JP2006276629A - Multi-projection display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-projection display capable of displaying a high quality image by suppressing afterimage by intermittent projection, and capable of displaying images that will not spoil light utilization efficiency. <P>SOLUTION: In the multi-projection display in which a plurality of projectors are arranged so that images from a plurality of projectors PJA, PJB, PJC,... provided with electro-optical modulation devices for modulating light from a light source according to an image data may be projected on the same position of a projection face, and in which the plurality of projectors perform complementary intermittent projection, each of the plurality of projectors PJA, PJB, PJC,... is provided with a projection control device which controls projection for autonomously changing projection and non-projection of the projector of itself, based on information regarding a projection and non-projection state of the projector of itself and the projection and non-projection state of the projectors other than itself. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multi-projection display in which a plurality of projectors perform complementary intermittent projection, an image projection control method in a multi-projection display, an image projection control program in a multi-projection display, and a projector.

  An image display device (a projector) using an electro-optic modulation device having a hold-type display mode such as a liquid crystal display device displays an image with a feeling of afterimage due to the characteristics of the liquid crystal display device when displaying a moving image. . This is a phenomenon that does not exist in a CRT (cathode ray tube) display device that performs impulse-like image display. On the other hand, the CRT display device can provide a sharp image with little afterimage feeling because there is a time during which nothing is projected every time the projection content is switched.

  In a projector using a liquid crystal display device, there is also a response period until the light modulation degree of the liquid crystal display device becomes relatively stable. This also contributes to an image having an afterimage. That is, when image data is written in the liquid crystal display device, the presence of the response speed in the projector cannot be ignored. If projection is performed during this response period, unintended changes in the image are displayed, and the quality of the image is impaired.

  On the other hand, projectors using liquid crystal display devices have been used in a wide range of fields because they are suitable for weight reduction, size reduction, and power saving. Therefore, in a projector using a liquid crystal display device, it is an extremely important issue to prevent an image display with a feeling of afterimage when displaying a moving image.

  As a method for reducing the afterimage feeling, a method in which the projector performs intermittent projection is conceivable. This prevents projection from being performed during the response period of the liquid crystal display device, whereby the projector projects an image during a stable period in which the light modulation degree of the liquid crystal display device is relatively stable. This method results in a discontinuous image similar to a CRT display device. Accordingly, the two problems that contribute to the afterimage feeling described above can be solved simultaneously.

  As a technique that enables non-hold-type image display by performing intermittent projection in a projector using a liquid crystal display device, for example, there are techniques disclosed in Patent Document 1 and Patent Document 2.

  The technique disclosed in Patent Document 1 provides means for condensing light from a light source, and also provides light deflection means for allowing light condensed by the light condensing means to be scrollable on a liquid crystal display device. . By providing such condensing means and light deflecting means, the irradiation surface of the light on the liquid crystal display device is changed with time, and the response period elapses according to the time when the light source is irradiated. As shown, a stable image is projected by writing the image.

  In the technique disclosed in Patent Document 2, a shutter is installed on the optical path of the light source, and switching between projection and non-projection of the light source is performed by opening and closing the shutter. The technique disclosed in Patent Document 2 can also project a stable image by adjusting the writing time so as not to project an unsteady image within the response period.

JP 2004-163915 A JP 2002-148712 A

  However, there is a possibility that the expected light quantity cannot be maintained because the projector performs intermittent projection. For example, the technique disclosed in Patent Document 2 is a method of providing time during which image display is not performed on a display surface such as a screen by controlling opening and closing of a shutter. There is a problem that it leads to a loss of light amount in time average.

On the other hand, in the technique disclosed in Patent Document 1, the light irradiation surface on the liquid crystal device is temporally changed by providing the light condensing means and the light deflecting means, thereby reducing the light quantity from the light source. It is supposed that it will not be damaged in time average. However, since not all of the light emitted from the light source is used for projection, there is a problem that the light use efficiency is low and the image has low brightness.
As a method for preventing a decrease in light use efficiency, it is considered to install a plurality of projectors capable of intermittent projection so that they can be superimposed and to form a multi-projection display in which the plurality of projectors perform complementary intermittent projection. It is done.

According to such a multi-projection display, it is possible to perform intermittent projection without impairing light utilization efficiency. However, in this multi-projection display, if the intermittent projection timing of a plurality of projectors is not adjusted between the projectors and is set randomly at each projector, only one projector will project at a certain time. In addition, the projection state may change with time such that two or more projectors perform overlapping projection at a certain time. Such a projection state causes a light amount distribution in which the total light amount on the screen changes to a plurality of values with time, that is, variation in the light amount. This variation in the amount of light causes flickering to the user and also causes deterioration in image quality.
In order to solve the problem of the variation in the amount of light, it is necessary to adjust the intermittent projection timing between the plurality of projectors, thereby eliminating the variation in the amount of light on the screen.

  In order to adjust the intermittent projection timing of a plurality of projectors, the plurality of projectors constituting the multi-projection display may be synchronized so that each of the plurality of projectors performs intermittent projection at an appropriate timing. In order to achieve this, for example, it is conceivable to synchronize using a vertical synchronization signal included in a video signal. However, a plurality of projectors receive a stream of content that does not exist such as a synchronization signal from a network or the like. In a multi-projection display that performs superimposed projection or the like, each projector needs to operate at a unique timing.

  Therefore, the present invention prevents variations in the amount of light in each frame in a multi-projection display in which the plurality of projectors are arranged so that images from a plurality of projectors capable of intermittent projection can be superimposed and projected on a projection surface. In addition, multiple projectors perform complementary intermittent projection to maintain a sufficient amount of light and enable high-quality image display with few afterimages and high-quality image display, and image projection in multi-projection displays It is an object to provide a control method, an image projection control program in a multi-projection display, and a projector.

  (1) The multi-projection display of the present invention is capable of projecting images from a plurality of projectors having an electro-optic modulation device that modulates light from a light source according to image data at the same position on a projection surface. And the plurality of projectors perform complementary intermittent projection, and each of the plurality of projectors is in a state of projection and non-projection of its own projector and projection and non-projection of projectors other than itself. A projection control device that performs projection control for autonomously switching between projection and non-projection of its own projector based on information on a projection state is provided.

  Thereby, the switching timing of projection and non-projection of a plurality of projectors can be optimized. For this reason, for example, it is possible to prevent a plurality of projectors from overlappingly projecting within a predetermined time in each frame, thereby preventing variation in the amount of light in each frame and making the amount of light uniform. be able to. Further, by performing complementary intermittent projection by a plurality of projectors, it is possible to display a high-quality image with a little afterimage feeling and with a sufficient amount of light while maintaining a sufficient amount of light.

(2) In the multi-projection display according to (1), the plurality of projectors may be able to project only during a stable period in which the light modulation degree of the electro-optic modulation device of each projector is relatively stable. preferable.
In this way, by using a plurality of projectors and performing intermittent projection so that projection can be performed only during the stable period of the electro-optic modulation device in each projector, a high-quality image with little afterimage is displayed. be able to.

(3) In the multi-projection display according to (2), in the plurality of projectors, an initial setting of a projection period when performing the intermittent projection may be set to a maximum projectable time within the stable period. preferable.
Thereby, it is possible to perform projection control using the maximum stable period.

(4) In the multi-projection display according to (2), in the plurality of projectors, an initial setting of a projection period when performing the intermittent projection is set to a minimum projectable time within the stable period. A featured multi-projection display.
In this case, the projection period as an initial setting is set to be as short as possible for each projector, thereby enabling projection closer to the impulse type.

(5) In the multi-projection display according to any one of (1) to (4), the projection control device performs evaluation for acquiring evaluation information necessary for evaluating an image projected on the projection plane. Information acquisition apparatus and image evaluation / projection condition change for performing projection condition change processing for evaluating an image on the projection plane based on the acquired evaluation information and changing the projection condition based on the evaluation result It is preferable to have a device.
By adopting such a configuration for the projection control apparatus, the multi-projection display described in (1) can be realized.

(6) In the multi-projection display according to (5), the evaluation information acquired by the evaluation information acquisition device is a light amount of a predetermined portion on the projection surface, and the image evaluation / projection condition change In the evaluation of the image performed by the apparatus, it is preferable to determine whether or not the plurality of projectors are performing temporally overlapping projections based on the amount of light acquired as the evaluation information.
Thereby, it is possible to appropriately determine overlapping projection of a plurality of projectors.

(7) In the multi-projection display according to (5) or (6), the image evaluation / projection condition change device switches the timing at which its projector switches from non-projection to projection and / or switches from projection to non-projection. It is preferable to determine whether or not a projector other than the projector is projecting at the timing based on the evaluation result of the image, and when the projector other than the projector is performing the projection, the projection condition changing process is preferably performed.
As described above, each projector autonomously performs the projection condition changing process, so that it is possible to reliably prevent the multiple projectors from overlappingly projecting.

(8) In the multi-projection display according to (7), the projection condition changing process is a timing for switching between projection and non-projection so that the projector of the projector performs projection in a non-projection period of the projector other than the projector. It is preferable to change the projection period and / or change the projection period.
By performing such processing as the projection condition changing processing, it is possible to reliably prevent overlapping projection of a plurality of projectors.

(9) In the multi-projection display according to (8), when the projection period is changed, the initial setting of the projection period when the intermittent projection is performed is set to the maximum projectable time within the stable period. In this case, it is preferable to shorten the maximum projectable time.
By performing such processing, it is possible to set an optimal projection period according to the projection status of each projector at that time.

(10) In the multi-projection display according to (8), when the projection period is changed, the initial setting of the projection period when the intermittent projection is performed is set to the minimum projectable time within the stable period. In this case, when it is determined that the projection of its own projector does not overlap with the projections of projectors other than its own and it is determined that the projection period of its own projector can be extended, the minimum projectable time is set to the maximum It is preferable to make it long within the range of the projectable time.
Also by performing such processing, it is possible to set an optimum projection period according to the projection status of each projector at that time.

(11) In the multi-projection display according to any one of (5) to (10), it is preferable that the projection condition changing process is performed recursively until the image evaluation result reaches a predetermined value.
By performing such recursive processing, switching between projection and non-projection of a plurality of projectors can be optimized.

(11) In the multi-projection display according to any one of (3) to (10), it is preferable that the projection condition changing process is performed recursively until the image evaluation result reaches a predetermined value.
By performing such recursive processing, switching between projection and non-projection of a plurality of projectors can be optimized.

  (12) The image projection control method in the multi-projection display of the present invention can project images from a plurality of projectors having an electro-optic modulation device that modulates light from a light source according to image data at the same position on the projection surface. The plurality of projectors are arranged in a multi-projection display method in which the plurality of projectors perform complementary intermittent projection, wherein each of the plurality of projectors projects projection and non-projection of its own projector. Projection control for autonomously switching between projection and non-projection of its own projector is performed based on information on the state and the projection and non-projection states of projectors other than itself.

This also provides the same effect as the multi-projection display described in (1). The image projection control method for the multi-projection display described in (12) also preferably has the characteristics described in (2) to (11).
In the image projection control method for a multi-projection display described in (12), the image evaluation / projection condition changing device obtains evaluation information necessary for evaluating an image projected on a projection surface. The second step of evaluating the image on the projection surface based on the acquired evaluation information, the third step of changing the projection condition based on the evaluation result of the image, and the projection condition after the change It is preferable to have a fourth step of performing the projection.

  (13) The image projection control program in the multi-projection display of the present invention can project images from a plurality of projectors having an electro-optic modulation device that modulates light from a light source according to image data at the same position on the projection surface. A plurality of projectors, and an image projection control program in a multi-projection display in which the plurality of projectors perform complementary intermittent projection, wherein each of the plurality of projectors projects projection and non-projection of its own projector. Projection control for autonomously switching between projection and non-projection of its own projector is performed based on information on the state and the projection and non-projection states of projectors other than itself.

This also provides the same effect as the multi-projection display described in (1). Also, the image projection control program in the multi-projection display described in (13) preferably has the characteristics described in (2) to (11).
In the image projection control program in the multi-projection display described in (13), the image evaluation / projection condition changing device obtains evaluation information necessary for evaluating an image projected on the projection surface. The second step of evaluating the image on the projection surface based on the acquired evaluation information, the third step of changing the projection condition based on the evaluation result of the image, and the projection condition after the change It is preferable that the fourth step of performing the projection can be executed.

  (14) A projector according to the present invention includes a plurality of projectors arranged so that images from a plurality of projectors having an electro-optic modulation device that modulates light from a light source according to image data can be projected at the same position on a projection surface. The projector is used for a multi-projection display in which the plurality of projectors perform complementary intermittent projection, and includes information regarding the projection and non-projection states of its own projector and the projection and non-projection states of projectors other than itself. And a projection control device that performs projection control for autonomously switching between projection and non-projection of the projector based on the projector.

  By using a plurality of such projectors, the multi-projection display described in (1) can be realized. In addition, since the projector according to the present invention can be realized by incorporating the projection control device into a general-purpose projector that has been used conventionally, the multi-projection display described in (1) can be realized at low cost and easily. . It is preferable that this projector also has the features described in (2) to (11).

Embodiments of the present invention will be described below.
[Embodiment 1]
FIG. 1 is a diagram illustrating a configuration of a multi-projection display according to the first embodiment. The multi-projection display shown in FIG. 1 has a plurality of projectors PJA, PJB, PJC,... Installed so that the image data distributed from the image data distribution apparatus 1 can be projected at the same position on the screen SCR as a projection surface. Have

  The image data distribution apparatus 1 outputs image data to be projected to each projector PJA, PJB, PJC,..., And a personal computer or the like can be used.

  The projectors PJA, PJB, PJC,... Have a function that can acquire the amount of light on the screen SCR and a function that can autonomously switch between image projection and non-projection, that is, an intermittent projection function. In addition, these projectors PJA, PJB, PJC,... Can perform complementary intermittent projection of the same image data output from the image data distribution apparatus as appropriate images in the respective projectors at the same location on the screen SCR. ing.

  FIG. 2 is a diagram showing the configuration of the multi-projection display of FIG. 1 in more detail. The projectors PJA, PJB, PJC,... Are representatively described only by the projector PJA, but the other projectors PJB, PJC,... Have the same components as the projector PJA. Yes.

  As shown in FIG. 2, the image data distribution apparatus 1 includes an image data input apparatus 11 that can input image data to be distributed to projectors PJA, PJB, PJC,... From a network, a video camera, a recording medium, or the like. The image data transmitting device 12 transmits the image data thus transmitted to each projector PJA, PJB, PJC,.

  On the other hand, the projectors PJA, PJB, PJC,... Have an image data receiving device 21 that receives the image data sent from the image data distribution device 1, an image data storage device 22 that stores the received image data, and Based on the image output device 23 that projects the image data stored in the image data storage device 22 onto the screen SCR, information on the projection and non-projection states of its own projector, and the projection and non-projection states of projectors other than itself. And a projection control device 26 that performs projection control for autonomously switching between projection and non-projection of its own projector. In the following, “a projector other than itself” will be referred to as “another projector”.

  The projection control device 26 is capable of acquiring evaluation information necessary for image evaluation such as the amount of light of the screen SCR, and the evaluation information acquired by the evaluation information acquiring device 24. Image evaluation / projection conditions for evaluating an image on the screen SCR based on image data (image data currently being projected) recorded in the image data storage device 22 and changing the projection condition based on the evaluation result And a change device 25.

  Although not shown, the image output device 23 includes a light source, an electro-optic modulation device (referred to as a liquid crystal display device), an optical system, and the like. The image output device 23 has a function capable of intermittent projection (referred to as intermittent projection function). This intermittent projection function performs projection only within the range of a stable period in which the light modulation degree of the liquid crystal display device is relatively stable, and does not project during periods other than the stable period (response period). The projection / non-projection switching timing and the projection period (referred to as a projection period) are arbitrarily set based on the image data from the image data distribution apparatus 1 and the projection condition change information output from the image evaluation / projection condition change apparatus 25. It can be changed to

  In the following description, switching from projection to non-projection and switching from non-projection to projection in each projector PJA, PJB, PJC,... Are referred to as “projection / non-projection switching”. It will be expressed as “switch”.

Further, the ON / OFF switching timings of the projectors PJA, PJB, PJC,... Are appropriately set so that each projector PJA, PJB, PJC,... Can project only within the stable period range. It shall be.
However, the projectors PJA, PJB, PJC,... Are not adjusted between the projectors PJA, PJB, PJC,.・ ・ If set randomly, the total amount of light on the screen SCR in each frame may change to multiple values with time, that is, the amount of light may vary. The variation in the amount of light also causes the user to flicker.

Therefore, in the present invention, in order to eliminate such a flickering problem, the ON / OFF switching timing when the projectors PJA, PJB, PJC,... Thus, the amount of light on the screen SCR is made uniform.
By the way, it is assumed that the multi-projection display of the present invention receives content that does not have a synchronization signal or the like from a network or the like and performs superimposed projection with a plurality of projectors. For this reason, it is necessary for each projector PJA, PJB, PJC,... Constituting the plurality of projectors to generate a unique timing and perform an ON / OFF switching operation.

  FIG. 3 is a flowchart for explaining the overall processing procedure of projection condition change processing (hereinafter simply referred to as adjustment processing) as adjustment processing performed by each projector PJA, PJB, PJC,. 3 shows the operation of one projector among the projectors PJA, PJB, PJC,... Note that the projectors PJA, PJB, PJC,... Already have unique information regarding their response periods, and are adjusted to project an image only within the range of the stable period obtained from the response period. Shall.

  Further, the projectors PJA, PJB, PJC,... Perform complementary intermittent projection on the same location on the screen SCR, and the evaluation information is projected from the projected images to the projectors PJA, PJB, PJC,. Is acquired and the process shown in FIG. 3 is performed.

  In FIG. 3, one projector starts projection (step S1), and it is determined whether another projector exists (step S2). If there is no other projector as a result of this determination, it is not necessary to perform the adjustment process as described in this embodiment, and the adjustment process ends (step S3). However, if there is another projector, the screen The amount of light on the SCR is evaluated (step S4).

  As the evaluation of the light amount on the screen SCR, it is determined whether or not there is a variation in the light amount (step S5). If there is no variation in the light amount, the adjustment process ends (step S6), and if there is a variation in the light amount, adjustment is performed. Processing is performed (step S7). Then, the image projection after the adjustment process is performed (step S8), and the process returns to step S4. Hereinafter, processing in each step of FIG. 3 will be described.

[Determining if another projector exists]
The evaluation information acquisition device 24 of the projectors PJA, PJB, PJC,... Acquires the amount of light on the screen SCR with a settable time resolution and passes the information to the image evaluation / projection condition change device 25. Since it is sufficient to acquire the light amount of an arbitrary part on the screen SCR, for example, by using an optical sensor (for example, a photodiode) that can detect the light amount at a specific position. realizable. However, since it is ideal that each projector PJA, PJB, PJC,... Can be evaluated in common, the amount of light at a common location is acquired by each projector PJA, PJB, PJC,. It is desirable.

  The image evaluation / projection condition changing device 25 first receives from the image data storage device 22 information about the amount of light currently being projected by its projector from the image data storage device 22. Next, based on the difference between the amount of light on the screen SCR and the amount of light projected by its own projector, the presence of other projectors and the sum of those amounts of light are obtained. At this time, the resolution in the time direction needs to be sufficiently smaller than one frame of the image.

  If it is determined that another projector is present based on the difference between the light amount on the screen SCR and the light amount projected by its own projector, the light amount on the screen is evaluated (step) as the next procedure. S4) and a determination (step S5) as to whether or not there is a variation in the amount of light.

[Determination of light intensity variation based on evaluation of light intensity on screen SCR]
FIG. 4 is a diagram showing an example of the light amount distribution in a predetermined portion of the screen SCR. As a result of evaluating the light quantity distribution in a predetermined portion on the screen SCR when another projector is present, as shown in FIG. 4A, in each frame, the light quantity value has two values including zero. If it is determined that the period during which the light amount is zero and the amount of light is zero is not more than twice for each frame, there is no variation in the light amount, and the image is broken. Therefore, when the light quantity distribution is as shown in FIG.

  On the other hand, as shown in FIG. 4B, if it is determined that the total amount of light changes to a plurality of three or more values with time in each frame, it may be recognized as flicker. There is. Therefore, when the light quantity distribution is as shown in FIG. 4B, it is necessary to perform the adjustment process, so the adjustment process of step S7 in FIG. 3 is performed.

[Adjustment processing (projection condition change processing)]
Each projector PJA, PJB, PJC,... Attempts to autonomously change the ON / OFF switching timing and projection period of its projector to reduce the variation in the amount of light on the screen SCR. This process is performed using the light quantity value on the screen SCR.

However, since such projectors PJA, PJB, PJC,... Are independently performed without mutual cooperation, for example, when adjustment processing is performed to randomly change the projection conditions, As a result, there is a possibility that the variation in the amount of light increases. Therefore, it is important to perform adjustment processing with an appropriate algorithm. This algorithm will be described later.
Then, after performing the adjustment process, projection is performed again under the changed projection conditions as the process of step S8.

[Image projection after adjustment processing]
After performing the adjustment process according to the procedure up to step S7, projection is performed under the projection conditions, and the image is evaluated again. That is, as a result of evaluating the light quantity on the screen SCR, it is evaluated whether the light quantity distribution as shown in FIG. 4A or the light quantity distribution as shown in FIG. 4B is obtained.
If the light quantity distribution as shown in FIG. 4A cannot be obtained as a result of the adjustment process, steps S4 to S8 in FIG. 3 are repeated recursively until the projectors PJA, PJB, The temporal change in the light amount due to PJC,... Becomes binary as shown in FIG. 4A, and flickering of the image can be reduced.

  The above procedure is desirably performed when normal image projection is performed without any particular intention of the user. However, if the adjustment process is simplified, as a process before the projectors PJA, PJB, PJC,... Project the image data intended by the user, a constant image data (for example, full white color) is obtained from all projectors. It is also preferable to project the image data) as adjustment image data all at once, and to recursively perform the processes of steps S4 to S8 described above for the adjustment image data.

Next, an algorithm for autonomously changing the ON / OFF switching timing and the projection period of the projectors PJA, PJB, PJC,... Will be described.
First, in order to simplify the description, there will be described an example in which there are two projectors and projection is performed by the two projectors PJA and PJB.

At this time, the projection periods t _A and t _B of the two projectors PJA and PJB are not projected (projected) in the response period of their projectors, but are projected only during the stable period, and within the range of the stable period. The maximum projectable time T _A and T _B are set so that the projection period becomes the longest. Note that the projection period can be changed within the range of 0 ≦ t _i ≦ T _i (i = A, B) as necessary. In addition, it is assumed that the existence of each projector is not acquired.

FIG. 5 is a diagram for explaining an example of the ON / OFF switching timing of the projectors PJA and PJB. Now, it is assumed that the projectors PJA and PJB are set with projection periods as shown in FIGS. 5A and 5B, respectively, with the time for switching between ON / OFF as the reference time.
In FIG. 5, it is assumed that a gray portion is non-projected and a white portion is projected. Here, it should be noted that the reference time of the projector PJA and the reference time of the projector PJB do not necessarily need to coincide with accuracy smaller than one frame. However, when actually projecting, it is sufficiently possible to perform time synchronization from the image data distribution apparatus 1 side with an accuracy of one frame.

  Now, the light quantity distribution when the image evaluation / projection condition changing device 25 of the projector PJA records the light quantity with reference to the projector PJA's own projector non-projection switching timing (the time of switching to non-projection) is shown in FIG. Is obtained as follows. A thick vertical line in FIG. 6 indicates a time when the projector PJA switches from projection to non-projection (OFF). The light amount distribution shown in FIG. 6 is a light amount distribution that gives flickering like the light amount distribution of FIG. 4B described above.

  FIG. 7 is a diagram showing a light quantity distribution measured by the projector PJA, excluding its own light quantity. That is, FIG. 7 shows a light amount distribution obtained by excluding the light amount produced by the projector PJA's own projector from the light amount distribution of FIG. In FIG. 7, ON means the timing when the projector PJA switches from non-projection to projection, and OFF means the timing when the projector PJA switches from projection to non-projection.

  As shown in FIG. 7, the projector PJA can recognize the presence of a projector other than the projector PJA by excluding the light quantity of the projector PJA. At that time, the image evaluation / projection condition changing device 25 can obtain the light quantity distribution as shown in FIG. 7 and at least the following four pieces of information (a) to (d).

(A) Information indicating whether another projector exists. This can be determined by the presence of a light quantity greater than the light quantity emitted by itself.
(B) Information indicating whether another projector is continuing the projection at the moment when it starts projection.
(C) Information as to whether another projector is continuing projection at the moment when it finishes projection.
(D) Information on whether other projectors are projecting during the period during which they are projecting.

  Here, if there is no other projector, it is assumed that there is no need to adjust the ON / OFF switching timing and / or the projection period. Here, two projectors PJA and PJB are taken as an example, but this is common to any two or more projectors. However, in the present invention, it is not necessary to recognize the number of projectors other than itself. The following describes how adjustment processing is performed when it is acquired that there is another projector.

  FIG. 8 is a flowchart for explaining an algorithm for changing projection conditions as adjustment processing. FIG. 8 mainly explains step S7 in more detail in the flowchart of FIG. 3 described above.

  In FIG. 8, first, it is determined whether or not projections with other projectors overlap, that is, whether or not adjustment processing is necessary (step S21). If there is no projection overlap with other projectors, adjustment processing is performed. If the projection ends with another projector (step S26), it is determined whether or not a process for shortening the projection period is necessary (step S22). If a process for shortening the projection period is necessary, a process for shortening the projection period is performed (step S23). If the process is not a process for shortening the projection period, a process for increasing or decreasing the ON / OFF switching timing is performed. It performs (step S24).

  In step S23, after performing the process of shortening the projection period, it is further determined whether or not the ON / OFF switching timing needs to be changed (step S25), and the ON / OFF switching timing needs to be changed. If so, it is also possible to perform processing (step S24) to make the ON / OFF switching timing earlier or later.

  The algorithm for changing the projection conditions as the adjustment process is configured based on the processing procedure shown in FIG. As shown in FIG. 8, each projector changes the ON / OFF switching timing of its own projector and / or changes the projection period. At this time, it is important how to obtain a value to be adjusted and an amount of change in order to obtain an ideal light amount from the obtained light amount distribution.

  First, a case where the projection conditions are changed randomly will be described. This adjustment process for randomly changing the projection condition is referred to as “random adjustment process”. This random adjustment process is to randomly change the ON / OFF switching timing and / or change the projection period as the projection condition of the projector.

  This random adjustment process will be described. First, as a process for determining whether or not to perform the adjustment process, the process of step S1 in FIG. 8, that is, the projection time of another projector when its own projector is switched ON / OFF. It is determined whether the bands overlap. If the bands do not overlap, it is determined that adjustment processing is not necessary for the projector of its own.

  When the projector changes from non-projection to projection or from projection to non-projection, if the other projector is in the projection state at any change, the projection period of the projector is shortened. To do. Also, the ON / OFF switching timing is always changed regardless of the presence or absence of adjustment processing related to the projection period.

  Here, the process of shortening the projection period is that the timing for switching from non-projection to projection is delayed by the minimum unit t on the time axis, and the timing for switching from projection to non-projection is the minimum unit t on the time axis. Make it fast. Also, the process of changing the ON / OFF switching timing randomly sets the ON / OFF switching timing earlier or later on the time axis by a minimum unit t.

When an appropriate switching timing is realized by performing the random adjustment process as described above, the adjustment process is not necessary for all projectors. In some cases, among the plurality of projectors, there may be a projector in which the projection period is zero and no projection is performed. In this case, a timing for switching from non-projection to projection is newly generated at random, and the algorithm described above is applied again after lighting for the maximum projectable time T _i .

  Since this random adjustment process requires a small amount of calculation required for the adjustment process, the processing load of the image evaluation / projection condition changing device 25 is small, and a state without any light quantity bias can be realized. However, on the other hand, it may take an enormous amount of time depending on the initial state of the projector and the number of projectors.

  Therefore, as a more realistic method, it is desirable to perform the process by giving a change amount corresponding to the situation to each of the adjustment processes described above. The adjustment process in the case where the adjustment process is performed by giving a change amount corresponding to the situation is referred to as a “situation-adaptive adjustment process” with respect to the above “random adjustment process”. This situation-adaptive adjustment process is performed based on the above-described random adjustment process. Hereinafter, the situation corresponding adjustment processing will be described.

  In the situation-related adjustment processing, the following cases are given regarding the relationship between the projector and the light quantity. 9 to 14 below are examples of the light amount distribution in one frame detected by a certain projector. In FIG. 9 to FIG. 14, the gray rectangle indicates the amount of light produced by the projection of its own projector, and the white rectangle indicates the amount of light produced by the projection of another projector.

FIG. 9 is a diagram illustrating an example of the case where the adjustment process is unnecessary in the situation corresponding adjustment process. FIG. 9A is a diagram showing a state in which the projection of its own projector and the projection of another projector do not overlap. FIG. 9B shows a state in which another projector is performing a series of ON / OFF switching operations within the projection period of its own projector.
9A and 9B show a state in which projections of other projectors are not duplicated at the ON / OFF switching timing of their projectors. Therefore, in such cases as shown in FIGS. 9A and 9B, it is assumed that adjustment processing is unnecessary.

  FIG. 10 is a diagram illustrating an example of the case where adjustment processing is necessary in the situation-related adjustment processing. The example of FIG. 10 is a state in which projections of other projectors overlap at the ON / OFF switching timing of its own projector, and there are at least two overlapping projectors. In the case shown in FIG. 10, it is assumed that adjustment processing is necessary.

  As shown in FIG. 10, when it is determined that adjustment processing is necessary, adjustment processing is performed such as shortening the projection period of its own projector. When the projection period shortening process is performed, no other process is performed. If this condition is not met, the ON / OFF switching timing is changed.

  In FIG. 10, the projections of the other two projectors overlap at the timing of switching on / off of their own projector, that is, at the timing of switching from non-projection to projection of their own projector. It is assumed that one of the projectors is in the projection state and another projector is in the projection state at the timing of switching from the projection of the projector of the own to the non-projection. However, this can be similarly considered when one projector other than itself is performing projection as shown by the white rectangle in FIG. 10 instead of two projectors other than itself.

  FIG. 11 is a diagram illustrating an example of a process for shortening the projection period of the projector in the case where there is an overlap as shown in FIG. As shown in FIGS. 11A and 11B, the timing for switching from non-projection to projection of the projector itself is delayed along the time axis by the minimum unit t, and the timing for switching from projection to non-projection is minimized. It is advanced along the time axis by the unit t.

  12 and 13 are diagrams showing an example of processing for changing the ON / OFF switching timing of its projector. As shown in FIG. 12A, the process of changing the ON / OFF switching timing is performed when the projections of other projectors overlap only at the moment of switching from non-projection to projection. As shown in FIG. 13A, the case where the projection of another projector overlaps only at the moment of switching from the projection of the projector to the non-projection is considered.

  As shown in FIG. 12A, when projections of other projectors overlap only at the moment of switching from non-projection to projection, first, the overlap time is detected (the detected overlap time is T 12B), as shown in FIG. 12B, the switching timing of the projector from non-projection to projection is delayed by 1/2 of the overlap time T on the time axis. That is, the switching timing of the projector from non-projection to projection is moved by T / 2 in the direction of the arrow x in FIG.

  As shown in FIG. 13A, when projections of other projectors overlap only at the moment of switching from projection to non-projection, the overlap time is first detected (detected) as described above. 13 (B), the switching timing from the projection of the projector to the non-projection is advanced by ½ of the overlap time T on the time axis, as shown in FIG. That is, the switching timing from the projection of the projector to the non-projection is moved by T / 2 in the arrow x ′ direction in FIG.

  The reason why the amount of change in the adjustment process of FIGS. 12 and 13 is T / 2 is that in this example, the number of projectors is two, and the two projectors independently adjust each other. As described above, the overlapping portions of the two projectors are separated from each other by T / 2 by the respective projectors, so that the overlapping of the projections of the two projectors can be eliminated.

  FIG. 14 is a diagram illustrating an example in which the projection period of its own projector is included in the projection period of another projector. In the case of the example shown in FIG. 14, the time T1 from the moment when the other projector is projected until the moment when the own projector is projected, and the time when the other projector is not projected, the other projector is not projected. Is compared with the time T2 until the moment becomes, and the timing from the non-projection to the projection of the projector is changed based on the comparison result.

  That is, as a result of the comparison between the time T1 and the time T2, the timing from the non-projection of the projector to the projection is moved in the direction of smaller values. For example, in the example of FIG. 14, since T1> T2, as shown in FIG. 14C, adjustment processing is performed such that the timing from non-projection to projection of the projector is moved in the arrow x direction by T + T2. Do. If the upper limit T0 of the change amount in the adjustment process is determined depending on the performance of the projector, a process of moving in the arrow x direction by T0 is performed. In this case, the timing is shifted stepwise in the process of recursively repeating the adjustment.

  By performing the situation corresponding adjustment process described above, as in the above-described random adjustment process, the variation in the light amount due to the overlap of projections of a plurality of projectors can be improved and the light amount can be made uniform. In this situation-adaptive adjustment process, the calculation burden associated with one adjustment process is greater than in the above-described random adjustment process, but in terms of the number of processes, the amount of light can be made uniform with a smaller number of processes. Therefore, this situation-adaptive adjustment process can be expected to have a greater effect when the number of projectors is large.

[Embodiment 2]
In the first embodiment, the two projectors PJA, PJA, PJB, PJC,... Are set as initial settings when executing an algorithm for autonomously changing the ON / OFF switching timing and the projection period of the projectors PJA, PJB, PJC,. The projection periods t _A and t _{B of the} PJB are set to the values of the maximum projectable times T _A and T _B in the stable period, and 0 ≦ t _i ≦ T _i (i = A, Adjustment processing that changes within the range of B) is performed.

On the other hand, in the multi-projection display according to the second embodiment, each projector performs projection as close to an impulse type as possible as an initial setting. In other words, the projectable time in the initial setting is as short as the projector allows, regardless of the maximum projectable time T _{i of} each projector (T _A and T _{B in} the case of two projectors PJA and PJB). Is set.
The projectable time set as the initial setting in the second embodiment will be referred to as the minimum projectable time. Further, it is assumed that the minimum unit for changing the projection period is set to a common value t in each projector.

  The configuration of the multi-projection display according to the second embodiment and the configuration of the image data distribution device 1, the projectors PJA, PJB, PJC,..., Etc. are described with reference to the multi-projection display according to the first embodiment. In the second embodiment, the illustration thereof is omitted.

FIG. 15 is a flowchart illustrating an algorithm for adjustment processing in the multi-projection display according to the second embodiment.
In FIG. 15, first, it is determined whether or not there is another projector (step S31). This can be determined by acquiring the light amount of a predetermined portion of the screen SCR as in the first embodiment. As a result of the determination, if the other projector is not present, its projector, a projection period is set to a value of the maximum projection available time T _i, and terminates the adjustment process. Thereby, the projector can realize optimization at the time of projection.

  On the other hand, if it is determined that there is another projector, the processing after step S32 in FIG. 15 is recursively performed. The process after step S32 is demonstrated. First, the amount of light on the screen SCR is evaluated by the same method as in step S4 in FIG. 3 (step S32), and it is determined from the evaluation result whether there is a change compared to the immediately previous light amount evaluation result. (Step S33). If there is no change compared to the previous light intensity evaluation result, the adjustment process is terminated, but if there is a change, it is determined whether or not there is an overlap with the projection of other projectors when switching from non-projection to projection of its own projector. (Step S34). As a result of this determination, if it is determined that there is an overlap, an overlap area reduction process is performed (step S35).

  If the result of determination in step S34 is that there is no overlap, it is determined whether or not there is overlap with projections of other projectors when switching from projection of the projector of the own projector to non-projection (step S34). S36). As a result of this determination, if it is determined that they overlap, the process returns to step S32 without performing the adjustment process. If it is determined that there is no overlap as a result of the determination in step S36, it is determined whether or not the projection period of the projector can be extended (step S37). Projection period extension processing is performed (step S38).

  If it is not possible to extend the projection period, whether or not the switching from the projection of its own projector to non-projection and the switching from non-projection to projection is continuous with respect to the projection of other projectors. Is determined (step S39). If any of these is continuous, the process returns to step S32 without performing the adjustment process, but if none of them is continuous, the ON / 0FF switching timing is changed (step S40).

  In the flowchart of FIG. 15, it is determined whether or not there is an overlap when switching from non-projection to projection of its own projector in step S34 at the moment when the projector switches from non-projection to projection. It is determined whether or not it is in a state. This will be described with reference to FIG.

  FIG. 16 is a diagram showing an example of the light amount distribution when another projector is in a projection state at the moment when its own projector switches from non-projection to projection. In the case of the light amount distribution as shown in FIG. In step S34, it is determined that there is an overlap when the projector is switched from non-projection to projection. In the second embodiment as well, in each drawing showing the light amount distribution, the rectangle shown in gray represents the light amount distribution of its own projector, and the rectangle shown in white represents the light amount distribution of other projectors.

  In addition, in the determination of whether or not it is continuous in step S39, “continuous” refers to a state in which the projections of the two projectors are continuous without overlapping as shown in FIG. Yes. In FIG. 17, at the moment when another projector is switched from projection to non-projection, its own projector is switched from non-projection to projection, so that the projections of the two projectors are continuous without overlapping.

  The overlap area reduction process in step S35 is performed when it is determined in step S34 that there is an overlap when the projector is switched from non-projection to projection, and is overlapped when the projector is switched from non-projection to projection. For example, it is determined that there is a case as shown in FIG. As shown in FIG. 16, when it is determined that there is an overlap when the projector is switched from non-projection to projection, a process of reducing the overlap area is performed.

  FIG. 18 is a diagram illustrating an example of the overlap area reduction process. As shown in FIG. 18A, when the time of the overlapping region is T3, as shown in FIG. 18B, the timing for switching from non-projection to projection is delayed by T3 on the time axis (arrow by T3). move in the x direction).

  In order to perform the processing as shown in FIG. 18, there is arbitraryness in how to select a projector that changes timing and the amount of change. However, it is desirable that all projectors share the method of selecting and changing the projector whose timing is changed. Here, the ON / OFF switching timing is changed as shown in FIG. 18B for the projector that switches from non-projection to projection. For the projector that is switched from projection to non-projection, processing such as ON / OFF switching timing change is not performed.

  As a result of performing the processing as shown in FIG. 18, the other projectors are switched to projection at the moment when one projector is switched to non-projection, so that the projection states of the two projectors are continuous without overlapping. It becomes. As a result, it is possible to prevent variation in the amount of light on the screen SCR due to switching of projections of a plurality of projectors.

  Next, the projection period extension process (step S38) will be described. This projection period extension process is performed when it is determined in step S37 that the projection period can be extended in the determination of whether the projection period can be extended.

19 and 20 are diagrams for explaining an example of a light amount distribution and a projection period extension process when the projection period can be extended.
FIG. 19A shows, as an example of the light amount distribution when the projection period can be extended, the projection of other projectors when the projector switches from non-projection to projection and when switching from projection to non-projection. It is not continuous and does not overlap. Further, it is assumed that the current projection period T0 of the projector is T0 <T _{i with} respect to the maximum projectable time T _i .

Since the state shown in FIG. 19A matches the condition that the projection period extension process in step S37 is possible, the projection period extension process is performed. In the projection period extension process, for example, as shown in FIG. 19B, switching from non-projection to projection is accelerated by a minimum unit t on the time axis, and switching from projection to non-projection is minimized on the time axis. Processing such as delaying by the unit t is performed. As a result, the projection period of its projector becomes T0 + 2t. However, the projection period when changing only a minimum unit t is the limit of the maximum projection available time T _i.

FIG. 20A shows an example of the light amount distribution when the projection period can be extended, either when the projector is switched from non-projection to projection or when switching from projection to non-projection. This is a case where it is continuous with the projection state of the projector (however, there is no overlap). Also in this case, it is assumed that the current projection period T0 of the projector is T0 <T _i with respect to the maximum projectable time T _i .

The state as shown in FIG. 20A also matches the condition that the projection period extension process in step S37 is possible, and thus the projection period extension process is performed. In the projection period extension process, as shown in FIG. 20B, the projection period is extended to a side that is not continuous with other projectors. In the case of FIG. 20A, if attention is paid to its own projector (the gray rectangle shown in the figure), when its own projector is switched from non-projection to projection, it is continuous with other projectors, so the opposite side. On the side of switching from the projection to the non-projection, the projection is switched from the projection to the non-projection with a minimum unit t delayed on the time axis. As a result, the projection period of its own projector is T0 + t. Incidentally, the projection period when the minimum unit t by changing the case shall be limited to maximum projectable time T _i.

  Note that, for example, as shown in FIG. 21, when the projector is continuous from the non-projection to the projection and at the timing to switch from the projection to the non-projection, it is continuous without overlapping with the projection state of other projectors. Projection period extension processing or ON / OFF switching timing change processing is not performed.

  Next, ON / OFF switching timing change processing (step S40) will be described. As a result of performing the processing up to step S37 in the flowchart of FIG. 15, it is determined that the projection period cannot be extended in step S37, and the projection / non-projection is changed in step S39. As a result of determining whether or not the switching from non-projection to projection is continuous, both the switch from projection to non-projection and the switch from non-projection to projection are continuous. This is done when it is determined that it is not.

According to these determination results, this step S40 is performed when the projection period T0 of the projector (projector PJA) is already extended to the maximum projectable time T _i , that is, when T0 = T _i. Process.

FIG. 22 is a diagram for explaining ON / OFF switching timing change processing. FIG. 22 (A) shows that neither the non-projection to the projection of the projector itself nor the projection to the non-projection is continuous with the projection state of other projectors. There is no state to do. Further, this is a case where the current projection period T0 of the projector is T0 = T _{i with} respect to the maximum projectable time T _i .

  In the case as shown in FIG. 22A, an ON / OFF switching timing change process in step S40 is performed. In this case, as shown in FIG. 22B, the ON / OFF switching timing changing process is T2 <T1, and therefore the timing at which the projector switches from non-projection to projection is delayed by time T2 on the time axis. To do. That is, the timing at which the projector switches from non-projection to projection is moved in the direction of the arrow x shown in the figure for a time T2.

  In any case, after the above adjustment process is performed, image evaluation after the adjustment process is performed. If an ideal evaluation result cannot be obtained, the adjustment process is further performed based on the evaluation result. By performing such recursive adjustment processing, an ideal evaluation result can be obtained after a predetermined time.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in each of the above-described embodiments, each projector does not acquire the presence of each other's projector, but indicates how many projectors the multi-projection display is configured for each projector. It is also possible to input the information and perform the adjustment process described above after knowing how many projectors each projector is operating.

  The present invention can also create an image projection control program in which the processing procedure for realizing the present invention described above is described, and the image projection control program can be recorded on various recording media. Therefore, the present invention also includes a recording medium on which the image projection control program is recorded. Further, the image projection control program may be obtained from a network.

FIG. 3 is a diagram illustrating a configuration of a multi-projection display according to the first embodiment. The figure which shows the structure of the multi-projection display of FIG. 1 in detail. 7 is a flowchart for explaining an overall processing procedure of adjustment processing performed by each projector PJA, PJB, PJC,. The figure which shows the example of light quantity distribution in the predetermined part of screen SCR. The figure explaining the example of the ON / OFF switching timing of projector PJA, PJB. The figure which shows light quantity distribution when the image evaluation / projection condition change apparatus 25 of projector PJA records light quantity on the basis of the switching timing to non-projection of the projector of projector PJA itself. The figure which shows the light quantity distribution which the projector PJA measured remove | excluded its own light quantity. 6 is a flowchart for explaining an algorithm for changing projection conditions as adjustment processing. The figure which shows the example when adjustment processing is unnecessary in the situation corresponding adjustment processing. The figure which shows the example in case adjustment processing is required in situation adjustment processing. The figure which shows an example of the process which shortens the projection period of an own projector when duplication like FIG. 10 exists. The figure which shows an example of the process which changes the ON / OFF switching timing of an own projector. The figure which shows the other example of the process which changes the ON / OFF switching timing of an own projector. The figure which shows the example in which the projection period of a personal projector is included in the projection period of another projector. 10 is a flowchart for explaining an algorithm for adjustment processing in the multi-projection display according to the second embodiment. The figure which shows an example of light quantity distribution in case the other projector is in the projection state at the moment when an own projector switches from non-projection to projection. The figure which shows the state which projection of two projectors is continuing without duplication. The figure which shows an example of an overlapping area reduction process. The figure explaining an example of light quantity distribution in case extension of a projection period is possible, and a projection period extension process. FIG. 6 is a diagram for explaining another example of the light amount distribution when the projection period can be extended and another example of the projection period extension process. The figure which shows the case where an own projector is continuing without the duplication state with the projection state of another projector in the timing which switches from non-projection to projection, and the timing which switches from projection to non-projection. The figure explaining the change process of ON / OFF switching timing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image data delivery apparatus, 24 ... Evaluation information acquisition apparatus, 25 ... Image evaluation / projection condition change apparatus, 26 ... Image projection control apparatus, PJA, PJB, PJC, ... Projector

Claims (14)

The plurality of projectors are arranged so that images from a plurality of projectors having an electro-optic modulation device that modulates light from a light source according to image data can be projected at the same position on a projection surface, and the plurality of projectors are complementary. A multi-projection display that performs intermittent projection,
Each of the plurality of projectors autonomously switches between projection and non-projection of its own projector based on information on the projection and non-projection states of its own projector and the projection and non-projection states of projectors other than itself. A multi-projection display having a projection control device for performing projection control. The multi-projection display according to claim 1.
The multi-projection display, wherein the plurality of projectors can project only during a stable period in which the light modulation degree of the electro-optic modulation device of each projector is relatively stable. The multi-projection display according to claim 2.
In the plurality of projectors, an initial setting of a projection period when the intermittent projection is performed is set to a maximum projectable time within the stable period. The multi-projection display according to claim 2.
In the plurality of projectors, an initial setting of a projection period when performing the intermittent projection is set to a minimum projectable time within the stable period. In the multi-projection display in any one of Claims 1-4,
The projection control apparatus evaluates an image on the projection plane based on the evaluation information acquisition apparatus that acquires evaluation information necessary for evaluation of an image projected on the projection plane, and the acquired evaluation information. And an image evaluation / projection condition change device that performs a projection condition change process for changing the projection condition based on the evaluation result. The multi-projection display according to claim 5, wherein
The evaluation information acquired by the evaluation information acquisition device is a light amount of a predetermined portion on the projection plane, and the image evaluation performed by the image evaluation / projection condition changing device is acquired as the evaluation information. A multi-projection display that determines whether or not the plurality of projectors are performing temporally overlapping projections based on a light amount. The multi-projection display according to claim 5 or 6,
The image evaluation / projection condition changing device evaluates whether the projector other than the projector is projecting at the timing when the projector is switched from non-projection to projection and / or the timing when the projector is switched from projection to non-projection. And a projection condition changing process when the projector other than the projector is projecting. The multi-projection display according to claim 7.
The projection condition changing process is characterized in that the projection timing and the non-projection change timing are changed and / or the projection period is changed so that the projector performs projection in a non-projection period of a projector other than the projector. Multi-projection display.
The multi-projection display according to claim 8.
The change of the projection period is characterized by shortening the maximum projectable time when the initial setting of the projection period when performing the intermittent projection is set to the maximum projectable time within the stable period. Multi-projection display. The multi-projection display according to claim 8.
The change of the projection period is such that when the initial setting of the projection period when performing the intermittent projection is set to the minimum projectable time within the stable period, the projection of its own projector is different from the projection of a projector other than itself. Multi-projection characterized in that when it is determined that there is no overlap and it is determined that the projection period of its own projector can be extended, the minimum projectable time is extended within the range of the maximum projectable time display. In the multi-projection display in any one of Claims 5-10,
The multi-projection display characterized in that the projection condition changing process performs a recursive process until the image evaluation result reaches a predetermined value. The plurality of projectors are arranged so that images from a plurality of projectors having an electro-optic modulation device that modulates light from a light source according to image data can be projected at the same position on a projection surface, and the plurality of projectors are complementary. An image projection control method in a multi-projection display that performs intermittent projection,
Each of the plurality of projectors autonomously switches between projection and non-projection of its own projector based on information regarding the projection and non-projection states of its own projector and the projection and non-projection states of projectors other than itself. An image projection control method for a multi-projection display, wherein projection control is performed. The plurality of projectors are arranged so that images from a plurality of projectors having an electro-optic modulation device that modulates light from a light source according to image data can be projected at the same position on a projection surface, and the plurality of projectors are complementary. An image projection control program in a multi-projection display that performs intermittent projection,
Each of the plurality of projectors autonomously switches between projection and non-projection of its own projector based on information regarding the projection and non-projection states of its own projector and the projection and non-projection states of projectors other than itself. An image projection control program for a multi-projection display, wherein projection control is performed. The plurality of projectors are arranged so that images from a plurality of projectors having an electro-optic modulation device that modulates light from a light source according to image data can be projected at the same position on a projection surface, and the plurality of projectors are complementary. A projector used in a multi-projection display that performs intermittent projection,
A projection control device that performs projection control for autonomously switching between projection and non-projection of its own projector based on information on the projection and non-projection states of its own projector and the projection and non-projection states of projectors other than itself A projector comprising: