Control method and program for projection device

Abstract

Using a measurement pattern selected according to the gamma characteristics, correction is performed for low-gradation colors close to black. [Solution] In a measurement pattern used for correcting low-gradation colors close to black, the difference between the lowest first gradation value and the second lowest first gradation value among multiple first gradation values ​​included in multiple gradation data is smaller than the difference between the highest first gradation value and the second highest first gradation value among multiple first input gradation values.

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a method for projecting four measurement patterns, from the first measurement pattern to the fourth measurement pattern, when a projection device corrects the white balance of intermediate gray tones. Here, the first measurement pattern is image data representing intermediate gray tones. The three measurement patterns from the second to the fourth measurement pattern are patterns in which each of the color components included in the first measurement pattern has been modified. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2016-161918 [Overview of the project] [Problems that the invention aims to solve]

[0004] In conventional techniques, when correcting low-gradation colors close to black, the gamma characteristic, which is a characteristic indicating the relationship between gradation and output brightness, causes the change in output brightness in response to changes in gradation to be small at low gradations, reducing the accuracy of detecting the measurement pattern necessary for black correction. In this case, it is possible to improve accuracy by using the first measurement pattern described above, but it is necessary to select the three measurement patterns from the second to the fourth measurement pattern according to the gamma characteristic. However, Patent Document 1 did not consider how to select them according to the gamma characteristic. [Means for solving the problem]

[0005] A control method for a projection device according to an aspect of the present invention includes: when each of a plurality of color lights corresponding one-to-one with the plurality of grayscale data is projected from the projection device onto a projection surface based on a plurality of grayscale data, acquiring a plurality of measurement data based on the output of a sensor that measures the reflected light reflected by each of the plurality of color lights onto 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 plurality of grayscale data includes at least one first grayscale value indicating at least one grayscale for a first color component, at least one second grayscale value indicating at least one grayscale for a second color component, The plurality of measurement data includes at least one third grayscale value indicating at least one grayscale for the third color component, and the plurality of measurement data includes a first brightness value indicating the brightness of reflected light of the color light corresponding to the first color component having the first grayscale value, a second brightness value indicating the brightness of reflected light of the color light corresponding to the second color component having the second grayscale value, and a third brightness value indicating the brightness of reflected light of the color light corresponding to the third color component having the third grayscale value, and the difference between the lowest first grayscale value and the second lowest first grayscale value among the plurality of first grayscale values ​​included in the plurality of grayscale data is smaller than the difference between the highest first grayscale value and the second highest first grayscale value among the plurality of first input grayscale values.

[0006] A program according to an aspect of the present invention is a program for controlling a projection device, which causes the projection device to perform the following actions when, based on a plurality of grayscale data, each of a plurality of colored lights corresponding one-to-one with the plurality of grayscale data is projected from the projection device onto a projection surface, the program acquires a plurality of measurement data based on the output of a sensor that measures the reflected light reflected by each of the plurality of colored lights onto 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 plurality of grayscale data consists of at least one first grayscale value representing at least one grayscale for a first color component, and at least one second grayscale value representing at least one grayscale for a second color component. The plurality of measurement data includes at least one second tone value and at least one third tone value indicating at least one tone for the third color component, and the plurality of measurement data includes a first brightness value indicating the brightness of reflected light of the color light corresponding to the first color component having the first tone value, a second brightness value indicating the brightness of reflected light of the color light corresponding to the second color component having the second tone value, and a third brightness value indicating the brightness of reflected light of the color light corresponding to the third color component having the third tone value, and the difference between the lowest first tone value and the second lowest first tone value among the plurality of first tone values ​​included in the plurality of tone data is smaller than the difference between the highest first tone value and the second highest first tone value among the plurality of first input tone values. [Brief explanation of the drawing]

[0007] [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 the gamma curve corresponding to the relationship between input gradation and output brightness in the superimposed DR region. [Figure 4] A graph showing the gamma curve corresponding to the relationship between input gradation and output brightness in the non-superimposed noise reduction region. [Figure 5] 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. [Figure 6]Explanatory diagram of the method for projecting a measurement pattern by the projection device 10A. [Figure 7] Functional block diagram of the correction unit 136. [Figure 8] Flowchart showing an operation example of the projection device 10A according to the first embodiment. [Figure 9] Diagram showing an example of the grid points LP. [Figure 10] Diagram showing an example of the grid points LP. [Figure 11] Diagram showing an example of the grid points LP. [Figure 12] Diagram showing an example of the 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] Diagram showing an example of the 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] Diagram showing an example of the 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] Diagram showing an example of the 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] Diagram showing an example of the 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] Diagram showing an example of the 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] Diagram showing an example of the interpolation curve R(34, 34, b) for interpolating the measured value of the R component among the measured values (R, G, B) calculated by the processing device 13. [Figure 19] Diagram showing an example of the interpolation curve G(34, 34, b) for interpolating the measured value of the G component among the measured values (R, G, B) calculated by the processing device 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 graph showing equations 10 to 12 in a space with R, G, and B components as the three axes. [Modes for carrying out the invention]

[0008] 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.

[0009] 1: First Embodiment The projection system 1 according to the first embodiment will be described below with reference to Figures 1 to 21.

[0010] 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 the "first projection device". Projection device 10B is an example of the "second projection device". Projection device 10C is an example of the "third projection device".

[0011] 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.

[0012] Projectors 10A, 10B, and 10C project various images or videos onto the projection surface SC. For example, among projectors 10A, 10B, and 10C, projector 10A acts as the master projector for projectors 10B and 10C. Projectors 10B and 10C act as slave projectors for projector 10A. Specifically, projector 10A transmits various control signals to projectors 10B and 10C. As a result, projector 10A controls projectors 10B and 10C. The above control signals include various correction values, which will be described later.

[0013] 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 10A, and the projection device 10A may supply the images projected by each projection device 10 to the projection devices 10B and 10C, respectively. In this embodiment, when projection devices 10A through 10C are not distinguished, they are 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 10A may read the image to be projected from its storage device 14 and then supply the image to be projected by each projection device to projection devices 10B and 10C. In this case, the projection system 1 does not necessarily have to include an image supply device 20.

[0014] In the example shown in Figure 1, projection device 10A projects projection image PI1 onto projection surface SC. Projection device 10B projects projection image PI2 onto projection surface SC. Projection device 10C projects projection image PI3 onto projection surface SC. 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.

[0015] 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.

[0016] 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 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 RL4 of projected image PI_A includes part PT5 of projected image PI2 and part PT6 of projected image PI3. Region RL5 of projected image PI_A includes part PT7 of projected image PI3.

[0017] 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. Superimposed regions DR are an example of "first regions". Non-superimposed regions NR are an example of "second regions".

[0018] 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.

[0019] The projector 11 is an optical 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.

[0020] 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".

[0021] 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.

[0022] 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.

[0023] 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®.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] The image analysis unit 133 analyzes the reflected light of the measurement pattern captured by the imaging device 12 and calculates a measurement value indicating the color of the measurement pattern in the captured image. This measurement value is an example of "measurement data".

[0028] The correction value calculation unit 134 calculates a correction value to be set in the correction unit 136, which will be described later, based on the measured values ​​calculated by the image analysis unit 133.

[0029] The following describes the measurement pattern projected by the projection control unit 131 in this embodiment.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] Furthermore, in typical projection devices, the input / output characteristics are adjusted to γ=2.2, for example, so when the gradation changes near 0, the change in light intensity is small. For this reason, in order to correct color unevenness in 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.

[0034] 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.

[0035] Conventionally, when black light with a grayscale level of 0 is projected onto the projection surface SC as the 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 grayscale level that is far from the corrected grayscale level results 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 grayscale levels from grayscale level 0 to grayscale level 1023, there was a problem in that the interpolation error became large.

[0036] 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.

[0037] Therefore, in this embodiment, the low-gradation light close to black that is projected as a measurement pattern is made up of multiple gradations.

[0038] 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 that is expected to be the output gradation corresponding to the output luminance (brightness) 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). Gradation A is an example of the "first value". Gradation B is an example of the "second value". Gradation C is an example of the "third value". The projection device 10A of the present embodiment can measure in detail the gradations required 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.

[0039] 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 lower than the expected gradation that is expected to be the output gradation corresponding to the output luminance after color unevenness correction. On the other hand, gradation C is higher than the expected gradation that is expected to be the output gradation corresponding to the output luminance after color unevenness correction. Gradation B is a gradation between gradation A and gradation C.

[0040] As described above, in the gradation close to black with a gradation of 0, as shown in FIG. 3, when the output luminance changes slightly, the change in chromaticity becomes large. 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 device 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 interpolating 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, using the γ curve.

[0041] The expected tonal range 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 tonal range will be low. On the other hand, if the color unevenness is significant due to the quality of the components used in the projection device (such as the projection lens), the expected tonal range will be set to high in order to ensure a minimum adjustment range.

[0042] 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 in light intensity of a predetermined amount or more between the two. As an example, grayscale level A is set so that the color difference 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.

[0043] 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.

[0044] 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 896, which is the lowest gradation in the 8th division of the gradation range from gradation 0 to gradation 1023.

[0045] In this embodiment, the gradation range from gradation 0 to gradation 1023 is divided into eight sections, but it is not particularly limited. For example, the gradation range from gradation 0 to gradation 1023 may be divided into seven sections or nine sections. When the gradation range from gradation 0 to gradation 1023 is divided into seven sections, 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.

[0046] The gradation of the measurement pattern for the non-overlapping region NR is set to three or more gradations including lower and higher gradations than the expected gradation corresponding to the output luminance 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 γ = 2.2. As an example, these three gradations are set as gradation B', gradation C', and gradation D (B' < C' < D). Gradation B' is an example of the "fourth value". Gradation C' is an example of the "fifth value". Gradation D is an example of the "sixth value". By setting the gradation of the measurement pattern for the non-overlapping region NR of the projection apparatus 10A of this embodiment to three or more gradations, the gradations required for correcting "black floating" on the low-gradation side close to black can be measured in detail. The expected gradation can be determined in advance by experiments, simulations, etc., for example.

[0047] 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 lower gradation than the expected gradation corresponding to the output luminance after correcting "black floating". On the other hand, gradation D is a higher gradation than the expected gradation corresponding to the output luminance after correcting "black floating". Gradation C' is a gradation between gradation B' and gradation D.

[0048] The difference between tone B' and tone C' is smaller than the difference between the highest tone and the second highest tone among the multiple input tone levels up to tone 1023. Here, the "highest tone" is, for example, tone 1023, which is the highest tone in the 8th division of the tone range from tone 0 to tone 1023. The "second highest tone" is, for example, tone 896, which is the lowest tone in the 8th division of the tone range from tone 0 to tone 1023.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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 R, G, and B color 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 be 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. 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 grayscale level 0, the following measurement pattern should also be used. 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 examples of "grayscale data". The grayscale value of r in (r,g,b) is an example of a "first grayscale value". The grayscale value of g in (r,g,b) is an example of a "second grayscale value". The grayscale value of b in (r,g,b) is an example of a "third grayscale value".

[0054] 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.

[0055] 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.

[0056] 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.

[0057] The combination of the R, G, and B components of the first measurement pattern, represented as the projected image PI1 projected from projection device 10A (r,g,b), is an example of "first grayscale data". The color light representing this first measurement pattern is an example of "first color light". The color light representing the first measurement pattern, represented as the projected image PI2 projected from projection device 10B, is an example of "second color light". In the superposition region DR, the "first color light" and the "second color light" overlap.

[0058] Furthermore, (r,g,b), which is the combination of the R, G, and B components of the second measurement pattern as the projected image PI1 projected from projection device 10A, is an example of "second grayscale data". Also, the color light representing the second measurement pattern as the projected image PI2 projected from projection device 10B is an example of "fourth color light". In the superposition region DR, the "third color light" and the "fourth color light" overlap.

[0059] 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.

[0060] 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.

[0061] 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 only 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.

[0062] 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.

[0063] The measurement pattern projected by the projection control unit 131 in this embodiment has been described above.

[0064] 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 21.

[0065] In Figure 2, the image acquisition unit 135 acquires the image to be projected from the image supply device 20.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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. However, since conventional methods cannot correct color unevenness in black near level 0, the correction value at level 0 is not calculated.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] The measurement pattern in question is one of the measurement patterns 1 through 13 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.

[0082] In the following, as an example, in the first measurement pattern used for correcting black color unevenness 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. This "first measurement pattern" corresponds to the "first gradation data" described above. 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. This second measurement pattern corresponds to the "second gradation data" described above. Furthermore, in order to simultaneously calculate a correction value when prioritizing the contrast ratio in the projection device 10A, the processing device 13 functions as a projection control unit 131, causing the projector 11 to also project a measurement pattern in which at least one of the R, G, and B color components has a grayscale of 0.

[0083] 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.

[0084] 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.

[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.

[0086] Here, the grayscale values ​​(r,g,b) are an example of "grayscale data". In the first measurement pattern's grayscale values ​​(r, g, b), r is an example of the "first grayscale value," g is an example of the "second grayscale value," and b is an example of the "third grayscale value." In the second measurement pattern's gradation values ​​(r, g, b), r is an example of a "fourth gradation value," g is an example of a "fifth gradation value," and b is an example of a "sixth gradation value."

[0087] On the other hand, "Measured Value (R, G, B)" is an example of "Measurement Data". "Measured Value (R, G, B)" corresponding to the first measurement pattern is an example of "First Measurement Data". "Measured Value (R, G, B)" corresponding to the second measurement pattern is an example of "Second Measurement Data". Of the measured values ​​(R, G, B) corresponding to the first measurement data, the R component value is an example of a "first brightness value" that indicates the brightness of the reflected light of the colored light corresponding to the "first color component" which has a "first grayscale value". Of the measured values ​​(R, G, B) corresponding to the first measurement data, the G component value is an example of a "second brightness value" that indicates the brightness of the reflected light of the colored light corresponding to the "second color component" which has a "second grayscale value". Of the measured values ​​(R, G, B) corresponding to the first measurement data, the B component value is an example of a "third brightness value" that indicates the brightness of the reflected light of the colored light corresponding to the "third color component" which has a "third grayscale value". Of the measured values ​​(R, G, B) corresponding to the second measurement data, the R component value is an example of the "fourth brightness value" which indicates the brightness of the reflected light of the colored light corresponding to the "first color component" having the "fourth grayscale value". Of the measured values ​​(R, G, B) corresponding to the first measurement data, the G component value is an example of the "fifth brightness value" which indicates the brightness of the reflected light of the colored light corresponding to the "second color component" having the "fifth grayscale value". Of the measured values ​​(R, G, B) corresponding to the first measurement data, the B component value is an example of the "sixth brightness value" which indicates the brightness of the reflected light of the colored light corresponding to the "third color component" having the "sixth grayscale value".

[0088] Furthermore, in order to make the notation easier to understand, when the projector 11 projects color light of gradation (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 .

[0089] The measured values ​​for five measurement patterns, in which only the R component of the color light gradation (r,g,b) is changed, are expressed as shown in the following equations 1 to 5.

number

[0090] In equations 1 to 5 above, r=22 is an example of the "first value". r=34 is an example of the "second value". r=60 is an example of the "third value". (R,G,B)(22,34,34) is an example of the "first measured value". (R,G,B)(34,34,34) is an example of the "second measured value". (R,G,B)(60,34,34) is an example of the "third measured value".

[0091] 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 in the color light gradation (r,g,b) as a measurement pattern. The interpolation curve R(r,34,34) is an example of a "curve showing the first characteristic". FIG. 13 is a diagram showing an example of an interpolation curve G(r, 34, 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 r, which is the R component, is changed among the gradations (r, g, b) of the colored light as the measurement pattern. FIG. 14 is a diagram showing an example of an interpolation curve B(r, 34, 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 r, which is the R component, is changed among the gradations (r, g, b) of the colored light as the measurement pattern.

[0092] By using these three interpolation curves R(r, 34, 34), interpolation curve G(r, 34, 34), and interpolation curve B(r, 34, 34), the processing device 13 can determine the measured values (R, G, B) when a colored light with an arbitrary gradation r (0 ≦ r ≦ 95) of the R component 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.

[0093] 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, which is the G component, is changed among the gradations (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, which is the G component, is changed among the gradations (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, which is the G component, is changed among the gradations (r, g, b) of the colored light as the measurement pattern.

[0094] The processing device 13 uses these three interpolation curves R(34,g,34), interpolation curve G(34,g,34), and interpolation curve B(34,g,34) to determine the measured values ​​(R,G,B) when color light with an arbitrary grayscale g (0≦g≦95) for the G component 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 ).

[0095] Figure 18 shows an example of an interpolation curve R(34,34,b) 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 B component, b, is changed in the color light gradation (r,g,b) as a 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 in the color light gradation (r,g,b) 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 in the color light gradation (r,g,b) as a measurement pattern.

[0096] 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 ).

[0097] 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

[0098] 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

[0099] 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

[0100] The processing unit 13 calculates the measured values ​​(R, G, B) by the image analysis unit 133 when the projector 11 projects color light of any output gradation (r, g, b) output from the correction unit 136 to the projector 11 onto the projection surface SC, using an arbitrary correction value. (r,g,b) =(R (r,g,b) ,G (r,g,b) ,B (r,g,b) ) can be estimated using equations 10 to 12 above.

[0101] The processing unit 13 calculates corrected output gradations (r, g, b) corresponding to each grid point LP as correction values ​​(adjustment values) so that the corrected brightness of black becomes the target brightness as seen from the imaging device 12, color unevenness of the corrected black is suppressed, and the chromaticity is uniform as seen from the imaging device 12.

[0102] Specifically, for each grid point LP, the processing unit 13 can calculate what color the reflected light of the colored light projected from the projector 11 onto the projection surface SC will appear to the imaging device 12, depending on which output gradation (r,g,b) is output from the correction unit 136 to the projector 11. The processing unit 13 can also perform the reverse calculation of this result. As a result, the processing unit 13 calculates the corrected output gradation (r,g,b) as a correction value (adjustment value) in accordance with the corrected brightness of black and the color unevenness of black.

[0103] Furthermore, projection devices 10A, 10B, and 10C have the same γ characteristics. As a result, if the processing device 13 in projection device 10A calculates the corrected output gradation (r,g,b) corresponding to each grid point LP in the projected image PI1, then in the superposition region DR of projected image PI1 and projected image PI2, it is possible to apply the same corrected output gradation (r,g,b) as the grid point LP in projected image PI1 to the grid point LP in projected image PI2 that is located near the grid point LP in projected image PI1.

[0104] 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 to the brightness correction circuit LC and the color uniformity correction circuit UC.

[0105] 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.

[0106] 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.

[0107] 2-1: Variation 1 In the above embodiment, the projection system 1 included projection devices 10A, 10B, and 10C. The projected image PI1 projected from projection device 10A, the projected image PI2 projected from projection device 10B, and the projected image PI3 projected from projection device 10B were tiled together, with some areas of each superimposed, to form the projected image PI_A. The correction of black color unevenness and "black floating" in the above embodiment was performed on the projected image PI_A.

[0108] However, color unevenness in black can be corrected even when the projection system 1 is equipped with only one projection device 10A.

[0109] 3: Summary of this disclosure A summary of this disclosure is provided below.

[0110] (Note 1) When a plurality of colored lights corresponding one-to-one to the plurality of colored lights are projected from a projection device onto a projection surface based on a plurality of grayscale data, the method includes obtaining a plurality of measurement data based on the output from a sensor that measures the reflected light reflected by each of the plurality of colored lights onto 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 plurality of grayscale data includes at least one first grayscale value indicating at least one grayscale for the first color component, at least one second grayscale value indicating at least one grayscale for the second color component, and for the third color component A method for controlling a projection device, wherein the plurality of measurement data include at least one third grayscale value representing at least one grayscale, the plurality of measurement data include a first brightness value representing the brightness of reflected light of a color corresponding to the first color component having the first grayscale value, a second brightness value representing the brightness of reflected light of a color corresponding to the second color component having the second grayscale value, and a third brightness value representing the brightness of reflected light of a color corresponding to the third color component having the third grayscale value, and the difference between the lowest first grayscale value and the second lowest first grayscale value among the plurality of first grayscale values ​​included in the plurality of grayscale data is smaller than the difference between the highest first grayscale value and the second highest first grayscale value among the plurality of first input grayscale values.

[0111] The control method described in Appendix 1, having the above configuration, allows for correction of low-gradation colors close to black using a measurement pattern selected according to the gamma characteristics for the first gradation value. As a result, the accuracy of correction of low-gradation colors close to black is improved.

[0112] (Note 2) The control method for the projection device according to Note 1, wherein the difference between the lowest second tone value and the second lowest second tone value among the multiple second tone values ​​included in the multiple tone data is smaller than the difference between the highest second tone value and the second highest second tone value among the multiple second tone values, and the difference between the lowest third tone value and the second lowest third tone value among the multiple third tone values ​​included in the multiple input data is smaller than the difference between the highest third tone value and the second highest third tone value among the multiple third tone values.

[0113] The control method described in Appendix 2, having the above configuration, allows for correction of low-gradation colors close to black, even for the second and third gradation values, using measurement patterns selected according to the gamma characteristics. As a result, the accuracy of correction for low-gradation colors close to black is improved.

[0114] (Note 3) The control method for the projection device according to Note 1, wherein the plurality of first tone values ​​included in the plurality of tone data include a first value, a second value greater than the first value, and a third value greater than the second value, and the plurality of first brightness values ​​included in the plurality of measurement data include a first measurement value, a second measurement value greater than the first measurement value, and a third measurement value greater than the second measurement value, and the first pair of the first value and the first measurement value, the second pair of the second value and the second measurement value, and the third pair of the third value and the third measurement value satisfy a curve showing a first characteristic that defines the plurality of first brightness values ​​for the plurality of first tone values, and calculating the correction data includes identifying a function showing the curve based on the first pair, the second pair, and the third pair, and identifying a correction value for correcting the color of the image based on the function.

[0115] The control method described in Appendix 3, having the above configuration, can correct cases where the first tone value has a value between the discrete values ​​by interpolating between discrete values ​​based on a plurality of discrete first tone values ​​and a plurality of discrete first brightness values ​​indicated by measurement data corresponding to the first tone value.

[0116] (Note 4) The control method for the projection device according to Note 3, wherein the plurality of first tone values ​​are divided into N first tone values ​​from the first tone value showing the smallest tone to the first tone value showing the largest tone, the first value, the second value and the third value belong to the division to which the first tone value showing the smallest tone belongs among the N divisions, and N is an integer of 3 or more.

[0117] The control method described in Appendix 4, having the above configuration, allows for more detailed correction of low-gradation colors close to black compared to relatively high-gradation colors.

[0118] (Note 5) The control method for a projection device according to Note 1, wherein the plurality of grayscale data includes grayscale data in which the first grayscale value, the second grayscale value, and the third grayscale value are equal to each other.

[0119] The control method described in Appendix 5, having the above configuration, allows the use of a gray pattern as the measurement pattern.

[0120] (Note 6) The projection device is a first projection device, the plurality of grayscale data are a plurality of first grayscale data, the plurality of measurement data are a plurality of first measurement data, the plurality of colored lights are a plurality of first colored lights, and the second projection device projects each of the plurality of second colored lights that correspond one-to-one with the plurality of first grayscale data onto the projection surface based on the plurality of first grayscale data, so that in the first region of the projection surface, the plurality of first colored lights and the plurality of second colored lights overlap, and based on the plurality of second grayscale data, the plurality of second colored lights that correspond one-to-one with the plurality of second grayscale data When each of the multiple third-colored lights is projected from the first projection device onto the projection surface, a plurality of second measurement data are obtained based on the output of the sensor that measures the reflected light reflected from the projection surface by each of the plurality of third-colored lights; when each of the plurality of fourth-colored lights corresponding one-to-one with the plurality of second-tone data is projected from the second projection device onto the projection surface, a plurality of second measurement data are obtained based on the output of the sensor that measures the reflected light reflected from the projection surface by each of the plurality of fourth-colored lights; and in the first region of the projection surface, The plurality of third-color lights and the plurality of fourth-color lights overlap, and correction data for correcting the color of the image displayed on the projection surface is calculated based on the plurality of second-color data and the plurality of second-measurement data in addition to the plurality of first-tone data and the plurality of first-measurement data, and each of the plurality of second-tone data includes at least one fourth-tone value indicating at least one gradation for the first color component, at least one fifth-tone value indicating at least one gradation for the second color component, and a sixth-tone value indicating at least one gradation for the third color component, and the plurality Each of the second measurement data includes a fourth brightness value indicating the brightness of reflected light of the color light corresponding to the first color component having the fourth grayscale value, a fifth brightness value indicating the brightness of reflected light of the color light corresponding to the second color component having the fifth grayscale value, and a sixth brightness value indicating the brightness of reflected light of the color light corresponding to the third color component having the sixth grayscale value, wherein the difference between the lowest fourth grayscale value and the second lowest fourth grayscale value among the plurality of fourth grayscale values ​​included in the plurality of grayscale data is smaller than the difference between the highest first grayscale value and the second highest first grayscale value among the plurality of first grayscale values.Control method for the projection device described in Appendix 1.

[0121] The control method described in Appendix 6, having the above configuration, can simultaneously correct the colors of multiple tiled projected images.

[0122] (Note 7) A control method for the projection device of Note 6, wherein only the plurality of first color lights are projected onto the second region of the projection surface, and the color correction of the image is to reduce color unevenness in the first region and to correct the brightness of the second region so that it is equal to the brightness of the first region.

[0123] The control method described in Appendix 7, having the above configuration, can simultaneously correct for uneven black color and "black level distortion" in multiple tiled projected images.

[0124] (Note 8) The control method for the projection device of Note 6, wherein the plurality of first tone values ​​included in the plurality of first tone data include a first value, a second value greater than the first value, and a third value greater than the second value, and the plurality of fourth tone values ​​included in the plurality of second tone data include a fourth value, a fifth value greater than the fourth value, and a sixth value greater than the fifth value, and the second value and the fourth value are equal to each other, and the third value and the fifth value are equal to each other.

[0125] The control method described in Appendix 8, having the above configuration, allows the use of a measurement pattern having a common gradation in the superimposed region DR and the non-superimposed region NR. As a result, the processing load is reduced. Consequently, the control method of this embodiment can improve the signal-to-noise ratio in the imaging device 12.

[0126] (Note 9) The projection method of the projection device described in Note 6, wherein the projection of the plurality of first-color lights from the first projection device and the projection of the plurality of second-color lights from the second projection device are synchronized with each other.

[0127] The control method described in Appendix 9, having the above configuration, can improve the signal-to-noise ratio in the imaging device 12.

[0128] (Note 10) A program for controlling a projection device, wherein, based on a plurality of grayscale data, when each of a plurality of colored lights corresponding one-to-one with the plurality of grayscale data is projected from the projection device onto the projection surface, the program causes the projection device to perform the following: acquire a plurality of measurement data based on the output from a sensor that measures the reflected light reflected by each of the plurality of colored lights onto 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 plurality of grayscale data includes at least one first grayscale value indicating at least one grayscale for the first color component, and at least one second grayscale value indicating at least one grayscale for the second color component. A program comprising a gradation value and at least one third gradation value indicating at least one gradation for a third color component, wherein the plurality of measurement data comprises a first brightness value indicating the brightness of reflected light of the color light corresponding to the first color component having the first gradation value, a second brightness value indicating the brightness of reflected light of the color light corresponding to the second color component having the second gradation value, and a third brightness value indicating the brightness of reflected light of the color light corresponding to the third color component having the third gradation value, wherein the difference between the lowest first gradation value and the second lowest first gradation value among the plurality of first gradation values ​​included in the plurality of gradation data is smaller than the difference between the highest first gradation value and the second highest first gradation value among the plurality of first input gradation values.

[0129] The program in Appendix 10, having the above configuration, and the control method of this embodiment, having the above configuration, can correct low-gradation colors close to black with respect to the first gradation value using a measurement pattern selected according to the gamma characteristics. As a result, the accuracy of correcting low-gradation colors close to black is improved. [Explanation of Symbols]

[0130] 1...Projection system, 10...Projection device, 10A...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, 136[2]:Color unevenness correction unit, 137...Communication control unit, DP...Grid point, DR...Superimposition area, LC...Brightness correction cycle Path, 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, PT1...Part, PT2...Part, PT3...Part, PT4...Part, PT5...Part, PT6...Part, PT7...Part, RL...Area, RL1...Area, RL2...Area, RL3...Area, RL4...Area, RL5...Area, SC...Projection surface, UL...Color unevenness correction circuit

Claims

1. When multiple color lights, each corresponding one-to-one with the multiple color lights, are projected from the projection device onto the projection surface based on multiple grayscale data, multiple measurement data are obtained based on the output from a sensor that measures the reflected light reflected by each of the multiple color lights onto the projection surface. Based on the aforementioned plurality of grayscale data and the plurality of measurement data, correction data is calculated for correcting the color of the image displayed on the projection surface. Includes, The plurality of grayscale data include at least one first grayscale value representing at least one grayscale for the first color component, at least one second grayscale value representing at least one grayscale for the second color component, and at least one third grayscale value representing at least one grayscale for the third color component. The plurality of measurement data include a first brightness value indicating the brightness of reflected light of the color light corresponding to the first color component having the first grayscale value, a second brightness value indicating the brightness of reflected light of the color light corresponding to the second color component having the second grayscale value, and a third brightness value indicating the brightness of reflected light of the color light corresponding to the third color component having the third grayscale value. Among the multiple first tone values ​​included in the multiple tone data, the difference between the lowest first tone value and the second lowest first tone value is smaller than the difference between the highest first tone value and the second highest first tone value among the multiple first input tone values. A method for controlling a projection device.

2. Among the multiple second tone values ​​included in the multiple tone data, the difference between the lowest second tone value and the second lowest second tone value is smaller than the difference between the highest second tone value and the second highest second tone value among the multiple second tone values. Among the multiple third-tone values ​​included in the multiple input data, the difference between the lowest third-tone value and the second lowest third-tone value is smaller than the difference between the highest third-tone value and the second highest third-tone value among the multiple third-tone values. A method for controlling a projection device according to claim 1.

3. The plurality of first grayscale values ​​included in the plurality of grayscale data include a first value, a second value greater than the first value, and a third value greater than the second value. The plurality of first brightness values ​​included in the plurality of measurement data include a first measurement value, a second measurement value greater than the first measurement value, and a third measurement value greater than the second measurement value. The first set of the first value and the first measured value, the second set of the second value and the second measured value, and the third set of the third value and the third measured value satisfy a curve that shows a first characteristic that defines a plurality of first brightness values ​​for a plurality of first grayscale values, Calculating the aforementioned correction data is Identifying the function that represents the curve based on the first set, the second set and the third set, Based on the aforementioned function, a correction value is identified for correcting the color of the image, including, A method for controlling a projection device according to claim 1.

4. The aforementioned plurality of first tone values ​​are divided into N values, from the first tone value representing the smallest tone to the first tone value representing the largest tone. The first value, the second value, and the third value belong to the category to which the first gradation value representing the smallest gradation belongs among the N categories. The above N is an integer greater than or equal to 3. A method for controlling a projection device according to claim 3.

5. The plurality of grayscale data includes grayscale data in which the first grayscale value, the second grayscale value, and the third grayscale value are equal to each other. A method for controlling a projection device according to claim 1.

6. The projection device is the first projection device, The aforementioned plurality of grayscale data are a plurality of first grayscale data, The aforementioned multiple measurement data are multiple first measurement data, The aforementioned plurality of colored lights are a plurality of first colored lights, The second projection device projects each of the multiple second color lights, which correspond one-to-one with the multiple first grayscale data, onto the projection surface based on the multiple first grayscale data, so that in the first region of the projection surface, the multiple first color lights and the multiple second color lights overlap. When multiple second-tone data are projected from the first projection device onto a projection surface, each of the multiple third-color lights corresponding one-to-one to the multiple second-tone data are projected onto the projection surface, a plurality of second measurement data are obtained based on the output from the sensor that measures the reflected light reflected by each of the multiple third-color lights onto the projection surface. When, based on the plurality of second grayscale data, each of the plurality of fourth-colored lights corresponding one-to-one with the plurality of second grayscale data is projected from the second projection device onto the projection surface, a plurality of second measurement data are obtained based on the output of the sensor that measures the reflected light reflected by each of the plurality of fourth-colored lights from the projection surface. In the first region of the projection surface, the plurality of third-color lights and the plurality of fourth-color lights overlap, Based on the plurality of first grayscale data and the plurality of first measurement data, as well as the plurality of second grayscale data and the plurality of second measurement data, correction data is calculated to correct the color of the image displayed on the projection surface. Each of the plurality of second grayscale data includes at least one fourth grayscale value representing at least one grayscale for the first color component, at least one fifth grayscale value representing at least one grayscale for the second color component, and a sixth grayscale value representing at least one grayscale for the third color component. Each of the plurality of second measurement data includes a fourth brightness value indicating the brightness of reflected light of the color light corresponding to the first color component having the fourth grayscale value, a fifth brightness value indicating the brightness of reflected light of the color light corresponding to the second color component having the fifth grayscale value, and a sixth brightness value indicating the brightness of reflected light of the color light corresponding to the third color component having the sixth grayscale value. Among the multiple fourth-level values ​​included in the aforementioned multiple level data, the difference between the lowest fourth-level value and the second lowest fourth-level value is smaller than the difference between the highest first-level value and the second highest first-level value among the aforementioned multiple first-level values. A method for controlling a projection device according to claim 1.

7. Only the plurality of first-color lights are projected onto the second region of the projection surface. The color correction of the aforementioned image involves reducing color unevenness in the first region and correcting the brightness of the second region so that it is equal to the brightness of the first region. A method for controlling a projection device according to claim 6.

8. The plurality of first grayscale values ​​included in the plurality of first grayscale data include a first value, a second value greater than the first value, and a third value greater than the second value. The plurality of fourth-tone values ​​included in the plurality of second-tone data include a fourth value, a fifth value greater than the fourth value, and a sixth value greater than the fifth value. The second value and the fourth value are equal to each other. The third value and the fifth value are equal to each other. A method for controlling a projection device according to claim 6.

9. Projecting the plurality of first-color lights from the first projection device and projecting the plurality of second-color lights from the second projection device are synchronized with each other. A method for controlling a projection device according to claim 6.

10. A program that controls a projection device, When multiple color lights, each corresponding one-to-one with the multiple color lights, are projected from the projection device onto the projection surface based on multiple grayscale data, multiple measurement data are obtained based on the output from a sensor that measures the reflected light reflected by each of the multiple color lights onto the projection surface. Based on the aforementioned plurality of grayscale data and the plurality of measurement data, correction data is calculated for correcting the color of the image displayed on the projection surface. The projection device is made to perform the following: The plurality of grayscale data include at least one first grayscale value representing at least one grayscale for the first color component, at least one second grayscale value representing at least one grayscale for the second color component, and at least one third grayscale value representing at least one grayscale for the third color component. The plurality of measurement data include a first brightness value indicating the brightness of reflected light of the color light corresponding to the first color component having the first grayscale value, a second brightness value indicating the brightness of reflected light of the color light corresponding to the second color component having the second grayscale value, and a third brightness value indicating the brightness of reflected light of the color light corresponding to the third color component having the third grayscale value. Among the multiple first tone values ​​included in the multiple tone data, the difference between the lowest first tone value and the second lowest first tone value is smaller than the difference between the highest first tone value and the second highest first tone value among the multiple first input tone values. program.

Images