until the image displayed on the screen SC becomes a rectangle. That is, in step S110, the user inputs the values of the projection angle parameters φp and θp so that the image is rectangular while checking the image displayed on the screen SC.

  In step S140, the adjustment range determination unit 434 sets the adjustment range of the aspect ratio of the image displayed on the screen SC. The process of step S140 is executed when the third setting area SF3 is selected by the user operating the operation unit. The process of step S140 will be further described later.

  In step S150, the adjustment parameter value acquisition unit 436 acquires the value of the adjustment parameter Rp of the aspect ratio given by the user. Specifically, when the user moves the slider provided in the third setting area SF3 by operating the operation unit, the adjustment parameter value acquisition unit 436 adjusts the aspect ratio according to the position of the slider. The value of parameter Rp is acquired. In the present embodiment, the value of the adjustment parameter Rp is a value within the adjustment range determined in step S140.

  In step S160, the image forming area determination unit 438 uses the projection angle parameters θp and φp values obtained in step S110 and the adjustment parameter Rp values obtained in step S150, to generate an image in the panel 200. The formation area is determined. Specifically, in step S120, the image forming area determining unit 438 preliminarily determines the image forming area using the values of the projection angle parameters θp and φp without using the adjustment parameter Rp, and step S160. Then, using the value of the adjustment parameter Rp, the preliminary image forming area is changed to determine the target image forming area. The process of step S160 will be further described later.

  In step S170, the correction execution unit 440 corrects the target image data to correct the corrected image so that the corrected image is formed in the image forming area in the panel 200 determined in step S160, as in step S130. Generate data. As a result, a rectangular image having an aspect ratio corresponding to the values of the projection angle parameters θp and φp given by the user and the value of the adjustment parameter Rp can be displayed on the screen SC.

  Note that the processes of steps S150 to S170 are actually repeatedly performed until the aspect ratio of the rectangular image displayed on the screen SC becomes the correct aspect ratio. That is, in step S150, the user inputs the value of the adjustment parameter Rp so that the aspect ratio of the rectangular image becomes the correct aspect ratio while checking the rectangular image displayed on the screen SC.

  Note that when the user operates the operation unit to instruct the image processing unit 410 to delete the setting screen SS, the distortion correction processing in FIG. 6 ends. Thereafter, the correction execution unit 440 corrects the target image data so that the corrected image is formed in the image forming area in the panel 200 that has already been set in the distortion correction processing of FIG. Generate.

A-4-1. Specific processing in step S120:
FIG. 8 is an explanatory diagram showing the image forming area WF1 determined in step S120. The image forming area WF1 is an area determined in step S120 when a rectangular image is displayed on the screen SC in step S130.

  In FIG. 8, for convenience of explanation, it is assumed that the actual projection angle θ is a significant value (a non-zero value) and the actual projection angle φ is zero. In this case, in step S110, if the user does not change the value of the projection angle parameter φp from the initial value (zero) but sequentially changes the value of the projection angle parameter θp, a trapezoidal image displayed on the screen SC. The slopes of the two side edges (left and right edges) are sequentially changed, and a rectangular image is displayed.

  As illustrated, the image forming area WF1 is determined using three vanishing points Vv1, Vh1, and Vm1 and a reference area WP1.

In the present embodiment, the reference area WP1 is preset and cannot be changed by the user. As described above, the size of the reference area WP1 is set based on the reference zoom position (reference angle of view) of the projection optical system 300. As the reference zoom position, for example, a zoom position that is expected to be used frequently among the zoom positions that can be adopted by the projection optical system 300 is employed. The aspect ratio of the reference area WP1 is equal to the aspect ratio (1: m ₀ ) of the target image.

The three vanishing points Vv1, Vh1, and Vm1 are determined using the projection angle parameters θp and φp values θ ₀ and φ ₀ when a rectangular image is displayed on the screen SC. The diagonal vanishing point Vm is further determined using a value m ₀ that defines the aspect ratio (1: m ₀ ) of the target image.

In step S120, the image forming area determination unit 438 first prepares a reference area WP1 corresponding to the reference zoom position (reference angle of view). Next, the image forming area determination unit 438 determines three vanishing points Vv1, Vh1, and Vm1 using the values θ ₀ and φ ₀ of the projection angle parameters θp and φp. In FIG. 8, since it is assumed that the actual projection angle φ is zero, the value φ ₀ of the projection angle parameter φp is zero. Accordingly, the three vanishing points Vv1, Vh1, and Vm1 are expressed by Expression (9), Expression (10), and Expression (11) using Expression (5), Expression (6), and Expression (7), respectively. The

  Thus, when the reference area WP1 is prepared and the three vanishing points Vv1, Vh1, and Vm1 are determined, the image forming area WF1 is determined as shown in FIG. In FIG. 8, the horizontal vanishing point Vh1 (equation (10)) is not shown because it exists at infinity.

  The lower base of the image forming area WF1 exists on a straight line passing through an infinite horizontal vanishing point Vh1 (not shown) and coincides with the lower side of the reference area WP1. The left side of the image forming area WF1 exists on a first straight line L1 that passes through the vertical vanishing point Vv1 and the lower leftmost point at the bottom of the image forming area WF1. The right side of the image forming area WF1 exists on a second straight line L2 that passes through the vertical vanishing point Vv1 and the lower bottom point of the image forming area WF1. The diagonal line of the image forming area WF1 exists on the third straight line L3 passing through the lower left end point of the image forming area WF1 and the diagonal vanishing point Vm1. The upper base of the image forming area WF exists on a straight line passing through an infinite horizontal vanishing point Vh1 (not shown) and the intersection of the second straight line L2 and the third straight line L3.

  The reference area WP1 is an area corresponding to the panel 200. Accordingly, in step S130, a corrected image is formed in the image forming area WF1 in the panel 200 determined in step S120. However, the actual zoom position (view angle) of the projection optical system 300 is different from the reference zoom position (reference view angle) corresponding to the reference area WP1. For this reason, in step S130, a rectangular image having an incorrect aspect ratio is displayed on the screen SC.

A-4-2. Specific processing in step S140:
Hereinafter, the aspect ratio deviation will be described using “magnification” corresponding to the zoom position (view angle) instead of the zoom position (view angle). Assume that the reference magnification corresponding to the reference zoom position is Z ₀ and the magnification corresponding to the actual zoom position of the projection optical system 300 is Z ₁ . Note that the magnification Z corresponding to the specific zoom position is set to a value corresponding to the reciprocal 1 / f of the focal length f at the specific zoom position. Therefore, the ratio of the two magnifications corresponding to the two zoom positions (for example, (actual magnification Z ₁ ) / (reference magnification Z ₀ )) is the ratio of the reciprocals of the two focal lengths at the two zoom positions (for example, ( It is equal to the focal length f _{0 at the} reference zoom position / (focal length f _{1 at the} actual zoom position)).

FIG. 9 is an explanatory diagram showing an actual projection state of the projection optical system 300 in step S130. When the magnification Z ₁ corresponding to the actual zoom position (field angle) of the projection optical system 300 matches the reference magnification Z ₀ , the projection optical system 300 projects an image in the state shown in FIG. However, since the magnification Z ₁ corresponding to the actual zoom position (view angle) of the projection optical system 300 is different from the reference magnification Z ₀ , the projection optical system 300 actually performs the image in the state shown in FIG. Is projected. Specifically, for the projection optical system 300, as shown in FIG. 9, a reference area WP1 ′, vanishing points Vv1 ′, Vh1 ′, Vm1 ′, and an image forming area WF1 ′ are set.

Any corresponding figures shown in FIGS. 8 and 9 are similar. That is, the reference area WP1 ′ and the image forming area WF1 ′ in FIG. 9 have a size Z ₁ / Z ₀ times that of the reference area WP1 and the image forming area WF1 in FIG. Further, the coordinate values of the vanishing points Vv1 ′, Vm1 ′, and Vm1 ′ in FIG. 9 have values Z ₁ / Z ₀ times the coordinate values of the vanishing points Vv1, Vm1, and Vm1 (FIG. 8) in FIG. Therefore, the diagonal vanishing point Vm1 ′ is expressed by the following formula (12).

As described above, in step S130, a rectangular image having an incorrect aspect ratio is displayed on the screen SC. This incorrect aspect ratio is set to 1: m ₁ . In the state shown in FIG. 9, the actual projection angle θ of the projector PJ is the value θ ₁ , the magnification corresponding to the actual zoom position of the projector PJ is Z ₁ , and the projector PJ has an aspect ratio of 1: m _1. This is a state to be realized when a rectangular image is displayed. Therefore, the diagonal vanishing point Vm1 ′ shown in FIG. 9 is expressed by the following equation (13).

  Since the coordinates of the diagonal vanishing point Vm1 ′ represented by the equation (12) and the coordinates of the diagonal vanishing point Vm1 ′ represented by the equation (13) are the same, the following equation (14) is established. To do.

If two equations included in the equation (14) are used, the aspect ratio deviation rate (m ₁ / m ₀ ) can be obtained as shown in the equation (15).

  Here, the magnification when the zoom position of the projection optical system 300 is at the tele end (tele end magnification) is Zt, and the magnification when the zoom position of the projection optical system 300 is at the wide end (wide end magnification) is Zw. To do.

If the actual zoom position of the projection optical system 300 is at the tele end (that is, when Z ₁ = Zt), the aspect ratio deviation rate Bθt (θ ₀ ) corresponding to the value θ ₀ is expressed by the equation (15). ) And is represented by the following formula (16). When the actual zoom position of the projection optical system 300 is at the wide end (that is, when Z ₁ = Zw), the aspect ratio deviation rate Bθw (θ ₀ ) corresponding to the value θ ₀ is expressed by the equation (15 ) And is represented by the following formula (17).

8 and 9, it is assumed that the projection angle parameter θp is a significant value and the projection angle parameter φp is zero. However, the projection angle parameter θp is zero and the projection angle parameter φp is zero. Even when it is a significant value, the aspect ratio of the image displayed on the screen SC may be different from the correct aspect ratio (1: m ₀ ). In this case, the equation (18) is established in the same manner as the equation (14).

Then, using the two equations included in Equation (18), the aspect ratio deviation rate (m ₁ / m ₀ ) can be obtained as shown in Equation (19).

Therefore, when the actual zoom position of the projection optical system 300 is at the telephoto end (that is, when Z ₁ = Zt), the aspect ratio deviation rate Bφt (φ ₀ ) corresponding to the value φ ₀ is expressed by the equation (19). ) And is represented by the following formula (20). When the actual zoom position of the projection optical system 300 is at the wide end (that is, when Z ₁ = Zw), the aspect ratio deviation rate Bφw (φ ₀ ) corresponding to the value φ ₀ is expressed by the equation (19). ) And is represented by the following formula (21).

FIG. 10 is a graph showing the deviation ratio of the aspect ratio. In the figure, the horizontal axis represents the values θ ₀ and φ ₀ of the projection angle parameters θp and φp, and the vertical axis represents the aspect ratio deviation rate (m ₁ / m ₀ ). Curves Dθt and Dθw indicate deviation rates Bθt (θ ₀ ) (formula (16)) and Bθw (θ ₀ ) (formula (17)), respectively. Curves Dφt and Dφw indicate deviation rates Bφt (φ ₀ ) (formula (20)) and Bφw (φ ₀ ) (formula (21)), respectively. Each curve shown in FIG. 10 is a curve when Z ₀ = 1.3, Zt = 1.0, and Zw = 1.6.

Since each curve is symmetrical with respect to the vertical axis, only the range where the values θ ₀ and φ ₀ are 0 or more is shown in FIG.

As can be seen from the two curves Dθt and Dθw, the deviation ratios Bθt (θ ₀ ) and Bθw (θ ₀ ) of the aspect ratio corresponding to the value θ ₀ are obtained when the actual zoom position of the projection optical system 300 is at the tele end. And the minimum when the actual zoom position of the projection optical system 300 is at the wide end. On the other hand, as can be seen from the other two curves Dφt and Dφw, the aspect ratio deviation rates Bφt (φ ₀ ) and Bφw (φ ₀ ) corresponding to the value φ ₀ are wide in the actual zoom position of the projection optical system 300. The maximum value is obtained at the end, and the minimum value is obtained when the actual zoom position of the projection optical system 300 is at the tele end.

In FIG. 10, the curve Dθt is drawn above the curve Dφw, but the vertical relationship between the two curves Dθt and Dφw depends on the relationship between the three magnifications Z ₀ , Zt, and Zw. For example, when Z ₀ = 1.1, Zt = 1.0, and Zw = 1.6, the vertical relationship between the two curves Dθt and Dφw is reversed. Similarly, in FIG. 10, the curve Dθw is drawn above the curve Dφt, but the vertical relationship between the two curves Dθw and Dφt depends on the relationship between the three magnifications Z ₀ , Zt, and Zw. For example, when Z ₀ = 1.1, Zt = 1.0, and Zw = 1.6, the vertical relationship between the two curves Dθw and Dφt is reversed.

In this embodiment, the adjustment range indicating the range of the aspect ratio adjustment parameter Rp is determined in accordance with the values θ ₀ and φ ₀ of the two projection angle parameters θp and φp. The value of the adjustment parameter Rp is the reciprocal of the deviation rate. That is, when the value of the adjustment parameter Rp is equal to the reciprocal of the actual deviation rate, the image displayed on the screen SC is a rectangular image (normal image) having a correct aspect ratio (1: m ₀ ). . In the present embodiment, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio are determined using Expression (22).

Here, Max [] is a function that selects a large value of the two values in the parentheses, and Min [] is a function that selects a small value of the two values in the parentheses. The value α is a large value of two values (absolute values) | θ ₀ | and | φ ₀ |. The maximum value Rmax is calculated using Expression (17) and Expression (20). The minimum value Rmin is calculated using Expression (16) and Expression (21).

As can be seen from the equation (22), in this embodiment, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio are large values of two values (absolute values) | θ ₀ | and | φ ₀ |. It is determined using α. The maximum value Rmax and the minimum value Rmin of the aspect ratio adjustment range are determined using the reference magnification Z ₀ , the tele end magnification Zt, and the wide end magnification Zw.

More specifically, the maximum value Rmax uses the first value obtained by using the value α, the reference magnification Z ₀ and the wide end magnification Zw, and the value α, the reference magnification Z ₀ and the tele end magnification Zt. The second value obtained in this way is determined to be a large value. Further, the minimum value Rmin is obtained by using the third value obtained by using the value α, the reference magnification Z ₀ and the tele end magnification Zt, and the third value obtained by using the value α, the reference magnification Z ₀ and the wide end magnification Zw. The value of 4 is determined to be a small value.

  As described above, when the aspect ratio adjustment ranges Rmin to Rmax are determined in step S140, in step S150, the user inputs the value of the adjustment parameter Rp. The value of the adjustment parameter Rp that can be input by the user is limited to a value within the adjustment range Rmin to Rmax. Specifically, the left end of the bar in the third setting area SF3 (FIG. 7) is set to the minimum value Rmin of the adjustment range, and the right end of the bar is set to the maximum value Rmax of the adjustment range. For this reason, the user can determine the value of the adjustment parameter Rp within the adjustment range Rmin to Rmax by moving the slider in the third setting area SF3.

A-4-3. Specific processing in step S160:
As described above, in step S160, the image forming area is determined in accordance with the values θ ₀ and φ _{0 of} the projection angle parameters θp and φp obtained in step S110 and the value of the adjustment parameter Rp obtained in step S150. Is determined.

FIG. 11 is an explanatory diagram showing the image forming area WF2 determined in step S160. FIG. 11 is substantially the same as FIG. 8, but the diagonal vanishing point Vm2 is changed. The coordinate of the diagonal vanishing point Vm2 is expressed by the following equation (23) obtained by multiplying the value m ₀ of the equation (11) indicating the coordinate of the diagonal vanishing point Vm1 by the value of the adjustment parameter Rp.

  As can be seen from the comparison between Expression (11) and Expression (23), the X coordinate value of the diagonal vanishing point Vm2 is different from the X coordinate value of the diagonal vanishing point Vm1, but the diagonal vanishing point Vm2 is different. Is the same as the Y coordinate value of the diagonal vanishing point Vm1.

  As shown in FIG. 11, the image forming area WF2 uses the reference area WP1, the vertical vanishing point Vv1 and the horizontal vanishing point Vh1 obtained in step S120, and the diagonal vanishing point Vm2 obtained in step S160. Has been determined. In other words, the image forming area WF2 changes the image forming area WF1 in accordance with the value of the adjustment parameter Rp, more specifically, the diagonal vanishing point Vm1 in the diagonal direction in accordance with the value of the adjustment parameter Rp. It is obtained by changing to vanishing point Vm2.

The coordinates of the diagonal vanishing point Vm2 shown in FIG. 11 are coordinates when the value of the adjustment parameter Rp is a value m ₀ / m ₁ equal to the reciprocal of the actual deviation rate m ₁ / m ₀ . Therefore, when a corrected image is formed in the image forming area WF2 shown in FIG. 11, a rectangular image (normal image) having a correct aspect ratio (1: m ₀ ) is displayed on the screen SC.

Equation (23) shows the coordinates of the diagonal vanishing point when the value θ ₀ of the projection angle parameter θp is a significant value and the value φ ₀ of the projection angle parameter φp is zero. When the values θ ₀ and φ _{0 of the} two projection angle parameters θp and φp are significant values, the coordinates of the diagonal vanishing point Vm2 are expressed by the following equation (24).

  As described above, the projector PJ according to the present embodiment is not provided with the sensor that detects the actual projection angles θ and φ of the projector PJ and the sensor that detects the actual zoom position of the projection optical system 300. Therefore, the projector PJ can be reduced in size. Further, the projector PJ can be easily manufactured, and the manufacturing cost of the projector PJ can be suppressed.

  As described above, when the projector PJ is not provided with a sensor for detecting the zoom position, the aspect ratio of the image displayed on the screen SC can deviate from the correct aspect ratio.

  However, in the projector PJ of the present embodiment, the adjustment range Rmin to Rmax of the aspect ratio of the rectangular image displayed on the screen SC is determined using the values of the projection angle parameters θp and φp given by the user. An appropriate adjustment range Rmin to Rmax can be set. Since the image forming area WF2 is set using the value of the adjustment parameter Rp within the appropriate adjustment range Rmin to Rmax, a rectangular image (correct image) having the correct aspect ratio can be easily displayed on the screen SC. It becomes possible to make it.

  By the way, the adjustment range can be set without using the value of the projection angle parameter, in other words, regardless of the value of the projection angle parameter. However, in this case, the adjustment range may be excessively narrowed or excessively widened. When the adjustment range is excessively narrow, a rectangular image (correct image) having a correct aspect ratio cannot be obtained. On the other hand, when the adjustment range is excessively wide, a normal image can be obtained, but it becomes difficult for the user to quickly set the value of the adjustment parameter, which is inconvenient. That is, as in the present embodiment, when an appropriate adjustment range is set using the value of the projection angle parameter, a rectangular image (correct image) having a correct aspect ratio can be obtained reliably, and the user can The value of the adjustment parameter can be set quickly.

The reference magnification Z ₀ and the telephoto end magnification Zt in the present embodiment and the wide end magnification Zw, respectively, corresponding to the reference information and the telephoto end information and the wide end information in the present invention.

A-5. Modification of the first embodiment:
In the first embodiment, the adjustment range of the aspect ratio is determined using Expression (22) including the value α. More specifically, in the first embodiment, the maximum value Rmax and the minimum value Rmin of the aspect ratio are the larger one α of the values | θ ₀ | and | φ ₀ | of the two projection angle parameters θp and φp. Is determined using the value of. For this reason, the case where the adjustment range of the aspect ratio is not the minimum necessary range may occur.

For example, consider the case in FIG. 10 where the value θ ₀ is about 30 degrees and the value φ ₀ is about 15 degrees. According to Equation (22), the value α is 30 degrees, and the maximum value Rmax is set to 1 / Bφt (30 degrees). However, in practice, it is sufficient that the maximum value Rmax is set to 1 / Bθw (30 degrees) smaller than 1 / Bφt (30 degrees).

  Therefore, in this example, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio are obtained by Expression (25) instead of Expression (22).

As can be seen from equation (25), in this example, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio are determined using two values θ ₀ and φ ₀ . The maximum value Rmax and the minimum value Rmin of the aspect ratio adjustment range are determined using the reference magnification Z ₀ , the tele end magnification Zt, and the wide end magnification Zw.

More specifically, the maximum value Rmax includes the first value obtained by using the value θ ₀ , the reference magnification Z ₀ and the wide end magnification Zw, the value φ ₀ , the reference magnification Z ₀ and the tele end magnification Zt. It is determined to be a large value of the second value obtained by using. The minimum value Rmin is obtained using the third value obtained using the value θ ₀ , the reference magnification Z ₀ and the tele end magnification Zt, and the value φ ₀ , the reference magnification Z ₀ and the wide end magnification Zw. The fourth value to be used is determined to be a smaller value.

In this example, the adjustment range of the aspect ratio is determined by separately using the values θ ₀ and φ ₀ of the two projection angle parameters θp and φp, so the aspect ratio adjustment range is set to the minimum necessary range. can do. However, as in the first embodiment, if the larger value α of the two values (absolute values) | θ ₀ | and | φ ₀ | is used, the adjustment range of the aspect ratio can be determined relatively easily. There is an advantage that can be.

B. Second embodiment:
In the first embodiment, the adjustment range of the aspect ratio is determined using the equation (22) including four deviation rates Bθt (α), Bθw (α), Bφt (α), and Bφw (α). These four deviation rates Bθt (α), Bθw (α), Bφt (α), and Bφw (α) can be understood from the equations (16), (17), (20), and (21). , The reference magnification Z ₀ is included. That is, in the first embodiment, the adjustment range of the aspect ratio is determined using the reference magnification Z _0.

In this embodiment, the adjustment range of the aspect ratio is determined without using the reference magnification Z _0. In the present embodiment, it is assumed that the reference magnification Z ₀ is equal to (Zt + Zw) / 2 (for example, Z ₀ = 1.3, Zt = 1.0, Zw = 1.6).

As described above, when Z ₀ = (Zt + Zw) / 2, the vertical relationship of the four curves Dθt, Dθw, Dθt, and Dφw is the same as in FIG. For this reason, in this embodiment, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio can be obtained by Expression (26) instead of Expression (22).

When Z ₀ = (Zt + Zw) / 2, 1 / Bφt (α) included in the equation relating to Rmax in equation (22) is always larger than 1 / Bθw (α). Therefore, in equation (26), the maximum value Rmax is determined using 1 / Bφt (α). The minimum value Rmin is determined for convenience using the maximum value Rmax. Specifically, 1 / Bθt (α) included in the equation regarding Rmin in equation (22) is always smaller than 1 / Bφw (α). As can be seen by paying attention to the two curves Dθt and Dφt, the first difference (1 / Bφt (α) −1) is always greater than the second difference (1-1 / Bθt (α)). large. For this reason, in Equation (26), the minimum value Rmin is determined using the first difference including 1 / Bφt (α) equal to the maximum value Rmax for convenience.

As can be seen from the equation (26), in this embodiment, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio are large values of two values (absolute values) | θ ₀ |, | φ ₀ | It is determined using α. Further, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio are determined using the tele end magnification Zt and the wide end magnification Zw.

By employing the present embodiment, without using the reference magnification Z _0, it is possible to determine the adjustment range of the aspect ratio. In the present embodiment, the case where the reference magnification Z ₀ is equal to (Zt + Zw) / 2 has been described. However, in the present embodiment, the reference magnification Z ₀ is expressed by using the magnifications Zt and Zw, so that an arbitrary case can be obtained. It is applicable to.

B-1. Modification of the second embodiment:
In the second embodiment, the adjustment range of the aspect ratio is determined using the equation (26) including the value α. In this case, as described above, the adjustment range of the aspect ratio is the minimum necessary. Cases that are not in the range may occur.

  Therefore, in this example, similarly to the modification of the first example, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio are obtained by Expression (27) instead of Expression (26).

As can be seen from Equation (27), in this example, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio are determined using two values θ ₀ and φ ₀ . Further, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio are determined using the tele end magnification Zt and the wide end magnification Zw.

More specifically, the maximum value Rmax is obtained by using the first value obtained by using the value θ ₀ , the tele end magnification Zt and the wide end magnification Zw, the value φ ₀ , the tele end magnification Zt and the wide end magnification Zw. It is determined to be a large value of the second value obtained by using. The minimum value Rmin is determined using the large value (that is, the maximum value Rmax).

If this example is adopted, the adjustment range of the aspect ratio can be determined without using the reference magnification Z _0, and the adjustment range of the aspect ratio can be set to the minimum necessary range.

C. Third embodiment:
In the first and second embodiments, the adjustment range of the aspect ratio is calculated based on the expressions (22) and (25) in consideration of the case where the values θ ₀ and φ ₀ of the projection angle parameters θp and φp are both significant. ), Formula (26), and formula (27).

However, when the value φ _{0 of} the second projection angle parameter φp is zero, or when the distortion correction processing of the projector PJ can be performed using only the first projection angle parameter θp (that is, the projector PJ When the distortion correction process cannot be performed using the two projection angle parameters θp and φp), the aspect ratio adjustment range may be determined using another formula.

In the above case, the deviation rates Bφt (φ ₀ ) and Bφw (φ ₀ ) are always 1. For this reason, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio can be obtained by Expression (28).

In Expression (28), the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio are determined using the value θ ₀ . The maximum value Rmax of the adjustment range of the aspect ratio is determined using the reference magnification Z ₀ and the wide end magnification Zw, and the minimum value Rmin is determined using the reference magnification Z ₀ and the tele end magnification Zt. Yes.

  As described above, when the expression (28) is used, the aspect ratio adjustment range is appropriately determined according to the value of the first projection angle parameter θp without considering the value of the second projection angle parameter φp. be able to.

Similarly, when the value θ _{0 of} the first projection angle parameter θp is zero, or when the distortion correction processing of the projector PJ can be executed using only the second projection angle parameter φp (that is, the projector PJ). In other words, the range of adjustment of the aspect ratio may be determined using another equation (when the distortion correction process of (2) cannot be performed using the two projection angle parameters θp and φp).

In the above case, the deviation rates Bθt (θ ₀ ) and Bθw (θ ₀ ) are always 1. For this reason, the maximum value Rmax and the minimum value Rmin of the adjustment range of the aspect ratio can be obtained by Expression (29).

In Expression (29), the maximum value Rmax and the minimum value Rmin of the aspect ratio adjustment range are determined using the value φ ₀ . The maximum value Rmax of the adjustment range of the aspect ratio is determined using the reference magnification Z ₀ and the tele end magnification Zt, and the minimum value Rmin is determined using the reference magnification Z ₀ and the wide end magnification Zw. Yes.

  As described above, when Expression (29) is used, the aspect ratio adjustment range is appropriately determined according to the value of the second projection angle parameter φp without considering the value of the first projection angle parameter θp. be able to.

As in the second embodiment, the scale factor Z ₀ magnification Zt, if expressed using Zw, without using the reference magnification Z _0, it is possible to determine the adjustment range of the aspect ratio.

  The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

(1) In the above embodiment, the zoom position of the projection optical system 300 is manually adjusted by the user. However, the adjustment mechanism of the projection optical system 300 may include an actuator. In the above embodiment, the projection angles θ and φ of the projector PJ are manually adjusted by the user. However, the projector PJ may include an actuator for changing the projection angles θ and φ. In this way, the user adjusts the actual zoom position of the projection optical system 300 and the actual projection angles θ and φ of the projector PJ by operating an operation unit (button or the like) provided on the projector PJ. Can do.

(2) In the above embodiment, the image forming area WF1, WF2 has been determined without using the reference magnification Z _0, instead of this, the image forming area WF1, WF2, using the reference magnification Z ₀ It may be determined. Specifically, the image forming area WF1, WF2 may be determined using the reference magnification Z ₀ is the reference area WP1 to determine.

(3) Although the above embodiment has been described on the assumption that the reference region WP1 (reference magnification Z ₀ ) is constant, the reference region WP1 (reference magnification Z ₀ ) may be changeable by the user. In this way, the aspect ratio adjustment range can be determined using the reference magnification Z ₀ set by the user.

  In the above embodiment, the tele end magnification Zt and the wide end magnification Zw are assumed to be constant values. However, the tele end magnification Zt and the wide end magnification Zw can be changed by the user. Also good.

  These modes are suitable when the projection optical system of the projector can be replaced by the user.

(4) In the above embodiment, magnifications Z ₀ , Zt, and Zw are used as information corresponding to the zoom position of the projection optical system, but instead, focal lengths and angles of view may be used. .

  In general, information relating to the magnification of the projection optical system corresponding to the zoom position of the projection optical system may be used.

(5) In the above embodiment, the left end value and the right end value of the bar in the third setting area SF3 (FIG. 7) are respectively set according to the minimum value Rmin and the maximum value Rmax of the adjustment range of the aspect ratio. has been edited. However, instead of this, the value at the left end and the value at the right end of the bar are not changed, and the movable range of the slider in the third setting area SF3 according to the maximum value Rmax and the minimum value Rmin of the adjustment range. May be changed.

  In the above embodiment, the user is prohibited from inputting a value outside the adjustment range of the aspect ratio, but may be allowed instead. In this case, for example, the image forming area determination unit 438 determines the image forming area using a value within the adjustment range that is closest to the input value outside the adjustment range (that is, the maximum value Rmax or the minimum value Rmin). That's fine.

  In general, the image forming area may be determined using an adjustment value within the adjustment range determined using the projection angle information.

(6) In the above embodiment, the projector PJ includes the image processing unit 410 for executing the distortion correction process, and corresponds to the image processing apparatus and the projector according to the present invention. However, the image processing unit 410 may be provided in a personal computer different from the projector. In this case, the computer corresponds to the image processing apparatus according to the present invention.

(7) In the above embodiment, the projector includes a liquid crystal panel, but instead includes a micromirror light modulator such as DMD (Digital Micromirror Device) (trademark of TI). May be. Alternatively, the projector may include a high-intensity cathode ray tube, a plasma display panel, an electroluminescence display panel, a light emitting diode display panel, a field emission display panel, or the like. As described above, as the image forming unit, a non-self-luminous device or a self-luminous device can be used.

(8) In the above embodiment, a part of the configuration realized by hardware may be replaced with software, and conversely, a part of the configuration realized by software may be replaced with hardware. Also good.

It is explanatory drawing which shows the relationship between the projector PJ and the screen SC. It is explanatory drawing which shows the relationship between the coordinate (x, y) on a screen, and the coordinate (X, Y) on a liquid crystal panel. It is explanatory drawing which shows the example of the image which should be formed on a liquid crystal panel. It is explanatory drawing which shows the relationship between the actual zoom position of a projection optical system, and the rectangular image displayed on the screen SC. It is a block diagram which shows typically the structure of the projector PJ. It is a flowchart which shows the procedure of a distortion correction process. It is explanatory drawing which shows an example of the setting screen SS. It is explanatory drawing which shows image formation area WF1 determined by step S120. It is explanatory drawing which shows the actual projection state of the projection optical system 300 in step S130. It is a graph which shows the deviation rate of an aspect ratio. It is explanatory drawing which shows image formation area WF2 determined by step S160.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Illumination optical system 200 ... Liquid crystal panel 300 ... Projection optical system 400 ... Control circuit 410 ... Image processing part 420 ... Setting screen synthetic | combination part 430 ... Image formation area setting part 432 ... Projection angle parameter value acquisition part 434 ... Adjustment range determination part 436 ... Adjustment parameter value acquisition unit 438 ... Image formation region determination unit 440 ... Correction execution unit PJ ... Projector SC ... Screen SF1 ... First setting region SF2 ... Second setting region SF3 ... Third setting region SS ... Setting screen Vh, Vh1 ... Horizontal vanishing point Vm, Vm1, Vm2 ... Diagonal vanishing point Vv, Vv1 ... Vertical vanishing point WF, WF1, WF2 ... Image forming area WP, WP1 ... Reference area

Claims (14)

An image processing apparatus for a projector, comprising: an image forming unit that emits light representing an image; and a projection optical system that projects the light emitted from the image forming unit onto a projection surface and that can adjust a zoom position. There,
An image forming region setting unit for setting an image forming region in which a significant image is to be formed in the image forming unit;
A correction execution unit that corrects target image data representing a target image and generates corrected image data representing a corrected image to be formed in the image forming region;
With
The image forming area setting unit
An adjustment range determination unit that determines an adjustment range of an aspect ratio of an image displayed on the projection plane, using projection angle information relating to the projection angle of the projector given by a user;
An image forming area determining unit that determines the image forming area using the projection angle information and an adjustment value within the adjustment range;
An image processing apparatus comprising: The image processing apparatus according to claim 1,
The adjustment range determination unit further includes tele-end information relating to the magnification of the projection optical system when the zoom position of the projection optical system is at the tele end, and the zoom position of the projection optical system at the wide end. An image processing apparatus that determines the adjustment range using wide end information related to a magnification of the projection optical system. The image processing apparatus according to claim 1 or 2,
The projection angle information includes a first rotation angle of the projector about a first axis that is orthogonal to a normal line of the projection plane and parallel to a lateral side of an image to be projected on the projection plane. A second rotation angle of the projector about a second axis perpendicular to the normal of the projection plane and parallel to a vertical side of the image to be projected on the projection plane; An image processing apparatus that is information indicating a large rotation angle. The image processing apparatus according to claim 2,
The projection angle information is
First angle information indicating a first rotation angle of the projector about a first axis that is orthogonal to the normal line of the projection plane and parallel to a lateral side of an image to be projected on the projection plane When,
A second rotation angle of the projector about a second axis that is perpendicular to the normal of the projection plane and parallel to a vertical side of the image to be projected on the projection plane; Angle information,
Including
The adjustment range determination unit
A larger one of the first value obtained using the first angle information and the wide end information and the second value obtained using the second angle information and the tele end information. Set the value to the maximum value of the adjustment range,
The smaller of the third value obtained using the first angle information and the tele end information, and the fourth value obtained using the second angle information and the wide end information An image processing apparatus that sets a value to a minimum value of the adjustment range. The image processing apparatus according to claim 2,
The projection angle information includes a first rotation angle of the projector about a first axis that is orthogonal to a normal line of the projection plane and parallel to a lateral side of an image to be projected on the projection plane. Including information to indicate,
The adjustment range determination unit
Using the projection angle information and the wide end information, determine the maximum value of the adjustment range,
An image processing apparatus that determines a minimum value of the adjustment range using the projection angle information and the tele end information. The image processing apparatus according to claim 2,
The projection angle information includes a second rotation angle of the projector about a second axis that is orthogonal to a normal line of the projection plane and parallel to a vertical side of an image to be projected on the projection plane. Including information to indicate,
The adjustment range determination unit
Using the projection angle information and the tele end information, determine the maximum value of the adjustment range,
An image processing apparatus that determines a minimum value of the adjustment range using the projection angle information and the wide end information. An image processing apparatus according to any one of claims 2 to 6,
The image processing apparatus, wherein the adjustment range determination unit further determines the adjustment range using reference information regarding the magnification of the projection optical system corresponding to a reference zoom position of the projection optical system. The image processing apparatus according to claim 7,
The image processing apparatus, wherein the reference information is given by the user. The image processing apparatus according to any one of claims 1 to 6,
The image processing area determining unit further determines the image forming area using reference information regarding the magnification of the projection optical system corresponding to a reference zoom position of the projection optical system. An image processing apparatus according to any one of claims 1 to 9,
The image formation region determination unit preliminarily determines the image formation region without using the adjustment value, and changes the preliminary image formation region using the adjustment value to change the image formation region. An image processing apparatus to determine. A projector,
The image forming unit;
The projection optical system;
The image processing apparatus according to any one of claims 1 to 10,
A projector comprising: An image processing method for a projector, comprising: an image forming unit that emits light representing an image; and a projection optical system that projects the light emitted from the image forming unit onto a projection surface and that can adjust a zoom position. There,
(A) setting an image forming area in which a significant image is to be formed in the image forming unit;
(B) correcting the target image data representing the target image to generate corrected image data representing the corrected image to be formed in the image forming region;
With
The step (a)
(A1) determining an adjustment range of an aspect ratio of an image displayed on the projection plane using projection angle information about a projection angle of the projector given by a user;
(A2) determining the image forming area using the projection angle information and an adjustment value within the adjustment range;
An image processing method comprising: Image processing for a projector comprising: an image forming unit that emits light representing an image; and a projection optical system that projects the light emitted from the image forming unit onto a projection surface and that can adjust a zoom position. A computer program for executing the program,
An image forming region setting function for setting an image forming region in which a significant image is to be formed in the image forming unit;
A correction execution function for correcting the target image data representing the target image and generating corrected image data representing the corrected image to be formed in the image forming area;
To the computer,
The image forming area setting function is:
An adjustment range determination function for determining an adjustment range of an aspect ratio of an image displayed on the projection plane, using projection angle information about the projection angle of the projector given by a user;
An image forming area determining function for determining the image forming area using the projection angle information and an adjustment value within the adjustment range;
A computer program comprising:   A computer-readable recording medium on which the computer program according to claim 13 is recorded.

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