Image projector, image projection method, and computer- readable recording medium recording program to allow computer to execute the method

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to an image projection device, an image projection method and a recording medium, and more specifically, an image projection device, an image projection method and the image projection method for projecting an image formed on an image forming member onto a projection surface via an image projection unit. Concers a computer-readable recording medium that records a program that causes a computer to perform a method.

【0002】

[Conventional technology]

In recent years, in an image projection device such as a video projector, it has been an extremely important requirement to project an electronically formed digital image onto a projection surface such as a screen without distortion. Conventionally, it has been known that when the orthogonality between the optical axis of the projector and the screen plane which is the projection surface is broken, a change called tilt occurs in the shape of the projected image.

【0003】

For example, FIG. 12 is a diagram illustrating tilt correction by conventional signal processing. As shown in FIG. 12, the light emitted from the light source arranged at the projection center 80 is formed on an image-forming plate (image-creating surface) 82 such as a transmissive liquid crystal display (LCD). An image was formed on a projection surface 84 such as a screen through an optical system such as a lens (not shown), and the image on the image formation surface was projected onto the screen.

【0004】

Here, if the optical axis of the projector is not orthogonal to the screen plane which is the projection plane, even if a normal rectangular image 86 is formed on the image forming plate 82 as shown in FIG. 12, the projection plane 84 side The deformed tilt image 88 will be projected.

【0005】

Therefore, in the conventional correction technique for the tilted image 88, in order to make the projected image projected on the projection surface 84 have a normal rectangular shape, signal processing is performed according to the position of the screen with respect to the projector to create an image. By forming a deformed image 90 on the plate 82 and forming the deformed image 90 on the projection surface 84 via an optical system, a normal corrected image 92 having a rectangular shape can be projected. ..

【0006】

Further, in Japanese Patent Application Laid-Open No. 9-327981, a projected test pattern image is photographed by a camera from the viewpoint of an image observer, and the characteristics of tilting are calculated from the photographed image data to determine correction parameters.

【0007】

[Problems to be Solved by the Invention]

However, in such a conventional image projection device, in the case of FIG. 12, the screen arrangement changes according to the installation conditions, so that the correction setting must be changed every time the installation conditions are different. There was a problem.

【0008】

Further, in the case of JP-A-9-327981 described above, there is a problem that a camera for taking a test pattern image must be separately prepared when obtaining a correction parameter.

【0009】

Furthermore, it is also conceivable to apply the fluoroscopic transformation from a plane (ui, vi) to a plane (Ui, Vi) to the tilt correction by using the following equations (1) and (2).

[Number 1]

<img file="JP2001069433A_D0001.tif" />【0010】

The characteristics of this perspective transformation are uniquely determined by the eight parameters a0 to a7, as shown in Eqs. (1) and (2). Since the positions of points on the plane are represented by two numerical values in xy coordinates, if the positions of four points before and after conversion are specified, the corresponding perspective conversion parameters can be uniquely determined. Specifically, eight parameters from a0 to a7 are obtained by solving simultaneous equations.

【0011】

FIG. 13 is a diagram for explaining the perspective transformation in the image projection device, (a) is a diagram showing the image positions before and after the transformation formed on the image forming surface, and (b) is projected on the screen. It is a figure which shows the image position before conversion and after conversion.

【0012】

In FIG. 13 (b), a normal rectangular image 86 formed on the image plane of FIG. 13 (a) is displayed so that the tilt image 88 projected on the screen becomes a corrected image 92 having a normal rectangular shape. A deformed deformed image 90 is formed. In FIG. 13 (a), xi and yi are the coordinates of four points on the rectangular image 86 before deformation, and Xi and Yi are the coordinates of four points on the deformed image 90.

【0013】

This method has the advantage that it is easy for the user to understand because the points at the four corners of the screen are taken as the coordinate positions of the four points specified before the perspective conversion and the user can specify the positions of the four corners of the screen that he / she wants to display on the screen. There is.

【0014】

However, on the other hand, when specifying the coordinate positions of four points, for example, it is necessary to select one of the four points and move it up, down, left, and right, which causes a problem that it takes time to specify.

【0015】

Moreover, since the screen surface is usually plain, the vertices are arranged horizontally or vertically, as shown in the corrected image 92 shown in FIG. 13 (b), or the aspect ratio of the corrected image 92. There is a problem that it is difficult to visually and accurately recognize that the image is correct, and it is difficult to know whether or not the projected image is in the correct position.

【0016】

The present invention has been made to solve the above problems, and is an image projection device and an image projection method capable of easily correcting the deviation of a projected image generated according to the installation position of the image projection unit with respect to the projection surface. An object of the present invention is to provide a recording medium on which a program for realizing the image projection method is recorded.

【0017】

[Means for solving problems]

In order to solve the above problems, the image projection device according to the invention according to claim 1 has an image projection unit including an image forming member that forms an image, and the image formed on the image forming member is displayed as the image. In an image projection device that projects onto a projection surface via a projection unit, a parameter input means for inputting information corresponding to angles in at least two directions of the projection surface and an image forming member according to the input angle of the projection surface. It is characterized by comprising an image transforming means for deforming an image to be formed so that an appropriate image is projected on the projection surface.

【0018】

According to the first aspect of the present invention, it is possible to perform correction with only a small parameter input of angles in at least two directions of the projection surface, and an appropriate projected image can be easily obtained.

【0019】

Further, in the invention according to claim 1, the image projection apparatus according to the invention according to claim 2 includes a perspective conversion parameter calculation unit in which the image transformation means calculates a perspective conversion parameter based on input information. The feature is that the fluoroscopic conversion processing unit that performs the conversion processing of the input image data in order to deform the image formed on the image forming member by using the fluoroscopic conversion parameter calculated by the fluoroscopic conversion parameter calculation unit is provided. And.

【0020】

According to the second aspect of the present invention, the image transforming means includes a perspective conversion parameter calculation unit and a perspective conversion processing unit, and it is possible to perform correction with only a small number of parameter inputs, which is easily appropriate. A projected image can be obtained.

【0021】

Further, in the image projection apparatus according to the invention of claim 3, in the invention of claim 1 or 2, the image projection unit has a zoom mechanism, and the image projection unit has a zoom mechanism according to the zoom position of the image projection unit. It is further provided with a screen position calculation means for calculating the screen position of the image formed on the image forming member.

【0022】

According to the third aspect of the present invention, since the screen position of the image formed on the image forming member can be calculated according to the zoom position of the zoom mechanism of the image projection unit, it is combined with the angle of the input projection surface. Accurate tilt correction can be performed with only a small number of parameter inputs, and an appropriate projected image can be easily obtained.

【0023】

Further, in the image projection apparatus according to the invention according to claim 4, in the invention according to claim 2 or 3, the parameter input means further inputs information corresponding to the rotation angle of the image projected on the projection surface. It is possible, and the perspective conversion parameter calculation unit automatically calculates information corresponding to the position and size of the projected image based on the input angle of the projection surface and the rotation angle of the projected image, and performs perspective conversion. It is characterized by calculating parameters.

【0024】

According to the fourth aspect of the present invention, the position and size of the projected image can be calculated based on the angle of the input projection surface and the rotation angle of the projected image. Accurate tilt correction can be performed with only a small number of parameter inputs, and an appropriate projected image can be easily obtained.

【0025】

Further, in the image projection apparatus according to the invention of claim 5, in the invention of claim 2 or 3, the parameter input means further projects a rotation angle, a position and a size of an image projected on a projection surface. The information corresponding to can be input, and the perspective conversion parameter calculation unit calculates the perspective conversion parameter based on the input angle of the projection surface, the rotation angle of the projected image, and the position and size of the projected image. It is characterized by that.

【0026】

According to the invention of claim 5, only a small number of parameter inputs are required so that the perspective conversion parameters are calculated based on the input projection angle, the rotation angle of the projection image, and the position and size of the projection image. Accurate tilt correction can be performed with, and an appropriate projected image can be easily obtained.

【0027】

Further, the image projection method according to the invention according to claim 6 is an image projection method in which an image formed on an image forming member is projected onto a projection surface via an image projection unit, and is an angle of at least two directions of the projection surface. By the parameter input step of inputting the information corresponding to, the screen position acquisition step of acquiring the screen position of the image formed on the image forming member, the information input by the parameter input step, and the screen position acquisition step. A fluoroscopic conversion parameter calculation step of calculating a fluoroscopic conversion parameter based on the acquired screen position information, and a fluoroscopic conversion process of image data input using the fluoroscopic conversion parameter calculated by the fluoroscopic conversion parameter calculation step. It is characterized by including a conversion processing step.

【0028】

According to the invention of claim 6, it is possible to perform correction with only a small parameter input of angles in at least two directions of the projection surface, and an appropriate projected image can be easily obtained.

【0029】

Further, the storage medium according to the invention of claim 7 records a program for causing a computer to execute the method according to claim 6, so that the program can be machine-readable, whereby the operation of claim 6 can be performed. It can be realized by a computer.

【0030】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of a computer-readable recording medium on which an image projection apparatus according to the present invention, an image projection method, and a program for causing a computer to execute the method are recorded will be described in detail with reference to the accompanying drawings.

【0031】

Here, after explaining the principle of the image projection device of the present invention, each embodiment will be referred to. In this embodiment, a liquid crystal projector is used as the image projection device.

【0032】

As described above, in order to perform tilt correction using the conventional image projection device, it was necessary to specify eight parameters from a0 to a7, but in the image projection device of the present invention, the following ~ For some reason, you don't have to specify eight parameters.

【0033】

The image plane provided on the image projection unit of the projector is orthogonal to the optical axis. Fluoroscopic transformation, which used to require 8 degrees of freedom, is intended to support arbitrary transformation of the angle and position of the image plane, so the projected image by the projector with the image plane fixed inside The degree of freedom of deformation is less than that of any fluoroscopic transformation. Therefore, if you exclude translation, rotation, enlargement / reduction on the screen 36, you only need to specify the screen angle (2) with respect to the optical axis and the screen position (1) on the image plane. Is enough.

【0034】

FIG. 3 is a diagram showing the arrangement of the projector and the screen. The projection center 30 in which the light source of the projector is arranged, the optical axis 32 extending from the projection center 30, and the transmission fixedly arranged in the projector to form an arbitrary image. A screen 36 for projecting an image formed on an image forming surface 34 such as a type liquid crystal display element (LCD) and an image formed on the image forming surface 34 through an optical system such as a light source or a lens of a projector is shown. The coordinate positions of the four points at the four corners are indicated by (xi, yi), and the distance from the projection center 30 to the image plane 34 is d.

【0035】

The "screen position on the image plane" of the degree of freedom specified above is shown by the distance d from the projection center 30 to the image plane 34 in Fig. 3 and the screen position (xi, yi) on the image plane. Will be done. Since these are the characteristics of the projector itself regardless of the arrangement of the screen 36, they can be treated as known information by investigating in advance. In the case of a projector having a zoom lens, the projection angle changes depending on the zoom position, but this can also be dealt with by detecting the lens position by checking the value of the projection angle at each zoom position in advance.

【0036】

Since the projector is usually installed on an almost horizontal surface such as a desk, there is almost no need to rotate the image on the screen when performing tilt correction. Further, the rotation component of this image can be corrected without changing the installation position of the projection device by rotating the image projection unit itself of the projector around the optical axis 32.

【0037】

In order to minimize the decrease in resolution when the image is deformed, it is desirable to take the largest rectangular shape in the displayable area. Further, if the maximum rectangle is taken, the amount of parallel movement and the size are uniquely determined, so that the degree of freedom is eliminated.

【0038】

As described above, if at least two parameters related to the screen angle can be specified, a rectangular screen having a desired aspect ratio can be reproduced on the screen 36. The image projection apparatus of the present invention can further facilitate the user's operation by designating only the number of parameters required for that purpose and calculating the parameters required for the tilt correction from the designated parameters. It is possible.

【0039】

Regarding the type and number of parameters specified by the user, for example, in the present embodiment, the following variations are possible.

【0040】

Specify three angles. That is, the angle formed by the optical axis 32 and the screen 36 (two) and the angle of rotation on the screen 36 (one) are specified. Then, among the perspective conversion parameters, the elements related to the size and the position are automatically determined so that the size of the display screen is maximized.

【0041】

Specify two angles. That is, the rotation correction on the screen 36 is omitted by fixing it, and only the angle (two) formed by the optical axis 32 and the screen 36 is used.

【0042】

Specify the three angles and the position and size of the screen. That is, when one image is divided and projected using a plurality of projectors, it is not always desirable that the screen size is always maximized, and the screen is continuous with the screen projected by another projector. The position and size need to be adjusted.

【0043】

(Embodiment 1) FIG. 1 is a block diagram showing a configuration example of a projector 10 according to a first embodiment of the present invention, and FIG. 2 shows an example of an operation button of the parameter input unit 12 of FIG. It is a figure. In the first embodiment, two parameters corresponding to the screen angle as the angle of the projection surface are specified, and eight perspective conversion parameters are obtained from the two specified parameters.

【0044】

In FIG. 1, the projector 10 is composed of a parameter input unit 12, a perspective conversion parameter calculation unit 14, a perspective conversion processing unit 16, an image projection unit 18, a screen position calculation unit 20, and the like.

【0045】

As shown in FIG. 2, the parameter input unit 12 has four buttons A, B, C, and D arranged in a cross shape here. The two buttons A and C correspond to the angle parameter θ, and the two buttons E and D correspond to the angle parameter φ. Each time these buttons are pressed, the angle is determined by a predetermined step. Is increased or decreased, and the angle is sent to the fluoroscopic conversion parameter calculation unit 14. The user repeats the button operation until the image projected on the screen 36 has a desired shape.

【0046】

The perspective conversion parameter calculation unit 14 calculates the perspective conversion parameter from the screen angle input by the user and the calculated projection angle based on the calculation method described later.

【0047】

The perspective conversion processing unit 16 executes a conversion process on the input image data by using the calculated perspective conversion parameter, and sends the deformed image data to the image projection unit 18.

【0048】

The image projection unit 18 forms an image on the image-forming surface based on the deformed image data that has undergone perspective conversion processing, and optically projects it on the screen 36. Further, the screen position calculation unit 20 detects the position of the image projection unit 18 zoom lens, and outputs the screen position on the image forming surface at the lens position with reference to a preset record.

【0049】

Next, the operation will be described. FIG. 4 is a diagram showing the arrangement and angle between the image plane and the screen. The origin O is the projection center, and the image plane (P1) is orthogonal to the x-axis at the distance d from the origin O.

【0050】

If the foot of the perpendicular line from the origin O to the screen surface (P2) is P, the angle between the OP and the z-axis is φ, and the foot of the perpendicular line from P to the xy plane is P', then OP' Let θ be the angle formed by the x-axis. Here, the length of the OP is set to "1", but since the length of this OP affects only the size of the projected image, the fluoroscopic conversion parameter finally obtained will change no matter how many. Absent.

【0051】

The coordinate system (u, v) on the image plane P1 has the origin at the intersection with the x-axis, the u-axis parallel to the y-axis, and the v-axis parallel to the z-axis. In addition, the coordinate system (U, V) on the screen P2 has P as the origin, and the V axis is taken in the direction in which the v axis on the image plane P1 is projected.

【0052】

At this time, from the coordinates (U, V) on the screen P2 to the coordinates (u, v) on the image plane P1, the parameters a0 to a7 of the fluoroscopic transformation in the above equations (1) and (2) are the above parameters θ. , Φ, and d can be expressed by the following equations (3) to (10).

[Number 2]

<img file="JP2001069433A_D0002.tif" />【0053】

If the parameters of this inverse transformation, that is, the perspective transformation from the coordinate system (u, v) on the image plane P1 to the coordinate system (U, V) on the screen P2, are parameters b0 to b7, the following As shown in Eq. (11), it can be obtained from the inverse matrix of a 3 × 3 matrix whose elements are ai.

【0054】

[Number 3]

<img file="JP2001069433A_D0003.tif" />X-1 in Eq. (11) above represents the inverse matrix of the matrix X.

【0055】

Then, the vertex positions (ui, vi) of the screen area on the image plane P1 are converted by the coefficients of the above equations (1), (2) and (3) to (10), and the vertex positions (Ui, Vi) are obtained. ) Indicates the positions of the four corners of the full screen area on the screen.

【0056】

The largest rectangle (hereinafter referred to as the maximum inscribed rectangle) that has the same aspect ratio as the image to be projected inside the quadrangle whose vertices are the vertices (Ui, Vi) of these four points on the screen. If the apex position of is obtained and then inversely converted to obtain the corresponding position on the image plane, the perspective conversion parameter can be obtained using the same method as before. The procedure for finding the vertex position of the maximum inscribed rectangle will be described below.

【0057】

Since the vertices of the maximum inscribed rectangle are in contact with the sides of the quadrangle, search for the largest inscribed rectangle that has a vertex at one point on each side while shifting the position of the points on the sides little by little. Therefore, the maximum inscribed rectangle can be obtained.

【0058】

FIG. 5 is a diagram illustrating a maximum inscribed rectangle inscribed in an arbitrary quadrangle. Assuming that one point on the side of the quadrangle 40 shown in FIG. 5 is p, the maximum rectangle 42 having the point p as the apex and inscribed in the quadrangle 40 can be obtained as follows.

【0059】

That is, the position of the intersection px between the straight line passing through the point p and parallel to the x-axis and the side is obtained. The quadrangle deformed by the perspective transformation has a convex shape in the range of normal angles, and if the quadrangle has a convex shape, it always intersects one side. Similarly, the straight line passing through the point p and parallel to the y-axis, the straight line passing through the point p and parallel to the diagonal line of the desired screen, and the intersections py and pd of the respective sides are obtained.

【0060】

Then, the result obtained by dividing the distance from the point p to px, py, pd by the width, height, and diagonal length of the target screen is found to be the minimum. In the example shown in FIG. 5, py is the minimum, and a rectangle with p and py as vertices is obtained. This is the largest inscribed rectangle with a vertex at point p. Further, while moving the position of the point p at an appropriate interval, the rectangle is obtained in the same manner, and the rectangle having the maximum size among the plurality of rectangles is obtained as the final maximum inscribed rectangle.

【0061】

By converting the vertex position of the maximum inscribed rectangle on the screen obtained in this way using the conversion coefficients of Eqs. (3) to (10), the vertex position of the deformed image region on the image plane is obtained. be able to. If the vertex positions on the image plane corresponding to this maximum inscribed rectangle are obtained, the perspective conversion parameters for converting the vertex positions at the four corners of the original image are the same as before, using equations (1) and (2). It can be obtained by solving.

【0062】

If the actual screen angle matches the specified angle parameter (θ, φ), the screen corrected based on the resulting fluoroscopic conversion parameter will have (Ui, Vi) as the apex on the screen. It can be in the desired shape.

【0063】

As described above, according to the first embodiment, when obtaining the perspective conversion parameters necessary for performing the tilt correction, the user may input at least two screen angles and perform a predetermined arithmetic process. The tilt correction can be easily performed.

【0064】

(Embodiment 2) The feature of the present embodiment 2 is that the rotation of the image on the screen is also corrected. The components different from the first embodiment are the contents of the parameter input unit and the fluoroscopic conversion parameter calculation unit. Since the basic block diagram of the image projection device is the same as that of FIG. 1 of the first embodiment, it will be referred to.

【0065】

FIG. 6 is a diagram showing an example of an operation button of the parameter input unit of the second embodiment, and FIG. 7 is a diagram showing a maximum inscribed rectangle having a constant rotation angle according to the second embodiment. 8 (a) and 8 (b) are diagrams for explaining the procedure for obtaining the maximum inscribed rectangle having a constant rotation angle in FIG. 7.

【0066】

As shown in FIG. 6, the parameter input unit 12 of the second embodiment further increases or decreases the rotation angle ψ on the screen to the buttons A to D of the parameter input unit 12 shown in FIG. 2 of the first embodiment. Two buttons E and F to indicate are added.

【0067】

Further, the fluoroscopic conversion parameter calculation unit 14 of the second embodiment is different from the first embodiment in that it performs a calculation operation for obtaining the maximum inscribed rectangle having a certain rotation angle instructed by the user.

【0068】

Next, the operation will be described. First, as shown in FIG. 8 (a), the four vertices indicating the projected image area 50a before rotation are rotated by an angle -ψ from the projection center 54 using the buttons E and F of the parameter input unit 12. Find the projected image area 50b.

【0069】

Then, the maximum inscribed rectangle 52a shown in FIG. 8B is obtained for the four vertices of the projected image region 50b according to the same procedure as in the first embodiment. Then, the four vertex positions of the maximum inscribed rectangle 52a obtained by this are rotated again by the angle ψ as shown in FIG. 8 (b) by using the buttons E and F of the parameter input unit 12 again.

【0070】

The maximum inscribed rectangle 52b thus obtained is the apex of the maximum inscribed rectangle 52 tilted by the desired angle ψ shown in FIG. 7. In the subsequent procedure, the perspective conversion parameter is obtained in the same manner as in the first embodiment.

【0071】

As described above, according to the second embodiment, when obtaining the perspective transformation parameters required for the tilt correction, the user inputs at least two screen angles and the rotation angle of the image on the screen. Therefore, it is possible to correct the rotation of the image on the clean screen by performing a predetermined arithmetic process.

【0072】

(Embodiment 3) The feature of the present embodiment 3 is to correct the position and size of the image on the screen. The components different from the first embodiment are the contents of the parameter input unit and the fluoroscopic conversion parameter calculation unit. Note that FIG. 1 will also be referred to for the block diagram of the third embodiment.

【0073】

FIG. 9 is a diagram showing an example of an operation button of the parameter input unit of the third embodiment. As shown in FIG. 9, the parameter input unit 12 of the third embodiment has buttons A to F of the parameter input unit 12 shown in FIG. 6 of the second embodiment, and the position parameters SX and SY of the display area. And 6 buttons G, H, I, J, K, L are added to indicate the increase / decrease of the magnification parameter m.

【0074】

Further, the fluoroscopic conversion parameter calculation unit 14 of the third embodiment is the same as that described in the second embodiment, and is the maximum inscribed rectangle according to the instruction parameters θ, φ, and ψ for the current screen angle. Is what you want.

【0075】

Next, the operation will be described. First, the inscribed rectangle is enlarged or reduced m times around its center of gravity according to the magnification parameter m. Then, the image is moved according to the position parameters SX and SY that indicate the vertex positions of the enlarged or reduced inscribed rectangle.

【0076】

Further, the perspective conversion parameter is obtained by using this image position as the four corner positions of the projected image area instead of the vertex positions of the maximum inscribed rectangle in the first embodiment.

【0077】

As described above, according to the third embodiment, when obtaining the perspective conversion parameters required for the tilt correction, the user has at least two screen angles, an image rotation angle on the screen, and a screen. By inputting the position and size of the image in the above and performing a predetermined arithmetic process, it is possible to correct the position and size of the image on the screen.

【0078】

(Embodiment 4) The feature of the present embodiment 4 is to realize the same operation as that of the first embodiment as software on a general computer system connected to an image projection device (projector).

【0079】

FIG. 10 is a block diagram showing a schematic configuration of a computer system 60 to which the image projection device 68 according to the fourth embodiment is connected, and FIG. 11 is a flowchart illustrating the operation of the fourth embodiment.

【0080】

The computer system 60 shown in FIG. 10 is composed of a CPU 62, a memory 64, a disk device 66, an image projection device 68, a display 70, a printer 72, a communication device 74, a floppy disk device 76, and the like. Connected via 78 .

【0081】

The CPU 62 controls the entire computer system 60, and by executing the software according to the fourth embodiment, the same operation as that of the first embodiment can be realized.

【0082】

The memory 64 stores various programs and parameters, software related to the fourth embodiment, and the CPU 62 corrects the projected image of the image projection device 68 based on these software. Further, the disk device 66 is a hard disk (HD) or the like capable of storing or reading a basic program, a large amount of data, or the like.

【0083】

The image projection device 68 is a projector that projects an input image here, and is connected to a computer system 60 and has an image projection unit that does not have a zoom mechanism, or an image projection unit that has a zoom mechanism. Any configuration that can output the detected zoom position can be used.

【0084】

The display 70 is a monitor for the user to grasp the operating status of the computer system 60 and check various input data, error messages, etc., and is composed of a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display Element), and the like. Therefore, the projected image of the image projection device 68 or the like may be monitored on the screen. Further, the printer 72 prints out the image information and the like displayed on the display 70 on paper.

【0085】

The communication device 74 can be connected to a network such as a LAN or a public telephone network to exchange data, and the software settings for controlling the image projection device 68 from a remote location can be changed via this. , Can be rewritten. Further, the floppy disk device 76 exchanges data via a floppy disk (hereinafter referred to as FD) 76a.

【0086】

Next, the operation will be described. In step S1 of FIG. 11, the screen angle parameter is input. That is, for example, by displaying images of buttons as shown in FIG. 2 on the screen of the display 70 and instructing them by clicking the mouse, it is possible to have the same effect as pressing the buttons in the first embodiment. it can. Further, each button may be assigned to each key on the keyboard for instruction, or the parameter may be instructed to be increased or decreased by the amount of dragging the mouse.

【0087】

Then, in step S2, the screen position on the image plane is acquired. Here, for example, when using an image projection device 68 without a zoom mechanism, the screen position on the image plane is constant, so the position information investigated in advance should be stored in the program and used. To.

【0088】

Further, unlike the above, when the image projection device 68 having a zoom mechanism and a means capable of detecting and outputting the zoom position is used, the CPU 62 reads the output zoom position via the interface and the output zoom position is read. It is possible to use the screen position information according to the position.

【0089】

Then, in step S3, the perspective conversion parameter is calculated. Here, the perspective conversion parameter is calculated from the input screen angle parameter and the screen position on the image plane by the calculation method described in the first embodiment.

【0090】

Then, in step S4, image data is input. Here, the image data recorded on the computer system 60 or the image data generated by another program is input.

【0091】

Then, in step S5, the perspective conversion process is performed. Here, using the calculated perspective conversion parameters, the perspective conversion process is executed by the calculation method described in the first embodiment, and the deformed image data is output to the image projection device 68 via the interface. To.

【0092】

Then, the process returns to steps S4 and S5 and the image data input process and the perspective conversion process are repeated until the end is instructed by the user or the input image data is completed.

【0093】

As described above, according to the fourth embodiment, the same operation as that of the first embodiment can be realized as software on a general computer system connected to an image projection device (projector).

【0094】

The image projection method described in the fourth embodiment is realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. This program is executed by being recorded on a computer-readable recording medium such as HD (hard disk), FD (floppy disk), CD-ROM, MO, or DVD, and read from the recording medium by the computer. Further, this program may be a transmission medium that can be distributed via a network such as the Internet.

【0095】

[Effect of the invention]

As described above, according to the invention of claim 1, it is possible to perform correction with only a small parameter input of at least two angles of the projection surface, and it is possible to easily obtain an appropriate projection image. This has the effect of obtaining an image projection device capable of

【0096】

According to the invention of claim 2, the image transforming means includes a perspective conversion parameter calculation unit and a perspective conversion processing unit, and it is possible to perform correction with only a small number of parameter inputs, and it is possible to easily perform appropriate projection. It has the effect of obtaining an image projection device capable of acquiring an image.

【0097】

According to the third aspect of the present invention, since the screen position of the image formed on the image forming member can be calculated according to the zoom position of the zoom mechanism of the image projection unit, it is less than the angle of the input projection surface. Accurate tilt correction can be performed only by inputting parameters, which has the effect of obtaining an image projection device capable of easily acquiring an appropriate projected image.

【0098】

According to the invention of claim 4, since the position and size of the projected image can be calculated based on the angle of the input projection surface and the rotation angle of the projected image, the position and size of the projected image can be calculated together with the angle of the input projection surface. Accurate tilt correction can be performed with only a small number of parameter inputs, and there is an effect that an image projection device capable of easily acquiring an appropriate projected image can be obtained.

【0099】

According to the invention of claim 5, only a small number of parameter inputs are required so that the perspective conversion parameter is calculated based on the input angle of the projection surface, the rotation angle of the projected image, and the position and size of the projected image. It is possible to perform accurate tilt correction, and it is possible to obtain an image projection device capable of easily acquiring an appropriate projection image.

【0100】

According to the invention of claim 6, it is possible to perform correction with only a small parameter input of angles in at least two directions of the projection surface, whereby an appropriate projected image can be easily obtained. It has the effect of obtaining an image projection method.

【0101】

According to the invention of claim 7, by recording a program that causes a computer to execute the method of claim 6, the program becomes machine readable, whereby the operation of claim 6 is performed by a computer. It has the effect of obtaining a recording medium that can be realized.

[Simple explanation of drawings]

[Figure 1]

It is a block diagram which shows one structural example of the image projection apparatus which concerns on Embodiment 1 of this invention.

[Figure 2]

It is a figure which shows an example of the operation button of the parameter input part of the image projection apparatus which concerns on Embodiment 1. FIG.

[Fig. 3]

It is a figure explaining the arrangement of the projection center, the image formation surface, and the screen in the image projection part of the image projection apparatus which concerns on this invention.

[Fig. 4]

It is a figure explaining the positional relationship between the projection center, the image formation surface, and the screen in the image projection part of the image projection apparatus which concerns on Embodiment 1. FIG.

[Fig. 5]

It is a figure explaining the maximum inscribed rectangle of the projection image of the image projection apparatus which concerns on Embodiment 1.

[Fig. 6]

It is a figure which shows an example of the operation button of the parameter input part of the image projection apparatus which concerns on Embodiment 2.

[Fig. 7]

It is a figure explaining the maximum inscribed rectangle of the projection image of the image projection apparatus which concerns on Embodiment 2.

[Fig. 8]

It is a figure explaining the procedure of calculating the maximum inscribed rectangle of the projected image of the image projection apparatus which concerns on Embodiment 2.

[Fig. 9]

It is a figure which shows an example of the operation button of the parameter input part of the image projection apparatus which concerns on Embodiment 3. FIG.

[Fig. 10]

It is a block diagram which shows the schematic structure of the computer system to which the image projection apparatus which concerns on this Embodiment 4 is connected.

[Fig. 11]

It is a flowchart explaining the operation of the image projection apparatus which concerns on Embodiment 4.

[Fig. 12]

It is explanatory drawing in the case of performing the tilt correction by signal processing using the conventional image projection apparatus.

[Fig. 13]

It is an explanatory view in the case where the tilt correction is performed by designating the four point positions of the four corners of the projected image, (a) is a view on the image plane, and (b) is a view on the screen.

[Explanation of symbols]

10 image projection device, 12 Parameter input section, 14 Perspective conversion parameter calculation unit, 16 Perspective conversion processing unit, 18 Image projection section, 20 Screen position calculation unit, 30 projection center, 32 optical axis, 34 Image plane, 36 screen surface, P1 image plane, P2 screen surface, 40 projected image, 42 Maximum inscribed rectangle, 50, 50a, 50b projection image, 52, 52a, 52b Maximum inscribed rectangle, 54 projection center, 60 computer system, 62 CPU, 64 memory, 66 disk unit, 68 Image Projector, 70 display, 72 printer, 74 Communication equipment, 76 Floppy disk device.