WO2006008791A1

WO2006008791A1 - Image projecting method, projector and computer program

Info

Publication number: WO2006008791A1
Application number: PCT/JP2004/010141
Authority: WO
Inventors: Kazuya Arakawa
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2004-07-15
Filing date: 2004-07-15
Publication date: 2006-01-26
Also published as: TWI244860B; TW200603617A

Abstract

A method for projecting an image automatically to the center of an object to which the image is to be projected (screen) when a projecting image is smaller than the dimensions of the object to which the image is to be projected. When it is decided that the size of a projecting image PJ not subjected to correction of trapezoidal distortion is smaller than the dimensions of the screen S, based on an image (3I) picked up at a camera section, a virtual contraction screen Vs having an aspect ratio identical to that of the projecting image is set in the center of the screen S and then adjustment of size and correction of trapezoidal distortion are carried out such that the projecting image coincides with the virtual contraction screen Vs.

Description

Specification

Image projection method, projector, and computer program

Technical field

[0001] The present invention automatically adjusts the size of a projected image at the stage of projection preparation.

, An image projection method capable of correcting trapezoidal distortion, and a projector that projects an image by such an image projection method, and for controlling a projector with a general-purpose computer for a control circuit of such a projector Concerning computer programs.

Background art

[0002] In a projector that projects an image onto an object to be projected such as a screen, white wall, and whiteboard, first, a plurality of settings related to projection are prepared as projection preparation so that appropriate projection can be performed from the installation location of the projector. Items need to be adjusted.

[0003] The setting items described above include focus adjustment, color correction, image size adjustment (zoom adjustment), and keystone distortion correction (keystone correction). In setting such items, test pattern images corresponding to the items are sequentially projected from the projector, and the state of the test pattern image projected on the projection object is fed back by imaging with an imaging device. Conventionally, it is generally configured to make adjustments and corrections. For example, in zoom adjustment, the zoom of the projection lens can be adjusted based on the user's instruction or the projector's automatic judgment so that the test pattern image for dimension adjustment projected on the projection object fits on the projection object. Adjust the function to enlarge or reduce the projected image. Note that projectors generally have an optical axis that passes through the lens center of the projection lens that is offset from the center of the projected image. The optical axis passing through the center) is usually used as a reference for adjustment. The projection preparation of such a projector is disclosed in Patent Document 1 below.

Patent Document 1: Japanese Unexamined Patent Publication No. 2000-241874

Disclosure of the invention

Problems to be solved by the invention [0004] By the way, the preparation for projection of the conventional projector as described above is generally based on the positions of the four corners of the projection target (for example, the screen) and the four corners of the projected image (projected image). The size of the projected image and the trapezoidal distortion are adjusted so that the four corners of the projected image coincide with the positions of the four corners of the projection object. However, in situations where there is not enough distance between the projector and the projection object, it may not be possible to project an image larger than the projection object even if the image is projected at the maximum size. It becomes impossible to match the four corners of the projected image with the positions of the four corners of the projection object.

[0005] In the above case, it is desirable to adjust so that an image is projected onto the central portion of the projection target. However, conventionally, projectors that automatically perform such adjustment are known. Being les, na les. Therefore, in such a case, there is a problem that it is necessary to manually perform the setting of the projection position of the image, the keystone distortion correction (keystone correction), and the like.

[0006] The present invention has been made in view of the above problems, and since a sufficient distance cannot be taken between the projection target and the projector, the projected image is In the case of projection that can only be projected with a size that is smaller than the size, a virtual projection frame is automatically set at the center of the projection object, and an image is projected onto this virtual projection frame. The main purpose is to provide an image projection method and a projector that projects an image by such an image projection method.

[0007] Further, in addition to the above-mentioned object, the present invention corrects trapezoidal distortion of a projected image and projects an image onto a virtual projection frame, and projects an image using such an image projection method. The purpose is to provide a projector.

Furthermore, in addition to the above-described object, the present invention has an object to provide an image projection method in which a virtual projection frame is set with the maximum size and a projector that projects an image by such an image projection method. To do. At this time, another object is to make it possible to easily set a virtual projection frame by using a known two-dimensional projective transformation.

Another object of the present invention is to provide a computer program for the projector control circuit as described above or for controlling the projector with a general-purpose computer. Means for solving the problem

[0010] In order to solve the above problems, an image projection method according to the present invention is directed to a rectangular projection object. When the modulated light generated by the spatial light modulator is generated in accordance with the information representing the projected rectangular projection image, and the modulated light generated by the spatial light modulator is projected onto the projection lens on the rectangular projection object. In the image projecting method, the spatial light modulation means generates modulated light according to information representing an image obtained by deforming the rectangular projection image, and projects the rectangular image on the projection object. When projected onto the rectangular projection object having the same aspect ratio as the shape projection image, the center of the rectangular projection object is smaller than the size of the rectangular projection object. A virtual projection frame having a rectangular shape with the centers being matched is set on the spatial light modulation means.

In order to solve the above problems, a projector according to the present invention includes a spatial light modulation unit that generates modulated light according to information representing a rectangular projection image projected onto a rectangular projection object, and the spatial A projection lens that projects the modulated light generated by the light modulation unit onto the rectangular projection target, and generates the modulated light in the spatial light modulation unit according to information representing an image obtained by deforming the rectangular projection image. In the projector that projects so as to form a rectangular image on the rectangular projection object, the projector has the same aspect ratio as the rectangular projection image and is projected onto the rectangular projection object. In this case, a virtual projection frame having a rectangular shape is set on the spatial light modulation unit in a state in which the center coincides with the center of the rectangular projection object smaller than the size of the rectangular projection object. Provide virtual projection frame setting means The features.

[0012] In such an image projection method and projector of the present invention, the center of the projection object has the same aspect ratio as the projection image when projected onto the projection object and is smaller than the dimension of the projection object. A rectangular virtual projection frame whose center is coincided with is set on the spatial light modulation means.

[0013] Further, the image projection method according to the present invention causes the spatial light modulation means to generate modulated light according to information representing a rectangular projection image projected onto the rectangular projection object, and the spatial light modulation means. When projecting the modulated light generated by the projection lens onto the rectangular projection object, the spatial light modulation means generates modulated light according to information representing an image obtained by deforming the rectangular projection image. In the image projection method for projecting to form a rectangular image on the projection target, the projection has the same external ratio as the rectangular projection image and is projected onto the rectangular projection target. The rectangle smaller than the size of the rectangular projection object A virtual projection frame having a rectangular shape with the center aligned with the center of the object to be projected is set on the spatial light modulation unit, and the four corners of the virtual projection frame set on the spatial light modulation unit are set. The deformation amount of the rectangular projection image on the spatial light modulation means is calculated so that the four corners of the rectangular projection image coincide with each other.

[0014] In addition, the projector according to the present invention includes a spatial light modulation unit that generates modulated light according to information representing a rectangular projection image projected onto a rectangular projection object, and a modulation generated by the spatial light modulation unit. A projection lens that projects light onto the rectangular projection object, and the spatial light modulation means generates modulated light according to information representing an image obtained by deforming the rectangular projection image, thereby generating the rectangular projection object. In a projector that projects a rectangular image on the body, the projected image has the same external ratio as the rectangular projected image and is projected onto the rectangular projection object when the rectangular image is projected. Virtual projection frame setting means for setting, on the spatial light modulation means, a virtual projection frame that is rectangular in a state in which the center coincides with the center of the rectangular projection object that is smaller than the shape of the projection object having the shape And the virtual projection frame setting means Calculation means for calculating the deformation amount of the rectangular projection image on the spatial light modulation means so that the four corners of the rectangular projection image coincide with the four corners of the virtual projection frame set on the interspace light modulation means It is characterized by providing.

[0015] In such an image projection method and projector of the present invention, the center of the projection object having the same aspect ratio as the projection image and smaller than the dimension of the projection object when projected onto the projection object. A rectangular virtual projection frame whose center is coincided with is set on the spatial light modulation means. Then, the deformation amount of the projection image is calculated so that the projection image is projected with the four corners of the virtual projection frame set on the spatial light modulation means being aligned, and the projection image is converted according to the calculation result. It is transformed and projected onto the projection target.

[0016] The image projection method according to the present invention is the image projection method invention described above, wherein the spatial light modulation means generates modulated light according to information representing the projection image that is not deformed, and the spatial light modulation is performed. An image pickup unit that captures images including the four corner positions of the projection image and the four corner positions of the projection object when the modulated light generated by the means is projected to the projection object with the maximum size through the projection lens. From the image captured by the imaging means, the positions of the four corners of the projection object and the positions of the four corners of the projection image are captured. The position of the four corners of the projection image specified on the coordinate system is specified, and at least one of the four corner positions of the projection target specified on the coordinate system is specified on the coordinate system. The virtual projection frame is set on the spatial light modulation means when it exists outside the window.

[0017] The projector according to the present invention is the projector according to the invention described above, wherein the modulated light generated by the spatial light modulation unit according to the information representing the projected image is not deformed and is maximized through the projection lens. From the image picked up by the image pickup means for picking up an image including the positions of the four corners of the projection image and the four corner positions of the target to be projected, and the image picked up by the image pickup means, Specifying means for specifying the positions of the four corners of the body and the positions of the four corners of the projection image on the coordinate system set in the imaging means, and the virtual projection frame setting means is configured so that the specifying means is on the coordinate system. When at least one of the specified four corner positions of the projection object is outside the four corner positions of the projection image specified on the coordinate system by the specifying means, A virtual projection frame is set.

[0018] In such an image projection method and projector according to the present invention, the projection lens according to the above-described image projection method and projector invention is further modified according to information representing a projected image having a rectangular shape. The image including the four corner positions of the projected image and the four corner positions of the projection object is projected by the imaging means when projected onto the projection object with the maximum size through the projection unit. Then, from the image captured by the imaging means, the positions of the four corners of the projection object and the positions of the four corners of the projection image are specified on the coordinate system set in the imaging means, and the object specified on the coordinate system is specified. A virtual projection frame is set when at least one of the four corner positions of the projecting body is located outside the four corner positions of the projected image.

[0019] Further, the image projection method according to the present invention is the image projection method according to the invention described above, based on the four corner positions of the projection target and the four corner positions of the projection image specified on the coordinate system. It is characterized in that a virtual projection frame of the size is set on the spatial light modulation means.

[0020] Furthermore, in the projector according to the present invention as set forth in the invention described above, the virtual projection frame setting means includes the positions of the four corners of the projection object and the front positions specified by the specifying means on the coordinate system. A virtual projection frame having the maximum size is set on the spatial light modulation means based on the positions of the four corners of the projected image.

In such an image projection method and projector according to the present invention, in the image projection method and projector invention described above, the positions of the four corners of the projection target and the four corner positions of the projection image specified on the coordinate system are set. Based on this, a virtual projection frame having the maximum dimension is set.

Furthermore, the image projection method according to the present invention is the virtual projection obtained by converting the aspect ratio of the projection target specified on the coordinate system into the aspect ratio of the projection image in the invention of the image projection method described above. By reducing the frame step by step, the reduction ratio at the time when all four corners of the virtual projection frame to be reduced step by step are positioned within the range of the projection image specified on the coordinate system. Based on this, a virtual projection frame having the maximum dimension is set on the spatial light modulation means.

[0023] Still further, in the projector according to the invention described above, the virtual projection frame setting means may use the aspect ratio of the projection object specified by the specifying means on the coordinate system as the aspect ratio of the projection image. By reducing the converted virtual projection frame stepwise, all four corners of the virtual projection frame reduced stepwise are positioned within the range of the projection image specified by the specifying unit on the coordinate system. A virtual projection frame having a maximum size is set on the spatial light modulation means based on the reduction ratio at the time point.

[0024] In such an image projection method and projector according to the present invention, in the above-described image projection method and projector invention, the aspect ratio of the projection object is determined by the aspect ratio of the projection target specified on the coordinate system. The virtual projection frame converted into the ratio is reduced stepwise. The maximum size of the virtual projection frame, which is reduced in stages, is maximized based on the reduction ratio when all the four corners of the virtual projection frame are located within the range of the projection image specified on the coordinate system. A virtual projection frame is set.

Furthermore, the image projection method according to the present invention is the image projection method invention described above, wherein the positional relationship of the four corners of the projection object is centered on the center of the projection object and the same aspect as the projection image. A virtual projection frame is set on the spatial light modulation means by converting the positional relationship of the four corners of the rectangle having a ratio using a two-dimensional projective transformation. [0026] Furthermore, in the projector according to the present invention as set forth in the invention described above, the virtual projection frame setting means is configured such that the positional relationship of the four corners of the projection object is centered on the center of the projection object, and A virtual projection frame is set on the spatial light modulation unit by converting the positional relationship of the four corners of the rectangle having an aspect ratio using a two-dimensional projective transformation.

[0027] In such an image projection method and projector according to the present invention, in the image projection method and projector invention described above, the positional relationship of the four corners of the projection object is centered on the center of the projection object and is the same as the projection image. The virtual projection frame is set by converting the positional relationship between the four corners of the rectangle having the aspect ratio using the two-dimensional projective transformation.

[0028] Further, the projector according to the present invention includes a spatial light modulation unit that generates modulated light according to information representing a rectangular projection image projected onto a rectangular projection object, and the spatial light modulation unit A projection lens for projecting the modulated light onto the rectangular projection object; and an imaging device, wherein the spatial light modulation means generates modulated light according to information representing an image obtained by deforming the rectangular projection image, and The projection target having the same outer ratio as the rectangular projection image for projecting to form a rectangular image on the projection target, and smaller than the dimension of the projection target In the projector that sets a rectangular virtual projection frame whose center coincides with the center of the image based on an image captured by the imaging device, modulated light representing test patterns indicating four corners of the rectangular projection image is transmitted as the spatial light. Let the modulation means generate Means for projecting from the projection lens toward the rectangular projection object, means for causing the imaging device to image the state in which the test pattern is projected toward the rectangular projection object, and Means for detecting the positions of the four corners of the rectangular projection object on the image captured by the imaging device; and means for detecting the positions of the four corners of the projected test pattern on the image captured by the imaging device. A means for examining the relative positional relationship between the four corners of the rectangular projection object and the four corners of the test pattern on the image picked up by the image pickup device, and the image picked up by the image pickup device; Means for determining the four corners of the virtual projection frame when at least one of the four corners of the rectangular projection object is not located within a range surrounded by the four corners of the projected test pattern. It is characterized by that.

[0029] In such a projector according to the present invention, test patterns indicating the four corners of the projected image are provided. The image is projected toward the projection object, and this state is imaged by the imaging device. On this image, the positions of the four corners of the projection object are detected, and the positions of the four corners of the projected test pattern are detected. Then, the relative positional relationship between the four corners of the projection object and the four corners of the test pattern on the image captured by the imaging device is examined, and from this result, at least one of the four corners of the projection object is projected. The four corners of the virtual projection frame are determined when they are not within the range surrounded by the four corners of the test pattern.

[0030] Further, the computer program according to the present invention includes a spatial light modulation unit that generates modulated light in accordance with information representing a rectangular projection image projected onto a rectangular projection body, and the spatial light modulation unit generates the spatial light. A projection lens for projecting the modulated light onto the rectangular projection object, and an imaging device, and causing the spatial light modulation means to generate modulated light according to information representing an image obtained by deforming the rectangular projection image. The computer that projects the image to form a rectangular image on the projection object has the same aspect ratio as the rectangular projection image and is smaller than the size of the rectangular projection object. A computer program for setting a rectangular virtual projection frame centered on the center of a shaped projection object based on an image captured by the imaging device, and showing four corners of the rectangular projection image test A procedure for causing the spatial light modulation means to generate modulated light representing a pattern and projecting the modulated light from the projection lens toward the rectangular projection object, and for directing the test pattern toward the rectangular projection object. A procedure for causing the imaging device to capture the projected state, a procedure for detecting the positions of the four corners of the rectangular projection object on the image captured by the imaging device, and an image captured by the imaging device The procedure for detecting the positions of the four corners of the projected test pattern in step (b) and the relative positional relationship between the four corners of the rectangular projection object and the four corners of the test pattern on the image captured by the imaging device are examined. When at least one of the four corners of the rectangular projection object is not located within the range surrounded by the four corners of the projected test pattern on the procedure and the image captured by the imaging device, Virtual projection frame Characterized in that to execute a procedure for determining four corners to the computer.

In such control of the computer program according to the present invention, test patterns indicating the four corners of the projected image are projected toward the projection target, and this state is captured by the imaging device, and the projection is performed on the image. Test patterns projected as the four corners of the body are detected The positions of the four corners are detected. Then, the relative positional relationship between the four corners of the projection object and the four corners of the test pattern on the image captured by the imaging device is examined, and from this result, at least one of the four corners of the projection object is projected. The computer controls so that the four corners of the virtual projection frame are determined in the case where the four corners of the virtual projection frame are located within the range surrounded by the four corners of the pattern.

The invention's effect

[0032] According to the image projection method and the projector according to the present invention as described above, when projected onto the projection object, the projection has the same aspect ratio as the projection image and is smaller than the dimension of the projection object. Since the rectangular virtual projection frame whose center coincides with the center of the body is set on the spatial light modulation means, it becomes easy to project the projection image smaller than the projection target.

[0033] Further, according to the image projection method and the projector according to the present invention, the center of the projection object having the same aspect ratio as the projection image when projected onto the projection object and smaller than the dimension of the projection object. Since a rectangular virtual projection frame whose center is coincided with the center is set on the spatial light modulation means and the projected image is projected on the virtual projection frame, the projection image is projected between the projection object and the projector. When the distance is not sufficient, adjustments that were previously done manually are automatically performed.

[0034] Further, according to the image projecting method and the projector according to the present invention, in the above-described invention, further, the image is projected to the projection object at the maximum size through the projection lens in accordance with the information representing the unmodified rectangular projection image. Since the necessity for the adjustment as described above is automatically determined from the image captured by the imaging device including the four corner positions and the four corner positions of the projection object, it requires manual labor. Without adjustment, the adjustment is automatically performed when the distance between the projection object and the projector is not sufficient.

[0035] Further, according to the image projection method and the projector according to the present invention, in the above invention, the virtual projection frame that has the maximum size when projected onto the projection object is automatically obtained without requiring a manpower. Is set.

Further, according to the image projection method and the projector according to the present invention, in the above invention, all of the four corners of the virtual projection frame reduced in stages are within the range of the projection image specified on the coordinate system. Based on the reduction ratio at the time of positioning, the virtual of the maximum dimension The projection frame is automatically set on the spatial light modulation means without requiring manual work.

[0037] Further, according to the image projection method and projector according to the present invention, in the above invention, the positional relationship of the four corners of the projection object is converted by using a two-dimensional projective transformation which is a well-known calculation method. The projection frame is easily set.

[0038] Further, according to the projector of the present invention, by examining the relative positional relationship between the four corners of the projection target and the four corners of the test pattern on the image captured by the imaging device, at least the four corners of the projection target are detected. The projector automatically performs the process of determining the four corners of the virtual projection frame when one is located within the range surrounded by the four corners of the projected test pattern. Even when there is not enough space between them, adjustments that were previously done manually are performed automatically.

[0039] Further, according to the computer program of the present invention, it is possible to realize the above-described image projection method by controlling the projector as described above or by controlling the projector with a general-purpose computer from the outside. Become.

Brief Description of Drawings

FIG. 1 is a block diagram showing an example of the internal configuration of an embodiment of a projector according to the present invention.

FIG. 2 is a schematic diagram showing a pixel configuration of a spatial light modulation device (panel) made of a liquid crystal panel included in a projection device section of a projector according to the present invention.

FIG. 3 is a schematic diagram of a test pattern image used for both zoom adjustment and trapezoidal distortion correction (keystone correction) in the projector according to the present invention.

FIG. 4 is a schematic diagram showing the appearance of a remote control device for a projector according to the present invention.

FIG. 5 is a flowchart showing a processing procedure performed by the projector according to the present invention during normal auto adjustment.

FIG. 6 is a schematic diagram when the frontal force of the screen is viewed when the thick frame portion of the test pattern image is projected onto the screen.

FIG. 7 is a schematic diagram showing the state shown in FIG. 6 as viewed on the camera coordinate system.

[Fig.8] A known two-dimensional projection change for the coordinate values of the four corners of the screen on the panel coordinate system It is a schematic diagram which shows the state which applied the conversion and set the coordinate value of the virtual reduction screen.

FIG. 9 is a schematic diagram showing a state in which two-dimensional projective transformation is performed so that the four corners of the projected image match the coordinate values of the four corners of the virtual reduced screen in the camera coordinate system.

FIG. 10 is a flowchart showing a processing procedure in which the system control unit executes the computer program according to the present invention during auto adjustment by the projector according to the present invention. Explanation of symbols

[0041] 1 Projector

2 Projection lens

3 Camera

8 Projection device section

8a Spatial light modulation device (panel)

10 System control section

10p program

11 Detector

12 Operation unit

25 Test pattern image

25b Thick frame (in test pattern image)

S screen

Vs virtual reduced screen

PJ projection image

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described with reference to the drawings showing the best mode for carrying out the invention. FIG. 1 is a block diagram showing an internal configuration example of an embodiment of a projector according to the present invention. The following explanation is an example when the image projection method according to the present invention is implemented by the projector according to the present invention. The image projection method according to the present invention functions not only as a device configured as a projector but also as a projector. For example, the present invention can also be applied to a case where a personal computer is connected to and controlled by a device having both of the above and a projector having only a function of projecting an image. [0043] The projector 1 according to the present embodiment has an auto adjustment function capable of automatically performing projection preparation. Specifically, the auto adjustment function projects a test pattern image from the projection lens 2 onto the projection target screen S during projection preparation, and the camera unit 3 captures the state of the test pattern image projected onto the screen S. Based on the four corner positions of the resulting screen S and the four corner positions of the test pattern image, projection preparation such as the size and position of the projected image (projected image) and keystone distortion (keystone) correction is automatically performed. This function is performed automatically. The auto adjustment function includes color correction, focus adjustment, and the like. However, since there is no direct relationship with the present invention, description thereof will be omitted.

The projector 1 includes an external connection unit 4 and an image conversion unit 5 as units that mainly perform processing on an image for projection input from the outside. In addition, the projector 1 includes a color control unit 6, a test pattern image switching unit 7, a projection device unit 8, a projection lens driving unit 9, and a projection lens 2 as parts that mainly perform processes related to projection. . Further, the projector 1 includes a camera unit 3 and a detection unit 11 as a part for performing processing mainly related to the auto adjustment function. Furthermore, the projector 1 includes an operation unit 12 and a remote control light receiving unit 13 of a remote controller (hereinafter referred to as a remote controller) 20 as means for receiving an operation by a user. The overall control of the projector 1 is performed by the system control unit 10.

The external connection unit 4 is connected to an external device that outputs an image for projection. The external connection unit 4 inputs a rectangular image output from the external device and transmits it to the image conversion unit 5. The image conversion unit 5 performs necessary conversion processing such as A / D conversion based on the control of the system control unit 10, and transmits the converted image to the projection device unit 8.

The color control unit 6 performs a process for adjusting the color of the projected image. Specifically, the color control unit 6 adjusts the balance of each color of R (red), G (green), and B (blue) based on the control of the system control unit 10 to thereby adjust the color of the projected image. Make corrections. The test pattern image switching unit 7 generates various test patterns necessary for the auto adjustment function based on the control of the system control unit 10 and transmits the test patterns to the projection device unit 8 as test pattern images.

[0047] The projection device unit 8 optically modulates information on the image to be projected (digital image data). Built-in spatial light modulation device 8a. The projection device unit 8 generates modulated light obtained by optically modulating the digital image data of various images transmitted from the image conversion unit 5, the test pattern image switching unit 7, and the system control unit 10 described later by the spatial light modulation device 8a. To do. The modulated light generated by the spatial light modulation device 8a of the projection device unit 8 in this way is projected onto the external screen S through the projection lens 2. As a result, an image to be projected is displayed on the screen S.

[0048] As the spatial light modulation device 8a, either a liquid crystal panel or a DMD (Digital Micromirrow Device) is generally used. When a liquid crystal panel is used as the spatial light modulation device 8a, each pixel associated with the dot unit of the digital data of the image to be projected transmits the light from the light source while displaying each dot of the image. As a result, modulated light for displaying an image as a whole is projected, and finally an image is displayed on the screen S. When DMD is used as the spatial light modulation device 8a, the light from the light source is reflected while switching the reflection angle of the micromirror (Micromirrow) associated with the dot unit of the digital data of the image to be projected. As a result, the image to be projected is projected in a state represented by the entire reflected light (modulated light), and finally the image is displayed on the screen S.

In the present embodiment, a configuration using a liquid crystal panel as the spatial light modulation device 8a is adopted. In the following description, an image to be projected is a liquid crystal panel as the spatial light modulation device 8a. The image is projected on the screen S by transmitting the light from the light source to the displayed image and projecting it from the projection lens 2. However, as described above, even when DMD is used, an image is displayed as reflected light (modulated light) as a whole by switching the reflection angle of a micro mirror corresponding to a pixel of digital image data. Therefore, in the same way that individual pixels can be specified in correspondence with the dots of digital image data on the liquid crystal panel, individual micromirrors are specified in correspondence with the dots of digital image data in DMD. It is possible.

FIG. 2 is a schematic diagram showing a pixel configuration of a liquid crystal panel spatial light modulation device (hereinafter simply referred to as a panel) 8 a included in the projection device unit 8 described above. As an example in this embodiment, panel 8a has 1024 pixels in the horizontal direction and 768 pixels in the vertical direction, that is, the XGA standard. A panel coordinate system is set with the pixel at the coordinate value (0, 0) in the upper left corner as the origin and the horizontal direction as the X axis and the vertical direction as the y axis. Yes. Therefore, when the coordinate values of the panel coordinate system corresponding to each pixel in the horizontal direction and the vertical direction are sent from the system control unit 10 to the projection device unit 8, the projection device unit 8 is based on the coordinate values of the panel coordinate system. Specifies the position and dimensions of the image to be displayed in the display range of panel 8a on the panel coordinate system. For example, if “127” is specified as the horizontal coordinate value and “127” is specified as the vertical coordinate value from the system control unit 10, the projection device unit 8 uses the pixel in the upper left corner of the panel 8a as the origin to A dot is displayed at the position of the 128th pixel in each direction and vertical direction.

[0051] Note that, when a DMD is used as the spatial light modulation device 8a, it is possible to set the same panel coordinate system as when the above-described liquid crystal panel is used. However, as described above, in the present embodiment, since the configuration using the liquid crystal panel is employed as the spatial light modulation device 8a, the configuration in which the liquid crystal panel is used as the spatial light modulation device 8a is also described in the following description. However, the concept regarding the panel coordinate system is basically the same when the liquid crystal panel is used as the spatial light modulation device 8a and when the DMD is used.

[0052] Although not shown, the projection lens 2 is zoomed (image size) in addition to the original lens necessary for enlarging the light beam (modulated light) transmitted through the panel 8a and projecting it on the screen S as an image. It is composed of a plurality of lenses such as an adjustment lens and a focus adjustment lens. The projection lens drive unit 9 has an actuator for changing the positions of the zoom adjustment lens and the focus adjustment lens of the projection lens 2. Then, the projection lens drive unit 9 performs zoom adjustment and focus adjustment by driving the actuator according to the control from the system control unit 10.

In addition, the camera unit 3 shown in FIG. 1 captures various test pattern images projected onto the screen S during automatic adjustment for projection preparation, and transmits the captured images to the detection unit 11. Note that the test pattern image projected from the projector 1 includes zoom adjustment and trapezoidal distortion correction as shown in the schematic diagram of FIG. 3, in addition to the color correction test pattern image and the focus adjustment test pattern (not shown). Test pad used for (keystone correction) Turn image 25 is provided. The test pattern image 25 has a thick frame test pattern (hereinafter referred to as a thick frame portion 25b) provided in the periphery corresponding to the outline of the projected image.

[0054] In the following description, the present invention is basically irrelevant to the color correction and focus adjustment processing using the test pattern image for color correction and the test pattern image for focus adjustment. These processes will not be described.

The detection unit 11 analyzes the captured image sent from the camera unit 3. This image analysis is performed on the camera coordinate system. The camera coordinate system is the coordinate system set for camera unit 3. More specifically, the camera coordinate system is a coordinate system set in the imaging field of view of the camera unit 3, and the camera unit 3 is the same as the panel coordinate system set in the spatial light modulation device 8a described above. This is a coordinate system with the upper left corner of the imaging field of view as the origin and the horizontal direction as the X axis and the vertical direction as the y axis. However, the camera coordinate system is actually set with the upper left corner of the image sensor panel (CCD panel) of the camera unit 3 as the origin, which means that the camera coordinates are set on the image captured by the camera unit 3. Can be considered.

Therefore, the detection unit 11 uses the conventionally known method based on the image captured by the camera unit 3 to obtain the coordinate values of the four corner positions of the screen S on the camera coordinate system, the test pattern image 25 of FIG. The coordinate values of the positions of the four corners of the projected image are detected according to the situation of the projector 1 at that time of the thick frame portion 25b. If these coordinate values are detected, the state of trapezoidal distortion of the screen S and the projected image (the thick frame portion 25b of the test pattern image 25) can be obtained based on the result. Needless to say. The detection unit 11 transmits the detection result as described above to the system control unit 10.

[0057] The operation unit 12 provided in the projector 1 has a plurality of buttons, switches, and the like. When the user operates these buttons and switches, the operation unit 12 corresponds to the operated buttons, switches, and the like. Accepts an operation instruction and transmits it to the system control unit 10. In addition, the remote control light receiving unit 13 receives an operation signal from the remote control 20 of the projector 1 and transmits it to the system control unit 10. FIG. 4 is a schematic diagram showing the external appearance of the remote controller 20. As shown in FIG. 4, the remote control 20 has up / down / left / right selection keys 20a-20d and a decision key 20e in addition to a plurality of buttons. A GUI is adopted that allows the user to select a required item from a plurality of items displayed on the menu image by operating the selection key 20a-20d and the decision key 20e.

It should be noted that the operation unit 12 is provided with up / down / left / right selection keys and determination keys similar to those of the remote controller 20. Therefore, when the same operation is performed on the operation unit 12 and the remote controller 20, the same instruction is given to the system control unit 10.

[0059] The system control unit 10 that controls each unit described above includes a ROM10a and a RAM 10b. ROMlOa is used to display a program 10p (computer program according to the present invention) that defines the contents of control performed by the system control unit 10, and various test pattern images and various menu images including the test pattern image 25 shown in FIG. This data is stored in advance. RAMlOb temporarily stores various data generated during control by the system control unit 10.

[0060] The system control unit 10 of the projector 1 of the present embodiment configured as described above performs an adjustment to match the projected image with the screen S by the process shown in the flowchart of FIG. Do. The following processing is executed by the system control unit 10 according to the program 10p stored in ROMlOa.

First, the system control unit 10 projects, for example, an all-white image (step Sl).

The detection unit 11 analyzes the image captured by the camera unit 3 in this state, thereby detecting the positions of the four corners of the screen S in the camera coordinate system (step S2). This is easily possible due to the difference between the reflectivity of the screen S and the reflectivity around it (for example, the wall surface).

Next, the system control unit 10 projects a test pattern image 25 for detecting a projected image frame including a thick frame portion 25b that is a test pattern for detecting a projected image frame shown in FIG. 3 (step S3). The detection unit 11 analyzes the image captured by the camera unit 3 in this state, thereby detecting the positions in the camera coordinate system of the four corners of the thick frame portion 25b, which is a test pattern for detecting the projected image frame (step S4). ). This is also possible easily by the difference between the reflectance of the thick frame portion 25b, which is a test pattern for detecting a projected image frame, and the surrounding reflectance. Next, the system control unit 10 performs zoom adjustment based on the positional relationship in the camera coordinate system of each of the four corners of the thick frame 25b, which is a test pattern for detecting the screen S and the projected image frame (step S5). This zoom adjustment can be performed by, for example, a test pattern for detecting a projected image frame. The thick frame portion 25b, which is a projected image frame detection test pattern, is enlarged or reduced by zooming until the thick frame portion 25b, which is a screen, reaches the end point of the screen S.

[0063] After the zoom adjustment, the detection unit 11 analyzes the positions of the four corners of the thick frame portion 25b, which is a test pattern for detecting a projected image frame, from the image captured by the camera unit 3 again. (Step S6), the position of the four corners of the screen S detected in step S2 in the camera coordinate system and the position of the four corners of the thick frame 25b after zoom correction detected in step S6. From the relationship, the positions in the panel coordinate system of the four corners of the thick frame portion 25b, which is a test pattern for detecting a projected image frame after zoom correction, that is, coordinate values are determined (step S7). As a result, the image to be projected is displayed on the panel 8a by being deformed in reverse to the shape projected on the screen S.

[0064] When the system control unit 10 sequentially executes the series of processes described above, the projection device unit 8 displays an image on the panel 8a according to the coordinate value given from the system control unit 10, and this is projected. Is projected to the full size of the screen S as a rectangular image with corrected trapezoidal distortion. Thus, the projection preparation for the projector 1 is automatically completed.

[0065] The processing by the system control unit 10 as described above is performed in the conventional general projection condition, that is, when the distance between the screen S and the projector 1 is sufficiently large, specifically, the projected image. This is a projection preparation process that is automatically performed when the size on the screen S is sufficiently larger than the size of the screen S and the keystone distortion is corrected and can be projected to the full size of the screen S. . However, in a situation where the distance between the screen S and the projector 1 is not sufficient, the maximum size on the screen S after correcting the trapezoidal distortion of the projected image is the dimension of the screen S. Because it may be smaller than this, the preparation process as described above cannot be performed.

[0066] Therefore, in the projector 1 according to the present invention, the screen S after correcting the trapezoidal distortion of the projected image (projected image) because a sufficient distance from the screen S cannot be taken for some reason. If the maximum size above is smaller than the size of the screen S, specifically, even if the thick frame 25b of the test pattern image 25 is projected at the maximum size. When all or one of the four corners of the screen S is located outside the thick frame portion 25b of the projected test pattern image 25, it is located at the center of the screen S, specifically the center. The image after correcting the trapezoidal distortion by matching the screens can be projected with a size smaller than the size of the screen S.

FIG. 6 and FIG. 7 are schematic diagrams for specifically explaining the state as described above. FIG. 6 is a schematic diagram when the state in which the thick frame portion 25b of the test pattern image 25 is projected onto the screen S is viewed from the front of the screen S. Since the projector 1 is not installed facing the screen S, the outline of the projected image (hereinafter referred to as the projected image PJ), in this case, the thick frame portion 25b of the test pattern image 25 has a trapezoidal distortion. Projected in the resulting state. FIG. 7 is a schematic diagram showing an image captured by the camera unit 3 of the projector 1 in the state shown in FIG. 6, that is, a state seen on the camera coordinate system. On the captured image 31, the thick frame portion 25b of the test pattern image 25 that is the outline of the projection image PJ is captured in a substantially rectangular shape, but the screen S is captured in a state in which a large trapezoidal distortion has occurred.

[0068] If the state shown in FIG. 6 is the case where the projection image PJ is projected at the maximum size, the projection image PJ, more specifically, the thick frame portion 25b of the test pattern image 25 is displayed. It is impossible to project with the dimensions of the screen S, with the keystone distortion corrected. Therefore, in such a case, in the projector 1 according to the present invention, a known two-dimensional projective transformation is applied to the coordinate values of the four corners of the screen S on the panel coordinate system as shown in the schematic diagram of FIG. Thus, a virtual screen (hereinafter referred to as a virtual reduced screen Vs) having the same aspect ratio as that of the panel 8a with a smaller size than the screen S and the center of the screen S is set. Then, a projection image PJ in which the trapezoidal distortion is corrected is projected so as to coincide with the dimensions of the virtual reduced screen Vs.

[0069] Specifically, a known two-dimensional projective transformation is applied to the positions of the four corners of the screen S on the image captured by the camera unit 3 (hereinafter referred to as coordinate values in the force coordinate system). Thus, the four corner positions of the virtual reduced screen Vs (camera coordinate system coordinate values) are obtained as a function of the reduction ratio, and the four corner positions of the virtual reduced screen Vs according to the reduction ratio (camera coordinate system coordinate values). Determine the coordinate values of the four corners of the virtual reduced screen Vs so that the image matches the four corner positions of the projected image PJ (coordinate values of the camera coordinate system) after correcting the trapezoidal distortion. The Then, a known two-dimensional projective transformation is performed so that the four corners of the projected image PJ coincide with the four corners of the determined virtual reduced screen Vs.

First, a calculation method for determining the coordinate values of the four corners of the virtual reduced screen Vs will be described. Of course, this calculation itself is executed by the system control unit 10 based on the result of the detection unit 11 analyzing the image captured by the camera unit 3. The input parameters are the coordinate values of the four corners of the screen S on the camera coordinate system, the coordinate values of the four corners of the projected image PJ (specifically, the thick frame portion 25b which is a test pattern for detecting the projected image frame), The X and y resolutions of the panel 8a of the projection device section 8 of the projector 1 are defined as follows (see Fig. 7).

[0071] · Coordinate values of the four corners of the screen S on the camera coordinate system:

(sxl, syl) sx2, sy2) 8 sx3, sy3), (sx4, sy4)

• Coordinate values of the four corners of the projected image PJ on the camera coordinate system:

(pjxl, pjyl), (pjx2, pjy2), (pjx3, pjy3), (pjx4, pjy4)

• Panel x resolution: col (—1024 for example, XGA: see Figure 2)

• Panel _y- direction resolution: row (for example XGA, 768: see Figure 2)

By the way, as shown in FIG. 2, the coordinate values (coordinate values on the panel coordinate system) of the four corners (PI, P2, P3, P4) of the panel 8a of the projection device unit 8 are as follows. In the embodiment, it is possible to express with the resolution conforming to the XGA standard, and the respective conversion destination coordinate values (coordinate values of the screen S on the camera coordinate system) are (Pxl, Pyl), (Px2, Py2 ), (Px3, Py3), (Px4, Py4). Note that PX is defined as a coordinate value at an arbitrary position on the panel 8a (a coordinate value on the panel coordinate system), and a conversion destination thereof, that is, a coordinate value on the camera coordinate system is defined as (LXX, LYY).

[0073] Panels at the four corners of the panel → Destination coordinate values

Coordinate value in coordinate system (coordinate value of screen on camera coordinate system)

P1 = (0, 0) → (Pxl, Pyl)

P2 = (col, 0) → (Px2, Py2)

P3 = (col, row) → (Px3, Py3)

P4 = (0, row) → (Px4, Py4)

PX = (LX, Ly) → (LXX, LYY) However, since the conversion destination coordinate values of the coordinate values in the panel coordinate system at the four corners of the panel 8a described above are the coordinate values of the screen S on the camera coordinate system, the following relationship is established.

Px 丄 = sxl, Pyl = syl

Px2 = sx2, Py2 = sy2

Px3 = sx3, Py3 = sy3

Px4 = sx4, Py4 = sy4

[0075] Next, normalized coordinate values (calculation coordinate values) for use in the calculation, that is, the coordinate values of the four corners of the panel 8a (panel coordinate system) are set to 0 and 1 for both the x and y axes. A value obtained by normalizing by converting to an intermediate value is obtained, and the above-mentioned conversion destination coordinate value (coordinate value in the camera coordinate system) is also normalized in the same manner. The coordinate values of the four corner positions pl, p2, p3, p4 of the panel represented by the coordinate values normalized on the panel coordinate system and the normalized position px on the panel are the original coordinate values (panel coordinate values ), And the coordinate value obtained by normalizing the original coordinate value and the conversion destination coordinate value (camera coordinate system coordinate value) are expressed as follows.

[0076] Original coordinate value: Conversion destination coordinate value

pl: (0, 0): (xl, yl) where (xl, yl) = (0, 0)

_P 2: (l, 0): (x2, y2)

_P 3: (l, l): (x3, y3)

_P 4: (0, 1): (x4, y4)

px: (χ, y): (χχ, yy)

[0077] The above relation is such that the calculation is simplified by offsetting one point (xl, yl) of the conversion destination to the corresponding one point (0, 0) in the original coordinate system. This is a general method for two-dimensional projective transformation. X, y values of normalized transformation destination coordinate values xl, χ2, χ3, χ4 and yl, y2, y3, y4 are the coordinate values of the four corners of the screen S on the camera coordinate system (Pxl, Pyl) , (Px2, Py2), (Px3, Py3), and (Px4, Py4). Where w is the width of the destination coordinate (width of the screen S on the camera coordinate system: length in the x direction), and h is the same height (height of the screen S on the camera coordinate system: in the y direction) Length).

[0078] xl = 0 where xl = (Pxl-Pxl) / w

x2 = (Px2-Pxl) / w x3 = (Px3-Pxl) / w

x4 = (Px4-Pxl) / w

yl = 0 where yl = (Pyl-Pyl) / h

y2 = (Py2-Pyl) / h

y3 = (Py2-Pyl) / h

y4 = (Py4-Pyl) / h

From the above relationship, conversion coefficients a, b, c, al, and so on for converting the original coordinate value (the coordinate value in the panel coordinate system) to the conversion destination coordinate value (the coordinate value of the screen S on the camera coordinate system) a2, bl, b2, aO, b0, and cO are obtained as follows. However, here, since it is a conversion coefficient for converting the original coordinate value (panel coordinate value) to the conversion destination coordinate value, a positive conversion coefficient is obtained. Note that a, b, and c are intermediate constants that are used to reduce redundant calculations even in the known two-dimensional projective transformation.

a = (x3 * y4-x4 * y3): Intermediate constant

b = (x2 * y3-x3 * y2): Intermediate constant

c = (x2 * y4-x4 * y2): Intermediate constant

al = a * x2

a2 = a * y2

bl = b * x4

b2 = b * y4

aO =-b + c

bO = ― a + c

cO = b + a-c

Next, the position on the panel 8a of the projection device unit 8 corresponding to the four corner positions of the virtual reduced screen Vs, that is, the coordinate value in the panel coordinate system is obtained. Note that the coordinate values of the positions corresponding to the four corner positions of the virtual reduced screen Vs on the panel 8a are (small xi, small yi) (see Fig. 2), and their positive transformation coordinate values (in the camera coordinate system). The coordinate values are defined as (virtual xi, virtual yi) (see Fig. 7). Where i is 1, 2, 3, 4 and 100. The / o coordinate value is the coordinate value of the position on the panel 8a corresponding to the position of the four corners of the screen S, specifically the panel 8a The coordinate values at the four corners.

[0082] 100% coordinate value → virtual reduced screen → forward conversion coordinate value

(On panel) Coordinate value (Panel coordinate system) (Camera coordinate system)

P1:, 0, 0) → (small xl, small yl) → (virtual xl, virtual yl)

P2: (col, 0) → (small x2, small y2) → (virtual x2, virtual y2)

P3: (col, row) → (small x3, small y3) → (virtual x3, virtual y3)

P4: (0, row) → (small x4, small y4) → (virtual x4, virtual y4)

[0083] For convenience of calculation, if the coefficient ctrx = col / 2, the coefficient ctry = row / 2, and the reduction ratio (variable value) of the virtual reduction screen Vs is scale (0% — 100%), it will be on the panel 8a. The coordinate values (small xi, small yi) at the four corners of the virtual reduced screen Vs in the panel coordinate system are expressed as follows. Here, since the reduction ratio scale of the virtual reduced screen Vs is a variable value between 0% and 100%, the coordinate values (small xi, small yi) of the four corners of the virtual reduced screen Vs in the panel coordinate system are reduced. It becomes a function of the ratio scale.

[0084] small xl = (0-ctrx) * scale / 100 + ctrx

small x2 = (col― ctrx) * scale / 100 + ctrx

small x3 = (col― ctrx) * scale / 100 + ctrx

small x4 = (0— ctrx) * scale / 100 + ctrx

small yl = (0— ctrx) * scale / 100 + ctrx

small y2 = (0— ctrx) * scale / 100 + ctrx

small y3 = (row― ctrx) * scale / 100 + ctry

small y4 = (row― ctrx) * scale / 100 + ctry

[0085] Next, the coordinate values of the four corners of the virtual reduced screen Vs on the camera image 31 captured by the camera unit 3, that is, the coordinate values of the four corners of the virtual reduced screen Vs in the camera coordinate system (virtual xi, virtual yi);

Specifically, positive conversion is performed on the coordinate values (small xi, small yi) of the four corners of the virtual reduced screen Vs in the panel coordinate system on the panel 8a obtained as described above. Thus, the coordinate values (virtual xi, virtual yi) of the four corners of the virtual reduced screen Vs on the camera image, that is, in the camera coordinate system are obtained. However, the coordinates of an arbitrary point PX in the panel coordinates (original coordinates) The values LX and LY are the coordinate values of the four corners of the virtual reduced screen Vs, small xl—samll x4, small yl one small y4, and any point on this panel coordinate (original coordinate) PX conversion coordinate (on the camera coordinate system) ) Coordinate values LXX and LYY are converted to virtual and reduced in the camera coordinate system. Screen Vs corner coordinate values virtual xl-virtual x4, virtual yl-one virtual y4, and finally virtual reduction in the camera coordinate system The coordinate values LXX and LYY of the four corners of screen Vs are obtained as follows.

[0087] LX: small x 丄, small x2, small x3, small x4

LY: small yl, small y2, small y3, small y4

LXX: virtual xl, virtual x2, virtual x3, virtual x4

LYY: virtual yl, virtual y2, virtual y3, virtual y4

[0088] x = LX ol where LX = 0 'col

y = LY / row where LY = 0 "-row

z = aO * x + bO * y + cO

xx = (al * x + bl * y) / z

yy = (a2 * x + b2 * y) / z

Therefore,

LXX = col * xx + Pxl

LYY = row * yy + Pyl

That is, by setting LX to small xi (i is 1, 2, 3, 4), virtual xi is obtained as LXX, and by setting LY to small yi, virtual is obtained as LYY. However, the coordinate values (virtual xi, virtual yi) obtained in this way are a function of the reduction ratio scale. Therefore, if the reduction ratio scale, specifically, the reduction ratio of the virtual reduction screen Vs to the screen S is not determined, a specific value cannot be obtained. The reduction ratio scale is determined as follows.

[0090] On the camera coordinate system, when the four corners of the virtual reduced screen Vs exist inside the projection image PJ (specifically, the thick frame portion 25b of the test pattern image 25), in other words, the corresponding coordinates respectively. If the relationship between the values virtual xi and pjxi and the relationship between virtual yi and pjyi satisfy all of the following eight conditions simultaneously, the trapezoidal distortion of the projected image PJ can be corrected (see Fig. 7). (virtual xl pjxl)> 0,

(virtual x2-pjx2) 0,

(virtual x3 pjx3) <0,

(virtual x4 — pjx4)> 0,

(virtual yl — pjyl)〉 0,

(virtual y2 one pjy2)> 0,

(virtual y3 — pjy3) <0, and

(virtual y4 — pjy4)

[0091] When all of the above eight conditions are satisfied at the same time, the force S means that all four corners of the virtual reduction screen Vs are located inside the projected image PJ on the camera coordinate system, and vice versa. If any one of the above eight conditions is not satisfied, it means that at least one of the four corners of the virtual reduced screen Vs is located outside the projected image PJ. Therefore, the coordinate value (virtual xi, virtual yi) of the virtual reduction screen Vs in the camera coordinate system described above is obtained while reducing the reduction ratio scale from 100% step by step, for example, in increments of 1% and 5%. In other words, if the above calculation is repeated in such a way that the size of the virtual reduced screen Vs on the camera coordinate system becomes gradually smaller, all the above eight conditions are satisfied. The reduction ratio scale is obtained, and at the same time, the coordinate values of the four corners of the virtual reduction screen Vs on the camera coordinate system at the reduction ratio scale are also obtained.

[0092] As described above, the coordinate values (virtual xi, virtual yi) of the four corners of the virtual reduced screen Vs in the camera coordinate system are obtained. On the other hand, the projection image PJ (specifically, the test image) in the camera coordinate system is obtained. Two-dimensional projective transformation is performed so that the four corners (coordinate values are (pjxi, pjyi)) of the thick frame 25b) of the pattern image 25 match. As a result, the projected image PJ is corrected for trapezoidal distortion and has the same size as the virtual reduced screen Vs. In other words, the projected image PJ is corrected for trapezoidal distortion and its four corners are virtual reduced screen Vs. It will be projected in a state that matches the four corners. FIG. 9 is a schematic diagram showing this state. This two-dimensional projective transformation itself is a known technique.

Specifically, by performing the following calculation, the four corners of the projected image PJ can be projected in accordance with the four corners of the virtual reduced screen Vs. It ’s no problem, but this operation This is executed by the system control unit 10 based on the result of the detection unit 11 analyzing the image captured by the camera unit 3.

[0094] The input parameters are the coordinate values of the four corners of the virtual reduced screen Vs on the camera coordinate system, the coordinate values of the four corners of the projection image PJ, and the X-direction and y-direction resolutions of the panel 8a. Each is defined as follows.

• Coordinate values of four corners (VP1, VP2, VP3, VP4) of virtual reduced screen Vs on camera coordinate system: virtual xi, virtual yl) Avirtual x2, virtual y2),

(virtual x3, virtual y 3), (virtual x4, virtual y4)

• Coordinate values of the four corners of the projected image PJ (bold frame 25b) on the camera coordinate system:

(pjxl, pjyl), (pjx2, pjy2), (pjx3, pjy3), (pjx4, pjy4)

'Panel x resolution: col

• y resolution of the panel: row

However, as an example, the panel resolution is col = 1024 and row = 768 for XGA (see Figure 2).

[0095] Here, the coordinates of the four corners (VP1, VP2, VP3, VP4) of the virtual reduced screen Vs on the camera coordinate system iiXvirtual xl, virtual yl), (virtual x2, virtual y2) Avirtual x3, virtual y 3) , (virtual x4, virtual y4) are (Pxl, Pyl), (Px2, Py2), (Px3, Py3), (Px4, Py4), and each conversion target coordinate value (coordinate value on the panel coordinate system) Is (0, 0), (col, 0), (col, row), (0, row). Note that PX is a coordinate value at an arbitrary position on the camera coordinate system.

Coordinate value of virtual reduced screen on camera coordinate system

→ Conversion destination coordinate value (coordinate value on the panel coordinate system)

VP1 = (Pxl, Pyl) → (0, 0)

VP2 = (Px2, Py2) → (col, 0)

VP3 = (Px3, Py3) → (col, row)

VP4 = (Px4, Py4) → (0, row)

PX = (LXX, LYY) → (LX, LY)

However, the coordinate values of the four corners (VP1, VP2, VP3, VP4) of the virtual reduced screen Vs on the camera coordinate system described above should match the coordinates of the four corners of the projected image PJ on the camera coordinate system. , The following relationship holds.

Pxl = jxl, Pyl = pjyl

Px2 = pjx2, Py2 = pjy2

Px3 = pjx3, Py3 = pjy3

Px4 = pjx4, Py4 = pjy4

[0097] Next, the coordinate values normalized for use in the calculation (coordinate values for calculation), that is, the coordinates of the four corners of the virtual reduced screen Vs on the camera coordinate system are 0 and 1 for both the x and y axes. The normalized value is obtained by converting to a value between and the panel coordinate value, which is the conversion destination coordinate value described above, is normalized in the same manner. The coordinate values of the four corners pi, p2, p3, p4 of the virtual reduced screen Vs on the camera coordinate system represented by the coordinate values thus normalized and any normalized point px on the camera coordinate system Is the original coordinate (camera coordinate system), and the coordinate value obtained by normalizing the coordinate value of the original coordinate and the coordinate value of the conversion destination (coordinate value of the panel coordinate system) is expressed as follows.

[0098] Original coordinate value: Conversion destination coordinate value

pl: (0, 0): (xl, yl) where (xl, yl) = (0, 0)

_P 2: (l, 0): (x2, y2)

_P 3: (l, l): (x3, y3)

_P 4: (0, 1): (x4, y4)

px: (χ, y): (χχ, yy)

[0099] The above relationship is such that the calculation is simplified by offsetting one point (xl, yl) of the conversion destination to the corresponding one point (0, 0) on the original coordinate system. This is a general technique in the known two-dimensional projective transformation. The normalized destination coordinate values X, y xl, x2, x3, x4 and yl, y2, y3, y4 are the coordinate values of the four corners of the virtual reduced screen Vs on the camera coordinate system (Pxl, Pyl), (Px2, Py2), (Px3, Py3), and (Px4, Py4) are used as follows.

[0100] xl = 0 However, xl = (Pxl-Pxl) ol

x2 = (Px2-Pxl) ol

x3 = (Px3-Pxl) ol

x4 = (Px4-PxD / col yl = 0 where yl = (Pyl-Pyl) / row

y2 = (Py2-Pyl) / Orchid

y3 = (Py2-Pyl) / Orchid

y4 = (Py4-Pyl) / row

[0101] From the above relationship, conversion coefficients a, b, c, al for converting the original coordinate value (camera coordinate system) to the conversion destination coordinate value (coordinate value of virtual reduced screen Vs on the panel coordinate system) , a2, bl, b2, aO, b0, cO are obtained as follows. However, here, since it is a conversion coefficient for converting the original coordinate value (the coordinate value of the virtual reduction screen Vs on the camera coordinate system) to the conversion destination coordinate value (panel coordinate system), a positive conversion coefficient is obtained. At the same time, inverse transform coefficients n aO, n b0, n cO, n al, n b l, n a2, n b2 are also obtained. Note that a, b, and c are intermediate constants that are used to reduce duplicate calculations even in the known two-dimensional projective transformation.

[0102] · Positive conversion coefficient

a =: (x3 * y4--x4 * y3): Intermediate constant

b =: (x2 * y3-x3 * y2): Intermediate constant

c =: (x2 * y4.-x4 * y2): Intermediate constant

al = a * x2

a2 = a * y2

b l = b * x4

b2 = b * y4

aO =-b + c

bO =-a + c

cO = b + a ― c

[0103] · Inverse transformation coefficient

n aO = (aO * b2-a2 * b2)

n bO = (al * bO _ aO * b l)

n cO = (a2 * b l-al * b2)

Next, the corresponding coordinate values on the panel coordinate system are calculated by inversely transforming the coordinate values of the four corners of the virtual reduced screen Vs on the camera coordinate system. However, on the camera coordinate system Arbitrary point PX The coordinate values LXX and LYY of the PX are the coordinate values sxi and syi at the four corners of the virtual reduction screen Vs, respectively, and by inverse transformation, the virtual reduction screen Vs on the camera coordinate system is finally obtained. The coordinate values LX and LY of the four corners on the panel coordinate system corresponding to the four corners are obtained as follows.

[0105] XX = (LXX-Pxl) / col where LXX = 0---col

yy = (LYY-Pyl) / row where LYY = 0 "row

zz = n aO * xx + n D0 * yy + n cO

x = (n al * xx + n bl * yy) / zz

y = (n a2 * xx + n b2 * yy) / zz

Therefore,

LX = col * x

LY = row * y

As described above, the projection image PJ can be made to coincide with the virtual reduction screen Vs, and more specifically, the four corners of the projection image PJ can be made to coincide with the four corners of the virtual reduction screen Vs.

FIG. 10 is a flowchart showing a processing procedure by the system control unit at the time of auto adjustment by the projector of the present invention. That is, in FIG. 10, as described above, the projected image PJ has a dimension that matches the virtual reduced screen Vs on the screen S with the trapezoidal distortion corrected. Specifically, the four corners of the projected image PJ are also trapezoidally distorted. 12 is a flowchart showing a processing procedure by the system control unit 10 including processing for displaying the corrected reduced screen Vs on the screen S so as to coincide with the four corners in a corrected state. The control shown in this flowchart is processed according to the program 10p stored in ROMlOa.

In the present embodiment, the system control unit 10 is configured to process each procedure in accordance with the program 10p stored in the ROMlOa. However, the projector of the present invention includes these procedures. Of course, it is possible to adopt a configuration in which part or all of the data is processed by dedicated hardware (dedicated circuit).

First, the user places the projector 1 in front of the screen S, and operates the operation unit 12 or the remote control 20 to give an instruction to perform automatic adjustment for projection preparation to the projector. System The system control unit 10 monitors whether or not an instruction to perform automatic adjustment for projection preparation and other instructions have been received (step S11). When an instruction other than an instruction for performing automatic adjustment for projection preparation is received (NO in step S11), system control unit 10 executes a process corresponding to the received instruction (step S12). When an instruction to perform automatic adjustment for projection preparation is received (YES in step S11), the system control unit 10 performs projection on the four corners of the virtual reduction screen Vs described above as well as automatic adjustment for the items of color correction and focus adjustment. The adjustment to match the four corners of the image PJ, specifically, the thick frame portion 25b of the test pattern 25 is started (step S13). In the following description, descriptions regarding color correction and focus adjustment are omitted.

[0110] At the start of auto adjustment, the system control unit 10 first detects positions (coordinate values) in the camera coordinate system of the four corners of the screen S from the image captured by the camera unit 3 (step S14), and then The positions (coordinate values) of the four corners of the thick frame 25b, which is a test pattern for detecting the projected image frame, are detected in the camera coordinate system (step S15), and the positional relationship between them, ie, the four corners of the screen S in the camera coordinate system. And the positions of the four corners of the thick frame portion 25b of the test pattern for detecting the projected image frame are examined (step S16). The system controller 10 detects the positions (coordinate values) of the four corners of the screen S and the projected thick frame 25b in the camera coordinate system in the same manner as in the flowchart of FIG. . As a result, when all four corners of the screen S in the camera coordinate system are located inside the thick frame portion 25b of the test pattern for detecting the projected image frame (NO in step S17), the system control unit 10 Normal adjustment, that is, normal auto adjustment (zoom adjustment and trapezoidal distortion correction) is performed so that the projected image PJ larger than the screen S matches the dimension of the screen S (step S21). After this, various images input from the external connection unit 4 can be projected onto the virtual reduced screen Vs on the screen S according to the user's instructions, so that the image projection is performed according to the instructions from the detection unit 11. Started (step S20).

[0111] On the other hand, if any one of the four corners of the screen S in the camera coordinate system is located outside the thick frame portion 25b of the test pattern for detecting the projected image frame (YES in step S17), the system The control unit 10 performs automatic adjustment to project an image on the center of the screen S. That is, the system control unit 10 first sets the camera coordinate system as described above. If the four corners of the virtual reduced screen Vs exist inside the thick frame 25b of the test pattern image 25 for detecting the projected image frame, in other words, the relationship between the corresponding coordinate values virtual xi and pjxi, and virtual yi And pjyi satisfy all of the following 8 conditions at the same time, the trapezoidal distortion of the projected image PJ can be corrected, so that the virtual reduced screen Vs on screen S can satisfy such conditions. Determine the four corners (step S18).

[0112] Then, zoom adjustment and keystone correction are performed so that the four corners of the thick frame portion 25b of the test pattern image 25 for detecting the projected image frame coincide with the four corners of the determined virtual reduced screen Vs (step S19). ). After that, various images input from the external connection unit 4 can be projected onto the virtual reduced screen Vs on the screen S according to the user's instructions. (Step S20).

[0113] In the above-described embodiment, the configuration in which the projection image PJ is projected from the single projector 1 onto the center of the screen S has been described. However, by applying the present invention, the projection images from the plurality of projectors are integrated. It is also possible to project side by side so that they do not overlap on one screen.

[0114] In the above-described embodiment, the virtual reduction screen Vs (virtual projection frame) is set based on the image captured by the camera unit 3, but the screen S (projected body) is related. For example, light detection sensors such as photodiodes are installed at the four corners of the screen S to detect the positions of the four corners of the screen S, and the projected image (specifically, the thick frame 25b of the test pattern 25) is zoomed. By configuring so that the four corners are detected by an operation, a lens shift operation, or the like, the present invention can be applied.

In the above-described embodiment, the projection image (specifically, the thick frame portion 25b of the test pattern 25) is matched with the four corners of the virtual reduced screen Vs (virtual projection frame), thereby projecting the projection image. Although the keystone distortion of the image is corrected, it is of course possible to use the virtual reduction screen Vs for zoom adjustment. In this case, zoom adjustment can be performed in a state where the center of the projected image coincides with the center of the screen S (projected body).

Claims

The scope of the claims

[1] Spatial light modulation means generates modulated light in accordance with information representing a rectangular projection image projected onto a rectangular projection object, and the modulated light generated by the spatial light modulation means is used as the rectangular object. When projecting the projection lens onto the projection lens, the spatial light modulation means generates modulated light in accordance with information representing an image obtained by deforming the rectangular projection image to form a rectangular image on the projection target. The image projection method to project

The center of the rectangular projection object having the same aspect ratio as the rectangular projection image and smaller than the size of the rectangular projection object when projected onto the rectangular projection object An image projection method comprising: setting a virtual projection frame having a rectangular shape in a state in which the centers coincide with each other on the spatial light modulator.

[2] According to the information representing the rectangular projection image projected onto the rectangular projection object, the spatial light modulation means generates modulated light, and the modulated light generated by the spatial light modulation means is used as the rectangular object. When projecting the projection lens onto the projection lens, the spatial light modulation means generates modulated light according to information representing an image obtained by deforming the rectangular projection image so that a rectangular image is formed on the projection target. The image projection method to project to

The center of the rectangular projection object having the same aspect ratio as the rectangular projection image and smaller than the size of the rectangular projection object when projected onto the rectangular projection object A virtual projection frame that is rectangular with the center aligned with the spatial light modulation means on the spatial light modulation means,

The deformation amount of the rectangular projection image on the spatial light modulator is calculated so that the four corners of the rectangular projection image coincide with the four corners of the virtual projection frame set on the spatial light modulator. To do

An image projection method characterized by the above.

[3] The spatial light modulation unit generates modulated light according to the information representing the unprojected projection image, and the modulated light generated by the spatial light modulation unit is maximized through the projection lens. When the image is projected onto a body, an image including the positions of the four corners of the projection image and the positions of the four corners of the projection object is captured by an imaging unit,

From the image captured by the imaging means, the positions of the four corners of the projection object and the projection image Specify the positions of the four corners of the image on the coordinate system set in the imaging means,

When at least one of the four corner positions of the projection target specified on the coordinate system exists outside the four corner positions of the projection image specified on the coordinate system, the spatial light modulation means Setting the virtual projection frame on

The image projecting method according to claim 1, wherein:

[4] A virtual projection frame having a maximum size is set on the spatial light modulation unit based on the positions of the four corners of the projection target specified on the coordinate system and the four corner positions of the projection image. The image projection method according to claim 3, wherein:

[5] The virtual projection frame obtained by converting the aspect ratio of the projection object specified on the coordinate system into the external ratio of the projection image is reduced in stages, thereby being reduced in stages. Based on the reduction ratio at the time when all four corners of the virtual projection frame are located within the range of the projection image specified on the coordinate system, a virtual projection frame of the maximum size is placed on the spatial light modulation means. 5. The image projection method according to claim 4, wherein the image projection method is set.

[6] The two-dimensional projective transformation is applied to the positional relationship of the four corners of the projection body with respect to the positional relationship of the four corners of the rectangle having the same aspect ratio as the projection image with the center of the projection target as the center. 5. The image projection method according to claim 4, wherein a virtual projection frame is set on the spatial light modulation means by conversion.

[7] Spatial light modulation means for generating modulated light according to information representing a rectangular projection image projected onto a rectangular projection object, and the modulated light generated by the spatial light modulation means for the rectangular projection A projection lens that projects onto the body, and causes the spatial light modulation means to generate modulated light in accordance with information representing an image obtained by deforming the rectangular projection image, thereby generating a rectangular image on the rectangular projection target. In the projector that projects so that

The center of the rectangular projection object having the same aspect ratio as the rectangular projection image and smaller than the size of the rectangular projection object when projected onto the rectangular projection object A projector comprising virtual projection frame setting means for setting a virtual projection frame having a rectangular shape with the center being coincident with the spatial light modulation means.

[8] Spatial light modulation means for generating modulated light in accordance with information representing a rectangular projection image projected onto a rectangular projection object, and the modulated light generated by the spatial light modulation means for the rectangular light A projection lens for projecting onto the projection target, and generating a modulated light in the spatial light modulation means according to information representing an image obtained by deforming the rectangular projection image to form a rectangular shape on the rectangular projection target In the projector that projects so that the image becomes

The center of the rectangular projection object having the same aspect ratio as the rectangular projection image and smaller than the size of the rectangular projection object when projected onto the rectangular projection object Virtual projection frame setting means for setting on the spatial light modulation means a virtual projection frame that is rectangular with the center being coincident with

The rectangular projection on the spatial light modulation means so that the four corners of the rectangular projection image coincide with the four corners of the virtual projection frame set on the spatial light modulation means by the virtual projection frame setting means. A projector comprising a calculation means for calculating a deformation amount of an image.

[9] The positions of the four corners of the projection image when the modulated light generated by the spatial light modulator according to the information representing the undeformed projection image is projected to the projection object with the maximum size through the projection lens. Imaging means for capturing an image including the four corner positions of the projection object;

And specifying means for specifying the positions of the four corners of the projection object and the positions of the four corners of the projection image on the coordinate system set in the imaging means from the image captured by the imaging means,

The virtual projection frame setting means is configured such that at least one of the positions of the four corners of the projection target specified by the specifying means on the coordinate system is the projection image specified by the specifying means on the coordinate system. 9. The projector according to claim 7, wherein a virtual projection frame is set on the spatial light modulation means when it exists outside the positions of the four corners.

[10] The virtual projection frame setting means sets a virtual projection frame having a maximum size based on the positions of the four corners of the projection target and the positions of the four corners of the projection image specified by the specifying means on the coordinate system. 10. The projector according to claim 9, wherein the projector is set on the spatial light modulator.

[11] The virtual projection frame setting unit is configured to stepwise a virtual projection frame obtained by converting the aspect ratio of the projection target specified by the specifying unit on the coordinate system into the aspect ratio of the projection image. The reduction ratio at the time when all of the four corners of the virtual projection frame that are reduced step by step are positioned within the range of the projection image specified by the specific means on the coordinate system. 11. The projector according to claim 10, wherein a virtual projection frame having a maximum dimension is set on the spatial light modulator based on the basis.

[12] The virtual projection frame setting means has a two-dimensional relationship between the four corners of the projection object and the rectangular corners having the aspect ratio of the projection image centered on the center of the projection object. 11. The projector according to claim 10, wherein a virtual projection frame is set on the spatial light modulator by performing conversion using projective conversion.

[13] Spatial light modulation means for generating modulated light in accordance with information representing a rectangular projection image projected onto a rectangular projection object, and the modulated light generated by the spatial light modulation means for the rectangular projection A projection lens that projects onto a body, and an imaging device, and generates spatial light modulation light in the spatial light modulation unit according to information representing an image obtained by transforming the rectangular projection image, and has a rectangular shape on the projection target. A rectangular shape having the same aspect ratio as that of the rectangular projection image for projecting into an image and having the center coincident with the center of the projection object that is smaller than the dimension of the projection object In the projector that sets the virtual projection frame based on the image captured by the imaging device,

Means for causing the spatial light modulation means to generate modulated light representing test patterns indicating the four corners of the rectangular projection image and projecting the modulated light from the projection lens toward the rectangular projection object;

Means for causing the imaging device to image the state in which the test pattern is projected toward the rectangular projection object;

Means for detecting positions of four corners of the rectangular projection object on an image captured by the imaging device;

Means for detecting positions of four corners of the projected test pattern on an image captured by the imaging device;

Means for examining the relative positional relationship between the four corners of the rectangular projection object and the four corners of the test pattern on the image captured by the imaging device;

On the image captured by the imaging device, at least of the four corners of the rectangular projection object Means for determining the four corners of the virtual projection frame when one of them is located within a range surrounded by the four corners of the projected test pattern.

A projector comprising:

Spatial light modulation means for generating modulated light according to information representing a rectangular projection image projected onto the rectangular projection object, and projecting the modulated light generated by the spatial light modulation means onto the rectangular projection object A projection lens and an imaging device, and the spatial light modulation means generates modulated light according to information representing an image obtained by transforming the rectangular projection image to form a rectangular image on the projection object. A computer having the same aspect ratio as that of the rectangular projection image, the center of which coincides with the center of the rectangular projection object that is smaller than the size of the rectangular projection object. A computer program for setting a virtual projection frame of a shape based on an image captured by the imaging device,

A procedure for causing the spatial light modulation means to generate modulated light representing test patterns indicating the four corners of the rectangular projection image and projecting the modulated light from the projection lens toward the rectangular projection target;

A procedure for causing the imaging device to image a state in which the test pattern is projected toward the rectangular projection object;

A procedure for detecting positions of four corners of the rectangular projection object on an image captured by the imaging device;

A procedure for detecting positions of four corners of the projected test pattern on an image captured by the imaging device;

A procedure for examining the relative positional relationship between the four corners of the rectangular projection object and the four corners of the test pattern on the image captured by the imaging device;

When at least one of the four corners of the rectangular projection object is located within a range surrounded by the four corners of the projected test pattern on the image captured by the imaging device. The procedure to determine the four corners of the virtual projection frame and

A computer program for causing the computer to execute.