Correction method, projection device, and program

Abstract

This technology corrects unevenness in black color and brightness in projected images when tiling is performed using multiple projection devices, without degrading the overall contrast ratio of the projected image. [Solution] The projected image PI, when projected onto the projection surface SC, has a first region RL1 that overlaps with the first projected image PI1, a second region RL4 that overlaps with the second projected image PI3, and a third region RL3 that does not overlap with the first projected image PI1 and the second projected image PI3. Based on a first target value that is the target brightness of the first color component in the first region RL1 and a second target value that is the target brightness of the first color component in the second region RL4, parameter correction values ​​are calculated so that the distribution of parameters defining the brightness of the third region RL4 becomes a continuous or stepped distribution in a first direction from the first region RL1 to the second region RL4.

Description

[Technical Field]

[0001] This invention relates to a correction method, a projection device, and a program. [Background technology]

[0002] Patent Document 1 discloses a projection system that projects a tiling image by combining projected images from multiple projection devices. Specifically, in the technology described in Patent Document 1, a first projection device projects a first projection image, a second projection device projects the second projection device, and a third projection device projects the third projection device. A first superimposed region is generated by superimposing a portion of the first projection image and a portion of the second projection image. A second superimposed region is generated by superimposing a portion of the second projection image and a portion of the third projection image. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-5018 [Overview of the project] [Problems that the invention aims to solve]

[0004] Individual differences exist between projection devices in terms of contrast ratio. In the technology described in Patent Document 1, when attempting to make the brightness of the first superimposed region and the brightness of the second superimposed region the same, due to individual differences in contrast ratio, it becomes necessary to adjust the brightness of the other superimposed region to match the brightness of the darker superimposed region. However, when the brightness of the other superimposed region is adjusted to match the brightness of the darker superimposed region, the overall contrast ratio of the projected image may deteriorate. [Means for solving the problem]

[0005] A correction method according to an aspect of the present invention is a method for correcting a projected image projected from a projection device, comprising: a first projection device projecting each of a plurality of first color lights corresponding one-to-one with a plurality of grayscale data onto a projection surface as a first projected image based on a plurality of grayscale data; a second projection device projecting each of a plurality of second color lights corresponding one-to-one with a plurality of grayscale data onto the projection surface as a second projected image based on the plurality of grayscale data; and when the projection device projects each of a plurality of third color lights corresponding one-to-one with a plurality of grayscale data onto the projection surface as a projected image based on a plurality of grayscale data, a plurality of measurement data corresponding one-to-one with the plurality of grayscale data is acquired based on the output from a sensor that measures the reflected light reflected from the projection surface, and correction data for correcting the color of the image displayed on the projection surface is calculated based on the plurality of grayscale data and the plurality of measurement data, wherein the projected image is projected onto the projection surface In this state, the projection has a first region overlapping with the first projection image, a second region overlapping with the second projection image, and a third region not overlapping with the first and second projection images, wherein the plurality of gradation data includes at least one gradation value indicating at least one gradation of the first color component, and the plurality of measurement data includes brightness values ​​indicating the brightness of reflected light of the color light corresponding to the first color component having the at least one gradation value, and calculating the correction data includes determining a first target value which is the target brightness of the first color component in the first region and a second target value which is the target brightness of the first color component in the second region, based on the plurality of gradation data and the plurality of measurement data, and calculating correction values ​​for the parameters based on the first target value and the second target value such that the distribution of parameters defining the brightness of the third region is a continuous or stepped distribution in a first direction from the first region to the second region.

[0006] A projection device according to an aspect of the present invention is a projection device that, when a first projection device projects each of a plurality of first color lights corresponding one-to-one with a plurality of grayscale data onto a projection surface as a first projection image based on a plurality of grayscale data, a second projection device projects each of a plurality of second color lights corresponding one-to-one with a plurality of grayscale data onto the projection surface as a second projection image based on the plurality of grayscale data, a third color light corresponding one-to-one with a plurality of grayscale data onto the projection surface as a projection image based on the plurality of grayscale data, the projection device performs the following: acquire a plurality of measurement data corresponding one-to-one with the plurality of grayscale data based on the output from a sensor that measures the reflected light reflected from the projection surface, and calculate correction data for correcting the color of the image displayed on the projection surface based on the plurality of grayscale data and the plurality of measurement data, wherein the projection image is in a state projected onto the projection surface. The projection system comprises a first region overlapping with the first projection image, a second region overlapping with the second projection image, and a third region not overlapping with the first and second projection images. The plurality of grayscale data includes at least one grayscale value indicating at least one grayscale of the first color component, and the plurality of measurement data includes brightness values ​​indicating the brightness of reflected light of the color light corresponding to the first color component having the at least one grayscale value. Calculating the correction data includes determining a first target value that is the target brightness of the first color component in the first region and a second target value that is the target brightness of the first color component in the second region, based on the plurality of grayscale data and the plurality of measurement data, and calculating correction values ​​for the parameters based on the first target value and the second target value such that the distribution of parameters defining the brightness of the third region is a continuous or stepped distribution in a first direction from the first region to the second region.

[0007] A program according to an aspect of the present invention is a program that causes a projection device to perform the following actions: projecting each of a plurality of first color lights corresponding one-to-one with a plurality of grayscale data onto a projection surface as a first projection image using a first projection device, projecting each of a plurality of second color lights corresponding one-to-one with a plurality of grayscale data onto the projection surface as a second projection image using a second projection device, and when the projection device projects each of a plurality of third color lights corresponding one-to-one with a plurality of grayscale data onto the projection surface as a projection image using a plurality of grayscale data, it obtains a plurality of measurement data corresponding one-to-one with the plurality of grayscale data based on the output from a sensor that measures the reflected light reflected from the projection surface, and calculates correction data for correcting the color of the image displayed on the projection surface based on the plurality of grayscale data and the plurality of measurement data, wherein the projection image is projected onto the projection surface. The projection has a first region that overlaps with the first projection image, a second region that overlaps with the second projection image, and a third region that does not overlap with the first projection image and the second projection image. The plurality of gradation data includes at least one gradation value indicating at least one gradation of the first color component, and the plurality of measurement data includes brightness values ​​indicating the brightness of the reflected light of the color light corresponding to the first color component having the at least one gradation value. Calculating the correction data includes determining a first target value that is the target brightness of the first color component in the first region and a second target value that is the target brightness of the first color component in the second region, based on the plurality of gradation data and the plurality of measurement data, and calculating correction values ​​for the parameters based on the first target value and the second target value such that the distribution of parameters defining the brightness of the third region is a continuous or stepped distribution in a first direction from the first region to the second region. [Brief explanation of the drawing]

[0008] [Figure 1] A diagram showing the overall configuration of projection system 1. [Figure 2] Block diagram of projection device 10A. [Figure 3]A graph showing a γ curve corresponding to the relationship between the input gradation and the output luminance in the overlapping region DR. [Figure 4] A graph showing a γ curve corresponding to the relationship between the input gradation and the output luminance in the non-overlapping region NR. [Figure 5] A graph showing γ curves corresponding to the relationships between the input gradation and the output luminance in the overlapping region DR and the non-overlapping region NR. [Figure 6] An explanatory diagram of the method of projecting the measurement pattern by the projection device 10A. [Figure 7] A functional block diagram of the correction unit 136. [Figure 8] A flowchart showing an operation example of the projection device 10A according to the first embodiment. [Figure 9] A diagram showing an example of the lattice point LP. [Figure 10] A diagram showing an example of the lattice point LP. [Figure 11] A diagram showing an example of the lattice point LP. [Figure 12] A diagram showing an example of an interpolation curve R(r, 34, 34) for interpolating the measured value of the R component among the measured values (R, G, B) calculated by the processing device 13. [Figure 13] A diagram showing an example of an interpolation curve G(r, 34, 34) for interpolating the measured value of the G component among the measured values (R, G, B) calculated by the processing device 13. [Figure 14] A diagram showing an example of an interpolation curve B(r, 34, 34) for interpolating the measured value of the B component among the measured values (R, G, B) calculated by the processing device 13. [Figure 15] A diagram showing an example of an interpolation curve R(34, g, 34) for interpolating the measured value of the R component among the measured values (R, G, B) calculated by the processing device 13. [Figure 16] A diagram showing an example of an interpolation curve G(34, g, 34) for interpolating the measured value of the G component among the measured values (R, G, B) calculated by the processing device 13. [Figure 17] A diagram showing an example of an interpolation curve B(34, g, 34) for interpolating the measured value of the B component among the measured values (R, G, B) calculated by the processing device 13. [Figure 18]This figure shows an example of an interpolation curve R(34,34,b) used to interpolate the R component of the measured values ​​(R,G,B) calculated by the processing unit 13. [Figure 19] This figure shows an example of an interpolation curve G(34,34,b) used to interpolate the G component of the measured values ​​(R,G,B) calculated by the processing unit 13. [Figure 20] This figure shows an example of an interpolation curve B(34,34,b) used to interpolate the measured value of the B component among the measured values ​​(R,G,B) calculated by the processing unit 13. [Figure 21] A flowchart showing the substeps SS4[1] to SS4[7] that make up step S4. [Figure 22] A diagram showing an example of grayscale values ​​(r, g, b) as correction values ​​in a grid point DP. [Figure 23] This figure shows examples of grayscale values ​​(r,g,b) as correction values ​​at grid point DP, and grayscale values ​​t at grid point NP adjacent to the boundary between the superimposed region DR and the non-superimposed region NR. [Figure 24] This figure shows an example of a method for determining the target grayscale value t for a grid point NP whose target grayscale value t is undetermined. [Figure 25] This figure shows an example of a method for determining the target grayscale value t for a grid point NP whose target grayscale value t is undetermined. [Figure 26] A diagram showing an example of how the grayscale value t, which is the target value, is calculated. [Figure 27] A diagram showing an example of how the grayscale value t, which is the target value, is calculated. [Figure 28] A diagram showing an example of how the grayscale value t, which is the target value, is calculated. [Figure 29] A diagram illustrating an example of smoothing. [Figure 30] A diagram illustrating an example of smoothing. [Figure 31] A diagram illustrating an example of the smoothing process for the grayscale value t, which is the target value. [Figure 32] A diagram illustrating an example of the smoothing process for the grayscale value t, which is the target value. [Figure 33] A diagram illustrating an example of the smoothing process for the grayscale value t, which is the target value. [Figure 34] A figure showing a three-dimensional representation of the target values ​​of each grid point NP before smoothing. [Figure 35] A diagram showing a three-dimensional representation of the target values ​​of each grid point NP after smoothing is complete. [Figure 36] A diagram illustrating the method for determining target values ​​for brightness and chromaticity at grid point DP and grid point NP, respectively, according to Modification 1. [Figure 37] A diagram illustrating the method for determining target values ​​for brightness and chromaticity at grid point DP and grid point NP, respectively, according to Modification 1. [Figure 38] A diagram illustrating the method for determining target values ​​for brightness and chromaticity at grid point DP and grid point NP, respectively, according to Modification 1. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, in each drawing, the dimensions and scale of each part have been appropriately changed from those of the actual parts. Furthermore, the embodiments described below are preferred specific examples of the present invention and are subject to various technically preferred limitations, but the scope of the present invention is not limited to these embodiments unless otherwise stated in the following description.

[0010] 1: First Embodiment The projection system 1 according to the first embodiment will be described below with reference to Figures 1 to 35.

[0011] 1-1: Configuration of the First Embodiment 1-1-1: Overall structure Figure 1 shows the overall configuration of projection system 1. Projection system 1 comprises projection device 10A, projection device 10B, projection device 10C, and image supply device 20. Projection device 10A is an example of a "first projection device". Projection device 10B is an example of a "projection device". Projection device 10C is an example of a "second projection device".

[0012] Projection devices 10A, 10B, 10C, and image supply device 20 are connected to each other via a communication line LN, enabling them to communicate with one another.

[0013] Projectors 10A, 10B, and 10C project various images or videos onto the projection surface SC. For example, among projectors 10A, 10B, and 10C, projector 10B acts as the master projector for projectors 10A and 10C. Projectors 10A and 10C act as slave projectors for projector 10B. Specifically, projector 10B transmits various control signals to projectors 10A and 10C. As a result, projector 10B controls projectors 10A and 10C. The above control signals include various correction values, which will be described later.

[0014] Furthermore, the image supply device 20 supplies various images to the projection devices 10A, 10B, and 10C. Each of the projection devices 10A, 10B, and 10C projects the images supplied by the image supply device 20 onto the projection surface SC. Alternatively, the image supply device 20 may supply images only to the projection device 10B, and the projection device 10B may supply the images projected by each projection device 10 to each of the projection devices 10A and 10B. In this embodiment, when projection devices 10A through 10C are not distinguished, they will be referred to as projection device 10. Alternatively, in the projection system 1, projection devices 10A, 10B, and 10C may each read the image to be projected from their respective storage devices 14 and project it onto the projection surface SC. Alternatively, projection device 10B may read the image to be projected from its storage device 14 and supply the image to be projected by each projection device to projection devices 10A and 10C. In this case, the projection system 1 does not necessarily have to include an image supply device 20.

[0015] In the example shown in Figure 1, projection device 10A projects projection image PI1 onto projection surface SC. Projection image PI1 is an example of a "first projection image". Projection device 10B projects projection image PI2 onto projection surface SC. Projection image PI2 is an example of a "projection image". Projection device 10C projects projection image PI3 onto projection surface SC. Projection image PI3 is an example of a "second projection image". Projection images PI1, PI2, and PI3 are projected onto projection surface SC, with parts of them overlapping each other, so that a single projection image PI_A is displayed on projection surface SC as a whole.

[0016] Specifically, projected image PI1 includes parts PT1 and PT2. Projected image PI2 includes parts PT3, PT4, and PT5. Projected image PI3 includes parts PT6 and PT7. Part PT1 of projected image PI1 and part PT3 of projected image PI2 are superimposed onto the projection surface SC. Additionally, part PT5 of projected image PI2 and part PT6 of projected image PI3 are superimposed onto the projection surface SC.

[0017] As a result, region RL1 of projected image PI_A includes part PT2 of projected image PI1 and part PT3 of projected image PI2. Region RL1 is an example of a "first region". Region RL2 of projected image PI_A includes only part PT1 of projected image PI1. Region RL3 of projected image PI_A includes only part PT4 of projected image PI2. Region RL3 is an example of a "third region". Region RL4 of projected image PI_A includes part PT5 of projected image PI2 and part PT6 of projected image PI3. Region RL4 is an example of a "second region". Region RL5 of projected image PI_A includes part PT7 of projected image PI3.

[0018] Of the multiple regions RL in the projected image PI_A, regions RL1 and RL4 are superimposed regions DR. On the other hand, regions RL2, RL3, and RL5 are non-superimposed regions NR.

[0019] In this embodiment, when multi-projection is performed by projection devices 10A, 10B, and 10C, the brightness of region RL1 is different from the brightness of region RL4.

[0020] 1-1-2: Projection device configuration Figure 2 is a block diagram of projection device 10A. Projection devices 10B and 10C may have the same configuration as projection device 10A. Alternatively, projection devices 10B and 10C may have the configurations essential for projection devices, but may not include at least one of the following: imaging device 12, imaging control unit 132, image analysis unit 133, correction value calculation unit 134, image acquisition unit 135, and correction unit 136. The projection device 10A comprises a projector 11, an imaging device 12, a processing device 13, a storage device 14, and a communication device 15. Each element of the projection device 10A is interconnected by one or more buses for communicating information. Furthermore, each element of the projection device 10A consists of one or more devices, and some elements of the projection device 10A may be omitted.

[0021] The projector 11 is a device that projects various projection images PI onto a projection surface SC such as a screen or wall. The projector 11 projects various projection images PI under the control of the processing device 13. The projector 11 includes, for example, a light source, a projection lens, a dichroic mirror, a prism, and a liquid crystal panel. Light from the light source is modulated using the liquid crystal panel, and the modulated light is projected onto the projection surface SC via the projection lens. The light source, projection lens, dichroic mirror, and prism are examples of projection optical systems.

[0022] The imaging device 12 is a device that captures the projected image PI projected onto the projection surface SC. The imaging device 12 captures various images under the control of the processing device 13. The imaging device 12 is, for example, an image sensor. The imaging device 12 is an example of a "sensor".

[0023] The processing unit 13 is a processor that controls the entire projection device 10A, and is composed of, for example, one or more chips. The processing unit 13 is composed of a central processing unit (CPU) that includes, for example, interfaces with peripheral devices, an arithmetic unit, and registers. Some or all of the functions of the processing unit 13 may be implemented by hardware such as a DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), and FPGA (Field Programmable Gate Array). The processing unit 13 may also include a SoC (System on Chip). The processing unit 13 executes various processes in parallel or sequentially.

[0024] The storage device 14 is a recording medium readable by the processing unit 13 and stores multiple programs, including the control program PR1 executed by the processing unit 13. The storage device 14 also stores a measurement pattern image projected from the projector 11 during the correction described later. Hereafter, the measurement pattern image may be referred to as a measurement pattern. The storage device 14 may consist of at least one of the following: ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and RAM (Random Access Memory). The storage device 14 may also be called a register, cache, main memory, or primary memory.

[0025] The communication device 15 is hardware acting as a transmitting and receiving device for communicating with other devices. The communication device 15 is also called, for example, a network device, network controller, network card, or communication module. The communication device 15 may be equipped with a connector for wired connection and an interface circuit corresponding to the connector. The communication device 15 may also be equipped with a wireless communication interface. Examples of connectors and interface circuits for wired connection include those conforming to wired LAN (Local Area Network), IEEE1394, and USB (Universal Serial Bus). Examples of wireless communication interfaces include those conforming to wireless LAN or Bluetooth®.

[0026] The processing unit 13 functions as a projection control unit 131, an imaging control unit 132, an image analysis unit 133, a correction value calculation unit 134, an image acquisition unit 135, a correction unit 136, and a communication control unit 137 by reading and executing the control program PR1 from the storage device 14. The control program PR1 may also be transmitted via a communication network from another device, such as a server that manages the projection device 10A.

[0027] The projection control unit 131 causes the projector 11 to project the above-mentioned measurement pattern onto the projection surface SC. The projection control unit 131 also causes the projector 11 to project the image acquired by the image acquisition unit 135 (described later) from the image supply device 20 onto the projection surface SC.

[0028] The imaging control unit 132 causes the imaging device 12 to image the reflected light of the measurement pattern projected onto the projection surface SC.

[0029] The image analysis unit 133 analyzes the reflected light of the measurement pattern captured by the imaging device 12 and calculates a measured value indicating the color of the measurement pattern in the captured image.

[0030] The correction value calculation unit 134 calculates a correction value to be set in the correction unit 136 (described later) based on the measurement values ​​calculated by the image analysis unit 133. This correction value is an example of "correction data".

[0031] The following describes the measurement pattern projected by the projection control unit 131 in this embodiment.

[0032] A typical projection device with color adjustment functionality divides the color range from the lowest black level to the highest white level into roughly equal parts, projects colored light with the corresponding color at each division point, and calculates a correction value based on the image captured of the projected colored light on the projection surface. In this process, the projection device estimates the intermediate color levels between the first colored light level and the second colored light level based on interpolation calculations such as spline interpolation, and calculates a correction value based on the results of this estimation.

[0033] Alternatively, a projection device with a standard color adjustment function, as another example, projected colored light with a base of intermediate gray tones and calculated correction values ​​based on the image captured from the projected colored light on the projection surface. In this case, for colors other than gray, the properties of additive color mixing were used to estimate them based on interpolation calculations, and correction values ​​were calculated based on the results of these estimations.

[0034] However, the color of low-gradation light, close to black (where the gradation is 0), is a color light that is gradually modulated with RGB added to the color light output from a liquid crystal panel that has black when the gradation is 0 (i.e., the transmittance of the liquid crystal panel is 0). As a result, the change in chromaticity u'v' is large, and conventional measurement methods have the problem of large estimation errors. Specifically, as the transmittance of the liquid crystal panel increases from a state where the gradation is 0, the ratio of each of the modulated RGB light, i.e., R light, G light, and B light, tends to change significantly. This change in ratio leads to a change in chromaticity u'v'. Furthermore, the unevenness in chromaticity u'v' that occurs when the transmittance of the liquid crystal panel is 0 is caused, for example, by color unevenness in the projection optical system. Color unevenness in the projection optical system is caused, for example, by chromatic aberration of the projection lens or the manufacturing precision of the prism.

[0035] Furthermore, in typical projection devices, the input / output characteristics are adjusted to γ=2.2, for example, so the change in light intensity when the gradation changes is small near gradation 0. Therefore, in order to correct the unevenness of black, it is necessary to raise the corrected output gradation (correction value) to a gradation where the change in light intensity when the gradation changes is sufficient to ensure a certain amount of change. Note that "output gradation" refers to the gradation of the colored light projected onto the projection surface SC, and means the gradation output from the correction unit 136, described later, to the projector 11.

[0036] Furthermore, in order to correct "black level distortion," which is the difference in brightness between the superimposed DR region and the non-superimposed NR region, it is necessary to increase the corrected output gradation (correction value) so that the brightness of the non-superimposed NR region is the same as the brightness of the superimposed DR region.

[0037] In conventional methods, when black light (level 0) is projected onto a projection surface SC as a reference projection light, and the measured value is calculated by analyzing the image result of the reflected light reflected from the projection surface SC, the measurement of a level far removed from the corrected level becomes larger, resulting in a large interpolation error. As a result, there was a problem in that it was not possible to calculate a highly accurate correction value. To put it simply, for example, when correcting black using projection light for each of the eight equal levels of the level range from level 0 to level 1023, there was a problem in that the interpolation error became large.

[0038] Furthermore, projected light on the low-gradation side, close to black, has low brightness, making it more susceptible to the effects of dark current noise and light shot noise. Therefore, when projecting monochromatic R, G, and B light onto the projection surface for each projection device, and analyzing the reflected light from the projection surface to calculate the measurement value, there was a problem with the large error included in the measurement value.

[0039] Therefore, in this embodiment, the low-gradation light close to black that is projected as a measurement pattern is made up of multiple gradations.

[0040] The gradation of the measurement pattern for the overlapping region DR shall be three or more gradations including a lower gradation and a higher gradation than the expected gradation, which is the output gradation corresponding to the output luminance expected after color unevenness correction. The reason for setting the gradation of the measurement pattern for the overlapping region DR to three or more gradations is that at least three gradations are required for curve fitting considering the input-output characteristic of γ = 2.2. As an example, these three gradations are set as gradation A, gradation B, and gradation C (A < B < C). The projection apparatus 10A of the present embodiment can measure in detail the gradations necessary for correcting color unevenness on the lower gradation side close to black by setting the gradation of the measurement pattern for the overlapping region DR to three or more gradations.

[0041] FIG. 3 is a graph showing a γ curve corresponding to the relationship between the input gradation and the output luminance in the overlapping region DR. As shown in FIG. 3, gradation A is a gradation lower than the expected gradation, which becomes the output gradation corresponding to the output luminance expected after color unevenness correction. On the other hand, gradation C is a gradation higher than the expected gradation, which becomes the output gradation corresponding to the output luminance expected after color unevenness correction. Gradation B is a gradation between gradation A and gradation C.

[0042] As described above, in the gradation close to black with a gradation of 0, as shown in FIG. 3, just a slight change in the output luminance results in a large change in the chromaticity. Therefore, if the color light with a gradation lower than gradation A is used as the projection light, the correction error becomes large. For this reason, it is preferable to perform correction after brightening black until the output luminance reaches a certain slope of the γ curve. The expected gradation corresponding to the output luminance at which the γ curve has a certain slope is predetermined. The projection apparatus 10A of the present embodiment measures at least three output gradations including gradation B, which is an intermediate gradation, in order to improve the fitting accuracy when curve interpolation is performed using the γ curve between gradation A, which is a gradation somewhat lower than the expected gradation, and gradation C, which is a gradation somewhat higher than the expected gradation.

[0043] The expected gradation is predetermined by the degree of color unevenness inherent in the projection device 10. For example, if color unevenness can be suppressed with minor adjustments, the expected gradation will be low. On the other hand, if, for example, the color unevenness is significant due to the quality of the components used in the projection device, the expected gradation will be set to high in order to ensure a minimum adjustment range.

[0044] The grayscale level A can be determined based on the guideline that the amount of light changes sufficiently when the grayscale level changes by one step. "Sufficient change in light intensity" means, for example, that when the image analysis unit 133 analyzes the imaging result of the measurement pattern before the grayscale level changes by one step and the imaging result of the measurement pattern after the grayscale level changes by one step, the light intensity changes to such an extent that the image analysis unit 133 can detect a difference of a predetermined amount or more between the two. As an example, grayscale level A is set so that the chromaticity Δu'v' becomes about 1 / 1000 when the grayscale level changes by one step. For example, in the case of a projection device with a contrast ratio of 2000:1, grayscale level A will be a grayscale level of 20 or higher when the maximum grayscale level is 1023. In the case of a projection device with a contrast ratio of 3000:1, grayscale level A will be a grayscale level of 15 or higher when the maximum grayscale level is 1023.

[0045] On the other hand, gradation C is a gradation that is less than or equal to the maximum value of 127 in the first division when the gradation range from gradation 0 to gradation 1023 is divided into eight parts. Alternatively, gradation C may also be a gradation that is less than or equal to the minimum value of 128 in the second division when the gradation range from gradation 0 to gradation 1023 is divided into eight parts.

[0046] As a result, the difference between gradation A and gradation B is smaller than the difference between the highest gradation and the second highest gradation among multiple input gradations up to 1023 gradations. Here, the "highest gradation" is, for example, gradation 1023, which is the highest gradation in the 8th division of the gradation range from gradation 0 to gradation 1023. The "second highest gradation" is, for example, gradation 898, which is the lowest gradation in the 8th division of the gradation range from gradation 0 to gradation 1023.

[0047] In this embodiment, the gradation range from gradation 0 to gradation 1023 is divided into eight intervals, but it is not particularly limited. For example, the gradation range from gradation 0 to gradation 1023 may be divided into seven intervals or nine intervals. When the gradation range from gradation 0 to gradation 1023 is divided into seven intervals, for example, the maximum value of the gradation width of the first division is 146, and gradation C may be a gradation of 146 or less.

[0048] The gradation of the measurement pattern for the non-overlapping region NR is set to three or more gradations including a lower gradation and a higher gradation than the expected gradation, which is the output gradation corresponding to the output luminance expected after correcting "black floating". The reason for setting the gradation of the measurement pattern for the non-overlapping region NR to three or more gradations is that at least three gradations are required for curve fitting considering the input-output characteristic of γ = 2.2. As an example, these three gradations are set to gradation B', gradation C', and gradation D (B' < C' < D). By setting the gradation of the measurement pattern for the non-overlapping region NR of the projection apparatus 10A of the present embodiment to three or more gradations, the gradations required for correcting "black floating" on the lower gradation side close to black can be measured in detail. The expected gradation is determined in advance by experiments, simulations, etc., for example.

[0049] FIG. 4 is a graph showing a γ curve corresponding to the relationship between the input gradation and the output luminance in the non-overlapping region NR. As shown in FIG. 4, gradation B' is a gradation lower than the expected gradation, which is the output gradation corresponding to the output luminance expected after correcting "black floating". On the other hand, gradation D is a gradation higher than the expected gradation, which is the output gradation corresponding to the output luminance expected after correcting "black floating". Gradation C' is a gradation between gradation B' and gradation D.

[0050] The difference between gradation B' and gradation C' is smaller than the difference between the highest gradation and the second highest gradation among multiple input gradations up to 1023 gradations. Here, the "highest gradation" is, for example, gradation 1023, which is the highest gradation in the 8th division of the gradation range from gradation 0 to gradation 1023. The "second highest gradation" is, for example, gradation 898, which is the lowest gradation in the 8th division of the gradation range from gradation 0 to gradation 1023.

[0051] The grayscale B' shown in Figure 4 is higher than the grayscale A shown in Figure 3. In the superimposed region DR, the projected light from two projectors 10 overlaps, so the brightness of the projected image PI in the superimposed region DR is the brightness of two projectors 10. In order to correct "black level lift," it is necessary to project higher grayscale light to the non-superimposed region NR than to the superimposed region DR, so the grayscale B' needs to be higher than the grayscale A.

[0052] Furthermore, when projecting bright colored light beyond the minimum range where color unevenness can be eliminated onto the superimposed DR area, the overall contrast ratio deteriorates. For this reason, it is preferable to project light with a color range within the minimum range where color unevenness can be eliminated onto the superimposed DR area.

[0053] Furthermore, by making grayscale A, grayscale B, and grayscale C in Figure 3 equal to grayscale B' and grayscale C' equal to grayscale C' in Figure 4, it is possible to share a portion of the measurement pattern between the correction related to the superimposed region DR and the correction related to the non-superimposed region NR.

[0054] Figure 5 is a graph showing the gamma curve corresponding to the relationship between input gradation and output brightness in the superimposed DR region and the non-superimposed NR region. Specifically, the projection control unit 131 may project a measurement pattern of at least four gradations, consisting of gradation A, gradation B=gradation B', gradation C=gradation C', and gradation D, onto the superposition area DR and the non-superposition area NR, and the image analysis unit 133 may analyze the measurement pattern image captured by the imaging device 12 to calculate the measured value. The projection control unit 131 may further project a measurement pattern of gradation 0 onto the superposition area DR and the non-superposition area NR, and the image analysis unit 133 may analyze the measurement pattern image captured by the imaging device 12 to calculate the measured value. As a result, it is possible to reduce the number of measurement patterns and shorten the measurement time.

[0055] To brighten the brightness of the measurement pattern, it is preferable that the measurement pattern is not a single color from the R, G, and B components, but rather a color obtained by changing one of the color components of the R, G, and B components based on a reference gray. Note that the R component is an example of the "first color component". The G component is an example of the "second color component". The B component is an example of the "third color component". In this case, it is preferable that the reference gray is a gray in which all of the R, G, and B components are close to the output gradation B after color unevenness correction in the superimposed region DR. As a result, the gradation of the measurement pattern will be the following 10 patterns. For the sake of explanation below, the values ​​of the R, G, and B components of measurement patterns 1 to 10 will be denoted as r, g, and b, respectively. r is an example of the "first gradation value". g is an example of the "second gradation value". b is an example of the "third gradation value". Measurement pattern 1: (r,g,b)=(D,B,B) Measurement pattern 2: (r,g,b)=(B,D,B) Measurement pattern 3: (r,g,b)=(B,B,D) Measurement pattern 4: (r,g,b)=(C,B,B) Measurement pattern 5: (r,g,b)=(B,C,B) Measurement pattern 6: (r,g,b)=(B,B,C) Measurement pattern 7: (r,g,b)=(B,B,B) Measurement pattern 8: (r,g,b)=(A,B,B) Measurement pattern 9: (r,g,b)=(B,A,B) Measurement pattern 10: (r,g,b)=(B,B,A) If the measurement pattern includes a grayscale level of 0, it is preferable to use the following measurement pattern. Measurement pattern 11: (r,g,b)=(0,B,B) Measurement pattern 12: (r,g,b)=(B,0,B) Measurement pattern 13: (r,g,b)=(B,B,0) The combinations of (r,g,b) of these measurement patterns projected from projector 11 onto projection surface SC are an example of "grayscale data".

[0056] The projection device 10A projects multiple color lights, each corresponding one-to-one with multiple grayscale data, onto the projection surface SC as the projected image PI1. The color light projected by the projection device 10A is an example of "first color light". The projection device 10B projects multiple colored lights, each corresponding one-to-one with multiple grayscale data, onto the projection surface SC as a projected image PI2. The colored lights projected by the projection device 10B are an example of "third-colored lights". The projection device 10C projects multiple colored lights, each corresponding one-to-one with multiple grayscale data, onto the projection surface SC as a projected image PI2. The colored light projected by the projection device 10B is an example of "secondary colored light".

[0057] By using the above measurement pattern, it is possible to brighten the measurement pattern, improve the signal-to-noise ratio of the imaging device 12, and reduce the error in the measured values. In conventional methods, for example, when correcting the R component among the R, G, and B components, a measurement pattern was sometimes used in which only the liquid crystal panel corresponding to the R component was driven, and the liquid crystal panels corresponding to the G and B components output black with a grayscale level of 0. In this embodiment, in order to improve the S / N ratio and to make the measurement pattern brighter, a measurement pattern with an increased R component, a decreased R component, an increased G component, a decreased G component, an increased B component, and a decreased B component are used, starting from a gray pattern where all R, G, and B components are grayscale level B.

[0058] Figure 6 is an explanatory diagram of the projection method of the measurement pattern by the projection device 10A. For the sake of simplicity, in Figure 6, the same reference numerals are used for the same components as in Figure 1. However, unlike Figure 1, Figure 6 shows only the projected image PI1 projected from projection device 10A and the projected image PI2 projected from projection device 10B, while the projected image PI3 projected from projection device 10C is omitted. Furthermore, since the projected image PI3 is omitted in Figure 6, the projected image PI2 will only have parts PT1 and PT4, and will not have part PT5. Consequently, the projected image PI2 will include regions RL1 and RL3, but will not include region RL4.

[0059] In Figure 6, the projected image PI1 projected by projection device 10A and the projected image PI2 projected by projection device 10B have the same measurement pattern. For example, both projected image PI1 and projected image PI2 are measurement pattern 1 described above. However, both projected image PI1 and projected image PI2 are not limited to measurement pattern 1; both may be any of measurement patterns 2 to 13. Furthermore, the projection of image PI1 by projection device 10A and the projection of image PI2 by projection device 10B are synchronized. That is, image PI2 is projected at the same time as image PI1.

[0060] By projecting the projected image PI using the projection method described above, the brightness of the superimposed region DR becomes more than twice as high as when the measurement pattern is projected with a single projection device 10, thereby improving the signal-to-noise ratio of the imaging device 12. As a result, the projection device 10A of this embodiment can suppress errors in the measured values ​​calculated by the image analysis unit 133. Furthermore, since the grayscale of any of the R, G, and B components of each measurement pattern is not zero, it is possible to reduce errors in the measured values ​​obtained using the imaging device 12.

[0061] In conventional methods of projecting measurement patterns from multiple projection devices, for example, one projection device might project a color light with a grayscale of 0 as the measurement pattern, while other projection devices project a black measurement pattern with a grayscale of 0. In this case, the brightness of the superimposed DR area becomes less than half compared to this embodiment. On the other hand, in order to improve the signal-to-noise ratio of the imaging device 12, the projection system 1 according to this embodiment projects the same color light as the measurement pattern simultaneously from all projection devices 10. As a result, the measurement pattern becomes more than twice as bright compared to the conventional projection method in which color light is projected as the measurement pattern from only one projection device.

[0062] Furthermore, in the method of projecting measurement patterns from multiple projection devices, another example is to project colored light as a measurement pattern from only one projection device, calculate the first measurement value by imaging the projected measurement pattern, and then project colored light as a measurement pattern from another projection device, calculate the second measurement value by imaging the projected measurement pattern. In this case, the first and second measurement values ​​are added together, but due to the errors in the first and second measurement values, the error in the sum of the first and second measurement values ​​becomes double. Specifically, measuring light with half the brightness worsens the signal-to-noise ratio, so the standard deviation of the error becomes √2 times, and adding the two measurement values ​​adds up the errors of both, resulting in a standard deviation of error that is √2 times. As a result, the final standard deviation of the error is 2 times, which is the product of √2 times and √2 times. Consequently, the noise in the signal-to-noise ratio becomes double. On the other hand, in this embodiment, since the number of measurements is only one, the noise in the signal-to-noise ratio is reduced.

[0063] In the above explanation, as an example, the effect was described when the liquid crystal panel in the projector 11 has three panels: one corresponding to the R component, one corresponding to the G component, and one corresponding to the B component. However, the same effect is achieved even when the liquid crystal panel has only one panel. This is because the signal-to-noise ratio improves as the light incident on the imaging device 12, which acts as an image sensor, becomes brighter.

[0064] The measurement pattern projected by the projection control unit 131 in this embodiment has been described above.

[0065] A specific example of how the correction value calculation unit 134 calculates the correction value will be described later in the explanation of the operation of this embodiment, with reference to Figures 8 to 35.

[0066] In Figure 2, the image acquisition unit 135 acquires the image to be projected from the image supply device 20.

[0067] The correction unit 136 corrects the image acquired by the image acquisition unit 135 using the correction value calculated by the correction value calculation unit 134.

[0068] Figure 7 is a functional block diagram of the correction unit 136. The correction unit 136 includes a brightness correction circuit LC and a color uniformity correction circuit UC.

[0069] The brightness correction circuit LC corrects the brightness of the image acquired by the image acquisition unit 135 using the correction value calculated by the correction value calculation unit 134. This correction includes the correction of the "black level" issue described above.

[0070] The color unevenness correction circuit UC corrects the color unevenness of the image acquired by the image acquisition unit 135 using the correction value calculated by the correction value calculation unit 134.

[0071] In Figure 2, the projection control unit 131 projects the image corrected by the correction unit 136 as the projected image PI onto the projection surface SC using the projector 11.

[0072] The communication control unit 137 causes the communication device 15 to send and receive various types of information with an external device. This information includes correction values ​​that are transmitted from projection device 10A to projection device 10B and projection device 10C, respectively.

[0073] 1-2: Operation of the First Embodiment Figure 8 is a flowchart showing an example of the operation of the projection device 10A according to the first embodiment.

[0074] In step S1, the projection device 10A calculates brightness correction values ​​and color uniformity correction values ​​for gradations other than black. Furthermore, the projection device 10A uses these correction values ​​to adjust the brightness and color of the projected image PI from projection devices 10A to 10C so that they are uniform among the projection devices 10.

[0075] Here, "black" refers to the color included in the first gradation range (which includes gradation 0) when the gradation range from the smallest gradation value (gradation 0) to the largest gradation value (gradation 1023) is divided into N sections. Here, N is an integer greater than or equal to 3. For the sake of explanation, N may be set to 8 below.

[0076] Furthermore, the brightness correction described above is a correction that reduces the difference in brightness between the superimposed region DR and the non-superimposed region NR for gradations other than black. Also, the method used for the color unevenness brightness correction described above may be a conventional method. For example, in Figure 1, the method may be one in which any region RL from regions RL1 to RL5 is designated as the target region, and the brightness and color unevenness are corrected by comparing the image value shown by the image value obtained by imaging the target region with the image value obtained by imaging the other regions RL.

[0077] In this case, the processing unit 13 functions as a color unevenness correction circuit UC, and the adjustment point when correcting the projected image PI is, for example, the grid points LP of the projected image PI, which are 11 rows x 21 columns. The number of gradations is based on the gradations at the boundaries when the gradation width from gradation 0 to gradation 1023 is divided into 8 equal parts.

[0078] In step S1, the processing unit 13 determines whether each of the grid points LP used as the color unevenness correction circuit UC is included in the superposition region DR or in the non-superposition region NR. For example, before step S1, the processing unit 13 projects a full white image as a projection image only from projector 11 and captures the full white image with the imaging device 12 of projection device 10A. Next, it projects a full white image as a projection image only from projection device 10B and captures the full white image with the imaging device 12 of projection device 10A. From these imaging results, the processing unit 13 detects the position of the right edge of the full white image projected from projection device 10A and the position of the left edge of the full white image projected from projection device 10B, and determines that the region from the position of the right edge to the position of the left edge is the superposition region DR in the coordinate system of the captured image. Then, based on the correspondence between the coordinate systems of the projection device 10A, the projection device 10B, and the captured image, which were generated before step S1, the superposition region DR in the captured image coordinate system is converted into the superposition region DR in the coordinate systems of the projection device 10A and the projection device 10B. Based on the captured image of the grid points LP, the processing device 13 determines whether each of the grid points LP belongs to the superposition region DR in the coordinate systems of the projection device 10A and the projection device 10B. The correspondence can be calculated, for example, by a well-known calibration technique using Gray code. The coordinate system of the projection device 10A is the two-dimensional coordinate system of the liquid crystal panel. The coordinate system of the projection device 10B is the same. The same also applies to the projection devices 10B and 10C. The process described above is merely an example, and the method for determining whether each grid point LP is included in the superposition region DR or the non-superposition region NR can be modified as appropriate.

[0079] Figures 9 to 11 show examples of grid points LP. More specifically, Figure 9 is an example of a grid point LP corresponding to the projected image PI1 projected from projection device 10A. Figure 10 is an example of a grid point LP corresponding to the projected image PI2 projected from projection device 10B. Figure 11 is an example of a grid point LP corresponding to the projected image PI3 projected from projection device 10C.

[0080] In Figures 9 to 11, grid point LP includes grid point DP, grid point NP, and grid point PP. In these figures, hatched circles indicate grid point DP included in the superimposed region DR. White circles indicate grid point NP included in the non-superimposed region NR. Circles with dotted outlines indicate grid point PP where it could not be determined whether it was included in the superimposed region DR or the non-superimposed region NR. For each grid point LP shown in Figures 9 to 11, there are measured values ​​calculated by the image analysis unit 133.

[0081] In step S2, the projection device 10A projects a black correction measurement pattern. Specifically, the processing device 13 in the projection device 10A functions as a projection control unit 131. The processing device 13 reads the measurement pattern from the storage device 14 and causes the projector 11 to sequentially project the measurement pattern onto the projection surface SC.

[0082] The measurement pattern in question is one of the measurement patterns 1 through 10 described above. As described above, these measurement patterns are based on gray with a grayscale of level B, where all of the R, G, and B components are used, and the grayscale of one of the R, G, and B components is changed.

[0083] In the following, as an example, in the first measurement pattern used for correcting the color unevenness of black in the superimposed region DR, the above-mentioned gradation A is gradation 22, the above-mentioned gradation B is gradation 34, and the above-mentioned gradation C is gradation 60. Furthermore, in the second measurement pattern used for correcting "black floating" in the non-overlapping region NR and for correcting black color unevenness, the above-mentioned gradation B' = gradation B is gradation 34, the above-mentioned gradation C' = gradation C is 60, and gradation D is gradation 95.

[0084] In step S3, the processing unit 13 in the projection device 10A functions as an image capture control unit 132. The processing unit 13 causes the imaging device 12 to image each measurement pattern projected onto the projection surface SC. The processing unit 13 also functions as an image analysis unit 133. The processing unit 13 analyzes the measurement patterns captured by the imaging device 12 and calculates a measurement value indicating the color of the measurement pattern in the captured image.

[0085] First, the processing unit 13 uses interpolation to determine the correspondence between the gradation values ​​(r,g,b) (0≦r,g,b≦95) of the color light as a measurement pattern projected by the projector 11 at each point of the grid point LP and the measured values ​​(R,G,B) indicating the color of the color light in the captured image, which are calculated by analyzing the color light as a measurement pattern captured by the imaging device 12. As described above, the gradation values ​​of the R, G, and B components of the colored light projected by the projector 11 are, for example, set to 5 gradations from gradation 0 to gradation 95. Here, the grayscale values ​​(r,g,b) are an example of "grayscale data." On the other hand, the "measured values ​​(R,G,B)" are an example of "measured data." The measured data includes the R component, G component, and B component, as well as brightness values ​​that indicate the brightness of the reflected light of the corresponding colored light.

[0086] In the following, for clarity of notation, when the projector 11 projects color light with grayscale values ​​(r,g,b) as a measurement pattern, the processing unit 13 calculates the R component of the measured value (R,G,B) that indicates the color of the color light in the captured image, and this is expressed as R (r,g,b) This is written as, and the G component is G (r,g,b) This is written as, and component B is B (r,g,b) This is how it is written. Furthermore, when expressing the R, G, and B components of the measured values ​​indicating the color of the colored light in the captured image collectively, (R,G,B) (r,g,b) =(R (r,g,b) ,G (r,g,b) ,B (r,g,b) ) is written as .

[0087] The measured values ​​of five measurement patterns in which only the R component of the color light gradation values ​​(r, g, b) is changed are expressed as shown in the following equations 1 to 5.

number

[0088] Figure 12 shows an example of an interpolation curve R(r,34,34) which interpolates the measured value of the R component in the measured value (R,G,B) calculated by the processing device 13 when only the R component, r, is changed from the grayscale value (r,g,b) of the color light as a measurement pattern. The interpolation curve R(r,34,34) is an example of a "curve showing the first characteristic". Figure 13 shows an example of an interpolation curve G(r,34,34) which interpolates the measured value of the G component in the measured value (R,G,B) calculated by the processing device 13 when only the R component, r, is changed in the color light gradation value (r,g,b) as a measurement pattern. Figure 14 shows an example of an interpolation curve B(r,34,34) which interpolates the measured value of the B component in the measured value (R,G,B) calculated by the processing device 13 when only the R component, r, is changed among the grayscale values ​​(r,g,b) of the color light as a measurement pattern.

[0089] The processing device 13 uses these three interpolation curves R(r, 34, 34), G(r, 34, 34), and B(r, 34, 34) to obtain the measured values (R, G, B) when a colored light with an R component of an arbitrary gradation r (0 ≤ r ≤ 95) is projected onto the projection surface SC. (r,g,b) =(R (r,g,b) , G (r,g,b) , B (r,g,b) ) can be estimated.

[0090] FIG. 15 is a diagram showing an example of an interpolation curve R(34, g, 34) that interpolates the measured value of the R component among the measured values (R, G, B) calculated by the processing device 13 when only the g component, which is the G component, is changed among the gradation values (r, g, b) of the colored light as the measurement pattern. FIG. 16 is a diagram showing an example of an interpolation curve G(34, g, 34) that interpolates the measured value of the G component among the measured values (R, G, B) calculated by the processing device 13 when only the g component, which is the G component, is changed among the gradation values (r, g, b) of the colored light as the measurement pattern. FIG. 17 is a diagram showing an example of an interpolation curve B(34, g, 34) that interpolates the measured value of the B component among the measured values (R, G, B) calculated by the processing device 13 when only the g component, which is the G component, is changed among the gradation values (r, g, b) of the colored light as the measurement pattern.

[0091] The processing device 13 uses these three interpolation curves R(34, g, 34), G(34, g, 34), and B(34, g, 34) to obtain the measured values (R, G, B) when a colored light with a G component of an arbitrary gradation g (0 ≤ g ≤ 95) is projected onto the projection surface SC. (r,g,b) =(R (r,g,b) , G (r,g,b) , B (r,g,b) ) can be estimated.

[0092] FIG. 18 is a diagram showing an example of an interpolation curve R(34, 34, b) that interpolates the measured value of the R component among the measured values (R, G, B) calculated by the processing device 13 when only the b component, which is the B component, is changed among the gradation values (r, g, b) of the colored light as the measurement pattern. Figure 19 shows an example of an interpolation curve G(34,34,b) which interpolates the measured value of the G component in the measured value (R,G,B) calculated by the processing device 13 when only the B component b is changed among the grayscale values ​​(r,g,b) of the color light as a measurement pattern. Figure 20 shows an example of an interpolation curve B(34,34,b) which interpolates the measured value of the B component in the measured value (R,G,B) calculated by the processing device 13 when only the B component b is changed among the grayscale values ​​(r,g,b) of the color light as a measurement pattern.

[0093] The processing device 13 uses these three interpolation curves R(34,34,b), G(34,34,b), and B(34,34,b) to determine the measured values ​​(R,G,B) when color light with a B component of any grayscale b (0≦b≦95) is projected onto the projection surface SC. (r,g,b) =(R (r,g,b) ,G (r,g,b) ,B (r,g,b) This makes it possible to estimate ).

[0094] As a result, as shown in equations 6 to 8 below, which use the above interpolation curves R(r,34,34), G(r,34,34), B(r,34,34), R(34,g,34), G(34,g,34), B(34,g,34), R(34,34,b), G(34,34,b), and B(34,34,b), when only one color component of the gradation value (r,g,b) of the color light projected from projector 11 is changed and the other color components are fixed at gradation 34, the measured values ​​(R,G,B) are as follows. (r,g,b) =(R (r,g,b) ,G (r,g,b) ,B (r,g,b) This makes it possible to estimate ).

number

[0095] In equations 6 to 8 above, of the gradation values ​​(r,g,b) of the color light projected from the projector 11, only one component of the R component (r), G component (g), and B component (b) is arbitrarily changed, while the other two components are fixed at gradation 34. Therefore, by applying the properties of additive color mixing to equations 6 to 8, the processing device 13 uses the following equation 9 to obtain the measured values ​​(R,G,B) when all components of the gradation values ​​(r,g,b) (0≦r,g,b≦95) of the color light are arbitrarily changed: (r,g,b) =(R (r,g,b) ,G (r,g,b) ,B (r,g,b) This makes it possible to estimate ).

number

[0096] Note that in Equation 9, the origin of additive color mixing is (r,g,b)=(34,34,34), not (r,g,b)=(0,0,0). When Equation 9 is expressed component by component, it becomes Equations 10 to 12 below. Figure 21 is a graph showing Equations 10 to 12 in a three-dimensional space with the R, G, and B components as the three axes.

number

[0097] The image analysis unit 133 uses the RGB values ​​calculated by equations 10 to 12, R (r,g,b) , G (r,g,b) , and B (r,g,b) Equation 13, which multiplies a matrix with the components by a transformation matrix M specific to the imaging device 12, converts RGB values ​​to XYZ values. As a result, the image analysis unit 133 can estimate the output values ​​XYZ for any grayscale. The transformation matrix M is a matrix for converting between RGB values ​​and output values ​​XYZ, and is determined in advance by performing a well-known calibration on the imaging device 12.

number

[0098] Furthermore, the image analysis unit 133 calculates the brightness component Y and the chromaticity component u'v' by converting the estimated XYZ values ​​into Yu'v' values ​​using the following equation 14.

number

[0099] In step S4, the processing unit 13 in the projection device 10A functions as a correction value calculation unit 134. The processing unit 13 calculates correction values ​​to be set for the brightness correction circuit LC and the color unevenness correction circuit UC, respectively, so that the brightness of the corrected black becomes the target brightness as seen from the imaging device 12, the color unevenness of the corrected black is suppressed, and the chromaticity is uniform as seen from the imaging device 12.

[0100] Figure 21 is a flowchart showing the substeps SS4[1] to SS4[7] that constitute step S4. In the flowchart shown in Figure 21, the processing unit 13 first calculates the correction value for the superimposed region DR, and then calculates the target brightness and chromaticity values ​​that are the target for correction of the non-superimposed region NR. Subsequently, the processing unit 13 calculates the correction value for the non-superimposed region NR based on the calculated target values.

[0101] In substep SS4[1], the processing unit 13 functions as a correction value calculation unit 134. The processing unit 13 calculates correction values ​​at grid points DP included in the superimposed region DR, assuming that the target brightness and chromaticity in the superimposed region DR are already determined by known methods. The processing unit 13 may use known methods as the method for calculating the correction values.

[0102] As an example, in Figure 1, the target value for the brightness of the R component in region RL1 of the superimposed region DR is an example of the "first target value". The target value for the brightness of the R component in region RL4 of the superimposed region DR is an example of the "second target value". The target value for the brightness of the G component in region RL1 of the superimposed region DR is an example of the "third target value". The target value for the brightness of the G component in region RL4 of the superimposed region DR is an example of the "fourth target value". The target value for the brightness of the B component in region RL1 of the superimposed region DR is an example of the "fifth target value". The target value for the brightness of the B component in region RL4 of the superimposed region DR is an example of the "sixth target value". In this embodiment, the first to sixth target values ​​are different for each of the multiple grid points LP. Note that each of the first to sixth target values ​​may be a single value. As a result of the correction described later, the brightness in the superimposed region DR is maintained at a brightness corresponding to these target values. Based on these target values, the processing unit 13 calculates correction values ​​for the parameters that define the brightness of the region RL3 included in the non-superimposed region NR.

[0103] Specifically, the processing unit 13 predetermines a target gradation value for the brightness of the superimposed region DR. This gradation value is the gradation value at which the output brightness is expected to correspond to the output gradation after color unevenness correction, as shown in Figure 3. For each grid point DP of the superimposed region DR shown in Figures 9 to 11, the processing unit 13 calculates a target brightness component Y from the determined gradation value. This "target brightness component Y" is the brightness component Y used to correct the "black level floating" mentioned above.

[0104] The processing unit 13 calculates a target brightness component Y for each grid point DP. Specifically, even if brightness unevenness originally exists within the superimposed region DR, the processing unit 13 does not uniformly adjust the brightness unevenness within the superimposed region DR, but rather calculates a correction amount for each grid point DP that matches the target brightness component Y. If the processing unit 13 were to uniformly adjust the brightness unevenness, it would be necessary to lower the brightness at each grid point DP, which would reduce the number of gradation steps that can be corrected at each grid point DP. The reason the processing unit 13 pre-determines a target brightness component Y for each grid point DP is to ensure a minimum correction amount that uniformly removes color unevenness at each grid point DP as described above.

[0105] Furthermore, the processing unit 13 predetermines the chromaticity component u'v' as a target value for the chromaticity of the superimposed region DR. This "chromaticity component u'v' as a target value" is the chromaticity component u'v' used to correct the color unevenness mentioned above. The processing unit 13 determines the same target value for the chromaticity component u'v' in all superimposed regions DR based on the average chromaticity among the three projectors 10 (projector 10A, projector 10B, and projector 10C), the average chromaticity in each projector 10, and the chromaticity design value of each projector 10 at the time of product shipment. In this case, after correction, the chromaticity will be the same in all superimposed regions DR. Alternatively, the processing unit 13 determines the chromaticity component u'v' as the same target value within each superimposed region DR based on the above parameters. In this case, after correction, the chromaticity will be the same within each superimposed region DR. As a result, color unevenness in the superimposed DR region is corrected.

[0106] The processing unit 13 uses equations 13 and 14 above to convert the target value Yu'v' value, which consists of the brightness component Y and the chromaticity component u'v', at each grid point DP within the superimposed region DR, into an RGB value. Furthermore, the processing unit 13 calculates the target gradation value (r, g, b) from the converted RGB value to be output from the correction unit 136 to the projection control unit 131. The processing unit 13 uses this as the ideal output value from the correction unit 136 to the projector 11.

[0107] Figure 22 shows an example of the target grayscale value (r,g,b) at the grid point DP calculated by the processing unit 13. In Figure 22, an example of the value of one of the r, g, and b components included in the grayscale value (r,g,b) is shown. Figure 22 corresponds to the projected image PI2 shown in Figure 11. Furthermore, each rectangle shown in Figure 22 represents a portion PT of the projected image PI, including each grid point LP shown in Figure 11. A portion PT1 contained within region RL1 is an example of a "first portion". Region RL1 contains multiple portions PT1. A portion PT3 contained within region RL3 is an example of a "third portion". Region RL3 contains multiple portions PT3. A portion PT4 contained within region RL4 is an example of a "second portion". Region RL4 contains multiple portions PT4. The numerical values ​​inside the rectangle above represent the values ​​of one of the r, g, and b components included in the target grayscale value (r, g, b). For the sake of simplicity, the values ​​in Figure 22 are shown as integers, but they may actually be decimals. The same applies to the values ​​shown below.

[0108] Furthermore, among the rectangles shown in Figure 22, those with double borders correspond to lattice point DP. As described above, lattice point DP is lattice point LP included in the superposition region DR. Rectangles with single borders correspond to lattice point NP. As described above, lattice point NP is lattice point LP included in the non-superposition region NR. Rectangles with double borders, one of which is a dotted line, correspond to lattice point PP. As described above, lattice point PP is lattice point LP that could not be determined to belong to either the superposition region DR or the non-superposition region NR.

[0109] In substep SS4[2] of Figure 21, the processing unit 13 functions as a correction value calculation unit 134. The processing unit 13 determines the target gradation value (r,g,b) at a grid point NP such that the brightness is at least the same between a grid point DP belonging to the superimposed region DR and a grid point NP belonging to the non-superimposed region NR that are adjacent to each other across the boundary between the superimposed region DR and the non-superimposed region NR. The target gradation value (r,g,b) at the grid point NP may be determined so that the color is at least the same.

[0110] The target gradation value (r,g,b) at grid point NP is calculated based on the target gradation value (r,g,b) at grid point DP. The specific calculation method is described below.

[0111] In Figure 22, lattice point DP1 is an example of lattice point DP. Similarly, lattice point NP1 is an example of lattice point NP. Lattice points DP1 and NP1 are adjacent to each other, separated by the boundary between the superposition region DR and the non-superposition region NR.

[0112] In Figure 22, the target grayscale values ​​(r,g,b) of grid point DP1 have already been calculated. The processing unit 13 applies equations 6 to 8 above to these grayscale values ​​(r,g,b) to estimate the RGB values ​​as measured by the imaging device 12. The processing unit 13 also calculates the estimated measured values ​​(R,G,B) (r,g,b) By applying the above formula 13, the RGB values ​​as measured values ​​are converted to XYZ values. Furthermore, the processing unit 13 applies the above formula 14 to the converted XYZ values, thereby converting the converted XYZ values ​​to Yu'v' values.

[0113] As a result, the Yu'v' value of grid point DP1 is calculated, and the processing unit 13 uses this Yu'v' value as the target Yu'v' value for grid point NP1. Furthermore, the processing unit 13 calculates the target gradation value (r,g,b) for grid point NP1 by working backward from this target Yu'v' value using equations 6 to 14 described above.

[0114] In Figure 22, a portion PT3 adjacent to region RL1, such as the portion PT3 containing grid point NP1, is an example of a "first adjacent portion GP1". On the other hand, a portion PT3 adjacent to region RL4 is an example of a "second adjacent portion GP2". The target value of the R component brightness at grid point NP included in the first adjacent portion GP1 is an example of a "seventh target value". The target value of the R component brightness at grid point NP included in the second adjacent portion GP2 is an example of an "eighth target value". Furthermore, region RL3 includes multiple intermediate portions CP between the first adjacent portion GP1 and the second adjacent portion GP2. The target value of the R component brightness at grid point NP included in the intermediate portions CP is an example of a "ninth target value". Furthermore, the direction from region RL1 to region RL4 in Figure 22 is an example of the "first direction".

[0115] For the sake of simplicity, the following explanation will focus on the brightness target value among the target values ​​for grid point NP1. Since the method for calculating the chromaticity target value is the same as that for the brightness target value, the explanation regarding the brightness target value also applies to the chromaticity target value.

[0116] When the brightness of grid point NP1 reaches the target value, the processing unit 13 calculates a grayscale value t as the target grayscale value (r,g,b) for grid point NP such that the r, g, and b components are (r,g,b)=(t,t,t). Specifically, the processing unit 13 calculates a grayscale value t such that when gray light is projected from the projector 11, the brightness at grid point DP1 and grid point NP1 are the same.

[0117] Figure 23 shows an example of the target grayscale value (r,g,b) at grid point DP and the target grayscale value t at grid point NP adjacent to the boundary between the superimposed region DR and the non-superimposed region NR. In Figure 23, the target tonal value t at grid point NP is larger than the target tonal value (r,g,b) at grid point DP. This is because the brightness at grid point DP is approximately twice that of grid point NP, so in order to make the brightness of both approximately equal, it is necessary to increase the target tonal value t at grid point NP in the non-overlapping region NR. Furthermore, without correction, the non-overlapping region NR will be darker than the overlapping region DR. Therefore, in order to make the brightness component Y the same for both the overlapping region DR and the non-overlapping region NR after correction, it is necessary to make the target tonal value t at grid point NP larger than the target tonal value (r,g,b) at grid point DP.

[0118] In substep SS4[3] of Figure 21, the processing unit 13 calculates further target grayscale values ​​t for grid point NP by averaging the target grayscale values ​​t of grid point NP calculated in substep SS4[2] with the target grayscale values ​​t of adjacent grid point NP.

[0119] Specifically, for a grid point NP whose target grayscale value t is undetermined, the processing unit 13 calculates the average value of the target grayscale values ​​t of at least one of the adjacent grid points NP (up, down, left, or right) whose target grayscale value t is determined. The processing unit 13 then sets the calculated average value as the target grayscale value t for the grid point NP whose target grayscale value t is undetermined.

[0120] Figures 24 and 25 show examples of methods for determining the target grayscale value t for a grid point NP whose target grayscale value t is undetermined.

[0121] In Figure 24, grid point NP2, whose target tone value t is undetermined, is located at the edge of the non-overlapping region NR. In this case, there are five grid points NP adjacent to grid point NP2: grid points NP3 to NP7. Of these grid points NP3 to NP7, grid point NP3 is set to a target tone value t=52. Grid point NP4 is set to a target tone value t=51. On the other hand, grid points NP5 to NP7 do not have a target tone value t set. Therefore, the processing unit 13 sets the average value of the target tone value t=52 of grid point NP3 and the target tone value t=51 of grid point NP4 as the target tone value t of grid point NP2.

[0122] In Figure 25, grid point NP8, whose target tone value t is undetermined, is located inside the non-overlapping region NR. In this case, there are eight grid points NP adjacent to grid point NP8: grid points NP9 to NP16. Of these eight grid points NP, grid point NP9 is set to a target tone value t=52. Grid point NP10 is set to a target tone value t=51. Grid point NP11 is set to a target tone value t=52. On the other hand, grid points NP12 to NP16 do not have a target tone value t set. Therefore, the processing unit 13 sets the average value of the target tone value t=52 of grid point NP9, the target tone value t=51 of grid point NP10, and the target tone value t=52 of grid point NP11 as the target tone value t of grid point NP8.

[0123] In substep SS4[4] of Figure 21, the processing unit 13 functions as a correction value calculation unit 134. The processing unit 13 determines whether the target grayscale value t has been calculated for all grid points NP in the non-overlapping region NR. If the target grayscale value t has been calculated for all grid points NP in the non-overlapping region NR ("YES" in substep SS4[4]), the processing unit 13 executes the process in substep SS4[5]. On the other hand, if the target grayscale value t has not been calculated for all grid points NP in the non-overlapping region NR ("NO" in substep SS4[4]), the processing unit 13 executes the process in substep SS4[3].

[0124] As a result, the processing unit 13 sequentially extends the grid points NP for calculating the target grayscale value t into the interior of the non-overlapping region NR.

[0125] Figures 26 to 28 show examples of the calculation status of the target tone value t. More specifically, Figure 26 shows the calculation status of the target tone value t for grid points NP adjacent to the inside of the non-overlapping region NR, compared to the state in Figure 25, for grid points NP adjacent to the boundary between the overlapping region DR and the non-overlapping region NR. Figure 27 shows the calculation status of the target tone value t for grid points NP adjacent to the inside of the non-overlapping region NR, for grid points NP for which the target tone value t was newly calculated in Figure 26. Figure 28 shows the state after the target tone value t has been calculated for all grid points NP.

[0126] In substep SS4[5] of Figure 21, the processing unit 13 functions as a correction value calculation unit 134. The processing unit 13 repeatedly smooths the target grayscale values ​​t of the calculated target grayscale values ​​t for grid points NP other than those adjacent to the boundary between the superimposed region DR and the non-superimposed region NR. Specifically, for grid points NP other than those adjacent to the boundary, the processing unit 13 smooths using the target grayscale values ​​t of valid grid points NP among the grid points NP adjacent to it in the upper, lower, left, and right directions.

[0127] As shown in Figure 28, when the processing unit 13 calculates the target tone value t of a grid point NP, it sequentially calculates the target tone value t of the grid point NP adjacent to the inside of the non-overlapping region NR, i.e., to the right, starting from the first overlapping region DR, region RL1, as described above. In parallel with this, the processing unit 13 sequentially calculates the target tone value t of the grid point NP adjacent to the inside of the non-overlapping region NR, i.e., to the left, starting from the second overlapping region DR, region RL4. As a result, in Figure 28, as an example, a large difference occurs between the target tone value t=45 of grid point NP17 and the target tone value t=41 of grid point NP18, which is adjacent to grid point NP17. In other words, there is a step between the target tone value t=45 of grid point NP17 and the target tone value t=41 of grid point NP18.

[0128] The processing unit 13 eliminates the step difference in the interpolated target grayscale value t and performs the smoothing described above so that the target grayscale value t of the grid point NP included in the non-overlapping region NR smoothly connects from region RL1, which is the first superimposed region DR, to region RL4, which is the second superimposed region DR. As a result, as described later, the target gradation value t, which is a parameter that defines the brightness of region RL3, a non-overlapping region NR, has a continuous or stepped distribution in the direction from region RL1 to region RL4.

[0129] Figures 29 and 30 show examples of smoothing. Figure 29 corresponds to Figure 24. Figure 30 corresponds to Figure 25.

[0130] In Figure 29, the processing unit 13 smooths the target gradation value t=51 at grid point NP2 using the target gradation values ​​t=52 at grid point NP3, t=51 at grid point NP4, t=51 at grid point NP5, t=50 at grid point NP6, and t=50 at grid point NP7.

[0131] In Figure 30, the processing unit 13 smooths the target gradation value t=51 at grid point NP8 using the target gradation values ​​t=52 at grid point NP9, NP10, NP11, NP12, NP13, NP14, NP15, and NP16.

[0132] In substep SS4[6] of Figure 21, the processing unit 13 functions as a correction value calculation unit 134. The processing unit 13 determines whether the range of change of the target grayscale value t at each grid point NP is below a threshold before and after smoothing. More specifically, the processing unit 13 determines whether the sum of the ranges of change of the target grayscale value t at all grid points NP is below a threshold. If the sum of the ranges of change of the target grayscale value t at all grid points NP is below a threshold ("YES" in substep SS4[6]), the processing unit 13 executes the process in substep SS4[7]. On the other hand, if the sum of the ranges of change of the target grayscale value t at all grid points NP exceeds a threshold ("NO" in substep SS4[4]), the processing unit 13 executes the process in substep SS4[5].

[0133] In other words, the processing unit 13 repeats the smoothing process until the sum of the changes in the target grayscale value t for all grid points NP falls below a threshold.

[0134] Figures 31 to 33 show examples of the smoothing process of the target tone value t. More specifically, Figure 31 shows an example of the target tone value t after the first smoothing process. Figure 32 shows an example of the target tone value t after the second smoothing process. Figure 33 shows an example of the target tone value t after the 18th smoothing process. Note that smoothing is considered complete after the 18th smoothing process shown in Figure 33.

[0135] As is clear from comparing Figures 31 to 33, the more times the smoothing process is performed, the smaller the difference in target grayscale values ​​t between adjacent grid points NP becomes overall.

[0136] Figure 34 shows a three-dimensional representation of the target grayscale value t for each grid point NP before smoothing. Figure 35 shows a three-dimensional representation of the target grayscale value t for each grid point NP after smoothing is complete. In both Figures 34 and 35, the x-axis indicates the column position of the grid point NP, the y-axis indicates the row position of the grid point NP, and the z-axis indicates the target grayscale value t. As is clear from comparing Figure 34 and Figure 35, after smoothing is complete, the steps in the target grayscale value t are eliminated compared to before smoothing.

[0137] In substep SS4[7] of Figure 21, the processing unit 13 functions as a correction value calculation unit 134. The processing unit 13 calculates a correction value at a grid point NP included in the non-overlapping region NR.

[0138] As described above, the processing unit 13 determines the target gradation value (t,t,t) of brightness at the grid point NP after smoothing is completed by processing up to substep SS4[6]. Based on the target gradation value (t,t,t), the processing unit 13 calculates a correction value at the grid point NP. The processing unit 13 may use a known method for calculating the correction value.

[0139] Specifically, the processing unit 13 calculates the brightness component from the target grayscale value (t,t,t). The processing unit 13 sets the calculated brightness component as the brightness component Y of the target value.

[0140] Furthermore, the processing unit 13 determines the chromaticity component u'v' of the target value in the same manner as the brightness component Y of the target value at the grid point NP, as described above.

[0141] The processing unit 13 converts the Yu'v' value, which is the target value at each grid point NP in the non-overlapping region NR, into an RGB value using the above equations 13 and 14. Furthermore, the processing unit 13 calculates the target gradation values ​​(r, g, b) as correction values ​​to be output from the correction unit 136 to the projector 11 using the converted RGB values.

[0142] In step S5 of Figure 8, the processing unit 13 in the projection device 10A functions as a correction value calculation unit 134. The processing unit 13 sets the correction values ​​calculated in step S4 into the brightness correction circuit LC and the color uniformity correction circuit UC.

[0143] In Figure 2, the image acquired by the processing unit 13, which functions as an image acquisition unit 135, is corrected by the brightness correction circuit LC and the color unevenness correction circuit UC, which are set to the above-mentioned correction values. As a result, the projected image PI, in which black color unevenness and "black floating" have been corrected, is projected from the projector 11 onto the projection surface SC.

[0144] 2: Variant The above configurations can be modified in various ways. Specific examples of modifications are given below. The configurations exemplified below and the configurations shown in the above embodiments can be merged as appropriate, within the bounds of mutual consistency. In the modified configurations exemplified below, for elements whose operation and function are equivalent to those in the embodiments, the reference numerals used in the above description will be reused, and detailed explanations of each will be omitted as appropriate.

[0145] 2-1: Variation 1 In the above embodiment, the processing unit 13 determined, as an example, the gradation value t as a target value at the grid point NP included in the non-overlapping region NR. However, the processing unit 13 may determine the target values ​​of brightness and chromaticity of the grid point DP included in the overlapping region DR and the grid point NP included in the non-overlapping region NR by other methods.

[0146] Figures 36 to 38 are explanatory diagrams illustrating the method for determining the target values ​​of brightness and chromaticity at grid point DP and grid point NP, respectively, according to Modification 1.

[0147] As shown in Figure 36, the processing unit 13 sets the target value of the brightness of the grid point NP to the target value of the grid point DP in region RL1, which is the first superimposed region DR, Y Lap1 Therefore, the target value Y of the grid point DP in region RL4, which is the second superposition region DR. Lap2 Towards this, the target values ​​of the lattice points NP included in the non-overlapping region NR are smoothly connected. On the other hand, with respect to the target value of the chromaticity of the lattice points NP, the processing device 13 may use a uniform target value chromaticity component u'v' for the first overlapping region DR, which is region RL1, the second overlapping region DR, which is region RL4, and the non-overlapping region NR.

[0148] Alternatively, as shown in Figure 37, the processing unit 13 sets the target value of the lattice point DP in region RL1, which is the first superimposed region DR, with respect to the target value of the brightness of the lattice point NP. Lap1 Therefore, the target value Y of the grid point DP in region RL4, which is the second superposition region DR. Lap2 Towards this, the target values ​​of the lattice points NP included in the non-overlapping region NR are smoothly connected. Furthermore, with respect to the target value of the chromaticity of lattice point NP, the processing unit 13 sets the target value u'v' of the lattice point DP in region RL1, which is the first overlapping region DR. Lap1 From this, the target value u'v' of the lattice point DP in region RL4, which is the second superimposed region DR. Lap2 To achieve this, the target values ​​of the lattice points NP included in the non-overlapping region NR may be smoothly connected.

[0149] Alternatively, as shown in Figure 38, the processing unit 13 may determine the target value of the lattice point NP included in the non-overlapping region NR using RGB values ​​instead of Yu'v' values, in a similar manner to that shown in Figure 37.

[0150] Furthermore, if the processing device 13 uses the method shown in Figure 38, as an example, in Figure 22, the brightness of the R component in region RL1 is the average value of the R component brightness in multiple parts PT1 included in region RL1. Also, the brightness of the R component in region RL3 is the brightness of the R component in multiple parts PT3 included in region RL3. Also, the brightness of the R component in region RL4 is the average value of the R component brightness in multiple parts PT4 included in region RL1.

[0151] 2-2: Variation 2 In the above embodiment, the processing device 13 performed the smoothing operation so that the gradation value (t,t,t) of the lattice point NP included in the non-overlapping region NR would smoothly connect from region RL1, which is the first overlapping region DR, to region RL4, which is the second overlapping region DR.

[0152] However, the processing unit 13 may perform the above smoothing so that the brightness component Y of the target value of the lattice point NP included in the non-overlapping region NR smoothly connects from region RL1, which is the first superimposed region DR, to region RL4, which is the second superimposed region DR. The brightness component Y is an example of a "parameter".

[0153] 3: Summary of this disclosure A summary of this disclosure is provided below.

[0154] (Note 1) A method for correcting a projected image projected from a projection device, comprising: a first projection device projecting each of a plurality of first color lights corresponding one-to-one with a plurality of grayscale data onto a projection surface as a first projected image based on a plurality of grayscale data; a second projection device projecting each of a plurality of second color lights corresponding one-to-one with a plurality of grayscale data onto the projection surface as a second projected image based on the plurality of grayscale data; and when the projection device projects each of a plurality of third color lights corresponding one-to-one with a plurality of grayscale data onto the projection surface as a projected image based on a plurality of grayscale data, the method includes: acquiring a plurality of measurement data corresponding one-to-one with the plurality of grayscale data based on the output from a sensor that measures the reflected light reflected from the projection surface; and calculating correction data for correcting the color of the image displayed on the projection surface based on the plurality of grayscale data and the plurality of measurement data, wherein the projected image is in the state projected onto the projection surface. A correction method comprising: a first region overlapping with the first projected image; a second region overlapping with the second projected image; and a third region not overlapping with the first and second projected images, wherein the plurality of gradation data include at least one gradation value indicating at least one gradation of a first color component; and the plurality of measurement data include brightness values ​​indicating the brightness of reflected light of the color light corresponding to the first color component having the at least one gradation value; and calculating the correction data includes determining a first target value which is the target brightness of the first color component in the first region and a second target value which is the target brightness of the first color component in the second region, based on the plurality of gradation data and the plurality of measurement data; and calculating correction values ​​for the parameters based on the first target value and the second target value such that the distribution of parameters defining the brightness of the third region is a continuous or stepped distribution in a first direction from the first region to the second region.

[0155] The correction method described in Appendix 1, having the above configuration, can correct the unevenness of black tones and brightness in the projected image PI when tiling is performed using multiple projection devices 10, without degrading the contrast ratio of the entire projected image PI.

[0156] Specifically, even if the brightness of the R component in region RL1, which is the first superimposed region DR, and the brightness of the R component in region RL4, which is the second superimposed region DR, are different at maximum gradation, the gradation distribution of region RL3, which is the non-superimposed region NR, changes continuously or stepwise, making the difference between the brightness of the R component in region RL1 and the brightness of the R component in region RL4 at maximum gradation less noticeable.

[0157] (Note 2) Each of the plurality of grayscale data includes at least one grayscale value that represents at least one grayscale for each of the plurality of color components, which further include the second color component and the third color component. Each of the plurality of measurement data includes a brightness value indicating the brightness of reflected light of the corresponding color light for each of the plurality of color components, which further include a second color component and a third color component having at least one gradation value. Calculating the correction data involves determining a third target value, which is the target brightness of the second color component in the first region, and a fourth target value, which is the target brightness of the second color component in the second region, based on the plurality of gradation data and the plurality of measurement data. Based on the third target value and the fourth target value, the distribution of parameters defining the brightness of the third region is in a first direction from the first region toward the second region. The correction method of Appendix 1 further includes: calculating correction values ​​for the parameters so that they are distributed continuously or in steps; determining a fifth target value which is the target brightness of the third color component in the first region and a sixth target value which is the target brightness of the third color component in the second region, based on the plurality of grayscale data and the plurality of measurement data; and calculating correction values ​​for the parameters based on the fifth target value and the sixth target value so that the distribution of the parameters defining the brightness of the third region is distributed continuously or in steps in a first direction from the first region to the second region.

[0158] The correction method described in Appendix 2, having the above configuration, allows the tonal distribution of the non-overlapping region NR, region RL3 to change continuously or stepwise, even if the brightness of the R, G, and B components of region RL1, which is the first superimposed region DR, differs from the brightness of the R, G, and B components of region RL4, which is the second superimposed region DR, at maximum tonal range. As a result, the difference between the brightness of the R component of region RL1 and the brightness of the R, G, and B components of region RL4 at maximum tonal range becomes less noticeable.

[0159] (Note 3) The correction method of Note 1, wherein the first region includes a plurality of first parts, the second region includes a plurality of second parts, the third region includes a plurality of third parts, the brightness of the first color component in the first region is the average value of the brightness of the first color component in the plurality of first parts, the brightness of the first color component in the second region is the average value of the brightness of the first color component in the plurality of second parts, and the brightness of the first color component in the third region is the brightness in each of the plurality of third parts.

[0160] The correction method described in Appendix 3, having the above configuration, can continuously or stepwise change the gradation distribution of region RL3 based on the average value of the brightness of the R component of part PT1 included in region RL1 at maximum gradation and the average value of the brightness of the R component of part PT4 included in region RL4.

[0161] (Note 4) The correction method according to Note 1, wherein the first region includes a first part adjacent to the third region, the second region includes a second part adjacent to the third region, the third region includes a plurality of third parts, the brightness of the first color component in the first region is the brightness of the first color component in the first part, the brightness of the first color component in the second region is the brightness of the first color component in each of the second parts, the distribution of parameters defining the brightness of the third region is continuous or stepped in a first direction from the first region to the second region, the brightness of the first color component in each of the plurality of third parts is continuous or stepped in a first direction from the first region to the second region, and the first part, the second part, and the plurality of third parts are aligned in one direction.

[0162] The correction method described in Appendix 4, having the above configuration, can continuously or stepwise change the gradation distribution of region RL3 based on the brightness of the R component of part PT1 adjacent to region RL3 included in region RL1 at maximum gradation, and the brightness of the R component of part PT4 adjacent to region RL3 included in region RL4.

[0163] (Note 5) The correction method of Note 1, wherein the first region includes a first part, the second region includes a second part, and the third region includes a plurality of third parts having a first adjacent part adjacent to the first region and a second adjacent part adjacent to the second region, and the first region, the second region and the plurality of third parts are aligned in one direction, and the first region includes a first part, the second region and the plurality of third parts are aligned in one direction, and the correction method of Note 1, comprising: determining a seventh target value which is the target brightness of the first color component in the first adjacent part based on the first target value so that the brightness of the first region, the second region and the third region are uniform, and the eighth target value which is the target brightness of the first color component in the second adjacent part based on the second target value so that the brightness of the first region, the second region and the third region are uniform, and the first part, the second part and the plurality of third parts are aligned in one direction.

[0164] The correction method described in Appendix 5, having the above configuration, optimizes the gradation values ​​of the color components of the first adjacent portion GP1 adjacent to region RL1 and the second adjacent portion GP2 adjacent to region RL4 within region RL3.

[0165] (Note 6) The correction method of Note 5, wherein the plurality of third parts further include a plurality of intermediate parts between the first adjacent part and the second adjacent part, and the calculation of correction values ​​for the parameters such that the distribution of parameters defining the brightness in the third region is a continuous or stepped distribution in a first direction from the first region to the second region, based on the first target value and the second target value, includes determining a ninth target value which is the target brightness of the first color component in each of the plurality of intermediate parts, based on the seventh target value and the eighth target value.

[0166] The correction method described in Appendix 6, having the above configuration, can optimize the gradation values ​​of each of the multiple intermediate parts CP.

[0167] (Note 7) The correction method of Note 5, wherein the first region includes a plurality of first parts, and the first region includes acquiring an image of the first region, specifying the brightness of the plurality of first parts and the chromaticity of the plurality of first parts in the image, maintaining the brightness of the plurality of first parts to a brightness corresponding to the first target value, and adjusting the chromaticity of the plurality of first parts to the same value.

[0168] The correction method described in Appendix 7, having the above configuration, can eliminate unevenness in black color.

[0169] (Note 8) A projection device that, when a first projection device projects each of a plurality of first color lights corresponding one-to-one with a plurality of grayscale data onto a projection surface as a first projection image based on a plurality of grayscale data, a second projection device projects each of a plurality of second color lights corresponding one-to-one with a plurality of grayscale data onto the projection surface as a second projection image based on the plurality of grayscale data, a projection device that, when a plurality of third color lights corresponding one-to-one with a plurality of grayscale data onto the projection surface as a projection image based on the plurality of grayscale data, acquires a plurality of measurement data corresponding one-to-one with the plurality of grayscale data based on the output from a sensor that measures the reflected light reflected from the projection surface, calculates correction data for correcting the color of the image displayed on the projection surface based on the plurality of grayscale data and the plurality of measurement data, wherein the projection image, when projected onto the projection surface, A projection device comprising: a first region overlapping with a projected image; a second region overlapping with a second projected image; and a third region not overlapping with the first and second projected images, wherein the plurality of gradation data include at least one gradation value indicating at least one gradation of a first color component; the plurality of measurement data include brightness values ​​indicating the brightness of reflected light of the color light corresponding to the first color component having the at least one gradation value; and calculating the correction data includes determining a first target value that is a target for the brightness of the first color component in the first region and a second target value that is a target for the brightness of the first color component in the second region, based on the plurality of gradation data and the plurality of measurement data; and calculating a correction value for the parameters based on the first target value and the second target value such that the distribution of parameters defining the brightness of the third region is a continuous or stepped distribution in a first direction from the first region to the second region.

[0170] The projection device described in Appendix 8, having the above configuration, can correct the unevenness of black and the brightness of the projected image PI when tiling is performed using multiple projection devices 10, without degrading the contrast ratio of the entire projected image PI.

[0171] Specifically, even if the brightness of the R component in region RL1, which is the first superimposed region DR, and the brightness of the R component in region RL4, which is the second superimposed region DR, are different at maximum gradation, the gradation distribution of region RL3, which is the non-superimposed region NR, changes continuously or stepwise, making the difference between the brightness of the R component in region RL1 and the brightness of the R component in region RL4 at maximum gradation less noticeable.

[0172] (Note 9) A program that causes a projection device to perform the following actions when, by the first projection device, based on a plurality of grayscale data, each of a plurality of first color lights corresponding one-to-one with the plurality of grayscale data is projected onto the projection surface as a first projection image; by the second projection device, based on the plurality of grayscale data, each of a plurality of second color lights corresponding one-to-one with the plurality of grayscale data is projected onto the projection surface as a second projection image; and by the first projection device, based on a plurality of grayscale data, each of a plurality of third color lights corresponding one-to-one with the plurality of grayscale data is projected onto the projection surface as a projection image, the program to perform the following actions: acquire a plurality of measurement data corresponding one-to-one with the plurality of grayscale data based on the output from a sensor that measures the reflected light reflected from the projection surface; and calculate correction data for correcting the color of the image displayed on the projection surface based on the plurality of grayscale data and the plurality of measurement data, wherein the projection image is, in the state projected onto the projection surface, the first A program comprising: a first region overlapping with a projected image; a second region overlapping with a second projected image; and a third region not overlapping with the first and second projected images, wherein the plurality of gradation data include at least one gradation value indicating at least one gradation of a first color component; the plurality of measurement data include brightness values ​​indicating the brightness of reflected light of the color light corresponding to the first color component having the at least one gradation value; and calculating the correction data includes determining a first target value which is the target brightness of the first color component in the first region and a second target value which is the target brightness of the first color component in the second region, based on the plurality of gradation data and the plurality of measurement data; and calculating correction values ​​for the parameters based on the first target value and the second target value such that the distribution of parameters defining the brightness of the third region is a continuous or stepped distribution in a first direction from the first region to the second region.

[0173] The program described in Appendix 9, having the above configuration, can correct the unevenness of black tones and brightness in the projected image PI when tiling is performed using multiple projection devices 10, without degrading the contrast ratio of the entire projected image PI.

[0174] Specifically, even if the brightness of the R component in region RL1, which is the first superimposed region DR, and the brightness of the R component in region RL4, which is the second superimposed region DR, are different at maximum gradation, the gradation distribution of region RL3, which is the non-superimposed region NR, changes continuously or stepwise, making the difference between the brightness of the R component in region RL1 and the brightness of the R component in region RL4 at maximum gradation less noticeable. [Explanation of Symbols]

[0175] 1...Projection system, 10...Projection device, 10A...Projection device, 10B...Projection device, 10B...Projection device, 10C...Projection device, 11...Projector, 12...Imaging device, 13...Processing device, 14...Storage device, 15...Communication device, 20...Image supply device, 131...Projection control unit, 132...Imaging control unit, 133...Image analysis unit, 134...Correction value calculation unit, 135...Image acquisition unit, 136...Correction unit, 137...Communication control unit, CP...Intermediate part, DP...Grid point, DR...Superimposed region, GP1...First adjacent part, G P2…Second adjacent area, LC…Brightness correction circuit, LN…Communication line, LP…Grid point, NP…Grid point, NR…Non-overlapping area, PI…Projected image, PI1…Projected image, PI2…Projected image, PI3…Projected image, PI_A…Projected image, PP…Grid point, PR1…Control program, PT…Part, RL…Area, UL…Color unevenness correction circuit, XYZ…Output value, Y…Brightness component, YLap1…Target value, YLap2…Target value, u'v'…Chromaticity component, u'v'Lap1…Target value, u'v'Lap2…Target value

Claims

1. A method for correcting a projected image projected from a projection device, When a first projection device projects each of a plurality of first-colored lights corresponding one-to-one to a plurality of grayscale data onto a projection surface as a first projection image based on a plurality of grayscale data, a second projection device projects each of a plurality of second-colored lights corresponding one-to-one to a plurality of grayscale data onto the projection surface as a second projection image based on the plurality of grayscale data, and the projection device projects each of a plurality of third-colored lights corresponding one-to-one to a plurality of grayscale data onto the projection surface as a projection image based on the plurality of grayscale data, a plurality of measurement data corresponding one-to-one to the plurality of grayscale data are acquired based on the output from a sensor that measures the reflected light reflected from the projection surface, This includes calculating correction data for correcting the color of the image displayed on the projection surface based on the plurality of grayscale data and the plurality of measurement data, The projected image, when projected onto the projection surface, has a first region that overlaps with the first projected image, a second region that overlaps with the second projected image, and a third region that does not overlap with the first and second projected images. The plurality of grayscale data include at least one grayscale value representing at least one grayscale of the first color component, The plurality of measurement data include a brightness value indicating the brightness of the reflected light of the color light corresponding to the first color component having at least one grayscale value, Calculating the aforementioned correction data is Based on the plurality of grayscale data and the plurality of measurement data, a first target value is determined for the brightness of the first color component in the first region, and a second target value is determined for the brightness of the first color component in the second region. This includes calculating correction values ​​for the parameters such that the distribution of the parameters defining the brightness of the third region is continuous or stepped in a first direction from the first region to the second region, based on the first target value and the second target value. Correction method.

2. Each of the aforementioned plurality of grayscale data includes at least one grayscale value that represents at least one grayscale for each of a plurality of color components, further including a second color component and a third color component. Each of the aforementioned plurality of measurement data includes a brightness value indicating the brightness of the reflected light of the corresponding colored light, each of the plurality of color components further including a second color component and a third color component having at least one gradation value. Calculating the aforementioned correction data is Based on the plurality of grayscale data and the plurality of measurement data, a third target value which is the target brightness of the second color component in the first region and a fourth target value which is the target brightness of the second color component in the second region are determined. Based on the third target value and the fourth target value, the correction values ​​for the parameters are calculated such that the distribution of the parameters defining the brightness of the third region is continuously or stepped in the first direction from the first region to the second region. Based on the plurality of grayscale data and the plurality of measurement data, a fifth target value which is the target brightness of the third color component in the first region and a sixth target value which is the target brightness of the third color component in the second region are determined. The method further includes calculating correction values ​​for the parameters such that the distribution of the parameters defining the brightness of the third region is continuously or stepped in a first direction from the first region to the second region, based on the fifth target value and the sixth target value. The correction method according to claim 1.

3. The first region includes a plurality of first parts, The aforementioned second region includes a plurality of second parts, The aforementioned third region includes a plurality of third parts, The brightness of the first color component in the first region is the average value of the brightness of the first color component in the plurality of first parts. The brightness of the first color component in the second region is the average value of the brightness of the first color component in the plurality of second portions. The brightness of the first color component in the third region is the brightness in each of the plurality of third parts. The correction method according to claim 1.

4. The first region includes a first portion adjacent to the third region, The aforementioned second region includes a second portion adjacent to the aforementioned third region, The aforementioned third region includes a plurality of third parts, The brightness of the first color component in the first region is the brightness of the first color component in the first portion, The brightness of the first color component in the second region is the brightness of the first color component in each of the second parts. The distribution of parameters defining the brightness of the third region being continuous or stepped in the first direction from the first region to the second region means that the brightness of the first color component in each of the plurality of third parts is continuous or stepped in the first direction from the first region to the second region. The first part, the second part, and the plurality of third parts are arranged in one direction. The correction method according to claim 1.

5. The first region includes the first portion, The aforementioned second region includes the second part, The third region includes a plurality of third parts having a first adjacent part adjacent to the first region and a second adjacent part adjacent to the second region. To ensure that the brightness of the first region, the second region, and the third region are uniform, a seventh target value is determined based on the first target value, which is the target brightness of the first color component in the first adjacent portion. This includes determining an eighth target value, which is the target brightness of the first color component in the second adjacent portion, based on the second target value, so that the brightness of the first region, the second region, and the third region becomes uniform. The first part, the second part, and the plurality of third parts are arranged in one direction. The correction method according to claim 1.

6. The plurality of third portions further include a plurality of intermediate portions between the first adjacent portion and the second adjacent portion, Based on the first target value and the second target value, the correction value of the parameter is calculated such that the distribution of the parameter defining the brightness in the third region is continuous or stepped in the first direction from the first region to the second region. This includes determining a ninth target value, which is the target brightness of the first color component in each of the plurality of intermediate portions, based on the seventh target value and the eighth target value. The correction method according to claim 5.

7. The first region includes a plurality of first parts, Acquiring an image of the first region, In the captured image, the brightness of the plurality of first portions and the chromaticity of the plurality of first portions are identified. Maintaining the brightness of the plurality of first parts to a brightness corresponding to the first target value, This includes adjusting the chromaticity of the plurality of first parts to the same value, The correction method according to claim 5.

8. A projection device, When a first projection device projects each of a plurality of first-colored lights corresponding one-to-one to a plurality of grayscale data onto a projection surface as a first projection image based on a plurality of grayscale data, a second projection device projects each of a plurality of second-colored lights corresponding one-to-one to a plurality of grayscale data onto the projection surface as a second projection image based on the plurality of grayscale data, and the projection device projects each of a plurality of third-colored lights corresponding one-to-one to a plurality of grayscale data onto the projection surface as a projection image based on the plurality of grayscale data, a plurality of measurement data corresponding one-to-one to the plurality of grayscale data are acquired based on the output from a sensor that measures the reflected light reflected from the projection surface, A projection device that performs the following: calculating correction data for correcting the color of an image displayed on the projection surface based on the plurality of grayscale data and the plurality of measurement data, The projected image, when projected onto the projection surface, has a first region that overlaps with the first projected image, a second region that overlaps with the second projected image, and a third region that does not overlap with the first and second projected images. The plurality of grayscale data include at least one grayscale value representing at least one grayscale of the first color component, The plurality of measurement data include a brightness value indicating the brightness of the reflected light of the color light corresponding to the first color component having at least one grayscale value, Calculating the aforementioned correction data is Based on the plurality of grayscale data and the plurality of measurement data, a first target value is determined for the brightness of the first color component in the first region, and a second target value is determined for the brightness of the first color component in the second region. This includes calculating correction values ​​for the parameters such that the distribution of the parameters defining the brightness of the third region is continuous or stepped in a first direction from the first region to the second region, based on the first target value and the second target value. Projection device.

9. In the projection device, When a first projection device projects each of a plurality of first-colored lights corresponding one-to-one to a plurality of grayscale data onto a projection surface as a first projection image based on a plurality of grayscale data, a second projection device projects each of a plurality of second-colored lights corresponding one-to-one to a plurality of grayscale data onto the projection surface as a second projection image based on the plurality of grayscale data, and the projection device projects each of a plurality of third-colored lights corresponding one-to-one to a plurality of grayscale data onto the projection surface as a projection image based on the plurality of grayscale data, a plurality of measurement data corresponding one-to-one to the plurality of grayscale data are acquired based on the output from a sensor that measures the reflected light reflected from the projection surface, A program that performs the following actions: calculates correction data for correcting the color of an image displayed on the projection surface based on the plurality of grayscale data and the plurality of measurement data, The projected image, when projected onto the projection surface, has a first region that overlaps with the first projected image, a second region that overlaps with the second projected image, and a third region that does not overlap with the first and second projected images. The plurality of grayscale data include at least one grayscale value representing at least one grayscale of the first color component, The plurality of measurement data include a brightness value indicating the brightness of the reflected light of the color light corresponding to the first color component having at least one grayscale value, Calculating the aforementioned correction data is Based on the plurality of grayscale data and the plurality of measurement data, a first target value is determined for the brightness of the first color component in the first region, and a second target value is determined for the brightness of the first color component in the second region. This includes calculating correction values ​​for the parameters such that the distribution of the parameters defining the brightness of the third region is continuous or stepped in a first direction from the first region to the second region, based on the first target value and the second target value. program.

Images