JP5614948B2 - Projection system and projection method - Google Patents

Description

  The present invention relates to an image display device and a control method therefor, and more particularly, to an image display device and a control method therefor that display images superimposed by a plurality of image projection means.

JP 2005-099863 A

  Conventionally, as a display device, a projector that projects an image generated by a liquid crystal panel onto a screen is known. In general, an image display device is always required to have a large screen, high brightness, high resolution, and high gradation.

  When realizing high brightness in a projection device, a multi-lamp projector is known that improves brightness by combining output lights of a plurality of light sources. For example, the brightness on the screen can be increased by increasing the number of two or four lamps and the number of lighting light sources (in this case, lamps). However, with this method, the high luminance part can be brightened, but the low luminance part is also brightened, and the contrast cannot be increased.

  In a two-lamp projector, a technique is known in which contrast control is increased by interlocking control of blocking light output from a light source lamp and intensity control of an image signal applied to a light modulation element that spatially modulates light source light ( Patent Document 1). When the brightness of the image signal is in the range of 0 to 1/2, the amplitude of the image signal applied to the light modulation element is doubled while blocking the output light of one light source lamp. When the brightness of the image signal is 1/2 or more, the output light of the two light source lamps is used, and the image signal is applied as it is to the light modulation element.

  On the other hand, as a method for achieving a bright projected image on a large screen with an inexpensive configuration, so-called stack projection is known in which a plurality of projectors having normal luminance are used and the same image is superimposed and projected on the same screen.

  The multi-lamp projector does not improve the gradation. In order to improve the gradation, a calculation accuracy and a memory for increasing the gradation are required, and a larger-scale arithmetic / processing circuit is required.

  The brightness of the stack projection can be easily increased. However, even with this method, simply superimposing a plurality of images reduces the contrast.

  The present invention has been made in view of such problems, and an object thereof is to provide an image display apparatus that realizes higher gradation and higher contrast and a control method thereof.

A projection system according to the present invention is a projection system that displays a single image by displaying images projected by a plurality of projection devices in an overlapping manner on a projection plane, and each of the plurality of projection devices emits light. An output light source; a light source control unit that controls the light source; and a modulation unit that transmits the light output from the light source with a transmittance according to an input image, wherein the projection system includes the plurality of light sources. Assigned gradation setting means for setting the assigned gradation of the projection apparatus, the light source control means, based on the assigned gradation and the gradation of the input image, to the input image, When the pixel of the gradation corresponding to the assigned gradation is included, the light source is controlled to be turned on, and the input image does not include the pixel of the gradation corresponding to the assigned gradation To turn off the light source The assigned gradation setting means compares the lifetimes of the light sources of the plurality of projection apparatuses, and sets the projection apparatus having the light source having the longer lifetime to be assigned to the lower gradation. Features.

The projection method according to the present invention is a projection method for displaying a single image by superimposing and displaying images projected by a plurality of projection devices on a projection plane, and each of the plurality of projection devices transmits light. a light source for outputting a light source control means for controlling the light source, the light output by the light source, and a modulation means for transmitting a transmission rate corresponding to the input image, by the attending gradation setting means The assigned gradations of the plurality of projection devices are set, and the light source control unit corresponds to the assigned gradations in the input image based on the assigned gradation and the gradation of the input image. Output light from the light source to the modulation means , and if the input image does not include a pixel of the gradation corresponding to the assigned gradation, the light from the light source does not output to the modulating means Controlling the charge of gradation setting unit compares the life of each light source of the plurality of projection devices, that the lifetime is set so as to charge gradation as projector low tone with a long light source It is characterized by.

  According to the present invention, high brightness by stack projection is realized by projecting images by the same input image so as to overlap each other by a plurality of projectors. By controlling the gradation area of each projector, it is possible to realize gradation that exceeds the expression ability of each projector. By individually controlling the light source of each projector, excess leakage light can be reduced and high contrast can be realized.

It is a schematic block diagram of one Example of this invention. It is a schematic block diagram of each projector. It is a 1st operation | movement flowchart. It is an explanatory schematic diagram of high gradation property and high contrast property at the time of stack projection. It is a 2nd operation | movement flowchart. It is a 3rd operation | movement flowchart.

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

  FIG. 1 shows a schematic block diagram of a system configuration to which one embodiment of an image display apparatus according to the present invention is applied. The projectors 100, 200, 300, and 400 function as image display means in the claims. A video signal source 500 such as a personal computer (PC), a DVD player, or a TV tuner outputs an image signal to be displayed. The distributor 600 distributes the image signal from the video signal source 500 to the projectors 100, 200, 300 and 400. The output video of the projectors 100, 200, 300, 400 is projected on the screen 700.

  In this embodiment, four projectors 100, 200, 300, and 400 are used to overlap and display on the same screen, but the number of projectors is not limited to this. Each projector 100, 200, 300, 400 may include a plurality of image display means and project an image obtained by combining or superimposing these display images. Furthermore, the display device is not particularly limited to a projector as long as it can display images.

  FIG. 2 shows a schematic block diagram of the projector 100, 200, 300, 400.

  The configuration of the projector 100 will be described. The input image receiving unit 101 receives image information from the distributor 600. The input image storage means 102 temporarily stores input image information for a predetermined number of frames. The gradation area determining unit 103 determines a gradation area that the projector 100 is in charge of. The display image generation unit 104 generates a display image that displays only a predetermined gradation region from a portion of the input image from the input image receiving unit 101 corresponding to the gradation region determined by the gradation region determination unit 103. To do. The modulation element 105 is an element whose transmittance varies spatially based on the display image generated by the display image generation unit 104. The display image determination unit 106 determines how to control the light source based on the display image information from the display image generation unit 104. The light source control unit 107 controls the light source according to the determination result of the display image determination unit 106. The light source 108 illuminates the modulation element 105. The light projecting unit 109 includes a polarizing plate, a combining optical system, and the like, and projects light from the light source 108 via the modulation element 105 onto an external screen or the like. The light source life determination unit 110 determines the light source life based on information such as the cumulative lighting time / lighting interval of the light source 108.

  Blocks 201-210, 301-310, 401-410 have the same functions as blocks 101-110.

  FIG. 3 shows an operation flowchart of this embodiment. FIG. 4 shows a conceptual diagram of gradation area sharing in the present embodiment. The operation of this embodiment will be described with reference to FIGS.

  The distributor 600 distributes the image signal from the video signal source 500 to each projector 100, 200, 300, 400 (S101). In this embodiment, the gradation of the input image is 10 bits, and the display limit gradation of each projector is 8 bits. The correlation is shown in FIG.

  The projector 100 receives the input image information from the distributor 600 by the input image receiving unit 101 (S111). The gradation area determining means 103 determines the gradation area that the projector 100 is in charge of (S112). Here, it is assumed that the projector 100 can express 8-bit gradation and is responsible for 0 to 255 gradations of the 10-bit gradation of the input image.

  In accordance with the determination in S112, the display image generation unit 104 performs gradation control according to the input image with respect to the gradation regions 0 to 255, and performs clipping at 255 for gradations exceeding 255 (S113). The image generated in this way by the display image generation unit 104 becomes the display image of the projector 100. The correlation between the input image information of the display image generation means 104 and the display image information is shown in FIG.

  The light source control means 107 controls the light source 108 according to the relationship between the input image information and the determined gradation area (0 to 255 gradations) (S114). Here, since the determined gradation area is 0 to 255 gradations, the light source 108 is controlled to be turned on regardless of the input image information.

  The modulation element 105 is modulated by the display image generated by the display image generation unit 104, and the light source 108 illuminates the modulation element 105. As a result, the display image generated by the display image generating unit 104 is projected and displayed on the screen 700 by the light projecting unit 109 (S115).

  Similarly, in the projector 200, the input image receiving unit 201 receives the input image information from the distributor 600 (S121). The gradation area determining means 203 determines the gradation area that the projector 200 is in charge of (S122). Here, the projector 200 can express 8-bit gradation, and is in charge of 256 to 511 gradations of the input image 10-bit gradation. In accordance with the determination in S122, the display image generation unit 204 clips the gradation areas 0 to 255 with 0, performs gradation control of the gradation areas 256 to 511 to 0 to 255 gradations, and selects gradation areas exceeding 511. Clipping is performed at 255 (S123). The image generated in this way by the display image generation unit 204 becomes the display image of the projector 200. The correlation between the input image information of the display image generation means 204 and the display image information is shown in FIG.

  The light source control means 207 controls the light source 208 according to the relationship between the input image information and the determined gradation region (256 to 512 gradations) (S124). For example, the light source 208 is turned off when the gradation of the input image is 255 or less, and is turned on when the gradation is 256 or more.

  The modulation element 205 is modulated by the display image generated by the display image generation unit 204, and the light source 208 illuminates the modulation element 205. As a result, the display image generated by the display image generating unit 204 is projected and displayed on the screen 700 by the light projecting unit 209 (S125).

  In the projector 300, the input image receiving unit 301 receives the input image information from the distributor 600 (S131). The gradation area determining means 303 determines the gradation area that the projector 300 is in charge of (S132). Here, it is assumed that the projector 300 can express 8-bit gradation and is responsible for 512-767 gradations of the input image 10-bit gradation. In accordance with the determination in S132, the display image generation unit 304 clips the gradation areas 0 to 511 with 0, controls the gradation areas 512 to 767 to 0 to 255 gradation, and clips the gradation areas exceeding 767 with 255. (S133). The image generated in this way by the display image generation unit 304 becomes the display image of the projector 300. The correlation between the input image information of the display image generation means 304 and the display image information is shown in FIG.

  The light source control means 307 controls the light source 308 according to the relationship between the input image information and the determined gradation area (512 to 767 gradations) (S134). For example, the light source 308 is controlled to be turned off when the gradation of the input image is 511 or less, and is turned on when it is 512 or more.

  The modulation element 305 is modulated by the display image generated by the display image generation unit 304, and the light source 308 illuminates the modulation element 305. As a result, the display image generated by the display image generating unit 304 is projected and displayed on the screen 700 by the light projecting unit 309 (S135).

  In the projector 400, the input image receiving unit 401 receives the input image information from the distributor 600 (S141). The gradation area determining means 403 determines the gradation area that the projector 300 is in charge of (S142). Here, it is assumed that the projector 400 can express 8-bit gradation and is in charge of 768-1023 gradations of the input image 10-bit gradation. In accordance with the determination in S142, the display image generation unit 404 clips the gradation areas 0 to 767 with 0, and controls the gradation areas 768 to 1023 to 0 to 255 gradations (S133). The image generated in this way by the display image generation unit 404 becomes the display image of the projector 400. The correlation between the input image information of the display image generation unit 404 and the display image information is shown in FIG.

  The light source control means 407 controls the light source 408 according to the relationship between the input image information and the determined gradation area (768 to 1023 gradation) (S144). For example, the light source 408 is controlled to be turned off when the gradation of the input image is 767 or less, and is turned on when it is 768 or more.

  The modulation element 405 is modulated by the display image generated by the display image generation unit 404, and the light source 408 illuminates the modulation element 405. As a result, the display image generated by the display image generating unit 404 is projected and displayed on the screen 700 by the light projecting unit 409 (S145).

  Projected images of the projectors 100, 200, 300, and 400 are projected at the same position on the screen 700 (step S151).

  As described above, according to the present embodiment, high brightness can be easily realized by stack projection. In addition, by determining the projector in charge of each gradation region, it is possible to realize a high gradation property that is higher than the gradation property that can be expressed by each projector. By controlling the light source of each projector by the input image, it is possible to reduce excess leakage light and achieve high contrast.

  In this embodiment, since each projector has only one light source, the light source of each projector is controlled by the maximum value of the whole gradation, but the present invention is not limited to this. For example, the projection area of each projector is divided into a plurality of areas, a light source is provided for each of the divided projection areas, and the gradation area of the input image for each projection area is determined to control the light source. Even with such a modified configuration, a similar effect can be obtained.

  When a light source is assigned to each pixel, the same effect can be obtained by determining the gradation region of the input image for each pixel and controlling each light source.

  In this embodiment, the gradation that can be expressed by each projector is 8 bits, and the gradation of the input image is 10 bits. However, the present invention is not limited to this. For example, when the gradation that each projector can represent is 8 bits and the gradation of the input image is 12 bits, the same effect can be obtained by using 16 stack projection projectors.

  Although the predetermined time after the lamp is turned on is uniform, the predetermined time may be changed according to the environment of the image display means. Alternatively, the same effect can be obtained by directly measuring the luminance curve after the lamp is lit and measuring the time until the predetermined luminance is obtained, and using that value.

  The method of superimposing images is not limited to superimposing for each projector. For example, the same effect can be obtained even when a plurality of image display devices are built in each projector (image display means) and image composition / overlay is performed in the projector.

  FIG. 5 shows another operation flowchart of the present embodiment. When a high compression mercury lamp is used as the light sources 108, 208, 308, and 408 to obtain high luminance, it takes time to turn on and off. In the flow shown in FIG. 5, a delay in turning on / off is considered.

  The distributor 600 distributes the image signal from the video signal source 500 to each projector 100, 200, 300, 400 (S101). Also here, it is assumed that the gradation of the input image is 10 bits and the display limit gradation of each projector is 8 bits. The correlation is shown in FIG.

  As an operation example, a case will be described in which the maximum luminance value of the input image is 256 or more and further 255 or less when the maximum luminance value is 255 or less. Therefore, FIG. 5 shows only the operations of projector 100 and projector 200.

  The projector 100 receives the input image information from the distributor 600 by the input image receiving unit 101 (S211). The received input image is temporarily stored in the input image storage means 102 (S212).

  The gradation area determining means 103 determines the gradation area that the projector 100 is in charge of (S213). Here, it is assumed that the projector 100 can express 8-bit gradation and is responsible for 0 to 255 gradations of the 10-bit gradation of the input image.

  First, black display is set in the display image generating means 104 (S214), and the light source 108 is turned on (S216). At first, even when the lighting control of the light source is performed, the predetermined luminance is not yet reached (S217), so step S218 is skipped and the black display data is transmitted to the modulation element 105 (S219).

  Then, the projection images of the projectors 100, 200,... Are superimposed and displayed (S202). At this stage, the display remains black. Thereafter, it is determined whether or not the display is finished (S203). If the display is not finished, the process returns to step S201. This series of operations is repeated for a predetermined time after the light source is turned on. When the predetermined time has elapsed, the light source luminance reaches a predetermined value (S217). At this time, the first stored input image data is read from the input image storage means 102, and the display data is transmitted to the modulation element 105 (S219).

  Thereafter, it is determined whether or not the display is finished (S203). If the display is not finished, the process returns to step S201. In this way, the input images are continuously displayed with a delay of a predetermined time.

  On the other hand, in the projector 200, the input image receiving unit 201 receives the input image information from the distributor 600 (step S221). The received input image is temporarily stored in the input image storage unit 202 (S222).

  The gradation area determination unit 203 determines the gradation area that the projector 200 is in charge of (S223). Here, it is assumed that the projector 100 can express 8-bit gradation and is responsible for 256 to 511 gradations of the input image 10-bit gradation.

  First, black display is set in the display image generation means 204 (S224). Whether to turn on the light source 208 is determined based on the input image information (S225). In the present embodiment, since the maximum luminance of the first input image is set to 255 or less, it is determined whether the light source is in a state after being turned on (S230). Since the light source is not in a state after being turned on (S230), the light source 208 is set to an idling state (S231). The black display data set in step S224 is transmitted to the modulation element 205 (S229).

  Each projector 100, 200. .. Are superimposed and displayed (s202). In this case, an image projected by the projector 100 is displayed.

  Thereafter, it is determined whether or not the display is finished (S203). If the display is not finished, the process returns to step S201.

  This series of operations is continued until the maximum luminance of the input image becomes 256 or more.

  When the maximum luminance of the input image becomes 256 or more, first, the input image in that state is temporarily stored in the input image storage unit 202 (S222).

  The gradation area determination unit 203 determines the gradation area that the projector 200 is in charge of (S223). Black display is set in the display image generation means 204 (S224), and it is determined from the input image information whether the light source 208 is turned on (S225). At this stage, since the maximum luminance of the input image is 256 or more, the light source 108 is turned on (S226). However, at first, even if the lighting control of the light source is performed, the predetermined luminance is not yet reached (S227), so step S228 is skipped and the black display data is transmitted to the modulation element 205 (S229).

  The projected images of the projectors 100, 200,... Are superimposed and displayed (S202). At this stage, a projection image by the projector 100 is displayed. Thereafter, it is determined whether or not the display is finished (S203). If the display is not finished, the process returns to step S201.

  This series of operations is repeated for a predetermined time after the light source is turned on. When the predetermined time has elapsed, the light source luminance reaches a predetermined value (S227). At this point, the first stored input image data is read from the input image storage unit 202, and the display data is transmitted to the modulation element 205 (S229). Thereby, an image in which the images of the projector 100 and the projector 200 are superimposed is displayed.

  Thereafter, it is determined whether or not the display is finished (step S203). If the display is not finished, the process returns to step S201.

  With this series of operations, the input images are continuously displayed with a delay of a predetermined time.

  When the maximum luminance of the input image is 255 or less, the light source is in an idling state after a predetermined time (S230) (S231). The black display data set in step S224 is transmitted to the modulation element 205 (S229).

  A series of these operations is repeated according to the state of the maximum luminance of the input image.

  As described above, according to the present embodiment, since the image data is held until the light source has a predetermined luminance, the light source can be turned on / off without interrupting the image display state. Thereby, it is possible to provide a high-contrast projection device with few restrictions.

  When performing light source control, idling control is performed instead of extinguishing control, whereby the light source can be controlled at a higher speed.

  In this embodiment, leakage light is reduced by performing black display while the light source is turned off or idling, but the present invention is not limited to this. For example, a further contrast improvement effect can be obtained by inserting a mechanical light shielding member instead of black display or changing the illumination optical path.

  Moreover, although the predetermined time after lighting of the light source is made uniform, the predetermined time may not be constant. For example, the predetermined time may be changed according to the environment of the image display means. Alternatively, the luminance curve after the light source is turned on may be directly measured to measure the time until a predetermined luminance is reached, and that time may be used as the predetermined time.

  The predetermined time is preferably set according to the maximum length of the time until the stable brightness of each light source is reached. However, communication may be performed between the image display means each time, and the maximum value of the combined image display means may be found and set to that value each time.

  FIG. 6 shows another operation flowchart of the present embodiment. In this operation example, the life of the light source of each image display means is determined, and control is performed so that the light source is averagely used as a whole, thereby extending the life of the light source.

  The distributor 600 distributes the input image information from the video signal source 500 to the projectors 100, 200, 300, and 400 (S301). In this embodiment, it is assumed that the gradation of the input image is 10-bit gradation and the display limit gradation of each projector is 8 bits. The correlation is shown in FIG.

  The projector 100 receives the input image information from the distributor 600 by the input image receiving unit 101 (S311). At the same time as or before the reception of the projector 100, the light source lifetime information is obtained from the light source lifetime determining means 110, 210, 310, 410 in the projectors 100, 200, 300, 400 that perform the superimposed projection this time (S312). Then, based on the light source lifetime information from each light source lifetime determining means 110, 210, 310, 410, the projector 100 compares the light source lifetimes of the four projectors relative to each other (S313). Based on the relative comparison of the light source lifetimes, the gradation area determining unit 103 determines the gradation area that the projector 100 is in charge of (S314).

  For example, assume that the projector 100 is determined to be the projector having the longest light source life. In this case, the gradation area determination unit 103 determines that the projector 100 is responsible for 0 to 255 gradations. Based on the determined gradation region (0 to 255 gradations), the display image generation unit 104 performs gradation control according to the input image from 0 to 255 gradations, and an input image with more than 255 gradations is 255. Clipping is performed with gradation (S315). The image generated in this way is used as a display image of the projector 100. The correlation between the input image information and the display image information is shown in FIG.

  The light source control means 107 controls the light source 108 based on the relationship between the input image information and the determined gradation region (0 to 255 gradations) (S316). Here, since the determined gradation region is 0 to 255 gradations, the light source 108 is controlled to be turned on regardless of the input image information. In accordance with the lighting of the light source 108, lighting information is input to the light source lifetime determining unit 110, and counted as the accumulated lighting time of the light source 108 (S317).

  The display image generated by the display image generation unit 104 modulates the modulation element 105, and the modulation element 105 is illuminated by the light source 108. The light projecting means 109 projects and displays the image whose intensity is modulated by the modulation element 105 (S318).

  The projector 200 receives the input image information from the distributor 600 by the input image receiving unit 201 (S321). At the same time or before the reception of the projector 200, the projector 200 obtains the light source lifetime information from the light source lifetime determination means 110, 210, 310, 410 (S322). Based on the light source lifetime information from each light source lifetime determining means 110, 210, 310, 410, the projector 200 compares the light source lifetimes of the four projectors relative to each other (S323). Based on the relative comparison of the light source lifetimes, the gradation area determining unit 203 determines the gradation area that the projector 200 is in charge of (S324). At the time of this determination, if there is a projector for which the gradation area has been previously determined, a mechanism that does not determine the same gradation area is incorporated.

  Here, for example, it is assumed that the projector 200 is determined to be the projector having the second longest light source lifetime. Based on the determination result, the gradation area determining unit 203 determines the gradation area that the projector 200 is in charge of (S324). Assume that the projector 200 can express 8-bit gradation, and is in charge of 256 to 511 gradations of the input image 10-bit gradation.

  Based on the determined gradation area (256 to 511 gradations), the display image generation unit 204 clips the gradation areas 0 to 255 with 0, and controls the gradation areas 256 to 511 to 0 to 255 gradations. The gradation region exceeding 511 is clipped by 255 (S325). The image generated in this way by the display image generation unit 204 becomes the display image of the projector 200. The correlation between the input image information of the display image generation means 204 and the display image information is shown in FIG.

  The light source controller 207 controls the light source 208 based on the relationship between the input image information and the determined gradation region (256 to 511 gradations) (S326). For example, the light source 208 is controlled to be turned off when the gradation of the input image is 255 or less, and is turned on when the gradation is 256 or more. When the light source 208 is turned on, lighting information is input to the light source life determination unit 210 and counted as the accumulated lighting time of the light source 208 (S327).

  The display image generated by the display image generation unit 204 modulates the modulation element 205, and the modulation element 205 is illuminated by the light source 208. The light projecting unit 209 projects and displays the image whose intensity is modulated by the modulation element 205 (S328).

  The projector 300 receives the input image information from the distributor 600 by the input image receiving unit 301 (S331). At the same time or before the reception of the projector 300, the projector 300 obtains the light source life information from the light source life determination means 110, 210, 310, 410 (S332). Based on the light source lifetime information from each of the light source lifetime determining means 110, 210, 310, 410, the projector 300 performs a relative comparison of the light source lifetimes of the four projectors (S333). Based on the relative comparison of the light source lifetimes, the gradation area determination unit 303 determines the gradation area that the projector 300 is in charge of (S334). At the time of this determination, if there is a projector for which the gradation area has been previously determined, a mechanism that does not determine the same gradation area is incorporated.

  Here, for example, it is assumed that the projector 300 is determined to be the projector having the third longest light source lifetime. Based on the determination result, the gradation area determination unit 303 determines the gradation area that the projector 300 is in charge of (S334). Assume that the projector 300 can express 8-bit gradation, and is responsible for 512-767 gradations of the input image 10-bit gradation.

  Based on the determined gradation area (512 to 767 gradations), the display image generation unit 304 clips the gradation areas 0 to 511 with 0 and controls the gradation areas 512 to 767 to 0 to 255 gradations. , 767 are clipped with 255 (S335). The image generated in this way by the display image generation unit 304 becomes the display image of the projector 300. The correlation between the input image information of the display image generation means 304 and the display image information is shown in FIG.

  The light source control unit 307 controls the light source 308 based on the relationship between the input image information and the determined gradation region (512 to 767 gradations) (S336). For example, the light source 308 is controlled to be turned off when the gradation of the input image is 511 or less and is turned on when the gradation is 512 or more. When the light source 308 is turned on, lighting information is input to the light source lifetime determination unit 310 and counted as the accumulated lighting time of the light source 308 (S337).

  The display image generated by the display image generation unit 304 modulates the modulation element 305, and the modulation element 305 is illuminated by the light source 308. The light projecting unit 309 projects and displays the image whose intensity is modulated by the modulation element 305 (S338).

  The projector 400 receives the input image information from the distributor 600 by the input image receiving unit 301 (S341). At the same time or before the reception of the projector 400, the projector 400 obtains the light source life information from the light source life determination means 110, 210, 310, 410 (S342). Based on the light source lifetime information from each light source lifetime determining means 110, 210, 310, 410, the projector 400 compares the light source lifetimes of the four projectors relative to each other (S343). Based on the relative comparison of the light source lifetimes, the gradation area determining means 403 determines the gradation area that the projector 400 is in charge of (S344). At the time of this determination, if there is a projector for which the gradation area has been previously determined, a mechanism that does not determine the same gradation area is incorporated.

  Here, it is assumed that projector 400 is determined to be the projector having the fourth longest light source lifetime. Based on the determination result, the gradation area determining unit 403 determines the gradation area that the projector 400 is in charge of (S344). Assume that the projector 400 can express 8-bit gradation and is in charge of gradations 768 to 1023 out of 10-bit gradation of the input image.

  Based on the determined gradation region (768 to 1023 gradation), the display image generation unit 404 clips the gradation regions 0 to 767 with 0, and controls the gradation regions 768 to 1023 to 0 to 255 gradations. The gradation region exceeding 1023 is clipped by 255 (S345). The image generated in this way by the display image generation unit 404 becomes the display image of the projector 400. The correlation between the input image information of the display image generating means 404 and the display image information is shown in FIG.

  The light source controller 407 controls the light source 408 based on the relationship between the input image information and the determined gradation region (768 to 1023 gradations) (S346). For example, the light source 408 is controlled to be turned off when the gradation of the input image is 767 or less, and is turned on when it is 768 or more. When the light source 408 is turned on, lighting information is input to the light source lifetime determination unit 410 and counted as the accumulated lighting time of the light source 408 (S347).

  The display image generated by the display image generation unit 404 modulates the modulation element 405, and the modulation element 405 is illuminated by the light source 408. The light projecting means 409 projects and displays the image whose intensity is modulated by the modulation element 405 (S348).

  The projected images of the projectors 100, 200, 300, and 400 are projected on the same position on the same screen (S351).

  As described above, according to the present embodiment, high brightness can be easily realized by stack projection. Further, by assigning each gradation area to a different projector, it is possible to realize a high gradation property that is higher than the gradation property that each projector can express. By controlling the light source of the projector in charge of each gradation region, it is possible to reduce excess leakage light and realize high contrast.

  Since the lighting time of the light source is accumulated and the gradation to be assigned is determined based on the accumulated lighting time, the lamp lighting time can be averaged. The total light source life and projector life can be extended.

  In this embodiment, the determination is made by accumulating the light source lighting time, but the present invention is not limited to this. For example, even if the determination is made based on the operating time of the projector, or the determination is based on the cumulative measurement of the output light energy of the light source, almost the same effect can be obtained.

  In this embodiment, the light source lifetime is determined by simple accumulation / simple addition of the lighting time of the light source, but the present invention is not limited to this. For example, the accumulated time may be calculated by adding a predetermined coefficient or weight to a light source having a different projection life coefficient due to a lamp having different irradiation energy or a structure. The accumulated time may be calculated by a coefficient or weighting according to the environment where the projector is placed, such as the ambient temperature.

  The present invention is not limited to determining the lifetime of the light source at the beginning of the stack projection and determining the responsible region of the gradation based on it. For example, the same effect can be obtained by comparing and determining the light source lifetime in real time even during projection, and changing the gradation in charge in real time according to the state. In particular, in use cases that are projected for a long time, it is possible to provide a more averaged usage by using the above method.

  When the gradation of the input image is 0, the life of the light source 108 can be extended by controlling the light source of the projector 100 to turn off.

100, 200, 300, 400: projector 500: video signal source 600: distributor 700: screen

Claims (12)

A projection system that displays a single image by displaying images projected by a plurality of projection devices in an overlapping manner on a projection plane,
Each of the plurality of projection devices is
A light source that outputs light;
Light source control means for controlling the light source;
Modulation means for transmitting the light output by the light source at a transmittance according to the input image;
The projection system has assigned gradation setting means for setting assigned gradations of the plurality of projection apparatuses,
The light source control means, based on the assigned gradation and the gradation of the input image,
Wherein the inputted image, if it contains the gradations of pixels corresponding to the representative gray scale is controlled to light up the light source,
When the input image does not include a pixel having a gradation corresponding to the assigned gradation, the light source is controlled to be turned off.
The assigned gradation setting means compares the lifetimes of the light sources of the plurality of projection apparatuses, and sets a lower gradation as the assigned gradation for a projection apparatus having a light source with a longer lifetime. Projection system.   2. The assigned gradation setting unit sets the lowest gradation for a projection apparatus having a light source with the longest life among the plurality of projection apparatuses as an assigned gradation. Projection system.   3. The assigned gradation setting means sets the highest gradation for the projection apparatus having the light source with the shortest life among the plurality of projection apparatuses as the assigned gradation. The projection system described.   The projection system according to any one of claims 1 to 3, wherein the assigned gradation setting unit determines the lifetime of the light source based on an accumulation of lighting time of the light source.   The projection system according to any one of claims 1 to 3, wherein the assigned gradation setting unit determines the lifetime of the light source based on an accumulation of output light energy of the light source. A projection system that displays a single image by displaying images projected by a plurality of projection devices in an overlapping manner on a projection plane,
Each of the plurality of projection devices is
A light source that outputs light;
Light source control means for controlling the light source;
Modulation means for transmitting the light output by the light source at a transmittance according to the input image;
The projection system has assigned gradation setting means for setting assigned gradations of the plurality of projection apparatuses,
The light source control means, based on the assigned gradation and the gradation of the input image,
Wherein the inputted image, if it contains the gradations of pixels corresponding to the representative gray scale is controlled to light up the light source,
When the input image does not include a pixel having a gradation corresponding to the assigned gradation, the light source is controlled to be turned off.
The projection system, wherein the assigned gradation setting means sets assigned gradations of the plurality of projection apparatuses based on light source lighting times of the light sources of the plurality of projection apparatuses.   The modulation means controls the transmissivity as the maximum gradation of the assigned gradation for an image having a gradation exceeding the gradation corresponding to the assigned gradation. The projection system according to claim 1   8. The transmittance according to claim 1, wherein the modulation unit controls the transmittance as the minimum gradation of the assigned gradation for an image having a gradation corresponding to the assigned gradation smaller. The projection system according to any one of claims   The projection system according to claim 1, wherein the assigned gradation setting unit sets the assigned gradation at the start of projection by the projection system.   The projection system according to claim 1, wherein the assigned gradation setting unit sets the assigned gradation during projection by the projection system. A projection method for displaying one image by displaying images projected by a plurality of projection devices in an overlapping manner on a projection plane,
Each of the plurality of projection devices is
A light source that outputs light;
Light source control means for controlling the light source;
Modulation means for transmitting the light output by the light source at a transmittance according to the input image;
Set responsible gradations of the plurality of projection devices by responsible gradation setting means
The light source control means, based on the assigned gradation and the gradation of the input image,
When the input image includes a pixel having a gradation corresponding to the assigned gradation, the light from the light source is output to the modulation means ,
When the input image does not include a pixel of a gradation corresponding to the assigned gradation, control is performed so that light from the light source is not output to the modulation unit ,
The assigned gradation setting means compares the lifetimes of the light sources of the plurality of projection apparatuses, and sets a lower gradation as the assigned gradation for a projection apparatus having a light source with a longer lifetime. Projection method. A projection method for displaying one image by displaying images projected by a plurality of projection devices in an overlapping manner on a projection plane,
Each of the plurality of projection devices is
A light source that outputs light;
Light source control means for controlling the light source;
Modulation means for transmitting the light output by the light source at a transmittance according to the input image;
Set responsible gradations of the plurality of projection devices by responsible gradation setting means
The light source control means, based on the assigned gradation and the gradation of the input image,
When the input image includes a pixel having a gradation corresponding to the assigned gradation, the light from the light source is output to the modulation means ,
When the input image does not include a pixel of a gradation corresponding to the assigned gradation, control is performed so that light from the light source is not output to the modulation unit ,
The projection method, wherein the assigned gradation setting means sets assigned gradations of the plurality of projection apparatuses based on light source lighting times of the light sources of the plurality of projection apparatuses.

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