JP2005092575A - Method for correcting three-dimensional image data, video controller, and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for correcting three-dimensional image data capable of obtaining high-quality images through effective use of three-dimensional image data; a video controller having this correction process function built in; and a projector having the built-in video controller. <P>SOLUTION: The video controller includes a three-dimensional engine 43 for projecting three-dimensional image data onto a two-dimensional plane; and a correction circuit 44 which, based on correction parameters including a parameter for specifying the relative position between the light bulb of a projector and a projection screen, sets both a virtual light bulb corresponding to the light bulb of the projector and a virtual projection screen opposite to the projection screen and which then specifies an image area for keystone corrections in the virtual light bulb and projects the three-dimensional image data in the position of the virtual projection screen related to the position of a predetermined pixel in the image area to sample the result as the image data of the predetermined pixel in the image area. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for correcting three-dimensional image data when an image is displayed using a projector, and a video controller and a projector with a built-in correction processing function.

When the image is displayed by the projector, various corrections are required for the image data. For example, when the keystone correction is applied to the three-dimensional image data, the three-dimensional image data is developed into a two-dimensional image and a light valve is developed. The keystone correction is performed by the same method as in the case of the two-dimensional image data after being transmitted to the side. Further, the correction is hardly performed in the video controller, and is performed in an external circuit on the light valve side (for example, Patent Document 1).
Japanese Patent Laid-Open No. 2002-51279

  When the image is displayed by the projector, various corrections as described above are necessary. For example, when performing the keystone correction, the three-dimensional image data is developed into a two-dimensional image and then the keystone correction is performed. However, the two-dimensional image is composed of data with grid restrictions, and the three-dimensional image data is not effectively used, and the image quality is limited. In addition, correction when displaying an image by a projector is performed not by the video controller but by an external circuit on the light valve side (Patent Document 1). Therefore, every time the video display mode (resolution) is changed. It was necessary to adjust the parameters.

  The present invention has been made to solve such problems, and a method for correcting three-dimensional image data in which high-quality images can be obtained by effectively using three-dimensional image data, and the correction thereof. It is an object of the present invention to provide a video controller incorporating a processing function and a projector incorporating the video controller.

  The three-dimensional image data correction method according to the present invention generates image data by projecting three-dimensional image data to a position corresponding to a pixel on the two-dimensional plane when the three-dimensional image data is developed on a two-dimensional plane. To do. When expanding three-dimensional image data onto a two-dimensional plane, the three-dimensional image data is projected to a position corresponding to a pixel on the two-dimensional plane, instead of unconditionally expanding the three-dimensional image data onto the two-dimensional plane. Therefore, for example, it is not necessary to perform an interpolation process or the like as in the prior art, and the three-dimensional image data can be used effectively. For this reason, when the image data processed in this way is projected, a high-quality image is obtained.

  According to the three-dimensional image data correction method of the present invention, image data is captured by projecting the three-dimensional image data to a position corresponding to a pixel on a two-dimensional plane based on a correction parameter set or captured in advance. When the three-dimensional image data is developed on the two-dimensional plane, the image data is generated according to the correction parameter, so that it is possible to generate image data corresponding to various forms.

  The three-dimensional image data correction method according to the present invention specifies an image area for performing keystone correction based on the correction parameter, and projects the three-dimensional image data at a position corresponding to a pixel of the image area. To generate image data. When performing the keystone correction, the 3D image data is generated by projecting the 3D image data to the position corresponding to the pixel in the image area, so that the 3D image data can be used effectively (interpolation). Therefore, when image data processed in this way is projected, a high-quality image can be obtained.

 A three-dimensional image data correction method according to the present invention includes a virtual light valve corresponding to a projector light valve based on a correction parameter including a parameter for specifying a relative position between the projector light valve and the projection screen. , Setting a virtual projection screen corresponding to the projection screen, specifying an image area for keystone correction in the virtual light valve, and positioning the three-dimensional image at the position of the virtual projection screen corresponding to the pixel of the image area Image data is projected and captured as image data of a pixel at a predetermined position in the image area.

  The video controller according to the present invention includes a three-dimensional engine that projects three-dimensional image data onto a two-dimensional plane, and a pixel on the two-dimensional plane when the three-dimensional engine develops the three-dimensional image data onto the two-dimensional plane. A first correction circuit that projects the three-dimensional image data at a corresponding position and captures the image data, and outputs the image data in the form of a digital signal. Since the three-dimensional engine projects the three-dimensional image data onto the position corresponding to the pixel on the two-dimensional plane, the three-dimensional image data can be used effectively. Therefore, the corrected image data Projecting a high-quality image. Further, since the correction process is performed in the video controller, it is not necessary to adjust the parameters each time, for example, even when the video display mode (resolution) is changed.

  In the video controller according to the present invention, the first correction circuit converts the three-dimensional image data into a pixel on a two-dimensional plane based on a first correction parameter set or captured in advance for the three-dimensional engine. Project to the corresponding position. The three-dimensional image data can be effectively used. For this reason, when this corrected image data is projected, a high-quality image can be obtained.

  In the video controller according to the present invention, the first correction circuit specifies an image area for performing keystone correction based on the correction parameter, and the three-dimensional image data is located at a position corresponding to a pixel of the image area. To generate image data.

  In the video controller according to the present invention, the first correction circuit includes a virtual parameter corresponding to the projector light valve based on a correction parameter including a parameter for specifying a relative position between the projector light valve and the projection screen. A light valve (correction screen) and a virtual projection screen (programmed screen) corresponding to the projection screen are set, an image area for keystone correction in the virtual light valve is specified, and the image area The three-dimensional image data is projected to the position of the virtual projection screen corresponding to the pixel position, and is taken in as image data of the pixel in the image area.

  The video controller according to the present invention is based on a two-dimensional engine that projects two-dimensional image data onto a two-dimensional plane, and a second correction parameter that is preset or captured in the image data projected onto the two-dimensional plane. And a second correction circuit for performing keystone correction. Since the correction processing is performed on the video controller side, it is not necessary to adjust the parameters each time, for example, even when the video display mode (resolution) is changed.

  A video controller according to the present invention includes a switching circuit that switches between an output of the first correction circuit and an output of the second correction circuit, and expands image data from the switching circuit to a frame memory to generate a frame And a VRAM control circuit for generating an image and outputting the frame image. Since the frame image is generated by appropriately switching the output of the first correction circuit and the output of the second correction circuit by the switching circuit, it corresponds to both the two-dimensional image data and the three-dimensional image data. It has become a thing.

  A projector according to the present invention is equipped with the above-described video controller, and a high-quality image can be obtained.

Embodiment 1. FIG.
FIG. 1 is a block diagram showing a configuration of a projector according to Embodiment 1 of the present invention. The projector 10 includes a CPU 12, a ROM 14, a RAM (main memory) 16, an input device 18, a storage device (storage device) 20, a video controller 22, and a VRAM (frame memory) 24. The projector 10 includes a light valve controller 26, a light source 28, a light valve 30, and a projection lens 32 as devices on the output side of the video controller 22, and an image from the projection lens 32 is projected onto the projection screen 34.

  The CPU 12 controls the entire projector 10, and the ROM 14 stores the program and the like. The RAM 16 functions as a main memory. The input device 18 inputs signals from switches and other devices (for example, other CPUs), and the CPU 12 performs various arithmetic processes based on input signals from the input device 18. The storage device 20 stores various image data. In this example, it is assumed that two-dimensional image data and three-dimensional image data (including model data, texture data, action data, for example) are stored. When the CPU 12 reads out and inputs the two-dimensional image data or the three-dimensional image data stored in the storage device 20, the video controller 22 performs a predetermined process to develop the VRAM 24, and the decompressed image data is displayed. Output to the light valve controller 26. Here, if the light valve 30 is SVGA, the number of pixels in one frame is 800 * 600. If the number of colors is 24-bit full color, 3 bytes of information are required for each color per dot. Here, 800 * 600 is used, but XGA (1024 * 768) or the like may of course be used. However, this value is uniquely determined by the resolution of the light valve 30 to be mounted.

  When the light valve controller 26 captures the image data developed in the VRAM 24, the light valve controller 26 converts the image data into an analog signal, and outputs it to the light valve 30 together with a timing signal. When the light valve 30 receives the image data together with the timing signal, the light valve 30 controls the light from the light source 28 to generate an image. Examples of the light valve (display device) 30 include those using an LCD (Liquid crystal display) and DMD (Digital Micro Mirror Device, a registered trademark of Texas Instruments) which is a light modulation element. An example using an LCD will be described. Note that projectors using an LCD include a single-plate type (one using one liquid crystal panel) and a three-plate type (using three liquid crystal panels corresponding to R, G, and B). A plate type (30R, 30G, 30B) is used. As the light source 28 of the projector 10, an ultrahigh pressure mercury lamp, a halogen lamp, an LED, or the like is used. In the present embodiment, for example, a halogen lamp is used. Regarding the configuration of the optical system of the projector 10, means for condensing and uniforming the light from the light source 28, means for separating the light from the light source 28 into R, G and B by a dichroic mirror, etc., and a light valve 30 are provided. Generally, there is a prism to be combined after passing through, and a projection lens group for actually projecting after that, but in this embodiment, those configurations are omitted because they are not directly related to the present invention. Only the projection lens 32 is shown.

  In this embodiment, when the light valve 30 (30R, 30G, 30B) receives image data together with a timing signal, the light valve 30 (30R, 30G, 30B) generates an image by controlling the transmittance of each liquid crystal panel 30R, 30G, 30B, and projects the image. Although enlarged by the lens 32 and displayed on the projection screen 34, the optical axis of the light valve 30 (30R, 30G, 30B) (or the optical axis of the projection lens 32) and the surface of the projection screen 34 are not orthogonal but oblique. Therefore, the video controller 22 performs keystone correction and the like.

  FIG. 2 is a block diagram showing details of the video controller 22. The video controller 22 includes a 2D (two-dimensional) engine 41, a correction circuit 42, a 3D (three-dimensional) engine 42, a correction circuit 44, a register 45, a switching circuit 46, and a VRAM control circuit 47. When the 2D image data of the storage device 20 is read and input by the CPU 12, the 2D engine 41 expands the 2D image data to generate a 2D image, and the correction circuit 42 describes the 2D image, which will be described later. Various correction processes are performed. In addition, when the 3D image data of the storage device 20 is read and input by the CPU 12, the 3D engine 43 performs a process of projecting the 3D image data onto a screen (2D plane) on the program (that is, a 2D image). Drawing process). At this time, the correction circuit 44 supplies a point for projecting the three-dimensional image data to the 3D engine. In the register 45, parameters when the correction circuits 42 and 44 perform the correction calculation are written by the processing of the CPU 12, and are used when the correction circuits 42 and 44 perform the correction calculation. The switching circuit 46 outputs the image data corrected by the correction circuit 42 or 44 based on the control command of the CPU 12 to the VARAM control circuit 47. The VARAM control circuit 47 draws a frame image on the VRAM 24 based on the output of the correction circuit 42 or 44 and outputs the frame image to the light valve controller 26 in the form of a digital signal.

  In the present embodiment, the correction circuit 42 and the correction circuit 44 perform various correction processes necessary for display by the projector at the stage of the video controller 22, for example, keystone correction (trapezoid correction), resizing (RESIZE), Corrections such as gamma (γ) correction and color unevenness correction are performed. The outline of these corrections will be described as follows.

  Keystone correction (keystone correction) is to correct keystone distortion caused by oblique projection on the screen surface. This correction depends on the installation form, but is inevitably determined once the installation form is determined. Thus, by storing the parameters for keystone correction in the register 45, correction according to the installation form is performed. This process will be described in detail. Resizing means converting the screen resolution, and the image data is converted in accordance with the resolution of the light valve 30 of the projector 10. For example, if the resolution of the original image data is 640 * 480 and the resolution of the light valve 30 is 800 * 600, 640 * 480 is enlarged to 800 * 600 and displayed. Since the resolution conversion itself is a well-known technique, its details are omitted, but normally, the resolution corresponding to the resolution of the light valve 30 is stored in the register 45, and the correction circuits 42 and 44 read it. The resolution of the light valve 30 is grasped.

  Gamma (γ) correction is performed to correct the nonlinear input / output characteristics (gamma characteristics) of the light valve (liquid crystal panel), and each color of red (R), green (G), and blue (B). The input / output characteristics are corrected by, for example, a look-up table (LUT) in which the correspondence between the linear gradation value of the signal and the non-linear gradation value for correcting the gamma characteristic is shown. Color unevenness correction is for correcting color unevenness in image data. Color unevenness correction data for correcting image data is obtained as follows. By projecting and displaying a uniform halftone image, typically a gray uniform image, and shooting the displayed projection image with a video camera, or measuring the brightness of the projected image with a luminance meter The distribution of color unevenness in the projected image is measured. Next, appropriate color unevenness correction data is obtained by repeatedly adjusting the image data of the pixel in which color unevenness occurs and measuring the color unevenness occurring in the projected image of the adjusted image data. In other words, the correction data has different values for each projector, and this depends on the characteristics of the individual device. Therefore, in this embodiment, color unevenness correction data is stored in the register 45.

Next, processing when performing keystone correction (keystone correction) in the video controller 22 of FIG. 2 will be described.
When the CPU 12 reads the two-dimensional image data stored in the storage device 20 and outputs it to the video controller 22, the 2D engine 41 expands the two-dimensional image data into a two-dimensional image, and the correction circuit 42 displays the image data (grid). Is corrected based on the correction parameter stored in the register 45 and sent to the switching circuit 46. The calculation process of the correction circuit 42 is the same as the conventional algorithm.

  When the CPU 12 reads out the three-dimensional image data stored in the storage device 20 and outputs it to the video controller 22, the correction circuit 44 designates the projection point based on the correction parameter stored in the register 45. The 3D engine projects 3D image data onto the projection point. The correction circuit 44 takes in the image data projected on the projection point and sends it out to the switching circuit 46.

  3 to 5 are explanatory diagrams of operations of the 3D engine 43 and the correction circuit 44. FIG. 3 is a diagram showing a geometric relationship when the 3D engine 43 projects the 3D image data onto the screen S on the program and the correction by the correction circuit 44, and FIG. 4 is a perspective view thereof. FIG. FIG. 5 is an explanatory diagram for drawing an image on the correction screen. The program screen S corresponds to the projection screen 34 in FIG. 1, the correction screen S ′ corresponds to the light valve 30 in FIG. 1, and FIGS. 3 and 4 illustrate the light valve. 30 corresponds to a state in which the angle 30 is inclined with respect to the projection screen 34 by an angle β. In FIGS. 3 and 4, for the sake of simplicity, it is assumed that the program screen S and the correction screen S ′ coincide with each other at the lower end. Further, the screens of FIGS. 3 to 5 are for convenience to make the calculation processing easy to understand, and do not necessarily mean that an image is actually drawn on the screen S or the correction screen S ′ in the program. Absent.

  3 and 4, the program screen S has a shape specified by points Q0, Q1, Q2, and Q3, and the correction screen S ′ is inclined with respect to the screen S by an angle β. It is assumed that the points P0 ′, P1 ′, P2, and P3 are specified. When the virtual light source viewpoint V ′ and the points Q0, Q1, Q2, and Q3 of the screen S are connected by lines, the points where the lines intersect the correction screen S ′ are P0 and P1, respectively. Keystone correction is performed by capturing and developing the image data of the screen S on the program in an area surrounded by P1, P2, and P3. Here, Qm and Pm are the midpoints of the line segments P0 and P1, and the line segments Q0 and Q1, respectively, the length of the line segments P0 and P1 is W (800 for AVGA resolution), and the length of the line segments Pm and P1. Is W1, the dimension a for specifying the trapezoid of FIG. 5 is represented by a = W / 2−W1. Since ΔV′P1Pm and ΔV′Q1Qm are similar, the distance from V ′ to Pm and Qm is calculated, the distance of the line segment V′Pm is m, and the distance of the line segment V′Qm is m ′. Then, W1 = (W / 2) * (m / m ′) and a = (W / 2) * (1−m / m ′). Further, the dimension b for specifying the trapezoid in FIG. 5 is obtained in the same manner as described above. In this way, the points P0 and P1 are specified by specifying the dimensions a and b. However, the boundary lines of the points P0 and P1 and the trapezoids P0, P1, P2, and P3 are not always present on the integer grid (position corresponding to the pixel) of the correction screen S ′. Are rounded to integer values outside the trapezoids P0, P1, P2, and P3.

  By the way, the relationship between the virtual light source viewpoint V ′ and the screen S on the program is the same ratio (similar shape) as the relationship between the projection lens 32 and the projection screen 34 of the actual projector 10. As shown in FIG. 6, the light emitted from the light source 28 passes through the light valve 30, is enlarged by the projection lens 32 at the diffusion angle α, and is projected onto the projection screen 34. In this case, the elevation angle of projection is β. When modeling is performed, it takes time for calculations such as refraction calculation of the projection lens 32, so the calculation is performed by virtualizing as shown in FIG. In FIG. 7, the projection lens 32 is removed and a place where the light diffused by the projection lens 32 converges is defined as a virtual light source viewpoint (V ′). The light valve 30 is closer to the light source than the projection lens 32, but is moved closer to the projection screen 34 to be a virtual light valve (corresponding to the correction screen S '). If each parameter in the case of modeling as shown in FIG. 7 is determined, V ′ and S at the time of correction are uniquely determined. Since α is uniquely determined by the lens to be used, parameters for adjustment are the distance d between the light source 28 and the projection screen 34 and the elevation angle β of projection.

  The position of the virtual light valve (S ′) can be arranged at any location in the direction of the virtual projection screen (S) from the virtual light source viewpoint V ′, but the virtual projection screen (S) is defined as an integer grid of 800 * 600. In order to obtain the same 800 * 600 light valve, it is arranged at a position as shown in FIG. Of course, if placed closer to the virtual light source (e.g., distance d / 2), the light valve has an integer grid of 400 * 300, so to obtain a resolution of 800 * 600, scan with a resolution of 0.5 units. There is a need.

  In the above description, correction in the vertical direction is described as an example, but correction in the horizontal direction is also performed in the same manner. It is also possible to arrange the virtual light valve on the right side of the virtual screen. If it is arranged as shown in FIG. 8, all the vertical resolutions of the light valve 30 can be used (of course, a similar shape between the projection screen and the virtual light source). The same result can be obtained by using the virtual light bulb. However, in this case, due to the aspect ratio, the image in the horizontal direction appears outside the screen (the horizontal resolution at the top of the trapezoid coincides).

FIG. 9 is a flowchart showing a process performed by the correction circuit 44.
(S1) The correction circuit 44 specifies an area for projecting image data on the correction screen (virtual light valve) S ′. That is, the trapezoids P0, P1, P2, and P3 are specified. This specifying method is as described above.
(S2) The correction circuit 44 sets the count n = 1 as the initial value in order to specify the rows (positions in the vertical direction) of the trapezoids P0, P1, P2, and P3. As a result, the rows of the line segments P0 and P1 are specified.
(S3) The correction circuit 44 captures the image data of the point P on the screen (virtual projection screen) S on the program corresponding to the point P ′ while changing the point P ′ along the line segments P0 and P1. An intersection point P between the line-of-sight vector V′P ′ and the screen S is obtained. The 3D engine 43 projects 3D image data onto the intersection P. The correction circuit 44 takes in the three-dimensional image data projected on the intersection P as the data of the point P ′. In this way, since the 3D image data is captured as it is as the data of the point P ′, it is possible to effectively utilize the 3D image data and no interpolation processing is required. High image data can be obtained. In this regard, in the case of two-dimensional image data, interpolation processing is necessary because of grid limitations.
(S4) When the correction circuit 44 takes in one line of image data, the correction circuit 44 sets the count n = n + 1 in order to move to the next line (vertical position). As a result, the next row of the line segments P0 and P1 is specified.
(S5) The correction circuit 44 determines whether or not the count n exceeds the row N corresponding to the row of the line segment P3P2, and if it is not the final row N, the process proceeds to the above processing (S3). Then, when the same processing is repeated and the processing is completed up to the line corresponding to the line P3P2, the correction calculation for one screen is completed. Then, the above processes (S2) to (S5) are repeated for the next screen.

  The image data fetched by the correction circuit 44 is sent to the VRAM control circuit 47 via the switching circuit 46, and the VRAM control circuit 47 writes the image data into the VRAM 24 to develop a frame image. This frame image is developed in an area corresponding to the trapezoids P0, P1, P2, and P3 in FIG. Note that, for the areas outside the trapezoids P0, P1, P2, and P3 in FIG. 5, the calculation of the intersection with the object is not necessary, so that the reduction in the calculation speed can be minimized.

  The VRAM control circuit 47 writes the image data into the VRAM 24 and develops it, reads the developed image data and outputs it to the light valve controller 26, and the light valve controller 26 converts the image data into an analog signal and converts it to the light valve. 30 is driven to generate an image on the light valve 30, and the image is enlarged by the projection lens 32 and projected onto the projection screen 34. The image projected on the projection screen 34 has been subjected to keystone correction and has been subjected to correction processing as described above, so that the image has a high quality.

  In the above description, an example of keystone correction has been described. However, the same processing is performed for corrections such as resizing (RESIZE), gamma (γ) correction, and color unevenness correction. In the above description, for the sake of simplicity, the example in which the lower end of the program screen S and the correction screen S ′ match is described. However, the lower ends of the two match. Also, the inclination between the program screen S and the correction screen S ′ is the same when the inclination is not only about the X axis in FIG. 4 but also about the Y axis and / or the Z axis. Thus, areas corresponding to the trapezoids P0, P1, P2, and P3 in FIG. 5 are obtained and processed in the same manner.

  Note that the projector of this embodiment is particularly useful for both rear and front projection televisions (correction parameters only need to be set once), but also for projectors that do not have a projection screen attached to the housing. The same applies.

  As described above, in the present embodiment, the three-dimensional image data, which is the original data, is not directly calculated after the three-dimensional image data is expanded into the two-dimensional image data. In this case, the correction calculation is performed by taking in the image data, so that the deterioration of display quality can be minimized. This correction processing is performed at the digital signal stage. Once an optimal correction parameter is set, it is not necessary to reset the correction parameter even if the video mode changes. In addition, since the correction circuit is provided in the video controller to perform various corrections, it is not necessary to provide a correction circuit outside, and the number of parts is reduced.

1 is a block diagram illustrating a configuration of a projector according to a first embodiment of the invention. The block diagram which showed the detail of the video controller of FIG. Explanatory drawing when performing keystone correction. FIG. 4 is a perspective view of FIG. 3. Explanatory drawing at the time of drawing an image on the correction screen. The figure which showed the relationship between a light valve and a screen. The figure which showed the relationship between a virtual light source viewpoint, a virtual light valve, and a virtual projection screen. The figure which showed the other relationship of a virtual light source viewpoint, a virtual light valve, and a virtual projection screen. The flowchart which showed the process in the correction circuit.

Explanation of symbols

10 projector, 12 CPU, 14 ROM, 16 RAM, 18 input device, 20 storage device, 22 video controller, 24 VRAM, 26 light valve controller, 28 light source, 30 light valve, 32 projection lens, 34 projection screen, 41 2D engine , 42 correction circuit, 43 3D engine, 44 correction circuit, 45 register, 46 switching circuit, 47 VRAM control circuit.

Claims (11)

  A method for correcting three-dimensional image data, wherein when three-dimensional image data is developed on a two-dimensional plane, the image data is generated by projecting the three-dimensional image data to a position corresponding to a pixel on the two-dimensional plane. .   2. The three-dimensional image data correction according to claim 1, wherein the three-dimensional image data is captured by projecting the three-dimensional image data to a position corresponding to a pixel on a two-dimensional plane based on a correction parameter set or captured in advance. Method.   An image area for performing keystone correction is specified based on the correction parameter, and image data is generated by projecting three-dimensional image data to a position corresponding to a pixel in the image area. 3. A method for correcting three-dimensional image data according to 1 or 2.   Based on a correction parameter including a parameter for specifying a relative position between the projector light valve and the projection screen, a virtual light valve corresponding to the projector light valve and a virtual projection screen corresponding to the projection screen are set. Then, an image area for performing keystone correction in the virtual light valve is specified, and the three-dimensional image data is projected onto the position of the virtual projection screen corresponding to the position of the pixel in the image area. 4. The method for correcting three-dimensional image data according to claim 3, wherein the image data is captured as pixel image data. A 3D engine that projects 3D image data onto a 2D plane;
A first correction circuit for projecting the three-dimensional image data to a position corresponding to a pixel on the two-dimensional plane and capturing the image data when the three-dimensional engine develops the three-dimensional image data on a two-dimensional plane; And a video controller for outputting the image data in the form of a digital signal.   The first correction circuit causes the three-dimensional engine to project three-dimensional image data on a position corresponding to a pixel on a two-dimensional plane based on a first correction parameter that is set or captured in advance. 6. A video controller as claimed in claim 5, characterized in that:   The first correction circuit specifies an image area for performing keystone correction based on the correction parameter, and generates three-dimensional image data at a position corresponding to a pixel of the image area to generate image data. The video controller according to claim 5 or 6, characterized in that:   The first correction circuit includes a virtual light valve corresponding to the projector light valve and a projection screen based on a correction parameter including a parameter for specifying a relative position between the projector light valve and the projection screen. A corresponding virtual projection screen is set, an image area for keystone correction is specified in the virtual light valve, and the three-dimensional image data is placed at the position of the virtual projection screen corresponding to the pixel position of the image area. 8. The video controller according to claim 7, wherein the video controller is projected and captured as image data of pixels in the image area. A 2D engine that projects 2D image data onto a 2D plane;
9. The apparatus according to claim 5, further comprising: a second correction circuit that performs keystone correction on the image data projected on the two-dimensional plane based on a second correction parameter set in advance. A video controller according to any one of the above. A switching circuit for switching and outputting the output of the first correction circuit and the output of the second correction circuit;
10. The video controller according to claim 9, further comprising a VRAM control circuit that expands image data from the switching circuit into a frame memory to generate a frame image and outputs the frame image. A projector equipped with the video controller according to claim 6.

Images