JP2018129600A - Projector, image display system, and captured image correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of reducing variation in the luminance of a captured image caused by difference in imaging angle.SOLUTION: A projector comprises: a projection part which projects a projection image onto a projection surface; an imaging part which captures the projection image displayed on the projection surface and generates a captured image; and a correction part which corrects the luminance of the captured image on the basis of the imaging angle of the imaging part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a projector, an image display system, and a method for correcting a captured image.

  A multi-projection system having a plurality of projectors forms a display image (hereinafter also simply referred to as a “display image”) by arranging projection images projected from the projectors on a projection surface. In a multi-projection system, there may be a variation in luminance due to individual differences between projectors in a plurality of projection images. The greater the variation in luminance, the lower the image quality of the display image.

  Patent Document 1 describes a technique that can suppress a reduction in image quality of a display image. In this technique, first, one camera captures a display image and generates a captured image. Subsequently, the image adjustment device controls at least one projector based on the variation in luminance of the plurality of projection images indicated in the captured image to reduce the variation in luminance of the projection image.

JP 2010-85562 A

  By the way, a configuration is conceivable in which a camera is mounted on each projector constituting the multi-projection system, and each camera captures a projection image projected on the projection surface from the projector on which the camera is mounted to generate a captured image. In order to reduce the variation in luminance of the projected image, a technique for controlling at least one projector based on the variation in luminance of the captured image can be considered.

However, this technique may cause the following problems.
On the projection surface, the light incident / reflection characteristics (light attenuation characteristics according to the incident angle and reflection angle of the light with respect to the projection surface) are not uniform. For this reason, the brightness of the captured image generated by the camera changes according to the imaging angle of the camera. For example, when the camera captures a projected image from the normal direction of the projection surface, the captured image is captured from the direction in which the camera is tilted with respect to the normal of the projection surface, even if the projected image is white in the captured image. In such a case, the projected image may be represented by yellowish white in the captured image. That is, in the plurality of captured images, there is a luminance variation that does not exist in the plurality of projection images on the projection surface, specifically, a luminance variation caused by a difference in imaging angle of each camera. For this reason, even if the projector is controlled based on the variation in the brightness of the plurality of captured images, it is difficult to suppress the variation in the brightness of the projection image. Therefore, there is a demand for a technique that can reduce variations in brightness of captured images caused by differences in imaging angles.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a technique capable of reducing variation in luminance of captured images caused by differences in imaging angles.

One aspect of the projector according to the present invention includes a projection unit that projects a projection image on a projection surface, an imaging unit that captures a projection image displayed on the projection surface and generates a captured image, and an imaging angle of the imaging unit. And a correction unit that corrects the luminance of the captured image based on.
When the light incident / reflection characteristics are not uniform on the projection surface, the captured image includes a luminance component corresponding to the imaging angle. According to this aspect, since the luminance of the captured image is corrected based on the imaging angle, the luminance component according to the imaging angle included in the captured image is brought close to the luminance component according to the specific imaging angle. Or it can be matched. Therefore, if the projector according to this aspect is used as a projector constituting the multi-projection system, it is possible to reduce variation in luminance due to a difference in imaging angle in a captured image captured by the imaging unit of each projector.

In one aspect of the projector described above, a correspondence relationship between an incident angle of the projection image on the projection surface, a reflection angle of the projection image from the projection surface, and a luminance attenuation rate of the projection image is stored. The correction unit includes a storage unit, and the correction unit determines a luminance of the captured image based on a luminance attenuation rate of the projection image corresponding to the incident angle and the reflection angle when the imaging angle is used as the reflection angle. It is desirable to correct
When the light incident / reflection characteristics are not uniform on the projection surface, the luminance of the captured image is attenuated by an attenuation rate corresponding to the imaging angle. According to this aspect, the brightness of the captured image is corrected based on the attenuation rate of the brightness of the projection image according to the imaging angle. For this reason, the luminance attenuation rate according to the imaging angle in the captured image can be brought close to or coincident with the luminance attenuation rate according to the specific imaging angle. Therefore, if the projector according to this aspect is used as a projector constituting the multi-projection system, it is possible to reduce variation in luminance due to a difference in imaging angle in a captured image captured by the imaging unit of each projector.

In one aspect of the projector described above, the correction unit is based on a luminance attenuation rate of the projection image corresponding to the incident angle and the reflection angle when the imaging angle is used as the incident angle and the reflection angle. It is desirable to correct the brightness of the captured image.
According to this aspect, since the imaging angle is used not only as the reflection angle but also as the incident angle, the number of parameters used for specifying the luminance attenuation rate of the projected image can be reduced.

1 aspect of the projector mentioned above WHEREIN: The said projection part projects a 1st projection image on the said projection surface with the light of a 1st wavelength range, and also projects a 2nd projection image on the said projection surface with the light of a 2nd wavelength range. The imaging unit captures the first projection image displayed on the projection plane to generate a first captured image, further captures the second projection image displayed on the projection plane, and captures the second captured image. And the storage unit corresponds to the incident angle of the first projection image on the projection surface, the reflection angle of the first projection image from the projection surface, and the luminance attenuation rate of the first projection image. Correspondence relationship between the first information indicating the relationship, the incident angle of the second projection image on the projection surface, the reflection angle of the second projection image from the projection surface, and the luminance attenuation rate of the second projection image And the correction unit is configured to store the imaging angle in the first projection. The luminance of the first captured image based on the luminance attenuation rate of the first projection image corresponding to the incident angle of the first projection image and the reflection angle of the first projection image when used as the reflection angle of the image. And the brightness of the second projection image corresponding to the incident angle of the second projection image and the reflection angle of the second projection image when the imaging angle is used as the reflection angle of the second projection image. It is desirable to correct the brightness of the second captured image based on the attenuation rate of the second captured image.
When the incident / reflection characteristics of light on the projection surface differ according to the wavelength range of light, the luminance attenuation rate according to the imaging angle in the captured image varies according to the wavelength range of the projected image. According to this aspect, the luminance of the first captured image is corrected based on the luminance attenuation rate according to the imaging angle in the first projection image, and based on the luminance attenuation rate according to the imaging angle in the second projection image. The brightness of the second captured image is corrected. For this reason, even if the incident / reflection characteristics of light on the projection surface are different depending on the wavelength range of light, the luminance attenuation rate corresponding to the imaging angle in the captured image of each wavelength range is set to the luminance corresponding to the specific imaging angle. It is possible to approach or match the attenuation rate of

In one aspect of the projector described above, it is desirable that the correction unit further corrects the luminance of the captured image based on an observation angle for the projection image projected on the projection surface.
When the incident / reflection characteristics of light are not uniform on the projection surface, the brightness of an image (hereinafter referred to as “observation image”) visually recognized when an observer observes the projection image on the projection surface is measured with respect to the projection image. It changes according to the angle. For this reason, in a situation where the projected image on the projection surface is observed at a specific observation angle, it is desired to improve the image quality of the observed image observed in that situation.
By the way, in a situation where the light incident / reflection characteristics are not uniform on the projection surface, if the imaging angle and the observation angle are different, there may be a difference in luminance between the projection image and the observation image indicated by the captured image. In this case, even if the projection image is adjusted based on the captured image, it is difficult to increase the image quality of the observation image due to the difference in luminance. Therefore, a technique for reducing the luminance difference between the projected image and the observed image indicated by the captured image is desired.
According to this aspect, the brightness of the captured image is further corrected based on the observation angle for the projection image. For this reason, the luminance component of the captured image can be brought close to or coincident with the luminance component according to the observation angle. Therefore, it is possible to reduce the difference in luminance between the projected image and the observed image indicated by the corrected captured image.
Further, if the projector of this aspect is used as a projector constituting the multi-projection system, it is possible to align the captured images taken by the imaging units of the projectors with observation images observed at a common observation angle. Therefore, for example, if the projection image is adjusted based on the captured image captured by the imaging unit of each projector, the image quality of the observation image can be increased.

In one aspect of the projector described above, a correspondence relationship between an incident angle of the projection image on the projection surface, a reflection angle of the projection image from the projection surface, and a luminance attenuation rate of the projection image is stored. A storage unit, wherein the correction unit determines the luminance attenuation rate of the projection image corresponding to the input angle and the reflection angle when the imaging angle is used as the reflection angle, and the observation angle as the reflection angle. It is desirable to correct the luminance of the captured image based on the luminance attenuation rate of the projection image corresponding to the incident angle and the reflection angle when used as the projection angle.
When the incident / reflection characteristics of light are not uniform on the projection surface, the brightness of the captured image is attenuated with an attenuation rate corresponding to the imaging angle, and the brightness of the observed image is attenuated with an attenuation rate corresponding to the observation angle. . According to this aspect, the luminance of the captured image is corrected based on the luminance attenuation rate of the projection image according to the imaging angle and the luminance attenuation rate of the projection image according to the observation angle. Therefore, the luminance attenuation rate according to the imaging angle in the captured image is brought close to or coincident with the luminance attenuation rate according to the specific imaging angle, and this attenuation rate is further set to the luminance attenuation rate according to the observation angle. Can be close to or matched. Therefore, it is possible to reduce the difference in luminance between the projected image and the observed image indicated by the corrected captured image.
Therefore, if the projector of this aspect is used as a projector constituting the multi-projection system, it is possible to align the captured images taken by the imaging units of the projectors with observation images observed at a common observation angle.

In one aspect of the projector described above, the correction unit has a luminance attenuation rate of the projection image corresponding to the input angle and the reflection angle when the imaging angle is used as the incident angle and the reflection angle, and Based on the incident angle when the imaging angle is used as the incident angle and the observation angle is used as the reflection angle and the luminance attenuation rate of the projected image corresponding to the reflection angle, It is desirable to correct the brightness.
According to this aspect, since the imaging angle is used not only as the reflection angle but also as the incident angle, it is possible to reduce the number of parameters used for specifying the luminance attenuation rate of the projection image.

1 aspect of the projector mentioned above WHEREIN: The said projection part projects a 1st projection image on the said projection surface with the light of a 1st wavelength range, and also projects a 2nd projection image on the said projection surface with the light of a 2nd wavelength range. The imaging unit captures the first projection image displayed on the projection plane to generate a first captured image, further captures the second projection image displayed on the projection plane, and captures the second captured image. And the storage unit corresponds to the incident angle of the first projection image on the projection surface, the reflection angle of the first projection image from the projection surface, and the luminance attenuation rate of the first projection image. Correspondence relationship between the first information indicating the relationship, the incident angle of the second projection image on the projection surface, the reflection angle of the second projection image from the projection surface, and the luminance attenuation rate of the second projection image And the correction unit is configured to store the imaging angle in the first projection. When the first projection image is used as the reflection angle of the image, the luminance attenuation rate of the first projection image corresponding to the incident angle of the first projection image and the reflection angle of the first projection image, and the observation angle are used as the first projection. Based on the incident angle of the first projection image when used as the reflection angle of the image and the attenuation rate of the luminance of the first projection image corresponding to the reflection angle of the first projection image, the first imaging The second projection corresponding to the incident angle of the second projection image and the reflection angle of the second projection image when correcting the brightness of the image and further using the imaging angle as the reflection angle of the second projection image The second projection corresponding to the attenuation rate of the brightness of the image and the incident angle of the second projection image and the reflection angle of the second projection image when the observation angle is used as the reflection angle of the second projection image. Based on image brightness decay rate , It is desirable to correct the luminance of the second image.
According to this aspect, the luminance of the first captured image is corrected based on the luminance attenuation rate according to the imaging angle in the first projection image and the luminance attenuation rate according to the observation angle in the first projection image. The Then, the luminance of the second captured image is corrected based on the luminance attenuation rate according to the imaging angle in the second projection image and the luminance attenuation rate according to the observation angle in the second projection image. For this reason, it becomes possible to change the brightness | luminance of a projection image into the brightness | luminance according to an observation angle for every wavelength range of a projection image.

One aspect of the image display system according to the present invention includes a first projector, a second projector, and a control device that controls at least one of the first projector and the second projector. The projector includes a first projection unit that projects a first image onto a first region of a projection surface, a first imaging unit that captures the first image displayed on the projection surface and generates a second image, and the first A first correction unit configured to generate a third image by correcting the luminance of the second image based on an imaging angle of the first imaging unit, wherein the second projector has a second region in the projection surface. Based on the second projection unit that projects four images, the second imaging unit that captures the fourth image displayed on the projection surface and generates a fifth image, and the imaging angle of the second imaging unit, Correct the brightness of the fifth image to produce the sixth image A second correction unit that performs at least one of the first projector and the second projector based on the relationship between the luminance of the third image and the luminance of the sixth image. And a luminance control unit that controls to reduce a difference between the luminance of the first image and the luminance of the fourth image.
According to this aspect, it is possible to make the luminance component caused by the imaging angle included in the captured image captured by the imaging unit of each projector approach or match the luminance component according to the specific imaging angle. Become. Therefore, it is possible to reduce the variation in the brightness of the captured image due to the difference in the imaging angle. Therefore, by controlling the projector using the corrected captured image, it is possible to reduce the variation among the projected images on the projection surface.

According to one aspect of the method for correcting a captured image of the present invention, a projection image is projected onto a projection surface, and an imaging unit captures the projection image displayed on the projection surface to generate a captured image, and an imaging angle of the imaging unit The brightness of the captured image is corrected based on the above.
Since the brightness of the captured image is corrected based on the imaging angle, the luminance component according to the imaging angle included in the captured image can be brought close to or coincident with the luminance component according to the specific imaging angle. become. Therefore, if the projector according to this aspect is used as a projector constituting the multi-projection system, it is possible to reduce variation in luminance due to a difference in imaging angle in a captured image captured by the imaging unit of each projector.

1 is a diagram showing an image display system 1 according to a first embodiment of the present invention. 1 is a diagram showing a projector 100. FIG. FIG. 3 is a diagram illustrating an example of a projection unit 101. It is the figure which showed an example of the projection image 100i displayed on the projection surface. It is the figure which showed the projection angle of the x direction of the measurement area | region i1, the imaging angle, and the observation angle. It is the figure which showed the projection angle of the y direction of the measurement area | region i1, the imaging angle, and the observation angle. It is the figure which showed an example of the captured image 100p. It is the figure which showed an example of the imaging angle information 103b. It is the figure which showed an example of the observation angle information 103c. It is the figure which showed an example of the attenuation factor information 103d. 1 is a diagram showing a projector 200. FIG. 4 is a flowchart for explaining the operation of the projector 100. 12 is a flowchart for explaining a process of step 1203; It is the figure which showed the projector 100X of 2nd Embodiment. It is a figure for _{demonstrating} the example which calculates projection angle (alpha) _i1 using the distance L1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the size and scale of each part are appropriately different from the actual ones. The embodiments described below are preferred specific examples of the present invention. For this reason, the technically preferable various restrictions are attached | subjected to this embodiment. However, the scope of the present invention is not limited to these forms unless otherwise specified in the following description.

<First Embodiment>
FIG. 1 is a diagram showing an image display system 1 according to the first embodiment of the present invention. The image display system 1 is also referred to as a “multi-projection system”. The image display system 1 includes a projector 100, a projector 200, and a control device 300. The projector 100 is an example of a first projector, and the projector 200 is an example of a second projector.

The control device 300 supplies the first image signal to the projector 100 and supplies the second image signal to the projector 200. The projector 100 projects the projection image 100i according to the first image signal onto the projection surface 400 such as a screen, and the projector 200 projects the projection image 200i according to the second image signal onto the projection surface 400. On the projection surface 400, the display image 11 in which the projection image 100i and the projection image 200i are arranged is displayed. The display image 11 is also referred to as a “composite image”. The display image 11 is observed by the observer 500.
The projected image 100i is an example of a first image, and the projected image 200i is an example of a fourth image. Of the projection surface 400, an area 401 on which the projection image 100i is projected is an example of a first area, and an area 402 on which the projection image 200i is projected is an example of a second area. The projection surface 400 is not limited to the screen and can be changed as appropriate. For example, the projection surface 400 may be a wall.

  The projector 100 includes an imaging unit 102 (see FIG. 2 described later) that captures a projection image 100 i displayed on the projection surface 400, and the projector 200 captures a projection image 200 i displayed on the projection surface 400. 202 (see FIG. 11 described later). Hereinafter, in a situation where the first image signal and the second image signal correspond to the same gradation (hereinafter referred to as “adjustment situation”), an image generated by imaging the projection image 100i by the imaging unit 102 is “imaged”. This is referred to as “image 100p”. In the adjustment state, an image generated by the imaging unit 202 capturing the projection image 200i is referred to as a “captured image 200p”. The captured image 100p and the captured image 200p are used, for example, to reduce variations in luminance between the projected image 100i and the projected image 200i on the projection surface 400.

Next, an outline of the present embodiment will be described.
First, outline 1 will be described.
The projection surface 400 does not have uniform light incident / reflection characteristics (light attenuation characteristics according to the incident angle and reflection angle of light on the projection surface 400). Therefore, in the projection image reflected on the projection surface 400, the attenuation rate changes according to the reflection angle on the projection surface 400. And the brightness | luminance of the projection image reflected by the projection surface 400 becomes low, so that an attenuation factor is large.
The imaging unit 102 receives the projection image 100i reflected by the projection surface 400 at a reflection angle corresponding to the imaging angle of the imaging unit 102, and generates a captured image 100p. For this reason, the luminance of the projection image 100 i received by the imaging unit 102 changes according to the imaging angle of the imaging unit 102. Therefore, the luminance of the captured image 100p changes according to the imaging angle of the imaging unit 102. For the same reason, the luminance of the captured image 200p also changes according to the imaging angle of the imaging unit 202. That is, the captured image 100p and the captured image 200p each include a luminance component corresponding to the imaging angle. Therefore, if the captured image 100p and the captured image 200p have different luminance components according to the imaging angle, even if the projector 100 or 200 is controlled based on the luminance difference between these luminance components, the projected image 100i and the projected image 200i It is difficult to reduce the luminance difference.

  In the present embodiment, the captured image 100p and the captured image 200p are so reduced that the difference between the luminance component according to the imaging angle included in the captured image 100p and the luminance component according to the imaging angle included in the captured image 200p is small. Is corrected. The control device 300 controls the projector 100 or 200 based on the difference in luminance between the corrected captured image 100p and the corrected captured image 200p to reduce the luminance difference between the projected image 100i and the projected image 200i. The description up to this point is the explanation of Outline 1.

Next, the outline 2 will be described.
As described above, since the incident / reflection characteristics of light are not uniform on the projection surface 400, the luminance of the display image 11 visually recognized by the observer 500 changes according to the observation angle of the observer 500. For this reason, when the situation where the display image 11 on the projection surface 400 is observed at a specific observation angle is assumed, it is desirable to improve the image quality of the observation image observed in that situation.
By the way, there is a possibility that a situation (hereinafter referred to as “non-corresponding situation”) in which the imaging angle corresponding to the corrected captured image 100p and the corrected captured image 200p does not correspond to the observation angle of the observer 500 may occur. is there. For this reason, even if the control device 300 controls the projector 100 or 200 based on the luminance difference between the corrected captured image 100p and the corrected captured image 200p under non-corresponding conditions, the image quality of the observed image is improved. It will be difficult to raise.

  In the present embodiment, the captured image 100p is corrected to generate a corrected image 100a so that the luminance difference between the display image formed by the captured image 100p and the captured image 200p and the observed image is small, and the captured image is generated. 200p is corrected to generate a corrected image 200a. The control device 300 controls the image quality of the observation image by controlling at least one of the projection image 100i and the projection image 200i based on the projection image 100i indicated by the correction image 100a and the projection image 200i indicated by the correction image 200a. Improve. This is the description of the outline 2.

  In the outline 1 and the outline 2, only one of the captured image 100p and the captured image 200p is used instead of the technique for correcting both the captured image 100p and the captured image 200p (hereinafter referred to as “first technique”). A correction method may be used.

Next, details of the present embodiment will be described.
FIG. 2 is a diagram showing the projector 100. The projector 100 includes a projection unit 101, an imaging unit 102, a storage unit 103, and a control unit 104.

  The projection unit 101 is an example of a first projection unit. The projection unit 101 projects the projection image 100 i onto the projection surface 400. FIG. 3 is a diagram illustrating an example of the projection unit 101. The projection unit 101 includes a light source 101a that emits light source light, a color separation optical system 101b, light modulation units 101cR, 101cG, and 101cB, a cross dichroic prism 101d, a projection lens 101e, and a lens shift mechanism 101f. It consists of

  The color separation optical system 101b separates the light source light into three colors of R (red) light, G (green) light, and B (blue) light. The red wavelength range is 610 nm to 750 nm, the green wavelength range is 500 nm to 560 nm, and the blue wavelength range is 435 nm to 480 nm. The color separation optical system 101b guides R light to the light modulation unit 101cR, guides G light to the light modulation unit 101cG, and guides B light to the light modulation unit 101cB. The color separation optical system 101b includes a first dichroic mirror 101b1, a second dichroic mirror 101b2, and reflection mirrors 101b3, 101b4, and 101b5.

  The first dichroic mirror 101b1 reflects R light and transmits G light and B light among the three colors of RGB light. The second dichroic mirror 101b2 reflects G light out of G light and B light and transmits B light.

  The R light reflected by the first dichroic mirror 101b1 is then reflected by the reflection mirror 101b4 and enters the light modulation unit 101cR. The G light transmitted through the first dichroic mirror 101b1 is then reflected by the second dichroic mirror 101b2 and enters the light modulation unit 101cG. The B light that has passed through the second dichroic mirror 101b2 is then reflected by the reflection mirrors 101b3 and 101b5 and enters the light modulation unit 101cB.

  Each of the light modulation units 101cR, 101cG, and 101cB modulates the spatial intensity distribution of incident light. Each of the light modulation units 101cR, 101cG, and 101cB is, for example, a liquid crystal light valve. Each of the light modulation units 101cR, 101cG, and 101cB is not limited to the liquid crystal light valve, and can be changed as appropriate.

  The light modulator 101cR modulates the R light from the reflection mirror 101b4 to generate R image light. The light modulation unit 101cG modulates the G light from the second dichroic mirror 101b2 to generate G image light. The light modulation unit 101cB modulates the B light from the reflection mirror 101b5 to generate B image light.

  The cross dichroic prism 101d combines the R image light, the G image light, and the B image light to generate combined light of a color image. The projection lens 101e enlarges the combined light (color image light) of the color image and projects it on the projection surface 400 for display.

  The lens shift mechanism 101f shifts the position of the projection image 100i on the projection surface 400 by shifting the projection lens 101e in a direction perpendicular to the optical axis 101eX of the projection lens 101e.

FIG. 4 is a diagram illustrating an example of a projection image 100 i displayed on the projection surface 400. Measurement areas i1 to i9 are shown in the projection image 100i. Hereinafter, each of the measurement regions i1 to i9 is also referred to as “measurement region in”. Here, n = 1 to 9. The measurement region in is used, for example, to specify the imaging angle of the imaging unit 102.
FIG. 4 further shows an optical path 1p, an optical path 1r, and an optical path 1o. The optical path 1p is an optical path through which the measurement region i1 indicated in the projection image 100i reaches the projection surface 400 from the projection unit 101. The optical path 1r is an optical path through which the measurement region i1 reflected by the projection surface 400 passes from the projection surface 400 to the imaging unit 102. The optical path 1o is an optical path through which the measurement region i1 reflected by the projection plane 400 reaches the observer 500 from the projection plane 400.
In FIG. 4, the y direction indicates the vertical direction. The x direction indicates a direction perpendicular to the vertical direction y. Hereinafter, the x direction is also referred to as “horizontal direction”, and the y direction is also referred to as “vertical direction”.

  Here, the projection angle, the imaging angle, and the observation angle will be described. The projection angle, the imaging angle, and the observation angle are indicated by angles with respect to the normal line H (see FIGS. 5 and 6) of the projection surface 400, respectively.

FIG. 5 shows the normal H of the projection surface 400, the angle α _i1 of the x-direction component of the projection angle of the measurement area i1, the angle α _oC1 of the x-direction component of the imaging angle of the measurement area i1, and the observation of the measurement area i1. It is the figure which showed angle (alpha) _oS1 of the x direction component of an angle. In FIG. 5, the measurement regions i1 to i3 are shown in a circle for ease of explanation.

FIG. 6 shows the normal H of the projection surface 400, the angle β _i1 of the y-direction component of the projection angle of the measurement area i1, the angle β _oC1 of the y-direction component of the imaging angle of the measurement area i1, and the observation of the measurement area i1. It is the figure which showed angle (beta) _oS1 of the y direction component of an angle. In FIG. 6, the measurement areas i1, i4 and i7 are shown in a circle for ease of explanation.

  Returning to FIG. The imaging unit 102 is an example of a first imaging unit. For example, the imaging unit 102 captures the projection image 100i projected on the projection surface 400 in the adjustment state, and generates the captured image 100p. The imaging unit 102 is fixed to the projector 100, and the angle of view of the imaging unit 102 is also fixed. For this reason, when the position of the projection image 100i is shifted on the projection surface 400 by the lens shift mechanism 101f, the position of the projection image 100i is also shifted on the captured image 100p. Furthermore, the position in the captured image 100p corresponds to the imaging angle for a part of the projected image 100i (for example, the measurement region in) indicated at the position. FIG. 7 is a diagram illustrating an example of the captured image 100p. In FIG. 7, the projected image 100i is shown in the captured image 100p.

  Returning to FIG. The storage unit 103 is an example of a computer-readable recording medium. Furthermore, the storage unit 103 is a non-transitory recording medium. The storage unit 103 is a known arbitrary type of recording medium such as a semiconductor recording medium, a magnetic recording medium, or an optical recording medium. The storage unit 103 may be a recording medium in which these recording media are combined. In this specification, “non-transient” recording media are readable by all computers except for recording media such as transmission lines that temporarily store transitory and propagating signals. However, this does not exclude volatile recording media.

  The storage unit 103 stores a program 103a, imaging angle information 103b, observation angle information 103c, and attenuation rate information 103d.

  The program 103a defines the operation of the projector 100. The program 103a may be provided in the form of distribution via a network (not shown) and then installed in the storage unit 103.

  The imaging angle information 103b is information regarding the imaging angle of the imaging unit 102. FIG. 8 is a diagram illustrating an example of the imaging angle information 103b. In the imaging angle information 103b shown in FIG. 8, the pixel position (x, y) and the imaging angle (horizontal component α, vertical component β) in the captured image 100p are associated with each other. Note that the captured image 100p is generated by the imaging unit 102 in which u pixels are arranged in the x direction and v pixels are arranged in the y direction.

The observation angle information 103c indicates an observation angle in a situation where the observer 500 observes the display image 11 from a presumed observation position. FIG. 9 is a diagram illustrating an example of the observation angle information 103c. In the observation angle information 103c shown in FIG. 9, the horizontal component α _oSt of the observation angle and the vertical component β _oSt of the observation angle are shown.

  The attenuation rate information 103d indicates light incident / reflection characteristics on the projection surface 400. Furthermore, the attenuation rate information 103d is a correspondence relationship between the incident angle (θi) of light on the projection surface 400, the reflection angle (θo) of light from the projection surface 400, and the attenuation rate (%) of light. Represents. The attenuation rate information 103d indicates the luminance attenuation rate (%) by f (θi, θo). FIG. 10 is a diagram schematically illustrating an example of the attenuation rate information 103d. In the example shown in FIG. 10, the state where the incident angle (θi) and the reflection angle (θo) are both 0 ° is used as the reference state (attenuation rate = 0%).

  Returning to FIG. The control unit 104 is a processing device (computer) such as a CPU (Central Processing Unit). The control unit 104 reads and executes the program 103a from the storage unit 103, thereby realizing an image signal correction unit 104a, an imaging angle determination unit 104b, and a captured image correction unit 104c.

  The image signal correction unit 104a receives the first image signal from the control device 300, and performs correction such as γ correction on the first image signal. The image signal correction unit 104a supplies the corrected first image signal to the projection unit 101, and causes the projection unit 101 to project the projection image 100i.

The imaging angle determination unit 104b determines the imaging angle of the imaging unit 102 based on the captured image 100p and the imaging angle information 103b. For example, the measurement region i7, where indicated in the pixel position of the captured image 100p (1, 1), the imaging angle determining unit 104b, an alpha ₁₁ as the horizontal component of the imaging angle of the imaging unit 102 of the measurement region i7 Then, β ₁₁ is determined as a vertical component of the imaging angle of the imaging unit 102 for the measurement region i7.

  The captured image correction unit 104c is an example of a correction unit and a first correction unit. The captured image correction unit 104 c corrects the luminance of the captured image 100 p based on the imaging angle of the imaging unit 102. In the present embodiment, the captured image correction unit 104c corrects the luminance of the captured image 100p based on the imaging angle of the imaging unit 102, the observation angle information 103c, and the attenuation rate information 103d, and generates a corrected image 100a.

  FIG. 11 is a diagram showing the projector 200. The projector 200 includes a projection unit 201, an imaging unit 202, a storage unit 203, and a control unit 204.

  The projection unit 201 is an example of a second projection unit. The projection unit 201 projects the projection image 200 i on the projection surface 400. The projection unit 201 has the same configuration as the projection unit 101 of the projector 100.

  The imaging unit 202 is an example of a second imaging unit. The imaging unit 202 captures the projection image 200i displayed on the projection surface 400 and generates a captured image 200p. The imaging unit 202 has the same configuration as the imaging unit 102 of the projector 100.

  The storage unit 203 is an example of a computer-readable recording medium. The storage unit 203 stores a program 203a, imaging angle information 203b, observation angle information 203c, and attenuation rate information 203d. The program 203a defines the operation of the projector 200. The imaging angle information 203b indicates the same content as the imaging angle information 103b of the projector 100. The observation angle information 203c indicates the same content as the observation angle information 103c of the projector 100. The attenuation rate information 203d indicates the same content as the attenuation rate information 103d of the projector 100.

  The control unit 204 is a processing device (computer) such as a CPU. The control unit 204 reads and executes the program 203a from the storage unit 203, thereby realizing an image signal correction unit 204a, an imaging angle determination unit 204b, and a captured image correction unit 204c.

  The image signal correction unit 204a receives the second image signal from the control device 300, and performs correction such as γ correction on the second image signal. The image signal correction unit 204a supplies the corrected second image signal to the projection unit 201 and causes the projection unit 201 to project the projection image 200i.

  The imaging angle determination unit 204b determines the imaging angle of the imaging unit 202 based on the captured image 200p and the imaging angle information 203b.

  The captured image correction unit 204c is an example of a second correction unit. The captured image correction unit 204c corrects the luminance of the captured image 200p based on the imaging angle of the imaging unit 202. In the present embodiment, the captured image correction unit 204c corrects the luminance of the captured image 200p based on the imaging angle of the imaging unit 202 determined by the imaging angle determination unit 204b, the observation angle information 203c, and the attenuation rate information 203d. Thus, the corrected image 200a is generated.

  The control device 300 includes a luminance control unit 301. The luminance control unit 301 supplies the first image signal to the projector 100 and supplies the second image signal to the projector 200. In addition, the luminance control unit 301 supplies a luminance value adjustment parameter to either or either of the projector 100 and the projector 200 based on the luminance relationship between the corrected image 100a and the corrected image 200a, and the projected image 100i. The brightness difference from the projected image 200i is reduced.

Next, the operation will be described. Hereinafter, operations performed in the adjustment state will be described. FIG. 12 is a flowchart for mainly explaining the operation of the projector 100.
The luminance control unit 301 supplies an R image signal SR corresponding to the R image 100iR in which the measurement regions i1 to i9 are shown on the R (red) background to the image signal correction unit 104a. The R image 100iR is an example of the projection image 100i, and the R image signal SR is an example of the first image signal. Each of the measurement regions i1 to i9 is a circle, the circumference is indicated by black, and the inside of the circle is indicated by R of the background color. Note that the shapes of the measurement regions i1 to i9 are not limited to circles and can be changed as appropriate. The image signal correction unit 104a performs correction such as γ correction on the R image signal SR. Subsequently, the image signal correction unit 104a supplies the corrected R image signal SR to the projection unit 101, and causes the projection unit 101 to project the R image 100iR with the R light (step S1201).

  Subsequently, the imaging unit 102 captures the R image 100iR displayed on the projection surface 400 to generate an R captured image 100pR (step S1202). The R captured image 100pR is an example of the captured image 100p. Subsequently, the imaging unit 102 supplies the R captured image 100pR to the control unit 104 (specifically, the imaging angle determination unit 104b and the captured image correction unit 104c).

  The control unit 104 corrects the R captured image 100pR to generate an R corrected image 100aR (step S1203). The R corrected image 100aR is an example of the corrected image 100a.

FIG. 13 is a flowchart for explaining the processing of step 1203.
When the imaging angle determination unit 104b receives the R captured image 100pR, the imaging angle when the imaging unit 102 images the measurement region in based on the pixel position (xn, yn) of each measurement region in in the R captured image 100pR. (Α _oCn , β _oCn ) is specified (step S1301). Specifically, the imaging angle determination unit 104b refers to the imaging angle information 103b (see FIG. 8), and for each measurement area in, the imaging angle (xn, yn) corresponding to the pixel position (xn, yn) of the measurement area in. α, β) is specified as the imaging angle (α _oCn , β _oCn ) for the measurement region in. In step S1301, the imaging angles (α _oC1 , β _oC1 ) to (α _oC9 , β _oC9 ) are specified.
Here, the pixel position corresponding to the center of the measurement region in is used as the pixel location (xn, yn) of the measurement region in. Note that the pixel position (xn, yn) of the measurement area in is not limited to the pixel position corresponding to the center of the measurement area in, and may be a pixel position corresponding to a part of the measurement area in.
Subsequently, the imaging angle determination unit 104b _supplies the imaging angles (α _oCn1 , β _oC1 ) to (α _oCn9 , β _oC9 ) to the captured image correction unit 104c.

When the captured image correction unit 104c receives the imaging angles (α _oC1 , β _oC1n ) to (α _oCn9 , β _oC9 ), it identifies the projection angle (α _in , β _in ) for each measurement region in on the projection surface 400. (Step S1302). Here, it is assumed that the distance between the projection unit 101 and the imaging unit 102 is sufficiently smaller than the distance from the projector 100 to the projection surface 400. For this reason, the captured image correction unit 104c _identifies the imaging angle (α _oCn , β _oCn ) as the projection angle (α _in , β _in ). In step S1302, the projection angles (α _oC1 , β _oC1 ) to (α _oC9 , β _oC9 ) are specified as the projection angles (α _i1 , β _i1 ) to (α _i9 , β _i9 ).

Subsequently, the captured image correction unit 104c _specifies the observation angles (α _oSt , β _oSt ) indicated by the observation angle information 103c as the observation angles (α _oSn , β _oSn ) (step S1303). In step S1303, the observation angles (α _oS1 , β _oS1 ) to (α _oSn9 , β _oS9 ) are specified.

  Subsequently, the captured image correction unit 104c extracts image information of each measurement region in from the R captured image 100pR (step S1304). In the present embodiment, the captured image correction unit 104c extracts image information (image information indicating R) inside the circumference of each measurement region in from the R captured image 100pR.

Subsequently, the captured image correction unit 104c generates a value of the CIE (Commission Internationale de l'Eclairage) color system corresponding to the image information indicating the measurement region in as the captured value (step S1305). As values of the CIE color system, for example, values of the XYZ color system (CIE 1931 color system), values of the X10Y10Z10 color system (CIE 1964 color system), chromaticity coordinates (x , Y), chromaticity coordinates (x10, y10) in the X10Y10Z10 color system are used. In addition, as the value of the CIE color system, the lightness or color coordinates of the CIELAB color space (CIE 1976 L ^* a ^* b ^* color space) or the lightness of the CIELV color space (CIE 1976 L ^* u ^* v ^* color space) Or color coordinates may be used.
In the present embodiment, the captured image correction unit 104c generates, as captured values (X _n , Y _n , Z _n ), values of the XYZ color system corresponding to the image information indicating the measurement region in. The step S1305, the imaging values _{(X 1, Y 1, Z} 1) ~ (X 9, Y 9, Z 9) is generated. Note that the captured image correction unit 104c may use a value different from the value of the XYZ color system as the value of the CIE display system.

  Subsequently, the captured image correction unit 104c specifies one of the measurement areas in which the captured image correction unit 104c has not corrected as the specified area im (step S1306).

Subsequently, the captured image correction unit 104c determines a luminance correction value Am for the designated area im (step S1307). In step S1307, the captured image correction unit 104c first specifies the attenuation rate K _Cm of the captured values (X _m , Y _m , Z _m ) of the designated area im. The attenuation factor K _Cm is an example of a first attenuation factor. Here, the attenuation rate K _Cm means an attenuation rate according to the projection angle (incident angle) and the imaging angle (reflection angle) for the designated region im. Furthermore, the attenuation rate K _Cm is an image (hereinafter referred to as “reference image”) when the designated area im is reflected on the projection surface 400 at a reflection angle of 0 ° after being projected onto the projection surface 400 at an incident angle of 0 °. The attenuation rate of the imaging value (X _m , Y _m , Z _m ) in the designated area im with respect to the imaging value of “)”. Here, the attenuation rate of the reference image is set to 0%. Therefore, by dividing the imaging value (X _m , Y _m , Z _m ) of the designated area im by the value of “1−attenuation rate K _Cm ”, the reference image (attenuation rate = 0%) is obtained for the designated area im. Can be obtained.

The captured image correction unit 104c uses the imaging angle for the designated area im as the incident angle and the reflection angle. Then, the captured image correction unit 104c specifies the attenuation rate of the brightness of the projection image corresponding to the incident angle and the reflection angle as the attenuation rate K _Cm using the attenuation rate information 103d (see FIG. 10).
For example, when the designated area im is the measurement area i1, the captured image correction unit 104c sets the attenuation rate K _C1 of the measurement area i1 as follows.
K _C1 = (f (α _i1 , α _oC1 ) + f (β _i1 , β _oC1 )) / 2
= (F (α _oC1 , α _oC1 ) + f (β _oC1 , β _oC1 )) / 2
The calculation result is used.

Subsequently, the captured image correction unit 104c determines the luminance attenuation rate for the observation image (hereinafter referred to as “observation image oim”) when the specified region im on the projection surface 400 is observed at the observation angle indicated by the observation angle information 103c. _Specify K _Sm . The attenuation factor K _Sm is an example of a second attenuation factor. Here, the attenuation rate K _Sm means an attenuation rate according to the projection angle (incident angle) and the observation angle (reflection angle) for the designated region im. Furthermore, the attenuation rate K _Sm means the attenuation rate of the luminance of the observed image oim with respect to the luminance of the reference image. Therefore, the observed image oim can be obtained by multiplying the reference image (attenuation rate = 0%) by the value of “1−attenuation rate K _Sm ”.

The captured image correction unit 104c uses the imaging angle for the specified area im as the incident angle, and uses the observation angle indicated by the observation angle information 103c as the reflection angle. Then, the captured image correction unit 104c specifies the attenuation rate of the luminance of the projection image corresponding to the incident angle and the reflection angle as the attenuation rate K _Sm using the attenuation rate information 103d (see FIG. 10).
For example, when the designated area im is the measurement area i1, the captured image correction unit 104c sets the attenuation rate K _S1 of the measurement area i1 as follows.
K _S1 = (f (α _i1 , α _oS1 ) + f (β _i1 , β _oS1 )) / 2
= (F (α _oC1 , α _oS1 ) + f (β _oC1 , β _oS1 )) / 2
The calculation result is used.

Subsequently, the captured image correction unit 104c obtains a calculation result “(1−1) by dividing the value of“ 1−attenuation rate K _Sm ”by the value of“ 1−attenuation rate K _Cm ”as the correction value Am for the designated region im. K _Sm ) / (1−K _Cm ) ”.

Subsequently, the captured image correction unit 104c corrects the captured values (X _m , Y _m , Z _m ) of the designated area im using the correction value Am (step S1308). In step S1308, if the imaging values (X _m , Y _m , Z _m ) of the specified area im after correction are imaging values (X _m ′, Y _m ′, Z _m ′), the captured image correction unit 104c As described above, the imaging values (X _m , Y _m , Z _m ) are corrected.
(X _m ′, Y _m ′, Z _m ′) = (X _m , Y _m , Z _m ) × (1−K _Sm ) / (1−K _Cm ).

  Subsequently, the captured image correction unit 104c cancels the designated area im (step S1309). Subsequently, the captured image correction unit 104c determines whether correction has been completed for all measurement regions in (step S1310). If correction has not been completed for all measurement regions in (step S1310: NO), the captured image correction unit 104c returns the process to step S1306.

  On the other hand, when the correction has been completed for all the measurement regions in (step S1310: YES), the captured image correction unit 104c selects the region where the R image 100iR is indicated from the entire region of the R captured image 100pR. Then, it is specified as a correction target area (step S1311).

  Subsequently, the captured image correction unit 104c calculates a correction value for a portion other than the measurement region in in the correction target region by linear interpolation using the correction value An of the measurement region in (step S1312). Since linear interpolation is a known technique, a detailed description is omitted.

Subsequently, the captured image correction unit 104c corrects the captured value by multiplying the captured value of the portion other than the measurement region in in the correction target region by the correction value of the portion (step S1313).
Through the processes in steps S1308 and S1313, the entire correction target area is corrected, and as a result, an R-corrected image 100aR is generated. Subsequently, the captured image correction unit 104 c supplies the R correction image 100 a R to the control device 300. Thus, step S1203 shown in FIG. 12 is completed.

  When the control device 300 receives the R correction image 100aR, the control device 300 supplies the image signal correction unit 104a with a G image signal SG corresponding to the G image 100iG in which the measurement regions i1 to i9 are shown on the background of G (green). The G image 100iG is an example of the projection image 100i, and the G image signal SG is an example of the first image signal. The image signal correction unit 104a performs correction such as γ correction on the G image signal SG, supplies the corrected G image signal SG to the projection unit 101, and transmits the G image to the projection unit 101 with G light. 100 iG is projected (step S1204).

  Subsequently, the imaging unit 102 captures the G image 100iG displayed on the projection surface 400 to generate a G captured image 100pG (step S1205). Subsequently, the imaging unit 102 supplies the G captured image 100pG to the imaging angle determination unit 104b and the captured image correction unit 104c.

  The control unit 104 corrects the G captured image 100pG to generate a G corrected image 100aG (step S1206). The process of correcting the G captured image 100pG to generate the G corrected image 100aG is similar to the process of correcting the R captured image 100pR and generating the R corrected image 100aR described above. For this reason, detailed description of step S1206 is omitted. The control unit 104 outputs the G corrected image 100aG to the control device 300.

  When the control device 300 receives the G correction image 100aG, the control device 300 supplies the image signal correction unit 104a with a B image signal SB corresponding to the B image 100iB in which the measurement regions i1 to i9 are shown on the background of B (blue). The B image 100iB is an example of the projection image 100i, and the B image signal SB is an example of the first image signal. The image signal correction unit 104a performs correction such as γ correction on the B image signal SB, supplies the corrected B image signal SB to the projection unit 101, and supplies the B image to the projection unit 101 with B light. 100 iB is projected (step S1207).

  Subsequently, the imaging unit 102 captures the B image 100iB displayed on the projection surface 400 to generate a B captured image 100pB (step S1208). The B captured image 100pB is an example of the captured image 100p. Subsequently, the imaging unit 102 supplies the B captured image 100pB to the imaging angle determination unit 104b and the captured image correction unit 104c.

  The control unit 104 corrects the B captured image 100pB to generate a B corrected image 100aB (step S1209). The B corrected image 100aB is an example of the corrected image 100a. The process of correcting the B captured image 100pB to generate the B corrected image 100aB is similar to the process of correcting the R captured image 100pR and generating the R corrected image 100aR described above. For this reason, detailed description of step S1209 is omitted. The control unit 104 outputs the B correction image 100aB to the control device 300.

  Further, the projector 200 is a method according to a method in which the projector 100 generates the R correction image 100aR, the G correction image 100aG, and the B correction image 100aB, and generates the R correction image 200aR, the G correction image 200aG, and the B correction image 200aB. Generate. Then, the projector 200 supplies the R correction image 200aR, the G correction image 200aG, and the B correction image 200aB to the control device 300.

  Each of the R corrected image 100aR, the G corrected image 100aG, and the B corrected image 100aB and each of the R corrected image 200aR, the G corrected image 200aG, and the B corrected image 200aB are images observed at the observation angle indicated by the observation angle information 103c. Show. For this reason, in the R correction image 100aR and the R correction image 200aR, the G correction image 100aG and the G correction image 200aG, and the B correction image 100aB and the B correction image 200aB, the luminance variation due to the difference in imaging angle is reduced or eliminated. Has been. Therefore, in the luminance difference between the R corrected image 100aR and the R corrected image 200aR, the luminance difference between the G corrected image 100aG and the G corrected image 200aG, and the luminance difference between the B corrected image 100aB and the B corrected image 200aB, the projector 100 The luminance difference due to the individual difference between the projector 200 and the projector 200 becomes dominant.

The luminance control unit 301 includes the luminance relationship between the R correction image 100aR and the R correction image 200aR, the luminance relationship between the G correction image 100aG and the G correction image 200aG, and the luminance between the B correction image 100aB and the B correction image 200aB. Based on the above relationship, the brightness value adjustment parameters for each of RGB are supplied to the projector 100 and / or the projector 200.
For example, when the luminance of the R correction image 100aR is lower than the luminance of the R correction image 200aR, the luminance control unit 301 increases the luminance of the R image 100iR so that the R correction image 100aR and the R correction image 200aR match in luminance. R brightness value adjustment parameters are supplied to the projector 100.
For example, when the luminance of the G correction image 200aG is lower than the luminance of the G correction image 100aG, the luminance control unit 301 sets the luminance of the G image 200iG so that the G correction image 200aG and the G correction image 100aG match in luminance. The G brightness value adjustment parameter to be increased is supplied to the projector 200.
The luminance control unit 301 reduces the difference between the luminance of the projection image 100i and the luminance of the projection image 200i in the adjustment state by separately supplying the luminance value adjustment parameters for RGB. The image signal correction units 104a and 204a correct the luminance of the R image according to the R luminance value adjustment parameter, correct the luminance of the G image according to the G luminance value adjustment parameter, and adjust the B luminance value adjustment parameter. The brightness of the B image is corrected according to

  According to the present embodiment, the captured image correction unit 104c corrects the luminance of the captured image 100p (the R captured image 100pR, the G captured image 100pG, and the B captured image 100pB) based on the imaging angle of the imaging unit 102. For this reason, the luminance component according to the imaging angle included in the captured image 100p can be brought close to or coincident with the luminance component according to a specific imaging angle (for example, imaging angle = 0 °).

  The captured image correction unit 104c corrects the luminance of the captured image 100p based on the luminance attenuation rate of the projection image corresponding to the incident angle and the reflection angle when the imaging angle is used as the reflection angle. Therefore, the luminance attenuation rate according to the imaging angle in the captured image 100p can be brought close to or coincident with the luminance attenuation rate according to a specific imaging angle (for example, imaging angle = 0 °).

  The captured image correction unit 104c further corrects the luminance of the captured image 100p based on the observation angle. For this reason, the luminance component of the captured image 100p can be brought close to or coincident with the luminance component according to the observation angle. Accordingly, it is possible to reduce the difference in luminance between the corrected image 100a (R corrected image 100aR, G corrected image 100aG, B corrected image 100aB) and the observed image.

  In the image display system 1, a luminance component corresponding to a specific imaging angle is converted into a luminance component corresponding to the imaging angle included in the captured image 100p and a luminance component corresponding to the imaging angle included in the captured image 200p. It is possible to approach or match. Therefore, it is possible to reduce variations in luminance between the captured image 100p and the captured image 200p due to the difference in imaging angle. Therefore, by controlling at least one of the projector 100 and the projector 200 based on the luminance relationship between the corrected image 100a and the corrected image 200a, the luminance of the projected image 100i and the projected image 200i on the projection surface 400 can be determined. The difference between can be reduced.

Second Embodiment
In the first embodiment, common attenuation rate information 103d is used when calculating attenuation rates for each of RGB. However, there is also a projection surface 400 having different incident / reflection characteristics for each RGB. Therefore, in the second embodiment of the present invention, attenuation rate information is used for each RGB.

  FIG. 14 is a diagram illustrating a projector 100X according to the second embodiment. In FIG. 14, the same components as those shown in FIG. Hereinafter, the projector 100X will be described focusing on differences from the projector 100.

  In the projector 100X, the attenuation rate information 103d includes attenuation rate information 103dR, attenuation rate information 103dG, and attenuation rate information 103dB.

The attenuation factor information 103dR indicates the incident / reflection characteristic of the R light on the projection surface 400. Furthermore, the attenuation rate information 103dR includes the incident angle (θi) of the R light on the projection surface 400, the reflection angle (θo) of the R light from the projection surface 400, and the attenuation rate (%) of the luminance of the R light. And the corresponding relationship. In the present embodiment, the attenuation rate information 103dR indicates the luminance attenuation rate (%) = f _R (θi, θo).

The attenuation rate information 103dG indicates the incident / reflection characteristics of G light on the projection surface 400. Furthermore, the attenuation rate information 103dG includes the incident angle (θi) of the G light on the projection surface 400, the reflection angle (θo) of the G light from the projection surface 400, and the attenuation rate (%) of the luminance of the G light. And the corresponding relationship. In the present embodiment, the attenuation rate information 103dG indicates the luminance attenuation rate (%) = f _G (θi, θo).

The attenuation rate information 103 dB indicates the incident / reflection characteristics of the B light on the projection surface 400. Furthermore, the attenuation rate information 103 dB includes the incident angle (θi) of the B light on the projection surface 400, the reflection angle (θo) of the B light from the projection surface 400, and the attenuation rate (%) of the luminance of the B light. And the corresponding relationship. In the present embodiment, the attenuation rate information 103 dB indicates the luminance attenuation rate (%) = f _B (θi, θo).

When the captured image correction unit 104c calculates the attenuation rate (hereinafter referred to as “K _RCn ”) when the imaging angle is used as the incident angle and the reflection angle for the measurement region in in the R captured image 100pR, the attenuation rate information 103 dR is used.
In this case, the attenuation rate K _RCn is K _RCn = (f _R (α _in , α _oCn ) + f _R (β _in , β _oCn )) / 2
= (F _R (α _oCn , α _oCn ) + f _R (β _oCn , β _oCn )) / 2
It becomes.

When the captured image correction unit 104c calculates an attenuation rate (hereinafter referred to as “K _GCn ”) when the imaging angle is used as the incident angle and the reflection angle for the measurement region in in the G captured image 100pG, the attenuation rate information 103 dG is used.
In this case, the decay rate K _GCn is K _GCn = (f _G (α _in , α _oCn ) + f _G (β _in , β _oCn )) / 2
= (F _G (α _oCn , α _oCn ) + f _G (β _oCn , β _oCn )) / 2
It becomes.

When the captured image correction unit 104c calculates the attenuation rate (hereinafter referred to as “K _BCn ”) when the imaging angle is used as the incident angle and the reflection angle for the measurement region in in the B captured image 100pB, the attenuation rate information 103 dB is used.
In this case, the attenuation rate K _BCn is K _BCn = (f _B (α _in , α _oCn ) + f _B (β _in , β _oCn )) / 2
= (F _B (α _oCn , α _oCn ) + f _B (β _oCn , β _oCn )) / 2
It becomes.

Similarly, the captured image correction unit 104c uses the attenuation rate (hereinafter referred to as “K _RSn ”) when the imaging angle is used as the incident angle and the observation angle is used as the reflection angle for the measurement region in in the R captured image 100pR. When calculating, attenuation rate information 103dR is used.
In this case, the attenuation rate K _RSn is K _RSn = (f _R (α _in , α _oSn ) + f _R (β _in , β _oSn )) / 2
= (F _R (α _oCn , α _oSn ) + f _R (β _oCn , β _oSn )) / 2
It becomes.

When the captured image correction unit 104c calculates an attenuation factor (hereinafter referred to as “K _GSn ”) when the imaging angle is used as the incident angle and the observation angle is used as the reflection angle for the measurement region in in the G captured image 100pG. The attenuation rate information 103dG is used.
In this case, the attenuation rate K _GSn is K _GSn = (f _G (α _in , α _oSn ) + f _G (β _in , β _oSn )) / 2
= (F _G (α _oCn , α _oSn ) + f _G (β _oCn , β _oSn )) / 2
It becomes.

When the captured image correction unit 104c calculates an attenuation rate (hereinafter referred to as “K _BSn ”) when the imaging angle is used as the incident angle and the observation angle is used as the reflection angle for the measurement region in in the B captured image 100pB. The attenuation rate information 103 dB is used.
In this case, the attenuation rate K _BSn is K _BSn = (f _B (α _in , α _oSn ) + f _B (β _in , β _oSn )) / 2
= (F _B (α _oCn , α _oSn ) + f _B (β _oCn , β _oSn )) / 2
It becomes.

Here, the RGB imaging values in the measurement region in are respectively (X _Rn , Y _Rn , Z _Rn ), (X _Gn , Y _Gn , Z _Gn ), (X _Bn , Y _Bn , Z _Bn ) and corrected. The imaging values of the subsequent measurement area in are represented by (X _Rn ', Y _Rn ', Z _Rn '), (X _Gn ', Y _Gn ', Z _Gn '), (X _Bn ', Y _Bn ', Z _Bn '). ). In this case, the captured image correction unit 104c obtains the captured values (X _Rn , Y _Rn , Z _Rn ), (X _Gn , Y _Gn , Z _Gn ), (X _Bn , Y _Bn , Z _Bn ) as follows. to correct.
(X _Rn ′, Y _Rn ′, Z _Rn ′) = (X _Rn , Y _Rn , Z _Rn ) × (1-K _RSn ) / (1-K _RCn ),
(X _Gn ′, Y _Gn ′, Z _Gn ′) = (X _Gn , Y _Gn , Z _Gn ) × (1-K _GSn ) / (1-K _GCn ),
(X _Bn ′, Y _Bn ′, Z _Bn ′) = (X _Bn , Y _Bn , Z _Bn ) × (1−K _BSn ) / (1−K _BCn ).

Here, when the red wavelength range is an example of the first wavelength range, the R image 100iR is an example of the first projection image, the R captured image 100pR is an example of the first captured image, and the attenuation rate information 103dR is the first This is an example of information, and the green wavelength range or the blue wavelength range is an example of the second wavelength range. For example, when the green wavelength range is an example of the second wavelength range, the G image 100iG is an example of the second projection image, the G captured image 100pG is an example of the second captured image, and the attenuation rate information 103dG is the second information. An example. When the blue wavelength range is an example of the second wavelength range, the B image 100iB is an example of the second projection image, the B captured image 100pB is an example of the second captured image, and the attenuation rate information 103dB is the second information. An example.
The first wavelength range is not limited to the red wavelength range, and may be a green wavelength range or a blue wavelength range. When the green wavelength range is an example of the first wavelength range, the blue wavelength range or the red wavelength range is an example of the second wavelength range. When the blue wavelength range is an example of the first wavelength range, the red wavelength range or the green wavelength range is an example of the second wavelength range.

  According to the present embodiment, attenuation rate information is used for each RGB. For this reason, in a situation where the projection surface 400 having different incident / reflection characteristics for each RGB is used, the attenuation rate for each RGB can be calculated with higher accuracy than when the common attenuation rate information is used for RGB. Become.

<Modification>
The present invention is not limited to the above-described embodiments. For example, various modifications as described below are possible. Further, one or a plurality of modifications arbitrarily selected from the modifications described below can be appropriately combined.

<Modification 1>
The number of measurement areas is not limited to nine. The number of measurement regions may be one or more. For example, when the number of measurement regions is 1, the captured image correction unit 104c generates a corrected image 100a by correcting the captured values of all the pixels of the captured image 100p using the correction values calculated for the measurement region. It is desirable to do.

<Modification 2>
The storage unit 103 may store the imaging angle. In this case, the imaging angle determination unit 204b determines the imaging angle by reading the imaging angle from the storage unit 103.

<Modification 3>
When the storage unit 203 stores information indicating the distance L1 from the projector 100 to the projection surface 400, the captured image correction unit 104c may calculate a projection angle for each measurement region in in step S1302.
FIG. 15 is a diagram for explaining an example in which the projection angle α _i1 is calculated using the distance L1. Here, it is assumed that the distance L1 and the distance La between the projection unit 101 and the imaging unit 102 are stored in the storage unit 103, and the imaging angle α _oC1 is calculated. In this case, the distance Lb = (tan α _oC1 ) × L1 and tan α _i1 = (Lb + La) / (L1) are established. From these two equations,
tanα _i1 = (Lb + La) / (L1) = [(tan α _oC1 ) × L1) + La] / (L1) is derived, and the captured image correction unit 104c calculates α _i1 from this equation. The captured image correction unit 104c calculates the projection angle β _i1 in the same manner as the imaging angle α _oC1 .
The captured image correction unit 204c also calculates a projection angle for each measurement region in, similarly to the captured image correction unit 104c. In this case, when calculating the attenuation rate in step S1307, the captured image correction units 104c and 204c use the incident angle calculated as described above instead of the imaging angle as the incident angle. For this reason, it is possible to obtain the attenuation rate with higher accuracy than in the case where the photographing angle is used as the incident angle.

<Modification 4>
In the second embodiment, attenuation rate information may not be stored for each RGB, but attenuation rate information may be stored for two of RGB. In this case, it is desirable to use attenuation rate information of other colors for a captured image corresponding to a color for which attenuation rate information is not stored.

<Modification 5>
The incident / reflection characteristics of the projection surface 400 are likely to be different depending on the type of the projection surface 400. Therefore, attenuation rate information corresponding to each of a plurality of types of projection surfaces 400 is stored in the storage unit 103, and the attenuation rate information used by the captured image correction unit 104c according to the type of the projection surface 400 that is actually used. May be selected.

<Modification 6>
When the observation angle information 103c is not stored in the storage unit 103 by the user, the captured image correction unit 104c may use a predetermined observation angle (default observation angle). For example, 0 °, 30 °, or 45 ° is used as the predetermined observation angle. Note that the predetermined observation angle can be changed as appropriate.

<Modification 7>
It may be considered that the luminance attenuation rate is sufficiently small in the observation image. In this case, the attenuation rate K _Sm can be regarded as zero. In this case, the storage unit 103 may not store the observation angle information 103c, and the storage unit 203 may not store the observation angle information 203c.

<Modification 8>
The control device 300 or the function of the control device 300 may be incorporated in the projector 100. In this case, the projector 100 receives an image signal from the outside of the projector 100, and generates a first image signal and a second image signal based on the image signal. The projector 100 supplies the second image signal to the projector 200.
Alternatively, the control device 300 or the function of the control device 300 may be incorporated in each of the projector 100 and the projector 200.

DESCRIPTION OF SYMBOLS 100 ... Projector, 101 ... Projection part, 102 ... Imaging part, 103 ... Memory | storage part, 104 ... Control part, 104a ... Image signal correction part, 104b ... Imaging angle determination part, 104c ... Captured image correction part.

Claims (10)

A projection unit that projects a projection image on a projection surface;
An imaging unit that captures a projected image displayed on the projection surface and generates a captured image;
A correction unit that corrects luminance of the captured image based on an imaging angle of the imaging unit. A storage unit that stores a correspondence relationship between an incident angle of the projection image on the projection surface, a reflection angle of the projection image from the projection surface, and a luminance attenuation rate of the projection image;
The correction unit corrects the luminance of the captured image based on a luminance attenuation rate of the projection image corresponding to the incident angle and the reflection angle when the imaging angle is used as the reflection angle. The projector according to claim 1.   The correction unit adjusts the luminance of the captured image based on the luminance attenuation rate of the projection image corresponding to the incident angle and the reflection angle when the imaging angle is used as the incident angle and the reflection angle. The projector according to claim 2, wherein the correction is performed. The projection unit projects a first projection image onto the projection surface with light in a first wavelength region, and further projects a second projection image onto the projection surface with light in a second wavelength region.
The imaging unit captures a first projection image displayed on the projection plane to generate a first captured image, and further captures a second projection image displayed on the projection plane to generate a second captured image. And
The storage unit indicates a correspondence relationship between an incident angle of the first projection image on the projection surface, a reflection angle of the first projection image from the projection surface, and a luminance attenuation rate of the first projection image. 2 indicating a correspondence relationship between one information, an incident angle of the second projection image on the projection surface, a reflection angle of the second projection image from the projection surface, and a luminance attenuation rate of the second projection image. Memorize information,
The correction unit has a luminance of the first projection image corresponding to an incident angle of the first projection image and a reflection angle of the first projection image when the imaging angle is used as a reflection angle of the first projection image. The brightness of the first captured image is corrected based on the attenuation rate of the first projected image, and the incident angle of the second projected image and the second projected image when the captured angle is used as the reflection angle of the second projected image. The projector according to claim 2, wherein the luminance of the second captured image is corrected based on a luminance attenuation rate of the second projection image corresponding to a reflection angle.   The projector according to claim 1, wherein the correction unit further corrects the luminance of the captured image based on an observation angle of the projection image projected on the projection surface. A storage unit that stores a correspondence relationship between an incident angle of the projection image on the projection surface, a reflection angle of the projection image from the projection surface, and a luminance attenuation rate of the projection image;
The correction unit uses the input image when the imaging angle is used as the reflection angle and the attenuation rate of the brightness of the projection image corresponding to the reflection angle, and when the observation angle is used as the reflection angle. The projector according to claim 5, wherein the brightness of the captured image is corrected based on a luminance attenuation rate of the projection image corresponding to the incident angle and the reflection angle.   The correction unit includes a luminance attenuation rate of the projection image corresponding to the input angle and the reflection angle when the imaging angle is used as the incident angle and the reflection angle, and the imaging angle as the incident angle. Using the observation angle as the reflection angle, and correcting the luminance of the captured image based on the luminance attenuation rate of the projection image corresponding to the incident angle and the reflection angle. The projector according to claim 6. The projection unit projects a first projection image onto the projection surface with light in a first wavelength region, and further projects a second projection image onto the projection surface with light in a second wavelength region.
The imaging unit captures a first projection image displayed on the projection plane to generate a first captured image, and further captures a second projection image displayed on the projection plane to generate a second captured image. And
The storage unit indicates a correspondence relationship between an incident angle of the first projection image on the projection surface, a reflection angle of the first projection image from the projection surface, and a luminance attenuation rate of the first projection image. 2 indicating a correspondence relationship between one information, an incident angle of the second projection image on the projection surface, a reflection angle of the second projection image from the projection surface, and a luminance attenuation rate of the second projection image. Memorize information,
The correction unit is
A luminance attenuation rate of the first projection image corresponding to an incident angle of the first projection image and a reflection angle of the first projection image when the imaging angle is used as a reflection angle of the first projection image; A luminance attenuation rate of the first projection image corresponding to an incident angle of the first projection image and a reflection angle of the first projection image when the observation angle is used as a reflection angle of the first projection image; The incident angle of the second projection image and the reflection angle of the second projection image when the luminance of the first captured image is corrected and the imaging angle is used as the reflection angle of the second projection image based on The luminance attenuation rate of the second projection image corresponding to the above, the incident angle of the second projection image and the reflection angle of the second projection image when the observation angle is used as the reflection angle of the second projection image Of the second projection image corresponding to The projector according to claim 6, wherein the brightness of the second captured image is corrected based on a brightness attenuation rate. A first projector, a second projector, and a control device that controls at least one of the first projector and the second projector;
The first projector is
A first projection unit that projects the first image onto the first region of the projection surface;
A first imaging unit that captures the first image displayed on the projection surface to generate a second image;
A first correction unit that generates a third image by correcting the luminance of the second image based on an imaging angle of the first imaging unit;
The second projector is
A second projection unit that projects a fourth image onto the second region of the projection surface;
A second imaging unit that captures a fourth image displayed on the projection surface to generate a fifth image;
A second correction unit that generates a sixth image by correcting the luminance of the fifth image based on an imaging angle of the second imaging unit,
The controller is
Based on the relationship between the luminance of the third image and the luminance of the sixth image, at least one of the first projector and the second projector controls one of the luminances of the first image and the fourth image. An image display system comprising a luminance control unit that reduces a difference from the luminance of the image. Project the projected image on the projection surface,
The imaging unit captures the projection image displayed on the projection surface to produce a captured image,
A method for correcting a captured image, wherein the brightness of the captured image is corrected based on an imaging angle of the imaging unit.