JP2019101066A - Multi-projection system, image processing device, and image display method - Google Patents

Abstract

To provide a multi-projection system, an image processing device, and an image display method.SOLUTION: In the multi-projection system including a plurality of projectors which are arranged so that projection images are mutually superimposed and the image processing device which generates an image to be projected by the plurality of projectors on the basis of an input image and outputs the generated image to the plurality of projectors, the image processing device includes a first image generation part which extracts a pixel having a luminance higher than a set luminance in the input image and re-arranges the extracted pixel, to correct a gradation value and generate the image and a second image generation part which corrects the gradation value of each pixel constituting the input image, to generate the image. The plurality of projectors include a first projector for projecting the image generated by the first image generation part and a second projector for reducing the brightness of light of the image generated by the second image generation part and projecting the image.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multi-projection system, an image processing apparatus and an image display method.

  There is known a multi-projection system capable of generating a high-resolution, high-brightness large-screen image that can not be realized by a single projector by superimposing images projected from a plurality of projectors on a screen (for example, a patent) Reference 1).

JP-A-5-103286

  However, the conventional multi-projection system has a problem that the contrast ratio is lowered as the bright part is brighter and the bright part is larger.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a multi-projection system, an image processing apparatus, and a display method capable of minimizing the portion where the contrast ratio is reduced.

  A multi-projection system according to an aspect of the present invention generates a plurality of projectors arranged so that projection images overlap each other, generates an image to be projected by the plurality of projectors based on an input image, and generates the plurality of generated images. In a multi-projection system including an image processing apparatus for outputting to a projector, the image processing apparatus extracts a pixel having a luminance higher than a set luminance in the input image and rearranges the extracted pixel to obtain a gradation value. And a second image generation unit for generating an image by correcting the gradation value of each pixel constituting the input image. Is generated by a first projector for projecting an image generated by the first image generation unit, and the second image generation unit. And a second projector that projects a dim image.

  An image processing apparatus according to an aspect includes at least one first projector that projects an image without reducing light, and reduces the image, among a plurality of projectors arranged such that projection images overlap each other An image processing apparatus that generates an image to be projected onto a second projector to be projected from an input image, and extracting pixels having a luminance higher than a set luminance in the input image, and rearranging the extracted pixels A first image generation unit that generates an image to be projected to the first projector by correcting the gradation value, and a luminance of each pixel that configures the input image, and thus the projection is performed to the second projector And a second image generation unit that generates an image to be output.

  The image display method according to one aspect extracts a pixel having a luminance higher than a set luminance in an input image, rearranges the extracted pixel, generates a first image whose tone value is corrected, and generates an input image. A second image is generated by correcting the luminance of each of the pixels to be configured, and the first image is projected from at least one of the plurality of projectors arranged such that the projection images are superimposed on each other, and the other projectors are generated. And the second image is dimmed and projected.

  According to the present application, it is possible to minimize the portion where the contrast is reduced.

FIG. 1 is a schematic view showing a configuration of a multi-projection system according to Embodiment 1. It is a block diagram explaining the composition of the optical system of a projector. FIG. 1 is a block diagram for explaining an internal configuration of an image processing apparatus according to a first embodiment. It is a figure which shows the image of display object. It is explanatory drawing explaining the appearance of the projection by the conventional projection system. It is a figure which shows an example of the image used in order to measure a contrast rate. It is a graph which shows the measurement result of the contrast ratio measured by changing the ratio of white variously. It is a figure which shows the example of a display by the conventional projection system. It is an explanatory view explaining an example of gradation data generated with an image processing device concerning this embodiment. It is a conceptual diagram which shows an example of a brightness correction database. 5 is a flowchart illustrating a procedure of processing performed by the image processing apparatus according to the first embodiment. It is a figure which shows an example of the optical image displayed on the screen by the multi projection system which concerns on this Embodiment. FIG. 7 is a schematic view illustrating the configuration of a multi-projection system according to Embodiment 2. It is an explanatory view explaining an example of division of an input picture. FIG. 13 is an explanatory diagram for explaining an example of gradation data generated by the image processing apparatus according to Embodiment 2; FIG. 16 is a flowchart illustrating the procedure of processing performed by the image processing apparatus according to Embodiment 2. FIG. FIG. 10 is a schematic view showing a configuration of a multi-projection system according to Embodiment 3. FIG. 18 is a block diagram for explaining an internal configuration of an image processing apparatus according to a third embodiment. FIG. 16 is a flowchart for describing the procedure of processing performed by the image processing apparatus according to Embodiment 3. FIG.

Hereinafter, the present invention will be specifically described based on the drawings showing the embodiments thereof.
Embodiment 1
FIG. 1 is a schematic view showing the configuration of the multi-projection system according to the first embodiment. The multi-projection system according to the first embodiment generates an image to be projected on two projectors 10 and 20 that project an image on a screen SC and two projectors 10 and 20, and generates the generated image on the projector 10, And 20 an image processing apparatus 100 for outputting the image data. The two projectors 10 and 20 are arranged such that the projected images overlap each other, and display an optical image by superimposing the projected images on the screen SC.

  The projectors 10 and 20 are, for example, rear projectors that project an image from the back side of the screen SC. One projector 10 is a projector for high brightness reproduction in which the light reduction filter 21 is not mounted, and reduces the light of an image (an image based on gradation data for high brightness reproduction) generated by the image processing apparatus 100. Project on the screen SC without The other projector 20 is a projector for low brightness reproduction on which the light reduction filter 21 is mounted, and reduces the light of the image (image based on the gradation data for low brightness reproduction) generated by the image processing apparatus 100. Project onto the screen SC.

  The image processing device 100 is a general-purpose or dedicated computer device, and receives, for example, digital image data captured by an imaging device 50 (see FIG. 3) such as an on-vehicle camera. The image processing apparatus 100 generates an image (gradation data) to be output to the projectors 10 and 20 from an input image based on the input image data, and outputs the generated image to each of the projectors 10 and 20. More specifically, the image processing apparatus 100 generates gradation data for high luminance reproduction mainly reproducing the high luminance part of the input image, outputs the generated gradation data to the projector 10, and Gray scale data for low brightness reproduction that reproduces a low brightness portion is generated, and the generated gray scale data is output to the projector 20.

  In this embodiment, gradation data for high luminance reproduction and gradation data for low luminance reproduction are generated separately, and an image is projected from the projectors 10 and 20 based on these gradation data. An optical image is formed on the SC. With such a configuration, in the present embodiment, the amount of light projected from the projector 10 for high brightness reproduction can be reduced as a whole, and the reduction in contrast of the optical image formed on the screen SC can be suppressed. It is possible.

  FIG. 2 is a block diagram for explaining the configuration of the optical system of the projector 10. The projector 10 includes, for example, a light source 11, a light control circuit 12, a reflector 13, mirrors 14, 14, 14, a polarizing plate 15, a liquid crystal panel 16, and a projection lens 17. The light source 11 emits light having an appropriate wavelength component. The light adjustment circuit 12 is a control circuit for adjusting the amount of light emitted from the light source 11. The reflector 13 condenses the light emitted from the light source 11. The plurality of mirrors 14, 14 guide the light collected by the reflector 13 to the polarizing plate 15. The polarizing plate 15 controls the polarization state of the light guided by the plurality of mirrors 14, 14. The liquid crystal panel 16 includes, for example, a color filter, and controls the amount of light transmission in each pixel based on an image (gradation data) input from the image processing apparatus 100 to create a color image. The projection lens 17 projects the color image produced by the liquid crystal panel 16 onto the screen SC.

  The projector 10 may include various lenses such as a relay lens and a Fresnel lens, various optical elements such as a PS composite element, and various filters such as an ultraviolet filter. The projector 10 may be a transmissive liquid crystal projector as described above, or may be a reflective liquid crystal projector or a digital mirror device projector.

  The projector 10 for high-intensity reproduction projects the color image produced by the liquid crystal panel 16 onto the screen SC without reducing the light, according to the above configuration. In addition to the above configuration, the projector 20 for low luminance reproduction also includes a light reduction filter 21 such as an ND filter (ND: Neutral Density) provided in front of the projection lens 17, and is produced by the liquid crystal panel 16. Dims the shot color image and projects it on the screen SC.

  In this embodiment, in the projector 20 for low luminance reproduction, the light reduction is performed by the light reduction filter 21 provided in front of the projection lens 17. However, the light reduction circuit 12 is configured to decrease the light. Of course it may be good.

  FIG. 3 is a block diagram for explaining the internal configuration of the image processing apparatus 100 according to the first embodiment. The image processing apparatus 100 includes, for example, a control unit 101, a storage unit 102, an input unit 103, and an output unit 104.

  The control unit 101 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and the like. A control program or the like for controlling the operation of each component of the hardware is stored in the ROM of the control unit 101. The CPU in the control unit 101 executes control programs stored in the ROM and various programs stored in the storage unit 102 described later, and controls the operation of each of the hardware units. The RAM provided in the control unit 101 stores data temporarily used during execution of various programs.

  The control unit 101 is not limited to the above configuration, and may be one or more processing circuits including a single core CPU, a multi-core CPU, a microcomputer, a volatile or non-volatile memory, and the like. Further, the control unit 101 may have functions such as a clock for outputting date and time information, a timer for measuring an elapsed time from giving a measurement start instruction to giving a measurement end instruction, and a counter for counting the number.

  The storage unit 102 includes a storage device using a static random access memory (SRAM), a flash memory, a hard disk, and the like. The storage unit 102 stores various computer programs executed by the CPU, data used when executing the various computer programs, and the like. The computer program stored in the storage unit 102 includes, for example, an image processing program for processing image data input through the input unit 103. Further, in the data stored in storage unit 102, in order to obtain a predetermined display luminance value (actual luminance) on screen SC, the luminance associated with the position on screen SC to define the relationship between the gradation value and the luminance. A correction database is included.

  The program stored in the storage unit 102 may be provided by a recording medium in which the program is readably recorded. The recording medium is, for example, a portable memory such as a universal serial bus (USB) memory, a secure digital (SD) card, a micro SD card, a compact flash (registered trademark) or the like. Various programs recorded on the recording medium are read from the recording medium using a reading device (not shown), and installed in the storage unit 102 included in the image processing apparatus 100. Further, when the image processing apparatus 100 includes a communication unit capable of communicating with an external communication apparatus, the program stored in the storage unit 102 may be provided by communication via the communication unit.

  The input unit 103 includes a connection interface for connecting an external device capable of outputting image data. Here, the external device connected to the connection interface is, for example, an imaging device 50 such as a digital camera or an on-vehicle camera. Also, the external device may be an information processing device such as a personal computer, a tablet terminal, a smartphone, a game machine or the like, or may be a video reproduction device such as a DVD reproduction device. The image data input into the image processing apparatus 100 through the input unit 103 is, for example, data in which each pixel is represented by each gradation value of RGB.

  The control unit 101 executes processing to generate tone data for high brightness reproduction and tone data for low brightness reproduction from the image data input through the input unit 103. Further, the control unit 101 executes processing of correcting the gradation value with reference to the luminance correction database so that the image displayed on the screen SC indicates the actual luminance. The processing content executed by the control unit 101 will be described in detail later.

  The output unit 104 includes a connection interface that connects the projectors 10 and 20. The output unit 104 outputs the gradation data for high luminance reproduction generated by the control unit 101 to the projector 10, and outputs the gradation data for low luminance reproduction to the projector 20.

  In the present embodiment, the control unit 101 executes the process of generating the gradation data to be output to the projectors 10 and 20 and the process of correcting the gradation value. An image processing unit including an arithmetic circuit, a buffer memory, and the like may be provided, and the image processing unit may be configured to execute the above-described processing.

  Hereinafter, the contrast ratio when an image is displayed by the conventional projection system will be described.

  FIG. 4 is a view showing an image to be displayed, and FIG. 5 is an explanatory view for explaining a state of projection by a conventional projection system. FIGS. 4A and 4C show images based on a black background, with a white square area in the middle. FIG. 4B shows an image likewise based on a black background, with gray square areas arranged in the central part. When the bit depth of the image to be displayed is 8 bits, the input tone value corresponding to black is 0, the input tone value corresponding to white is 255, and the input tone value corresponding to gray is 128, for example. is there. The square area shown in FIG. 4B has the same area as the square area shown in FIG. 4A, and the square area shown in FIG. 4C has a smaller area than the square area shown in FIG. 4A.

  FIGS. 5A to 5C show states in which the images to be displayed shown in FIGS. 4A to 4C are input to the projector and projected onto the screen SC. Ideally, light should not be projected onto the black background, but the brighter the brighter part, the larger the brighter part, the brighter the part of the input tone value 0 can be seen. For example, when the projected images of FIG. 5A and FIG. 5B are compared, the phenomenon that the luminance of the background portion is higher in the projected image shown in FIG. 5A than in the projected image shown in FIG. Further, when the projected images of FIG. 5A and FIG. 5C are compared, the phenomenon that the luminance of the background portion is higher in the projected image shown in FIG. 5A than in the projected image shown in FIG. That is, in the conventional projection system, as the bright part is brighter and the bright part is larger, the contrast ratio is lowered. This is because if there is a bright part in the image to be displayed, diffuse reflection in the projection lens will brighten not only the part near the bright part but also the dark part of the background.

  The change of the contrast ratio when the ratio of white in the input image is variously changed will be described.

  FIG. 6 is a view showing an example of an image used to measure the contrast ratio. 6A to 6D show images in which one or more circular regions of white (input tone value 255) are arranged based on a black (input tone value 0) background.

  The two images shown in FIG. 6A show an image in which a white circular area is arranged by 4% in a black background area. The image shown on the left side of FIG. 6A has a white ratio of 4% by arranging a white circular area in the central part of the background area, and the image shown on the right side of FIG. 6A is separated from the central part of the background area. By arranging a plurality of white circular regions, the ratio of white is 4%. The same applies to FIGS. 6B to 6D, and shows images in which the ratio of white is 10%, 20%, and 30%, respectively.

  When the contrast ratio is measured for an image with a percentage of white of 4%, a projector is used to separately project the image shown on the right side of FIG. 6A and the image shown on the left side of FIG. 6B. Then, the illuminance of the central portion of each projection image is measured by an illuminance meter, and the ratio of the two is determined to measure the contrast ratio. The contrast ratio can be measured in the same manner for images in which the proportion of white is 10%, 20%, and 30%.

  FIG. 7 is a graph showing the measurement results of the contrast ratio measured by variously changing the proportion of white. The horizontal axis of the graph indicates the proportion of white in the input image, and the vertical axis indicates the contrast ratio. The measured contrast ratio was about 6000 when a black image (the percentage of white was 0%) was displayed. The contrast ratio decreased as the proportion of white in the input image increased, and reached about 400 when an image with a proportion of 50% white was displayed. As described above, it was confirmed that as the bright area in the image increases, the contrast is significantly reduced.

FIG. 8 is a view showing an example of display by a conventional projection system. For example, when the image to be displayed is an image obtained by imaging a night scene including a street lamp, the brightness in the vicinity of the street lamp reaches about 10000 to 50000 cd / m ² while the brightness of the background portion such as a road is It becomes about 0.05-1.00 cd / m < ² >. If an image including such a luminance distribution is to be reproduced on the screen SC, a contrast ratio of about 10000 to 1000000 is required.

  However, as described above, as the bright part in the input image is brighter and the bright part is larger, the contrast ratio is lowered, so it is difficult to realize the above contrast ratio. For example, as shown in FIG. 8A, when an input image in which bright and dark areas are mixed is output to the projector and the image is projected from the projector onto the screen, the influence of diffuse reflection in the projection lens as described above As a result, not only the bright parts but also the dark parts become bright, as shown in FIG. 8B, the contrast ratio in the projected image on the screen decreases.

  Based on the above consideration, in the present embodiment, the gradation data for reproducing the high luminance part from the input image and the gradation data for reproducing the low luminance part are separated and projected from the projector 10 for high luminance reproduction. The reduction of the contrast ratio is suppressed by reducing the amount of light as a whole.

  FIG. 9 is an explanatory diagram for explaining an example of gradation data generated by the image processing apparatus 100 according to the present embodiment. When the image processing apparatus 100 according to the present embodiment acquires image data representing an input image through the input unit 103, the gradation data reproduces the high luminance part of the input image and the gradation data reproduces the low luminance part. And generate.

  Gradation data for reproducing a high luminance portion is generated by extracting a pixel having a luminance higher than the set luminance in the input image and rearranging the extracted pixel to correct the gradation. The set luminance may be a preset fixed value, or may be a value determined as a percentage of the maximum luminance in the input image. When the input image is an image in which bright parts and dark parts are mixed as shown in FIG. 9, only the area of the bright part is extracted as a pixel having a luminance higher than the set luminance. The extracted pixels are rearranged at the same position as the pixel position of the input image of the extraction source, and black (pixel value 0) pixels are arranged in the other parts, and the gradation is used to reproduce the high luminance part. Gradation data is generated after the value correction.

  Gradation data for reproducing a low luminance portion is generated by correcting the gradation value of each pixel constituting the input image so that the optical image on the screen SC shows actual luminance. For correction of the gradation value, in order to obtain a predetermined display luminance value (actual luminance) on the screen SC, reference is made to the luminance correction database which defines the relationship between the gradation value and the luminance value in association with the position on the screen SC. To be executed. In the region from which the high luminance portion is extracted, the gradation value is corrected on the assumption that high luminance pixels are superimposed as described later.

FIG. 10 is a conceptual view showing an example of the luminance correction database. FIG. 10A shows data defining the relationship between the gradation value and the luminance value in association with the position on the screen SC in order to reproduce the high luminance portion, and FIG. 10B shows the screen SC in order to reproduce the low luminance portion. It shows data that defines the relationship between the gradation value and the luminance value in association with the upper position. The luminance correction database has a position field and an input tone value field. In the position field, the position on the screen SC is recorded by the X coordinate and the Y coordinate. In the field of “100” as the display luminance value, gradation values to be input to the projectors 10 and 20 are obtained in order to obtain display luminance of 100 cd / m ² at each position on the screen SC. Similarly, in the field of “200” as the display luminance value, the gradation value to be input to the projector 20 to obtain the display luminance of 200 cd / m ² at each position on the screen SC is recorded. The same applies to the fields having display luminance values of “10000” and “50000”. The relationship between the display luminance and the gradation value at each position on the screen SC is such that an image whose gradation value at each pixel is known is projected from the projectors 10 and 20 onto the screen SC and is displayed at a predetermined observation position. It is obtained by measuring the brightness of multiple points on the screen using a two-dimensional brightness meter or spot brightness meter installed. In addition, when predetermined | prescribed display brightness is not obtained in the corresponding position on screen SC, it has shown by the code | symbol of "-".

  By referring to the luminance correction database as shown in FIG. 10, it is possible to correct the gradation value of each pixel constituting the input image so that the optical image on the screen SC indicates the actual luminance. For example, it is assumed that the set luminance is 150 and it is desired to display an image having a specific luminance value at the position (2048, 1080) on the screen SC. When displaying the luminance value 10000 at this position, the gradation value of the image reproducing the high luminance part is corrected to “128”, and the gradation value of the image reproducing the low luminance part is corrected to “0”. Alternatively, the gradation value of the image reproducing the high luminance portion is corrected to, for example, “126” so that the luminance value of the image of the high luminance portion becomes 9900 at the position (2048, 1080) on the screen SC. The gradation value of the image reproducing the low luminance portion may be corrected to, for example, “200” so that the luminance value of the image of the luminance portion is 100. The method of distributing the luminance values is not limited to the above, and there is no problem if the total value of the luminances is equal to the target luminance value. Also, when it is desired to display a luminance value of 100, the gradation value of the image for high luminance reproduction is corrected to 0, and the gradation value of the image for low luminance reproduction is set to 200, because it is below the set value. to correct.

  If desired display luminance is not recorded in the luminance correction database, correction tone values may be determined using interpolation processing of an arbitrary method such as linear interpolation. In the present embodiment, although the correction gradation value is given by the luminance correction database, it is not necessary to be in the database format, and the relationship between the display luminance and the correction gradation value at each position on the screen SC is Any data may be shown.

Hereinafter, the procedure of processing performed by the image processing apparatus 100 will be described.
FIG. 11 is a flowchart for explaining the procedure of processing performed by the image processing apparatus 100 according to the first embodiment. The control unit 101 of the image processing apparatus 100 acquires image data related to an input image through the input unit 103 (step S101). The image data acquired by the control unit 101 is, for example, data in which each pixel is represented by a gradation value such as RGB. Further, the image data acquired by the control unit 101 may be data expressed using tristimulus value data X, Y, Z of the CIE color system defined by CIE (Commission Internationale de l'Eclairage), The luminance values at the pixels may be represented by CIELAB (CIE L * a * b *) values, CIE RGB (CIE Red Green Blue) values, or any other format.

  The control unit 101 extracts a pixel having a luminance higher than the set luminance in the acquired input image, rearranges the extracted pixel, corrects the gradation value, and outputs it to the projector 10 for high luminance reproduction. Tone data (image) is generated (step S102).

  Further, the control unit 101 refers to the brightness correction database stored in the storage unit 102, and outputs the gray scale data (a gray scale data to the projector 20 for low brightness reproduction in which the gray scale value of each pixel constituting the input image is corrected) Image) is generated (step S103).

  In this flowchart, for convenience, the procedure is described to generate gradation data for low luminance reproduction after generating gradation data for high luminance reproduction, but after generating gradation data for low luminance reproduction A procedure of generating gradation data for high luminance reproduction may be used, or a procedure of generating gradation data for high luminance reproduction and gradation data for low luminance reproduction in parallel may be used.

  Next, the control unit 101 outputs the gradation data for high brightness reproduction generated in step S102 to the projector 10 through the output unit 104, and outputs the gradation data for low luminance generated in step S103 to the projector 20. (Step S104).

  Note that there is a possibility that shape distortion may occur in the optical image formed on the screen SC according to the arrangement relationship between the projectors 10 and 20 and the screen SC, so the control unit 101 projects from each of the projectors 10 and 20 The shape correction may be performed so that the shape of the optical image to be formed becomes a rectangular shape having the same size. If the positional relationship between the projectors 10 and 20 and the screen SC is known, the control unit 101 can perform shape correction using known geometric transformation.

  The projector 10 projects an image based on the gradation data for high brightness reproduction input from the image processing apparatus 100 on the screen SC, and the projector 20 receives the gradation for low brightness reproduction input from the image processing apparatus 100. Project an image based on the image on the screen SC. Since these projectors 10 and 20 are arranged such that the projected images overlap each other, one optical image is formed on the screen SC.

  FIG. 12 is a view showing an example of an optical image displayed on the screen SC by the multi-projection system according to the present embodiment. In the present embodiment, the gradation data for reproducing the high luminance part from the input image and the gradation data for reproducing the low luminance part are separated, and the projector 10 for high luminance reproduction which may cause a decrease in contrast rate. The light amount is reduced as a whole, and gradation correction is performed so that the optical image shows actual luminance. As a result, as shown in FIG. 12, it is possible to perform actual luminance display while minimizing the portion where the contrast decreases.

Second Embodiment
In the first embodiment, the multi-projection system including the projector 10 for high luminance reproduction and the projector 20 for low luminance reproduction has been described. However, the projector 10 for high luminance reproduction and the projector for low luminance reproduction are described. A plurality of units 20 may be provided.
In the second embodiment, a multi-projection system in which four projectors 10 for high luminance reproduction and five projectors 20 for low luminance reproduction will be described.

  FIG. 13 is a schematic view for explaining the configuration of the multi-projection system according to the second embodiment. The multi-projection system according to the second embodiment generates an image to be projected on the projectors 10A to 10D for high luminance reproduction, the projectors 20A to 20E for low luminance reproduction, and these projectors 10A to 10D and 20A to 20E, The image processing apparatus 100 outputs the generated image to the projectors 10A to 10D and 20A to 20E.

  The light reduction filter 21 is not mounted on the projectors 10A to 10D for high luminance reproduction, and the image generated by the image processing apparatus 100 (image based on the gradation data for high luminance reproduction) is dimmed. Project onto the screen SC. The light reduction filter 21 is mounted on the projectors 20A to 20E for low luminance reproduction, and reduces the image (image based on the gradation data for low luminance reproduction) generated by the image processing apparatus 100. Project on the screen SC.

  In the example shown in FIG. 13, one projector 10A for high brightness reproduction is disposed between the two projectors 20A and 20B for low brightness reproduction in the upper stage, and two projectors 10B for high brightness reproduction in the middle stage, One projector 20C for low luminance reproduction is disposed between 10C, and in the lower part, one projector 10D for high luminance reproduction is disposed between two projectors 20D and 20E for low luminance reproduction. The projectors 10A to 10D and 20A to 20E are arranged such that projection images overlap each other, and display one optical image by overlapping the projection images on the screen SC.

  The number and arrangement of the projectors 10A to 10D and 20A to 20E are not limited to the example shown in FIG. 13, and may be appropriately designed according to the required luminance, the number of pixels, the resolution, etc. of the optical image. Further, in the present embodiment, the light reduction filters 21 mounted on the projectors 20A to 20E for low luminance reproduction do not have to be the same, and for example, the light reduction filters for reducing light to 1/100 and 1/1000. As in the case of a light reducing filter, a projector may be mixed with a plurality of types of light reducing filters.

  In this embodiment, gradation data for high luminance reproduction and gradation data for low luminance reproduction are generated separately, and an image is projected from the projectors 10 and 20 based on these gradation data. An optical image is formed on the SC. When generating gradation data for high luminance reproduction, the input image is divided into a plurality of partial areas according to the arrangement of the projector for high luminance reproduction, and each of the divided partial areas is a floor for high luminance reproduction. Generate key data.

  FIG. 14 is an explanatory view for explaining an example of division of an input image. The projectors 10A to 10D for reproducing high brightness are disposed one on the upper stage, two on the middle stage, and one on the lower stage. Corresponding to the arrangement of such projectors 10A to 10D, the input image is, for example, a partial area 500A occupying the upper 1/3 area, a partial area 500B occupying the central left area, and a partial area occupying the central right area It is divided into four partial areas 500C and a partial area 500D that occupies the lower 1/3 area. That is, partial areas 500A to 500D are divided to correspond to the positions of projectors 10A to 10D, respectively.

  FIG. 15 is an explanatory diagram for explaining an example of gradation data generated by the image processing apparatus 100 according to the second embodiment. When image processing apparatus 100 according to the present embodiment acquires image data representing an input image through input unit 103 and divides the image into partial areas 500A to 500D corresponding to the arrangement of projectors 10A to 10D, each partial area 500A The gradation data to reproduce the high luminance part of the input image is generated from 500D to 500D.

  Gradation data for reproducing a high luminance portion is generated by extracting a pixel having a luminance higher than the set luminance in the input image, and rearranging the extracted pixel to correct the gradation value. The set luminance may be a preset fixed value, or may be a value determined as a percentage of the maximum luminance in the input image. If the input image is, for example, an image in which bright parts and dark parts are mixed as shown in FIG. 14 and the partial area 500A includes bright parts, pixels higher than the set luminance are extracted from the partial area 500A. Ru. The extracted pixels are rearranged at the same position as the input image of the extraction source, and black (pixel value 0) pixels are arranged in the other parts in other parts to reproduce the high luminance part In order to correct the gradation value, gradation data is generated.

  The same applies to the case where the partial region 500C includes a pixel having a luminance higher than the set luminance. A pixel having a luminance higher than the set luminance is extracted from the partial region 500C, rearranged at the same position as the input image of the extraction source, and a pixel of black (pixel value 0) is arranged in the other part, Gradation data is generated after correction of the gradation value to reproduce the luminance portion.

  On the other hand, when the partial regions 500B and 500D do not include a pixel having a luminance higher than the set luminance, gradation data in which only black (pixel value 0) pixels are arranged is generated.

  The gradation data for reproducing the low luminance portion is the same as that of the first embodiment. That is, it is generated by correcting the gradation value of each pixel constituting the input image so that the optical image on the screen SC indicates actual brightness. For correction of the gradation value, in order to obtain a predetermined display luminance value (actual luminance) on the screen SC, reference is made to the luminance correction database which defines the relationship between the gradation value and the luminance value in association with the position on the screen SC. To be executed.

  In the present embodiment, a luminance correction database is prepared for each of the projectors 10A to 10D for high luminance reproduction and the projectors 20A to 20E for low luminance reproduction, and the gradation data to be output to each of the projectors 10A to 10D and 20A to 20E When generating H, correction of gradation values is performed in accordance with the respective luminance correction databases. The tone value correction method is the same as that of the first embodiment, and the distribution of the luminance values is appropriately performed so that the total value of the luminances becomes equal to the target luminance value.

Hereinafter, the procedure of processing performed by the image processing apparatus 100 will be described.
FIG. 16 is a flowchart for explaining the procedure of processing performed by the image processing apparatus 100 according to the second embodiment. The control unit 101 of the image processing apparatus 100 acquires image data related to an input image through the input unit 103 (step S201). The image data acquired by the control unit 101 is, for example, data in which each pixel is represented by a gradation value such as RGB. Further, the image data acquired by the control unit 101 may be data expressed using tristimulus value data X, Y, Z of the CIE color system defined by CIE (Commission Internationale de l'Eclairage), and each pixel The luminance value in may be expressed by CIELAB (CIE L * a * b *) value, CIERGB (CIE Red Green Blue) value, or any other format.

  The control unit 101 divides the input image into a plurality of partial areas 500A to 500D according to the arrangement of the projectors 10A to 10D for high luminance reproduction (step S202).

  Next, the control unit 101 extracts pixels having a luminance higher than the set luminance in each of the partial regions 500A to 500D, rearranges the extracted pixels, and corrects the gradation value to each of the projectors 10A to 10D. Tone data (image) to be output is generated (step S203).

  Further, the control unit 101 refers to the brightness correction database stored in the storage unit 102, and outputs the gray scale value of each pixel constituting the input image to the projectors 20A to 20E for low brightness reproduction with the gray scale values corrected. Data (image) is generated (step S204).

  In this flowchart, for convenience, the procedure is described to generate gradation data for low luminance reproduction after generating gradation data for high luminance reproduction, but after generating gradation data for low luminance reproduction A procedure of generating gradation data for high luminance reproduction may be used, or a procedure of generating gradation data for high luminance reproduction and gradation data for low luminance reproduction in parallel may be used.

  Next, the control unit 101 outputs the gradation data for high luminance reproduction generated in step S203 to the projectors 10A to 10D through the output unit 104, and the gradation data for low luminance generated in step S204 in the projector 20A. .About.20 E (step S205). At this time, the control unit 101 outputs the gradation data for high brightness reproduction generated from each of the partial regions 500A to 500D to the projectors 10A to 10D at the corresponding positions.

  Note that there is a possibility that shape distortion may occur in the optical image formed on the screen SC according to the arrangement relationship between the projectors 10A to 10D and 20A to 20E and the screen SC, the control unit 101 selects each projector 10A. The shape correction may be performed such that the shapes of the optical images projected from 10D and 20A to 20E become rectangular shapes having the same size. If the positional relationship between the projectors 10A to 10D and 20A to 20E and the screen SC is known, the control unit 101 can perform shape correction using known geometric transformation.

  The projectors 10A to 10D project an image based on the gradation data for high luminance reproduction input from the image processing apparatus 100 on the screen SC, and the projectors 20A to 20E reproduce the low luminance reproduction input from the image processing apparatus 100. Project an image based on the desired gray scale onto the screen SC. Since these projectors 10A to 10D and 20A to 20E are arranged such that the projected images overlap each other, one optical image is formed on the screen SC.

  In the present embodiment, it is possible to reduce the area for projecting the high brightness part in each projector, and it is possible to reduce the amount of light projected from each of the projectors 10A to 10D for high brightness reproduction as a whole. As compared to the case where a plurality of high brightness areas are included in the projection image projected from one projector, the reduction in contrast can be suppressed.

Third Embodiment
In the third embodiment, a configuration in which the projector 10 for high luminance reproduction has the transparent liquid crystal 18 mounted thereon will be described.

  FIG. 17 is a schematic view showing the configuration of the multi-projection system according to the third embodiment. The multi-projection system according to the third embodiment generates an image to be projected on two projectors 10 and 20 that project an image on a screen SC and two projectors 10 and 20, and generates the generated image on the projector 10, And 20 an image processing apparatus 100 for outputting the image. The two projectors 10 and 20 are arranged such that the projected images overlap each other, and display an optical image by superimposing the projected images on the screen SC.

  The projectors 10 and 20 are, for example, rear projectors that project an image from the back side of the screen SC. One of the projectors 10 is a projector for reproducing high luminance on which the transparent liquid crystal 18 is mounted, and controls the light transmittance of the transparent liquid crystal 18 to thereby control the high luminance portion of the image generated by the image processing apparatus 100. , And blocks the other portion, thereby projecting an image reproducing the high-intensity portion onto the screen SC. Here, the transparent liquid crystal 18 is provided in front of the projection lens 17 (see FIG. 2), and has a configuration in which a light source, a light guide plate and the like are removed from a normal liquid crystal display. The transparent liquid crystal 18 is preferably a liquid crystal from which a color filter is removed or a liquid crystal designed for monochrome display in order to increase the light transmittance. The other projector 20 is a projector for low brightness reproduction on which the light reduction filter 21 is mounted, and reduces the light of the image (image based on the gradation data for low brightness reproduction) generated by the image processing apparatus 100. Project onto the screen SC.

  The image processing device 100 is a general-purpose or dedicated computer device, and receives, for example, digital image data captured by an imaging device 50 (see FIG. 18) such as an on-vehicle camera. The image processing apparatus 100 generates an image (gradation data) to be output to the projectors 10 and 20 from an input image based on the input image data, and outputs the generated image to each of the projectors 10 and 20. More specifically, the image processing apparatus 100 generates gradation data for high luminance reproduction mainly reproducing the high luminance part of the input image, outputs the generated gradation data to the projector 10, and Gray scale data for low brightness reproduction that reproduces a low brightness portion is generated, and the generated gray scale data is output to the projector 20. In addition, the image processing apparatus 100 transmits the high brightness portion of the image projected from the projector 10 and shields the other portions, the same gradation data or transparent liquid crystal 18 as the high brightness reproduction projector 10. The gradation data corrected in consideration of the installation position information is output to the transparent liquid crystal 18.

  In this embodiment, gradation data for high luminance reproduction and gradation data for low luminance reproduction are generated separately, and an image is projected from the projectors 10 and 20 based on these gradation data. An optical image is formed on the SC. In addition, the transparent liquid crystal 18 is mounted on the projector 10, and only the high luminance portion is transmitted, and the other portions are shielded. With such a configuration, in the present embodiment, the amount of light projected from the projector 10 for high brightness reproduction can be reduced as a whole, and the reduction in contrast of the optical image formed on the screen SC can be suppressed. It is possible.

  FIG. 18 is a block diagram for explaining the internal configuration of the image processing apparatus 100 according to the third embodiment. The image processing apparatus 100 includes, for example, a control unit 101, a storage unit 102, an input unit 103, and an output unit 104.

  The control unit 101 includes a CPU, a ROM, a RAM, and the like. A control program or the like for controlling the operation of each component of the hardware is stored in the ROM of the control unit 101. The CPU in the control unit 101 executes control programs stored in the ROM and various programs stored in the storage unit 102 described later, and controls the operation of each of the hardware units. The RAM provided in the control unit 101 stores data temporarily used during execution of various programs.

  The control unit 101 is not limited to the above configuration, and may be one or more processing circuits including a single core CPU, a multi-core CPU, a microcomputer, a volatile or non-volatile memory, and the like. Further, the control unit 101 may have functions such as a clock for outputting date and time information, a timer for measuring an elapsed time from giving a measurement start instruction to giving a measurement end instruction, and a counter for counting the number.

  The storage unit 102 includes a storage device using an SRAM, a flash memory, a hard disk, and the like. The storage unit 102 stores various computer programs executed by the CPU, data used when executing the various computer programs, and the like. The computer program stored in the storage unit 102 includes, for example, an image processing program for processing image data input through the input unit 103. Further, in the data stored in storage unit 102, in order to obtain a predetermined display luminance value (actual luminance) on screen SC, the luminance associated with the position on screen SC to define the relationship between the gradation value and the luminance. A correction database is included. In addition, the storage unit 102 includes information indicating the relationship between gradation data to be input to the transparent liquid crystal 18 and the transmittance of light, and information indicating the relationship between pixels on the image projected by the projector 10 and pixels of the transparent liquid crystal 18. It may be configured to include the included database.

  The program stored in the storage unit 102 may be provided by a recording medium in which the program is readably recorded. The recording medium is, for example, a portable memory such as a USB memory, an SD card, a micro SD card, or a compact flash. Various programs recorded on the recording medium are read from the recording medium using a reading device (not shown), and installed in the storage unit 102 included in the image processing apparatus 100. Further, when the image processing apparatus 100 includes a communication unit capable of communicating with an external communication apparatus, the program stored in the storage unit 102 may be provided by communication via the communication unit.

  The input unit 103 includes a connection interface for connecting an external device capable of outputting image data. Here, the external device connected to the connection interface is, for example, an imaging device 50 such as a digital camera or an on-vehicle camera. Also, the external device may be an information processing device such as a personal computer, a tablet terminal, a smartphone, a game machine or the like, or may be a video reproduction device such as a DVD reproduction device. The image data input into the image processing apparatus 100 through the input unit 103 is, for example, data in which each pixel is represented by each gradation value of RGB.

  The control unit 101 executes processing to generate tone data for high brightness reproduction and tone data for low brightness reproduction from the image data input through the input unit 103. Further, the control unit 101 executes processing of correcting the gradation value with reference to the luminance correction database so that the image displayed on the screen SC indicates the actual luminance. Further, the control unit 101 executes processing for generating gradation data for controlling the light transmittance of the transparent liquid crystal 18 as necessary. The processing content executed by the control unit 101 will be described in detail later.

  The output unit 104 includes a connection interface for connecting the projectors 10 and 20 and a connection interface for connecting the transparent liquid crystal 18. The output unit 104 outputs the gradation data for high luminance reproduction generated by the control unit 101 to the projector 10, and outputs the gradation data for low luminance reproduction to the projector 20. Further, the output unit 104 outputs, to the transparent liquid crystal 18, gradation data generated by the control unit 101 in order to control the light transmittance of the transparent liquid crystal 18.

  In the present embodiment, processing to generate gradation data to be output to the projectors 10 and 20 and gradation data for controlling light transmittance in the transparent liquid crystal 18 and processing to correct gradation values Although the configuration performed by the control unit 101 is described, an image processing unit including various arithmetic circuits, buffer memories, and the like may be provided in the image processing apparatus 100, and the above-described processing may be performed by the image processing unit.

  FIG. 19 is a flowchart for explaining the procedure of processing performed by the image processing apparatus 100 according to the third embodiment. The control unit 101 of the image processing apparatus 100 acquires image data related to an input image through the input unit 103 (step S301). The image data acquired by the control unit 101 is, for example, data in which each pixel is represented by a gradation value such as RGB. Further, the image data acquired by the control unit 101 may be data expressed using tristimulus value data X, Y, Z of the CIE color system defined by CIE, and the luminance value in each pixel is the CIELAB value. , CIE RGB values, or any other format.

  The control unit 101 extracts a pixel having a luminance higher than the set luminance in the acquired input image, rearranges the extracted pixel, corrects the gradation value, and outputs it to the projector 10 for high luminance reproduction. Tone data (image) is generated (step S302). In step S302, when correcting the gradation value, the gradation value of each pixel may be determined in consideration of the transmittance of light in each pixel of the transparent liquid crystal 18 described later.

  Further, the control unit 101 refers to the brightness correction database stored in the storage unit 102, and outputs the gray scale data (a gray scale data to the projector 20 for low brightness reproduction in which the gray scale value of each pixel constituting the input image is corrected) Image) is generated (step S303).

  Further, the control unit 101 generates gradation data to be output to the transparent liquid crystal 18 (step S304). Here, the control unit 101 can generate gradation data in which the gradation value for each pixel of the transparent liquid crystal 18 is appropriately set by referring to the database included in the storage unit 102. For example, when it is desired to perform display with a luminance of 10000 in a pixel on a projection image, a gradation value 255 (for example, 50% of transmittance) is input to the transparent liquid crystal 18 and the transparent liquid crystal is used for the projector 10 for high luminance reproduction. In consideration of the transmittance (= 50%) at 18, the tone value corresponding to the luminance 20000 may be input. Further, when it is desired to perform display with a luminance of 10000 in a pixel on the projection image, a gradation value 128 (for example, a transmittance of 10%) is input to the transparent liquid crystal 18 and the transparent liquid crystal is used for the projector 10 for high luminance reproduction. In consideration of the transmittance (= 10%) at 18, the tone value corresponding to the brightness 100000 may be input. Thus, if the value obtained by multiplying the display brightness of the projector 10 assuming that the transparent liquid crystal 18 is not mounted and the transmittance of the transparent liquid crystal 18 is equal to the target brightness value, the floor for the projector 10 is obtained. It is possible to set tone data and gradation data for the transparent liquid crystal 18 as appropriate.

  When the projection resolution of the projector 10 matches the resolution of the transparent liquid crystal 18 and the projection area of the projector 10 matches the control area of the transparent liquid crystal 18, the floor to be output to the transparent liquid crystal 18 The tone data may be the same as the tone data to be output to the projector 10. In this case, the processing according to this step may be omitted, and the gradation data generated in step S302 may be used.

  In this flowchart, for convenience, the procedure is described to generate gradation data for low luminance reproduction after generating gradation data for high luminance reproduction, but after generating gradation data for low luminance reproduction A procedure of generating gradation data for high luminance reproduction may be used, or a procedure of generating gradation data for high luminance reproduction and gradation data for low luminance reproduction in parallel may be used.

  Next, the control unit 101 outputs, through the output unit 104, the gradation data for high brightness reproduction generated in step S302 and the gradation data generated in step S303 to the projectors 10 and 20, respectively, and also generated in step S304. The gradation data is output to the transparent liquid crystal 18 (step S305).

  Note that there is a possibility that shape distortion may occur in the optical image formed on the screen SC according to the arrangement relationship between the projectors 10 and 20 and the screen SC, so the control unit 101 projects from each of the projectors 10 and 20 The shape correction may be performed so that the shape of the optical image to be formed becomes a rectangular shape having the same size. If the positional relationship between the projectors 10 and 20 and the screen SC is known, the control unit 101 can perform shape correction using known geometric transformation.

  The projector 10 projects an image based on the gradation data for high brightness reproduction input from the image processing apparatus 100 on the screen SC, and the projector 20 receives the gradation for low brightness reproduction input from the image processing apparatus 100. Project an image based on the image on the screen SC. Further, in the transparent liquid crystal 18, the light transmittance is controlled according to the gradation data input from the image processing apparatus 100. Since the projectors 10 and 20 are arranged such that the projected images overlap each other, one optical image is formed on the screen SC.

  In the present embodiment, only the high-intensity part is transmitted by the transparent liquid crystal 18 and the other part is shielded. Therefore, the amount of light projected from the projector 10 for high-intensity reproduction can be reduced as a whole. It is possible to suppress the decrease in the contrast of the optical image formed on the screen SC.

  In the present embodiment, as in the first embodiment, the projector 10 for high brightness reproduction and the projector 20 for low brightness reproduction are respectively provided. However, the present embodiment is the same as the third embodiment. A plurality of projectors 10 for high brightness reproduction and a plurality of projectors 20 for low brightness reproduction may be provided. In this case, the transparent liquid crystal 18 is mounted on each of the projectors 10 for high brightness reproduction.

  It should be understood that the embodiment disclosed herein is illustrative in all respects and not restrictive. The scope of the present invention is indicated not by the meaning described above but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

10, 20 Projector 18 Transparent liquid crystal 21 Light reduction filter 50 Imaging device 100 Image processing device 101 Control unit 102 Storage unit 103 Input unit 104 Output unit SC screen

Claims (9)

A plurality of projectors arranged such that projection images are mutually superimposed; and an image processing apparatus for generating images to be projected on the plurality of projectors based on an input image and outputting the generated images to the plurality of projectors. In a multi-projection system comprising
The image processing apparatus is
A first image generation unit which extracts a pixel having a luminance higher than a set luminance in the input image, rearranges the extracted pixel, and corrects a gradation value to generate an image;
A second image generation unit configured to generate an image by correcting the gradation value of each pixel constituting the input image;
The plurality of projectors are
A first projector for projecting an image generated by the first image generation unit;
And a second projector configured to dim and project the image generated by the second image generation unit. A plurality of first projectors,
The first image generation unit
The input image is divided into a plurality of partial areas according to the arrangement of the first projector, pixels having luminance higher than the set luminance are extracted for each of the divided partial areas, and the extracted pixels are rearranged The multi-projection system according to claim 1, wherein an image addressed to the first projector corresponding to each partial area is generated by correcting the gradation value. The image processing apparatus is
A storage unit for storing data indicating the relationship between the gradation value and the value related to the actual luminance;
The first image generator and the second image generator may
An optical image obtained by superimposing the projection image projected by the first projector and the projection image projected by the second projector with reference to the data stored in the storage unit represents actual brightness. The multi-projection system according to claim 1, wherein the gradation value of the pixel is corrected as shown. The image processing apparatus is
The multi-projection system according to any one of claims 1 to 3, further comprising: a shape correction unit configured to correct shape distortion of a projected image by the first projector and the second projector. The multi-projection system according to any one of claims 1 to 4, wherein the second projector comprises a light reduction filter for reducing and projecting an image. The multi-projection system according to any one of claims 1 to 4, wherein the second projector includes a light adjustment circuit that adjusts a projection light amount, and dims the light by the light adjustment circuit to project an image. . The multi-projection system according to any one of claims 1 to 6, wherein the first projector includes a transparent liquid crystal that shields an area equal to or less than the set luminance. Among a plurality of projectors arranged such that projected images overlap each other, at least one first projector that projects an image without reducing light and a second projector that projects an image while reducing light are projected An image processing apparatus that generates an image to be generated from an input image, and
A first image for generating an image to be projected by the first projector by extracting a pixel having a luminance higher than a setting luminance in the input image, rearranging the extracted pixel, and correcting a gradation value A generation unit,
A second image generation unit configured to generate an image to be projected by the second projector by correcting the luminance of each pixel forming the input image. Extracting a pixel having a luminance higher than the setting luminance in the input image, rearranging the extracted pixel, and generating a first image whose tone value is corrected;
Generating a second image in which the luminance of each pixel constituting the input image is corrected;
An image display method comprising: projecting the first image from at least one of a plurality of projectors arranged such that projection images overlap each other; and reducing and projecting the second image from another projector.