JP5406904B2 - Image projection device - Google Patents

Description

  The present invention relates to an image projection apparatus, and more particularly to a calibration technique thereof.

  2. Description of the Related Art Conventionally, there is a rear projection type display device that uses a transmission screen and projects an image onto a screen from a surface side (back side) opposite to a surface side (front side) observed by an observer. Further, as a development of this system, there is a high-definition rear projection type large screen display device that projects images from a plurality of projectors onto a screen and displays them as a single image.

  In this rear projection type large-screen display device, a plurality of projected images are connected (bonded) to form a single image, so it is necessary to take the following measures.

  First, it is necessary to take measures for correcting the distortion of each projection image. A method of adjusting the angle of the projector so that the projection image does not distort, and a distortion that cancels the distortion that occurs in the projection image in advance. A method to give to is proposed. In any method, means for detecting information relating to distortion of the projected image is required, and a method using a digital camera or a sensor arranged on a screen has been proposed.

  Secondly, it is necessary to take a measure for correcting the connection of the projected images, and a technique for smoothly connecting the images by providing an area where adjacent images overlap is proposed. In this technique, means for detecting information of overlapping areas is necessary, and a method for extracting a correction value from an image photographed by a digital camera has been proposed.

  Third, it is necessary to take measures to correct the color of each projected image. The reference image is projected on the screen from the projector, the entire projected reference image is shot with a digital camera, and the correction is made from the shot image. A method of extracting a value and performing color correction using the correction value has been proposed.

  The above-described correction value acquisition work (adjustment work) for performing a series of corrections is referred to as calibration. This calibration is performed when the image projection system is installed, and is also performed when an influence due to a change with time occurs. Is called.

  However, in the conventional image projection system, the digital camera is installed outside the screen (front side) and the calibration is executed. When the calibration is executed, the user can set the installation position, angle, The focus etc. had to be adjusted, and the burden on the user for the adjustment was excessive.

  In view of this, a configuration is conceivable in which the digital camera is fixed in advance inside the casing inside the screen (rear side) to reduce the burden of adjustment work when performing calibration. However, in this case, since the image on the screen is taken from a direction different from the direction in which the image projected on the screen is viewed (front side), it is difficult to make an appropriate adjustment. Occurs.

  The present invention has been made to solve the above-described conventional problems, and even when a digital camera used for performing calibration is installed in a housing on the rear side of the screen, the rear surface can be appropriately adjusted. An object of the present invention is to provide a projection type image projection system.

  The present invention is an image projection system for projecting an image onto the screen from the back side of a transmissive screen, the projection means for projecting the image onto the screen from the back side, and a reference for generating reference image information of the reference image An image generating means; a photographing means capable of photographing the screen from the inside of the housing; receiving a reference image information from the reference image generating means; and photographing a reference image projected on the screen from the projection means; A removal unit that removes the influence of external light on the reference image projected on the screen from the projection unit, and a correction that calculates a correction value based on the image information of the reference image from which the influence of external light has been removed by the removal unit Value calculating means, correction value storing means for storing correction value information obtained by the correction value calculating means, and correcting the image information from the video signal source to In order to supply the unit, and having a correction means for correcting using the correction value information stored in the correction value storage means to said image information.

  Examples of the removing means include the following modes.

  (1) Means capable of shielding outside light reaching the photographing means through the screen.

  (2) Image information obtained when the screen is photographed by the photographing means without projecting an image from the projection means onto the screen, and the photographing means in a state where a reference image is projected from the projection means onto the screen. Means for performing an operation for removing the influence of external light on the basis of image information obtained when the screen is imaged.

  Further, the image projection system stores information obtained based on respective image information when the screen is photographed from the back side and the front side of the screen in a state where a reference image is projected from the projection unit onto the screen. You may have the means to do.

  According to the present invention, even if a photographing means for photographing a reference image is provided on the back side of the screen and a reference image is taken, appropriate correction data can be obtained by removing the influence of external light. Therefore, it is possible to perform appropriate adjustment.

It is a figure showing an example of basic composition of an image projection system concerning a 1st embodiment of the present invention. It is the figure which showed the basic structural example of the image projection system which concerns on the 2nd Embodiment of this invention. It is the figure which showed the functional structure of the image projection system which concerns on the 2nd Embodiment of this invention. It is the flowchart which showed the operation | movement by the structure of FIG. It is the figure which showed the basic structural example of the image projection system which concerns on the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
(Device configuration)
FIG. 1 is a diagram illustrating a basic configuration example of an image projection system according to the first embodiment. This image projection system is a rear projection type image projection system that projects images from a plurality of projectors onto the screen from the rear side of the transmissive screen and displays them as a single image. A similar image projection system is assumed for the form.

  A projector 102 is installed inside the housing 101 of the display unit 100 (only one projector is shown in the figure, but a plurality of projectors are actually arranged). An image is projected on a transmissive screen 105 via a mirror 103 and a mirror 104. Further, the digital camera 106 is fixed at a predetermined position (a predetermined position inside the housing 101) so that the back side of the screen 105 can be photographed from inside the housing 101.

  Further, the display unit 100 is provided with a shielding sheet (light shielding sheet) 107 that can cover the entire surface of the screen 105, and external light that enters the inside of the housing from the front side of the screen 105 by the shielding sheet 107 is attached. It can be shielded. Since this shielding sheet 107 can be taken up by the take-up roller 108, the entire screen 105 can be covered as required. Since the outside light is shielded by the casing 101 except for the portion where the screen 105 is disposed, the influence of the outside light on the digital camera 106 is removed when the shielding sheet 107 is fully closed. In addition, you may make it shield external light using the shielding door which can be opened and closed besides a shielding sheet. Further, the shielding sheet and the shielding door may be used for screen protection and viewing when not in use.

  The output of the digital camera 106 is connected to the processing unit 120, and is configured so that image data of a captured image can be transmitted to the processing unit 120 by a general serial communication interface such as IEEE1394 or RS232C.

  Image data output from the digital camera 106 is input to the correction value calculation circuit 121 of the processing unit 120 via the serial communication interface described above. A reference image generation circuit 122 is connected to the correction value calculation circuit 121, and a predetermined correction value calculation is performed based on image data sent from the digital camera 106 and reference image data from the reference image generation circuit 122. Processing is performed. That is, when performing the adjustment work (calibration), the shielding sheet 107 is fully closed and the reference image is projected from the projector 102 onto the screen 105. Therefore, the influence of external light captured by the digital camera 106 is removed. A correction value corresponding to the difference between the image data of the reference image thus generated and the reference image data from the reference image generation circuit 122 is obtained by correction value calculation processing.

  A correction value table 123 is connected to the correction value calculation circuit 121 so that correction value data obtained by the correction value calculation circuit 121 is stored. The correction value table 123 can be configured using a rewritable nonvolatile memory such as an EEPROM.

  A correction circuit 124 is connected to the correction value table 123. A video signal (video data) is input to the correction circuit 124, and the video signal is corrected using the correction value data stored in the correction value table 123.

  The video signal output from the correction circuit 124 is input to the projector 102 via the switch 140. When the switch 140 is on the reference image generation circuit 122 side, the reference image data from the reference image generation circuit 122 is input to the projector 102.

(Operation)
Next, the operation of this embodiment will be described.

  At the time of adjustment work (calibration), the switch 140 is set to the reference image generation circuit 122 side, and the shielding sheet 107 is pulled out from the take-up roller 108 to cover the entire surface of the screen 105, so that outside light does not enter the housing 101. Like that.

  Subsequently, the reference image is projected from the projector 102 onto the screen 105, the reference image projected onto the screen 105 is photographed by the digital camera 106, and the image data of the photographed reference image is transmitted to the correction value calculation circuit 121. To do. The correction value calculation circuit 121 calculates a correction value from the image data of the reference image from which the influence of external light transmitted from the digital camera 106 is removed and the reference image data from the reference image generation circuit 122, and is obtained. The corrected value data is stored in the corrected value table 123. Furthermore, the switch 140 is switched to the correction circuit 124 side, and the adjustment work is completed.

  When the image is actually projected onto the screen, the shielding sheet 107 is wound up by the winding roller 108 so that the image can be viewed from the front side of the screen 105. By inputting the video signal to the correction circuit 124 in such a state, the video signal is corrected using the correction value data stored in the correction value table 123, and an image based on the corrected video signal is displayed on the projector. 102 is projected onto the screen 105.

  As described above, in this embodiment, the influence of external light is removed by a shielding member such as a shielding sheet. Therefore, a reference image capturing digital camera is provided on the back side of the screen to capture the reference image. However, appropriate correction data can be acquired, and appropriate adjustment can be performed.

[Embodiment 2]
(Device configuration)
FIG. 2 is a diagram illustrating a basic configuration example of an image projection system according to the second embodiment. In addition, the same reference number is attached | subjected about the component corresponding to the component of 1st Embodiment shown in FIG.

  The basic configuration of the display unit 100 is the same as that of the first embodiment shown in FIG. However, in the first embodiment, the influence of external light is mechanically removed by the shielding sheet. However, in the present embodiment, the influence of external light is removed by processing in the processing unit 120. For this reason, the projector 102 is turned on / off by the power switch 109 to perform adjustment work.

  Specifically, the process of photographing the screen 105 with the digital camera 106 in a state where the power switch 109 is turned off and no image is projected from the projector 102 onto the screen 105 (a state where the light quantity of the projector 102 is zero), and the power switch 109 Is turned on, and a process of photographing the screen 105 by the digital camera 106 in a state where a reference image is projected from the projector 102 onto the screen 105 is performed. Note that a relay or the like can be used for the power supply 109 switch, which can be electrically controlled.

Regarding the processing unit 120 and the switch 140, the basic configurations of the correction value calculation circuit 121, the reference image generation circuit 122, the correction value table 123, and the correction circuit 124 are the same as those in the first embodiment shown in FIG. . However, in this embodiment, since the influence of external light is removed by the processing in the processing unit 120, the bank switching circuit 125, the frame memory 126, and the external light removal circuit 127 are provided.

  That is, the image data output from the digital camera 106 is input to the bank switching circuit 125, and the bank switching circuit 125 outputs the data from the digital camera 106 corresponding to the on / off state of the power switch 109. The storage destination in the frame memory 126 is switched for both image data. The frame memory 126 is connected to the external light removal circuit 127, and the external light removal circuit 127 uses the both image data stored in the frame memory 126 to perform an operation for removing the influence of the external light. Yes.

(Operation)
Next, the operation of this embodiment will be described.

  At the time of adjustment work (calibration), first, the power switch 109 is turned off so that the light quantity of the projector 102 is zero, so that no image is projected from the projector 102 onto the screen 105. Under such a state, the screen 105 is photographed from the back side by the digital camera 106, and the image data of the photographed image is stored in one bank of the frame memory 126 via the bank switching circuit 125. In this way, image data reflecting only the external light component is obtained.

  Subsequently, the power switch 109 is turned on, the reference image data is supplied from the reference image generation circuit 122 to the projector 102 via the switch 140, and the reference image is projected from the projector 102 onto the screen 105. Under such a state, the screen 105 is photographed from the back side by the digital camera 106, and the image data of the photographed reference image is stored in the other bank of the frame memory 126 via the bank switching circuit 125. In this way, image data of the reference image reflecting the external light component is obtained.

  Subsequently, the external light removal circuit 127 performs arithmetic processing using both image data stored in both banks of the frame memory 126 to obtain image data of the reference image from which the influence of the external light component has been removed. That is, since both image data stored in both banks of the frame memory 126 include an external light component, the influence of the external light component is removed by performing arithmetic processing using both image data. The image data of the reference image thus obtained can be obtained.

  The image data of the reference image from which the influence of the external light obtained by the external light removal circuit 127 is removed is sent to the correction value calculation circuit 121. The correction value calculation circuit 121 calculates the correction value from the image data of the reference image from which the influence of the external light from the external light removal circuit 127 is removed and the reference image data from the reference image generation circuit 122, and is obtained. The correction value data is stored in the correction value table 123. Furthermore, the switch 140 is switched to the correction circuit 124 side, and the adjustment work is completed.

  When the video is actually projected on the screen, the video signal is input to the correction circuit 124, whereby the video signal is corrected using the correction value data stored in the correction value table 123, and the corrected video signal is corrected. Is projected from the projector 102 onto the screen 105.

  In the above-described example, the screen 105 is photographed once each corresponding to the off state and the on state of the power switch 109 during the adjustment work. It is also possible to improve accuracy.

  As described above, in the present embodiment, the influence of external light is removed by the external light removal circuit. Therefore, a reference image capturing digital camera may be provided on the back side of the screen to capture the reference image. Therefore, it is possible to acquire appropriate correction data and perform appropriate adjustment.

(Functional configuration and flowchart)
FIG. 3 is a diagram showing a functional configuration of the image projection system according to the second embodiment, and FIG. 4 is a flowchart showing an operation according to the configuration of FIG. Hereinafter, description will be made with reference to these drawings.

  During the adjustment operation, the light source switch unit 201 is turned off to reduce the light amount of the image projection unit 202 so that no image is projected from the image projection unit 202 to the transmissive display unit 203 (S11). Subsequently, the transmissive display unit 203 is photographed from the back side by the imaging unit 204 (S12), and the image data of the photographed image is stored in the first storage unit 206 via the storage area switching unit 205 (S13).

  Next, the signal switching unit 207 is switched to the reference image generation unit 208 side (S14), the light source switch unit 201 is turned on, the light source of the image projection unit 202 is caused to emit light, and the reference image is projected onto the transmissive display unit 203. (S15). Subsequently, the transmissive display unit 203 is photographed from the back side by the imaging unit 204 (S16), and the image data of the photographed image is stored in the second storage unit 209 (S17).

  Next, using the image data stored in the first storage unit 206 and the second storage unit 209, the external light removal calculation unit 210 performs calculation to remove the influence of external light, and the calculation result is input to the correction value calculation unit 211. Transfer (S18).

  Subsequently, the correction value calculation unit 211 calculates a correction value from the image data of the reference image from which the influence of the external light from the external light removal calculation unit 210 is removed and the reference image data from the reference image generation unit 208. The obtained correction value is stored in the correction value storage unit 212 (S19).

  Finally, by switching the signal switching unit 207 to the correction unit 213 side (S20), when the image is actually projected on the transmissive display unit 203, the signal from the video signal source 214 is corrected by the correction unit 213. Then, an image based on the corrected video signal is projected from the image projection unit 202 to the transmissive display unit 203.

[Embodiment 3]
(Device configuration)
FIG. 5 is a diagram illustrating a basic configuration example of an image projection system according to the third embodiment. In the present embodiment, new components are further added to the second embodiment shown in FIG. Therefore, the same reference numerals are given to the components corresponding to the components of the second embodiment shown in FIG.

  The basic configuration of the display unit 100, the processing unit 120, and the switch 140 is the same as that of the second embodiment shown in FIG. However, in the present embodiment, the processing unit 120 is further provided with a flash memory 128 as a nonvolatile memory.

  The flash memory 128 is provided to correct a difference between an image viewed from the back side of the screen 105 and an image viewed from the front side (observation surface side). In other words, when an image is projected from the projector 102 onto the screen 105, there is a difference in image characteristics between the back side and the front side of the screen 105 due to the characteristics of the screen 105 and the like. This is stored in the flash memory 128.

  The inspection device 160 creates correction data and writes the created correction data to the flash memory 128. The inspection device 160 includes frame memories 161 and 162, a difference circuit 163, and a flash memory writer 164.

  The frame memory 161 stores image data obtained by taking a reference image from the back side of the screen 105 with the digital camera 106, and the frame memory 162 takes a reference image from the front side of the screen 105 with the digital camera 170. The image data obtained in this way is stored. A difference circuit 163 is connected to the frame memories 161 and 162, and the difference circuit 163 performs a difference calculation between the respective image data stored in the frame memories 161 and 162. A flash memory writer 164 is connected to the difference circuit 163 so that difference data obtained by the difference circuit 163 is written into the flash memory 128.

(Operation)
Next, the operation of this embodiment will be described.

  At the factory shipment stage, correction data (difference data) is written in the flash memory 128 as follows. First, a reference image is projected from the projector 102 onto the screen 105 in a place not affected by outside light such as a dark room, and the reference images are obtained by the digital cameras 106 and 170 from the back side and the front side of the screen 105, respectively. The reference image data is stored in the frame memories 161 and 162, respectively. Subsequently, difference data is created from the reference image data by the difference circuit 163, and the difference data is written into the flash memory 128 by the flash memory writer 164. The flash memory 128 in which the difference data is written is mounted in the processing unit 120.

  In this way, the basic operation when using the image projection system shipped from the factory is the same as the operation described in the second embodiment. However, since the difference data is stored in the flash memory 128, the calculation referring to the difference data stored in the flash memory 128 is performed when the external light removal circuit 127 performs the calculation during the adjustment work. .

  In the above-described example, the difference data is written to the flash memory 128 by the flash memory writer 164 in the inspection apparatus 160. However, a writing function to the flash memory 128 may be provided in the processing unit 120. In this case, the difference data obtained by the inspection device 160 is transmitted to the processing unit 120, and the difference data is written to the flash memory 128 mounted in the processing unit 120.

  As described above, in the present embodiment, the reference images are taken from the back side and the front side of the screen, and the difference data of the respective reference image data is stored in the flash memory in advance. The difference in image characteristics can be corrected, and more appropriate adjustment can be performed.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 Display part 101 Case 102 Projector 103,104 Mirror 105 Screen 106 Digital camera 107 Shielding sheet 108 Winding roller 109 Power switch 120 Processing part 121 Correction value calculation circuit 122 Reference image generation circuit 123 Correction value table 124 Correction circuit 125 Bank switching Circuit 126 Frame memory 127 External light removal circuit 128 Flash memory 140 Switch 160 Inspection device 161, 162 Frame memory 163 Difference circuit 164 Flash memory writer 170 Digital camera

Claims (1)

A projector in the housing of the image projection device configured to project light onto the back of the screen;
Configured to take a first image of the back side of the screen while the projector is turned off, and further, while the projector projects a third image to the back side of the screen, A first camera configured to capture a second image of the back side of the screen;
A second camera configured to capture a fifth image of the front surface of the screen not reflecting external light components while the projector projects the third image onto the back surface of the screen; ,
The image data of the first image, and the image data of the second image, and differential data between the image data of the second image data and the fifth image of the image, on the basis, the and configured to calculate to obtain the image data of the fourth image obtained by removing the influence of external light on the image projected on the back of the screen, and the external light effect removal means to remove the influence of outside light,
And configured to calculate a correction value based on the image data of the third image data and the fourth image of the image, and calculating means,
Correction means configured to correct the input video signal based on the calculated correction value,
An image projection apparatus configured to project the image based on the corrected video signal on the back surface of the screen.

Images