Image correction method and program

Abstract

The desirable image quality displayed varies depending on the operating environment of the projection device and the type of projected content. [Solution] The image correction method includes: acquiring one of a plurality of correction pieces of information for correcting the third image PI_A based on first information indicating which of the following should be prioritized: the contrast ratio of the third image PI_A having a first image PI1 projected by the first projection device 10A onto the projection surface SC and a second image PI2 projected by the second projection device 10B onto the projection surface SC, and a second area NR where the first image PI1 and the second image PI2 do not overlap; and the color unevenness of the third image PI_A; and performing a correction based on the first correction piece to reduce the difference in brightness of black on the projection surface SC between the first area DR and the second area NR, and the color unevenness in the third image PI_A.

Description

[Technical Field]

[0001] This invention relates to an image correction method and a program. [Background technology]

[0002] Patent Document 1 discloses a projector for projecting an image, comprising an offset unit, a color unevenness correction unit, a black adjustment unit, and an inverse correction unit. The offset unit is a brightness adjustment means that has the function of offsetting the signal level of the entire video signal (the entire image). The color unevenness correction unit is a brightness adjustment means that adjusts the brightness unevenness of the projected image and makes the brightness of the projected image uniform across the surface. The black adjustment unit is a black adjustment means that adjusts the brightness of the non-overlapping region so that the brightness of the black in the overlapping region where the projected image projected by the projector and the projected image projected by another projector overlap on the projection surface is the same as that of the non-overlapping region where they do not overlap. The inverse correction unit subtracts an offset amount corresponding to a value set by the user from the already increased offset amount if the offset unit is set to offset in the direction of adding the signal level, or if the color unevenness correction unit is set to offset in the direction of adding the signal level of the overlapping region. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2013-254028 [Overview of the project] [Problems that the invention aims to solve]

[0004] In the method described in Patent Document 1, color unevenness correction is performed using predetermined values, which may result in a sacrifice of contrast. However, the desirable quality of the displayed image varies depending on the operating environment of the projection device and the type of projected content. [Means for solving the problem]

[0005] An image correction method according to an aspect of the present invention includes: acquiring one correction information from a plurality of correction information for correcting a third image based on first information indicating which of the following should be prioritized: the contrast ratio of a third image having a first region in which a first image projected by a first projection device onto a projection surface and a second image projected by a second projection device onto the projection surface overlap, and a second region in which the first image and the second image do not overlap, and the color unevenness of the third image; and performing a correction based on the one correction information to reduce the difference in brightness of black on the projection surface between the first region and the second region, and the color unevenness in the third image.

[0006] A program according to an aspect of the present invention causes a processor to perform the following actions: firstly, to select one of a plurality of correction pieces of correction for correcting a third image, based on first information indicating which of the following should be prioritized: the contrast ratio of a third image having a first region where a first image projected by a first projection device onto a projection surface and a second image projected by a second projection device onto the projection surface overlap, and a second region where the first image and the second image do not overlap, and the color unevenness of the third image; and to perform correction based on the one correction piece of correction to reduce the difference in brightness of black on the projection surface between the first region and the second region, and the color unevenness in the third image. [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] Functional block diagram of the correction unit 136. [Figure 4] A flowchart showing an example of operation of the projection device 10A according to the first embodiment. [Figure 5] A diagram showing an example of a grid point LP. [Figure 6] A diagram showing an example of a grid point LP. [Figure 7] A diagram showing an example of a grid point LP. [Figure 8] This figure shows the projected image PI_A after correction prioritizing the contrast ratio, and the luminance BA_a before correction and luminance BA_b after correction in the projected image PI_A. [Figure 9] This figure shows the projected image PI_A after correction prioritizing the accuracy of color uniformity correction, and the luminance BA_a before correction and BA_b after correction in the projected image PI_A. [Figure 10] Diagram illustrating the luminance gradient. [Figure 11] Diagram illustrating the luminance gradient. [Figure 12] Diagram illustrating the luminance gradient. [Figure 13] A diagram showing an example of luminance BA. [Figure 14] A diagram showing an example of the color uniformity correction value UA. [Figure 15] An explanatory diagram of the correction method that leaves a step difference in the drivetrain. [Figure 16] A diagram showing an example of luminance values ​​BA_a, BA_c, and BA_b. [Figure 17] A figure showing an example of the corrected projected image PI_A. [Figure 18] A flowchart showing the substeps SS4[1] to SS4[5] that make up step S4. [Figure 19] A diagram showing an example of the correction region of an LC brightness correction circuit. [Figure 20] An explanatory diagram showing the processing procedures for the brightness correction circuit LC and the color uniformity correction circuit UC. [Figure 21] A diagram showing an example of the calculation process for the color uniformity correction value S0, brightness correction value C0, ideal output value Ai, and color uniformity correction value S1 in substep SS4[1]. [Figure 22] A diagram showing an example of the calculation process for the color uniformity correction value S0, brightness correction value C0, ideal output value Ai, and color uniformity correction value S1 in substep SS4[2]. [Figure 23] A diagram showing an example of the calculation process for the color uniformity correction value S0, brightness correction value C0, ideal output value Ai, and color uniformity correction value S1 in substep SS4[2]. [Figure 24]A diagram illustrating the processing steps in substep SS4[3]. [Figure 25] A diagram showing an example of the calculation process for the color uniformity correction value S0, brightness correction value C0, ideal output value Ai, and color uniformity correction value S1 in substep SS4[3]. [Figure 26] A diagram showing an example of the calculation process for the color unevenness correction value S0, brightness correction value C0, ideal output value Ai, and color unevenness correction value S1 in substep SS4[4]. [Figure 27] A diagram showing an example of the calculation process for the color unevenness correction value S0, brightness correction value C0, ideal output value Ai, and color unevenness correction value S1 in substep SS4[5]. [Figure 28] A flowchart showing the substeps SS4[1] to SS4[8'] that make up step S4. [Figure 29] This figure shows an example of the calculation process for the color uniformity correction value S0_G, brightness correction value C0, ideal output value Ai_G, and color uniformity correction value S1_G in substep SS4[5']. [Figure 30] This figure shows an example of the calculation process for the color uniformity correction value S0_G, brightness correction value C0, ideal output value Ai_G, and color uniformity correction value S1_G in substep SS4[6']. [Figure 31] A diagram showing an example of the operation screen OP1. [Figure 32] A diagram showing an example of the operation screen OP2. [Figure 33] A diagram showing an example of the operation screen OP3. [Figure 34] A flowchart showing substeps SS4[1]_1 to SS4[1]_7 that constitute substep SS4[1]. [Figure 35] A diagram showing an example of target grayscale values ​​(r,g,b) in a grid point dynamic programming (DP). [Figure 36] This figure shows an example of the target grayscale value (r,g,b) at grid point DP and the target grayscale value t at grid point NP adjacent to the boundary between the superimposed region DR and the non-superimposed region NR. [Figure 37] A diagram illustrating an example of a method for determining the target grayscale value t for a grid point NP whose target grayscale value t is undetermined. [Figure 38] A diagram illustrating an example of a method for determining the target grayscale value t for a grid point NP whose target grayscale value t is undetermined. [Figure 39] A diagram showing an example of how the target grayscale value t is calculated. [Figure 40] A diagram showing an example of how the target grayscale value t is calculated. [Figure 41] A diagram showing an example of how the target grayscale value t is calculated. [Figure 42] A diagram illustrating an example of smoothing. [Figure 43] A diagram illustrating an example of smoothing. [Figure 44] A diagram illustrating an example of the smoothing process for the target grayscale value t. [Figure 45] A diagram illustrating an example of the smoothing process for the target grayscale value t. [Figure 46] A diagram illustrating an example of the smoothing process for the target grayscale value t. [Figure 47] A figure showing a three-dimensional representation of the target values ​​of each grid point NP before smoothing. [Figure 48] A diagram showing a three-dimensional representation of the target values ​​of each grid point NP after smoothing is complete. [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 48.

[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 information processing device 20. Projection device 10A is an example of the "first projection device". Projection device 10B is an example of the "second projection device".

[0011] Projection devices 10A, 10B, and 10C, and the information processing 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 10B. 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 information processing 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 information processing device 20 onto the projection surface SC. Alternatively, the information processing 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 supply the image to be projected by each projection device 10 to projection devices 10A and 10C, respectively. In this case, the projection system 1 does not necessarily have to include an information processing device 20.

[0014] Furthermore, if projection device 10A is the master projection device 10, and projection devices 10B and 10C are slave projection devices 10, the information processing device 20 transmits a control signal to projection device 10A for the purpose of controlling it. Projection device 10A may also transmit control signals to projection devices 10B and 10C.

[0015] The information processing device 20 may, for example, be a PC (Personal Computer), a tablet, or a smartphone.

[0016] In the example shown in Figure 1, projection device 10A projects projection image PI1 onto projection surface SC. Projection image PI1 is an example of a "first image". Projection device 10B projects projection image PI2 onto projection surface SC. Projection image PI2 is an example of a "second image". 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. Projection image PI_A is an example of a "third image".

[0017] 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.

[0018] As a result, the projection surface SC region RL1 will have part PT2 of projection image PI1 and part PT3 of projection image PI2 projected onto it. The projection surface SC region RL2 will have only part PT1 of projection image PI1 projected onto it. The projection surface SC region RL3 will have only part PT4 of projection image PI2 projected onto it. The projection surface SC region RL4 will have part PT5 of projection image PI2 and part PT6 of projection image PI3 projected onto it. The projection surface SC region RL5 will have part PT7 of projection image PI3 projected onto it.

[0019] Of the multiple regions RL on the projection surface SC, 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".

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

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

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

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

[0024] The storage device 14 is a recording medium readable by the processing unit 13 and stores multiple programs, including the control program PG1 executed by the processing unit 13. The storage device 14 also stores a measurement pattern image projected from the projector 11 during the correction described later. Hereafter, the measurement pattern image may be referred to as a measurement pattern. The storage device 14 may consist of at least one of the following: ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and RAM (Random Access Memory). The storage device 14 may also be called a register, cache, main memory, or primary memory.

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

[0026] The processing unit 13 functions as a projection control unit 131, an imaging control unit 132, an image analysis unit 133, a correction value calculation unit 134, an image acquisition unit 135, a correction unit 136, and a communication control unit 137 by reading and executing the control program PG1 from the storage device 14. The control program PG1 may also be transmitted via a communication network from another device, such as a server that manages the projection device 10A.

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

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

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

[0030] The correction value calculation unit 134 calculates a correction value to be set in the correction unit 136, which will be described later, based on the measured values ​​calculated by the image analysis unit 133. 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 4 to 48.

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

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

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

[0034] However, the color of low-gradation light, close to black (gradation 0), is a color light that is obtained by adding gradually modulated RGB light to color light that has black as the entirety (gradation 0). As a result, the change in chromaticity is large, and conventional measurement methods have the problem of large estimation errors. Therefore, in this embodiment, a color light having the color of each gradation, which is divided more finely than gradations above the predetermined gradation, is projected as a measurement pattern. This reduces the estimation error in the low-gradation range close to black compared to when measurements are performed with the same fineness regardless of the gradation. For example, the range up to 125 gradations in the first division of the gradation width from gradation 0 to gradation 1023 may be divided equally. The fineness of the division can be two or more divisions. Furthermore, it is preferable to use a measurement pattern of gray included between gradation 0 and the predetermined gradation, and multiple measurement patterns in which one of the R, G, and B color components is changed based on the gray measurement pattern. Compared to dividing the low-tone range equally, the accuracy of estimating the change in chromaticity in the low-tone range is improved.

[0035] Returning to Figure 2, the image acquisition unit 135 acquires the image to be projected from the information processing device 20.

[0036] 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.

[0037] Figure 3 is a functional block diagram of the correction unit 136. The correction unit 136 comprises a brightness correction circuit LC and a color uniformity correction circuit UC.

[0038] 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 correction for so-called "black level floating." "Black level floating" refers to the difference in brightness between the superimposed region DR and the non-superimposed region NR on the projection surface SC when the projection device 10 attempts to display a black image with a grayscale of 0 on the projection surface SC by projecting the projected image PI onto the projection surface SC. Therefore, correcting "black level floating" can be said to be a brightness correction that reduces the difference in brightness between the superimposed region DR and the non-superimposed region NR.

[0039] 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. Details of the brightness correction circuit LC and the color unevenness correction circuit UC will be described later.

[0040] 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.

[0041] 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.

[0042] 1-2: Operation of the First Embodiment Figure 4 is a flowchart showing an example of the operation of the projection device 10A according to the first embodiment.

[0043] 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.

[0044] Here, "black" refers to the color contained within 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 7 below. In the case of N=7, "black" refers to the color contained within the gradations between gradation 0 and gradation 146.

[0045] 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 brightness and color unevenness 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.

[0046] In this case, the adjustment point when the processing unit 13 corrects the color unevenness of 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 of the gradation range, which is divided into 7 equal parts from gradation 0 to gradation 1023.

[0047] In step S1, the processing unit 13 determines whether each of the grid points LP used as the color unevenness correction circuit UC is included in the superposition region DR or in the non-superposition region NR. For example, before step S1, the processing unit 13 projects a full white image as a projection image only from projector 11 and captures the full white image with the imaging device 12 of projection device 10A. Next, it projects a full white image as a projection image only from projection device 10B and captures the full white image with the imaging device 12 of projection device 10A. From these imaging results, the processing unit 13 detects the position of the right edge of the full white image projected from projection device 10A and the position of the left edge of the full white image projected from projection device 10B, and determines that the region from the position of the right edge to the position of the left edge is the superposition region DR in the coordinate system of the captured image. Then, based on the correspondence between the coordinate systems of the projection device 10A, the projection device 10B, and the captured image, which were generated before step S1, the superposition region DR in the captured image coordinate system is converted into the superposition region DR in the coordinate systems of the projection device 10A and the projection device 10B. Based on the captured image of the grid points LP, the processing device 13 determines whether each of the grid points LP belongs to the superposition region DR in the coordinate systems of the projection device 10A and the projection device 10B. The correspondence can be calculated, for example, by a well-known calibration technique using Gray code. The coordinate system of the projection device 10A is the two-dimensional coordinate system of the liquid crystal panel. The coordinate system of the projection device 10B is the same. The same also applies to the projection devices 10B and 10C. The process described above is merely an example, and the method for determining whether each grid point LP is included in the superposition region DR or the non-superposition region NR can be modified as appropriate.

[0048] Figures 5 to 7 show examples of grid points LP. More specifically, Figure 5 is an example of a grid point LP corresponding to the projected image PI1 projected from projection device 10A. Figure 6 is an example of a grid point LP corresponding to the projected image PI2 projected from projection device 10B. Figure 7 is an example of a grid point LP corresponding to the projected image PI3 projected from projection device 10C.

[0049] In Figures 5 to 7, 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 5 to 7, there are measured values ​​calculated by the image analysis unit 133.

[0050] In step S2 of Figure 4, the projection device 10A projects the black correction measurement pattern described above. 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.

[0051] 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.

[0052] First, the processing unit 13 uses interpolation to determine the correspondence between the gradation values ​​(r, g, b) 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. The interpolation operation should be appropriate depending on the type and number of measurement patterns used. For example, the processing unit 13 may perform curve interpolation using a spline curve. Alternatively, the processing unit 13 may perform parabolic interpolation. Alternatively, the processing unit 13 may perform cubic curve interpolation. One example of such cubic curve interpolation is cubic interpolation.

[0053] The image analysis unit 133 converts RGB values ​​into XYZ values ​​by using equation 9, which multiplies a matrix whose components are RGB values ​​representing the color of the colored light in the estimated captured image by a transformation matrix specific to the imaging device 12. As a result, the image analysis unit 133 can estimate the output values ​​XYZ for any grayscale.

[0054] Furthermore, the image analysis unit 133 calculates the brightness component Y and the chromaticity component u'v' by converting the estimated XYZ values ​​into Yu'v' values ​​using the following equation 1.

number

[0055] Returning to Figure 4, 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.

[0056] In this embodiment, the processing unit 13 calculates multiple types of correction values. The purpose of calculating multiple types of correction values ​​will be explained below.

[0057] In conventional correction functions, a single correction value was calculated based on the captured image, such as the measurement pattern, to ensure uniform color and brightness, and this value was then set in the correction circuit. Furthermore, when using multiple projection devices, a uniform brightness correction value was applied to the non-overlapping noise reduction (NR) to correct "black level floating."

[0058] When correcting black color unevenness using conventional correction functions, the lowest brightness black is corrected to a higher brightness black, resulting in the black becoming brighter in the projected image. Therefore, there is a trade-off between the accuracy of color unevenness correction and the brightness of the corrected black.

[0059] Figure 8 shows the projected image PI_A when correction is performed prioritizing the contrast ratio, and the luminance BA_a before correction and the luminance BA_b after correction for the projected image PI_A. Figure 9 shows the projected image PI_A when correction is performed prioritizing the accuracy of color uniformity correction, and the luminance BA_a before correction and the luminance BA_b after correction for the projected image PI_A. As shown in Figure 8, when correction is performed prioritizing the contrast ratio, color uniformity remains in the superimposed region DR. On the other hand, as shown in Figure 9, when correction is performed prioritizing the accuracy of color uniformity correction, the contrast ratio decreases.

[0060] However, depending on the environment in which the projection device is used and the type of projected content, there are cases where it is desirable to accurately correct color unevenness, such as when projecting content that is entirely black or dark in color, as the unevenness of black is easily noticeable. On the other hand, there are also cases where it is desirable for the black to be dark, such as when the projection device is used in a dark environment. Conventional methods that calculate only one correction value could not address the problem that the appropriate correction value differs depending on the environment in which the device is used and the type of projected content.

[0061] Another problem is that if there is significant luminance unevenness in the colored light projected from a single projector, the degree of "black level elevation" varies depending on the location within the projected image (PI). As a result, conventional methods for correcting "black level elevation" sometimes resulted in a luminance gradient between the superimposed DR (Dark Reduction) and non-superimposed NR (Noise Reduction) regions, leading to edge enhancement.

[0062] Figures 10 to 12 are explanatory diagrams of the luminance gradient. In Figure 10, the dashed line represents the color uniformity correction value UA. The numbers at both ends of the dashed line are the values ​​of the color uniformity correction value UA. The thick solid line represents the luminance BA as the ideal output value. In the superimposed DR region of Figure 23, the luminance BA is the color uniformity correction value UA plus the luminance BL1 of the "black level" light projected from the adjacent projector 10. In the superimposed DR region of Figure 24, the luminance BA is the color uniformity correction value UA plus the luminance BL2 of the "black level" light projected from the adjacent projector 10. In the superimposed DR region of Figure 25, the luminance BA is the color uniformity correction value UA plus the luminance BL3 of the "black level" light projected from the adjacent projector 10. Here, BL1 > BL2 > BL3. Furthermore, as shown in Figures 10 to 12, in the non-overlapping region NR, the luminance BA is the value obtained by adding the brightness correction value LA to the color uniformity correction value UA. Note that the color uniformity correction value UA differs between the superimposed region DR and the non-superimposed region NR. Furthermore, the color uniformity correction value UA is linearly interpolated between the grid points DP included in the superimposed region DR and the grid points NP included in the non-superimposed region NR.

[0063] As shown in Figure 11, an ideal luminance distribution is one where the luminance BA of the superimposed region DR and the luminance BA of the non-superimposed region NR are the same value, resulting in no luminance gradient. However, the luminance BL1 of the "black floating" light differs depending on the location in the superimposed region DR, and the color unevenness correction value UA also differs depending on the location in the non-superimposed region NR. On the other hand, the brightness correction value LA is uniformly the same value within the superimposed region DR. Therefore, as shown in Figures 10 and 12, a step occurs in the luminance BA between the superimposed region DR and the non-superimposed region NR. Due to the characteristics of human vision, when there is a step in the luminance BA, it appears as if an outline exists at the location where the step occurs.

[0064] In calculating the correction values ​​for the grid points LP shown in Figures 10 to 12, especially when the spacing between the grid points LP is narrow, the luminance gradient becomes steeper between the grid points DP included in the superimposed region DR and the grid points NP included in the non-superimposed region NR, which can further exaggerate the contours.

[0065] Figure 13 shows an example of luminance BA as an ideal output value for making the brightness uniform between the superimposed region DR and the non-superimposed region NR at grid point LP included in the projected image PI. Figure 14 shows an example of the color unevenness correction value UA when the correction value is divided into a brightness correction value LA and a color unevenness correction value UA based on the luminance BA shown in Figure 13. As shown by arrow AR1 in Figure 13, if luminance unevenness exists in the direction of the boundary between the superimposed region DR and the non-superimposed region NR at grid point NP adjacent to grid point DP, a luminance gradient occurs as shown by arrow AR2 in Figure 14.

[0066] Therefore, a correction method can be considered in which a step difference DD in the luminance BA, which is the ideal output value, is deliberately left to prevent a luminance slope that emphasizes contours from occurring near the boundary line between the superimposed region DR and the non-superimposed region NR. Figure 15 is an explanatory diagram of the correction method that leaves a step difference DD. In Figure 15, a step difference DD in the luminance BA remains at the boundary line BD between the superimposed region DR and the non-superimposed region NR, but the luminance BA in the superimposed region DR and the luminance BA in the non-superimposed region NR are both flat, and no luminance slope occurs. In this case, the processing unit 13 deliberately performs a correction that prevents the occurrence of a luminance slope, thereby mitigating the emphasis on contours.

[0067] However, the degree to which contours are emphasized and the degree to which differences in brightness BA are noticeable vary depending on the user's subjective perception. For this reason, conventional technology, which calculates only one correction value, cannot address the problem that the appropriate correction value differs depending on the usage of the projection device and the type of projected content.

[0068] Therefore, in this embodiment, with regard to black color correction, the projection device 10 calculates a correction value based on multiple parameters and performs the correction using the correction value selected by the user.

[0069] First, the first parameter indicates whether to prioritize contrast ratio or color uniformity in the projected image PI_A. Specifically, the first parameter specifies whether the brightness of the projected image PI_A should be set to a brightness that prioritizes contrast ratio, a brightness that prioritizes the accuracy of black color uniformity correction, or a brightness that is somewhere in between. The processing unit 13 calculates several types of target values ​​as target values ​​for the corrected brightness corresponding to each of the first parameters, and calculates a correction value that results in each of these target values.

[0070] If the first parameter indicates brightness prioritizing contrast ratio, the processing unit 13 performs the correction by increasing only the R and B components without brightening the black areas at all. The reason the processing unit 13 increases only the R and B components and not the G component is that increasing all three components—R, B, and G—would cause the black areas to brighten rapidly. If the G component were to be increased in addition to the R and B components, the processing unit 13 would limit the amount by which the G component is increased.

[0071] If the first parameter indicates a brightness that prioritizes the accuracy of correcting black color unevenness, the processing unit 13 slightly brightens the black color within a range that allows for high-precision correction of black color unevenness. Specifically, the processing unit 13 brightens the black color by a predetermined amount and corrects color unevenness by increasing or decreasing all color components, including the R, G, and B components.

[0072] When the first parameter indicates a brightness level between the two brightness levels mentioned above, the processing unit 13 makes the black slightly brighter than when the first parameter indicates a brightness level that prioritizes contrast ratio. This brightness is darker than when the first parameter indicates a brightness level that prioritizes accuracy in correcting black color unevenness. In this case, the adjustment range for black is narrower than when the first parameter indicates a brightness level that prioritizes accuracy in correcting black color unevenness, so the accuracy of black correction may be lower compared to when the first parameter indicates a brightness level that prioritizes contrast ratio, but the deterioration of the contrast ratio is less compared to this case.

[0073] Figure 16 shows an example of a target brightness BA_a when the first parameter prioritizes contrast ratio, a target brightness BA_c when the first parameter prioritizes accuracy in correcting black color unevenness, and a target brightness BA_b when it is an intermediate value between the two. In the example shown in Figure 16, brightness BA_a is the output brightness when the input gradation is gradation 0 in the same γ curve as above. Brightness BA_b is the output brightness when the input gradation is between gradation 22 and gradation 34 in the same γ curve. Brightness BA_c is the output brightness when the input gradation is between gradation 34 and gradation 95 in the same γ curve. Note that the input gradation values ​​corresponding to brightness BA_b and brightness BA_c in Figure 16 are examples and may be different from those in Figure 16.

[0074] Figure 17 shows an example of the corrected projected image PI_A. More specifically, in Figure 17, projected image PI_A1 is the projected image when the target luminance value in Figure 16 is luminance BA_a. Projected image PI_A2 is the projected image when the target luminance value in Figure 16 is luminance BA_b. Projected image PI_A3 is the projected image when the target luminance value in Figure 16 is luminance BA_c.

[0075] As shown in Figure 17, the black in projected image PI_A1 is the darkest, and the black in projected image PI_A3 is the brightest. The black in projected image PI_A2 is an intermediate shade of black between that of projected image PI_A1 and the black in projected image PI_A2.

[0076] After three target values ​​are calculated as ideal output values ​​corresponding to each of the three first parameters, the processing unit 13 calculates ideal color unevenness correction values ​​for the superimposed region DR for each of the target values ​​of luminance BA_a, luminance BA_b, and luminance BA_c. Next, the processing unit 13 calculates correction values ​​for the non-superimposed region NR that correspond to the ideal color unevenness correction values ​​for the superimposed region DR, so that the chromaticity and luminance are the same as the corrected superimposed region DR.

[0077] The processing unit 13 divides the correction value corresponding to the target value into a brightness correction value and a color uniformity correction value based on the second parameter. The second parameter is a parameter that indicates the degree to which the boundary between the superimposed region DR and the non-superimposed region NR is noticeable in the projected image PI_A. The second parameter can also be said to be a parameter that indicates the uniformity of brightness in the projected image PI after black has been corrected based on the first parameter. The second parameter specifies whether to prioritize the uniformity of brightness between the superimposed region DR and the non-superimposed region NR, to prioritize the flatness of brightness in each of the superimposed region DR and the non-superimposed region NR, or to use an intermediate value between the two.

[0078] If the second parameter indicates that brightness uniformity should be prioritized, the processing unit 13 corrects "black level floating" using both the brightness correction circuit LC and the color unevenness correction circuit UC shown in Figure 3. In this case, the correction method corresponds to the luminance gradient explanatory diagram shown in Figure 10 or Figure 12, and there is a risk that the area near the boundary line BD of the projected image PI_A may be contour-enhanced.

[0079] If the second parameter indicates that brightness flatness in the superimposed region DR and the non-superimposed region NR should be prioritized, the processing unit 13 uses both the brightness correction circuit LC and the color unevenness correction circuit UC shown in Figure 3 to correct "black level floating". The correction method in this case corresponds to the luminance gradient explanatory diagram shown in Figure 15, where there is no risk of edge enhancement near the boundary line BD of the projected image PI_A, but the brightness differs depending on whether it is the superimposed region DR or the non-superimposed region NR.

[0080] If the second parameter indicates an intermediate value between the two cases described above, the processing unit 13 calculates correction values ​​for both the case where the second parameter prioritizes brightness uniformity and the case where the second parameter prioritizes brightness flatness in the superimposed region DR and the non-superimposed region NR, and uses the average of these values ​​as the correction value for the intermediate case. In this case, the luminance slope becomes gentler than when the second parameter prioritizes brightness uniformity, and the degree of edge enhancement decreases. Also, in this case, the difference in brightness between the superimposed region DR and the non-superimposed region NR is halved compared to the case where the second parameter prioritizes brightness flatness in the superimposed region DR and the non-superimposed region NR.

[0081] As described above, the processing unit 13 calculates a total of 3 × 3 = 9 correction values ​​by performing three corrections based on the first parameter and three corrections based on the second parameter. However, the processing unit 13 may calculate three correction values ​​based only on the first parameter, or three correction values ​​based only on the second parameter. Also, the number of first parameters may be two or more, and may be four or ten. The same applies to the second parameter. Furthermore, the number of first parameters and second parameters may differ, for example, two for the first parameter and three for the second parameter.

[0082] Figure 18 is a flowchart showing the substeps SS4[1] to SS4[5] that constitute step S4, when the second parameter prioritizes brightness uniformity.

[0083] In substep SS4[1], the processing unit 13 calculates ideal output values ​​for all grid points LP in the superimposed region DR and the non-superimposed region NR. Specifically, the processing unit 13 calculates ideal output values ​​to correct color unevenness in the superimposed region DR as correction values ​​for grid points DP included in the superimposed region DR. The processing unit 13 also calculates ideal values ​​to correct color unevenness in the non-superimposed region NR and to match the brightness of the non-superimposed region NR to the brightness of the superimposed region DR as correction values ​​for grid points LP included in the non-superimposed region NR. After these processes, the processing unit 13 decomposes the ideal output values ​​for grid points DP included in the superimposed region DR and grid points NP included in the non-superimposed region NR into correction values ​​to be set in the brightness correction circuit LC and correction values ​​to be set in the color unevenness correction circuit UC. The ideal output values ​​are an example of "target gradation values". The method for calculating the "ideal output value" mentioned above will be explained later in section "1-3: Addendum (Method for Calculating the Ideal Output Value)".

[0084] Here, we will describe the specifications of the brightness correction circuit LC, which is controlled by the brightness correction circuit LC, and the color uniformity correction circuit UC, which is controlled by the color uniformity correction circuit UC.

[0085] Figure 19 shows an example of the correction region of the brightness correction circuit LC. In Figure 19, the superimposed region DR and the non-superimposed region NR are the correction regions that the brightness correction circuit LC targets. When the brightness correction circuit LC performs correction on black, it functions as a circuit that corrects so-called "black floating". The brightness correction circuit LC can be set to any shape as the correction region, as shown in Figure 19. In addition, the brightness correction circuit LC can be set to a brightness correction value C0, which is a uniform adjustment amount for each of the superimposed region DR and the non-superimposed region NR as exemplified in Figure 19.

[0086] On the other hand, the color unevenness correction circuit UC can set a correction value for each of the discrete grid points LP exemplified in Figures 5 to 7. Furthermore, the color unevenness correction circuit UC can set a color unevenness correction value S as an adjustment value for each discrete gradation. Here, as an example, we set color unevenness correction values ​​S for eight gradations. Specifically, the color unevenness correction value S at gradation 0 is S0, the color unevenness correction value at gradation 146 is S1, and the color unevenness correction value at gradation 1023 is S7. In addition, the color unevenness correction values ​​S for gradations between gradation 0, gradation 146...1023 are determined by linear interpolation.

[0087] Figure 20 is an explanatory diagram showing the processing procedure of the brightness correction circuit LC and the color unevenness correction circuit UC. As shown in Figure 20, when an image with a grayscale of 0 is input to the brightness correction circuit LC, the brightness correction value C0 is added to the input value. In the case of grayscale of 0, the brightness correction value output from the brightness correction circuit LC is C0. When the brightness correction value C0 is output from the brightness correction circuit LC to the color unevenness correction circuit UC, the color unevenness correction circuit UC linearly interpolates between the point where the x-coordinate is grayscale of 0 and the y-coordinate is the color unevenness correction value S0 and the point where the x-coordinate is grayscale of 146 and the y-coordinate is the color unevenness correction value S1, thereby obtaining the following equation 2. According to the following equation 2, the output value A of the color unevenness correction circuit UC is u The following is calculated. Note that the color unevenness correction value S1 has already been calculated in step S1 of Figure 4.

number

[0088] At the grid point LP, the output value A can be obtained by using equation 2 above. u The following is calculated. For pixels between grid points LP, linearly interpolated values ​​are calculated.

[0089] Figure 21 shows the color uniformity correction value S0, brightness correction value C0, and ideal output value A in substep SS4[1]. i, and it is a diagram showing an example of the calculation status of the color unevenness correction value S1. In FIG. 21, for the sake of simplification of explanation, the lattice points DP included in the overlapping region DR are set to 1 column vertically and 3 rows horizontally, and the lattice points NP included in the non-overlapping region NR are set to 3 columns vertically and 3 rows horizontally. As shown in FIG. 21, at the stage where the sub-step SS4[1] is completed, for the ideal output value A i and the color unevenness correction value S1, values are calculated for all lattice points DP and lattice points NP. On the other hand, for the color unevenness correction value S0 and the brightness correction value C0, values are not calculated for any lattice points DP and lattice points NP. Note that the numerical values shown in FIG. 21 are integers, but they are integers for the convenience of explanation. The values corresponding to the lattice points DP and the lattice points NP may be decimal numbers. The same applies to the following drawings.

[0090] In sub-step SS4[2] of FIG. 18, the processing device 13 calculates the color unevenness correction value S0 and the brightness correction value C0 for the lattice points DP included in the overlapping region DR. Specifically, the processing device 13 divides the ideal output value A i for the lattice points DP included in the overlapping region DR into the color unevenness correction value S0 and the brightness correction value C0. [[ID=十二]]

[0091] [[ID=十三]] The processing device 13 pre-determines the brightness correction value C0 = C Lap for the overlapping region DR, and calculates the color unevenness correction value S0 = S0 u at gradation 0 so that the output value A i which is the final output value becomes the ideal output value A Lap = A Lap The brightness correction value C0 = C Lap the ideal output value A i = A Lap the color unevenness correction value S1 = S1 Lap at gradation 146 are already known. Substituting these values into Equation 2 results in Equation 3. By transforming Equation 3 into Equation 4, the value of the color unevenness correction value S0 = S0 Lap is calculated. In FIG. 21, the ideal output value A i included in the overlapping region DR is the above ideal output value A i = A Lap as described above. Note that the color unevenness correction value S0 = S0 for the superimposed region DR Lap This is an example of the "first color unevenness correction value".

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[0092] Note that the brightness correction value C0 of the superimposed region DR is set to C Lap Set = 0, and set the color unevenness correction value S0 to S0 Lap =A Lap That's fine.

[0093] Figures 22 and 23 show the color uniformity correction value S0, brightness correction value C0, and ideal output value A in substep SS4[2]. i This figure shows an example of the calculation status of the color unevenness correction value S1. Note that Figure 35 is C Lap This is the figure when =20. Figure 23 is C Lap This figure shows the case where = 0. As shown in Figures 22 and 23, when substep SS4[2] is completed, the ideal output value A i Regarding the color unevenness correction value S1, values ​​have been calculated for all grid points DP and NP. Furthermore, regarding the color unevenness correction value S0 and brightness correction value C0, values ​​have been calculated for grid points DP included in the superimposed region DR. As described above, at the substep SS4[2] stage, the brightness correction value C0 and the color unevenness correction value S0 are determined for each grid point DP included in the superimposed region DR.

[0094] In substep SS4[3] of Figure 18, the processing unit 13 calculates a color unevenness correction value S0 and a brightness correction value C0 for grid points NP included in the non-overlapping region NR that are adjacent to grid points DP included in the superimposed region DR, with the boundary between the non-overlapping region NR and the superimposed region DR in between.

[0095] When a grid point DP and a grid point NP are adjacent, the processing unit 13 calculates a brightness correction value C0 for the grid point NP such that the color unevenness correction value S0 for level 0 at the grid point NP is the same as the color unevenness correction value S0 for level 0 at the grid point DP.

[0096] Figure 24 is an explanatory diagram of the processing in substep SS4[3]. The projected image PI1 shown in Figure 24 corresponds to the projected image PI1 shown in Figure 5.

[0097] In Figure 24, the grid point NP enclosed by the dotted line is adjacent to the superimposed region DR, with the boundary between the non-superimposed region NR and the superimposed region DR in between. In substep SS4[3], the processing unit 13 calculates a correction value for the grid point NP. The grid point DP enclosed by the solid line is the grid point DP in the superimposed region DR adjacent to the grid point NP.

[0098] When the processing unit 13 calculates the brightness correction value C0 at the grid point NP0 shown in Figure 24, the color unevenness correction value S0 at the grid point NP0 is equal to the color unevenness correction value S0 at the grid point DP0. Lap The brightness correction value C0 at grid point NP0 should be the same as C NonLap The following calculation is performed. Grid points NP0 and DP0 are located in the same row of the grid and are adjacent in the row direction. Even if a grid point PP exists between grid points NP0 and DP0 whose ownership cannot be determined (either the superimposed region DR or the non-superimposed region NR), the grid points DP0 and NP0 that are closest to each other in either the row or column direction, across the boundary between the non-superimposed region NR and the superimposed region DR, are treated as adjacent grid points. Ideal output value A i =A NonLap Color unevenness correction value S1 = S1 in 146 gradations NonLap , and color unevenness correction value S0 = S0 Lap The values ​​of are known, and substituting these values ​​into Equation 2 gives Equation 5. By transforming Equation 5 into Equation 6, we get the brightness correction value C0 = C NonLap The value is calculated.

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[0099] Figure 25 shows the color uniformity correction value S0, brightness correction value C0, and ideal output value A in substep SS4[3]. i This figure shows an example of the calculation status of the color unevenness correction value S1. In Figure 25, the ideal output value A of a lattice point NP adjacent to lattice point DP, which is included in the non-superposition region NR. i However, the ideal output value A mentioned above i =A NonLap Therefore, the color unevenness correction value S1 for a grid point NP adjacent to grid point DP among the grid points NP included in the non-overlapping region NR is the above color unevenness correction value S1 = S1. NonLap Therefore, the color unevenness correction value S0 at the grid point DP included in the superimposed region DR is S0 = S0. Lap Therefore, using these values ​​and equation 6, the brightness correction value C0 = C for the grid point NP adjacent to grid point DP is obtained. NonLap This is calculated. As shown in Figure 25, at the stage when substep SS4[3] is completed, the ideal output value A i Regarding the color unevenness correction value S1, values ​​have been calculated for all grid points DP and NP. Furthermore, regarding the color unevenness correction value S0 and the brightness correction value C0, values ​​have been calculated for grid points DP included in the superimposed region DR, and for grid points NP adjacent to grid point DP among the grid points NP included in the non-superimposed region NR.

[0100] In substep SS4[4] of Figure 18, the processing unit 13 calculates the brightness correction value C0=C for the grid points NP adjacent to the superimposed region DR, which is located across the boundary between the non-superimposed region NR and the superimposed region DR, as calculated in substep SS4[3]. NonLap Therefore, the brightness correction value C0 = C in the entire non-overlapping region NR. NonLapThe brightness correction value C0 = C is determined uniformly for grid points NP adjacent to the superimposed region DR, across the boundary between the non-superimposed region NR and the superimposed region DR, which was calculated in substep SS4[3]. NonLap The average value is calculated, and this average value is used as the brightness correction value C0 = C for all grid points NP included in the non-overlapping region NR. NonLap As described above with reference to Figure 19, the brightness correction circuit LC sets a brightness correction value C0, which is a uniform adjustment amount (offset amount) for both the superimposed region DR and the non-superimposed region NR.

[0101] Figure 26 shows the color uniformity correction value S0, brightness correction value C0, and ideal output value A in substep SS4[4]. i This figure shows an example of the calculation status of the color unevenness correction value S1. In Figure 25, the brightness correction value C0 = C was set at the grid point NP adjacent to the superimposed region DR, with the boundary between the non-superimposed region NR and the superimposed region DR in between. NonLap The average value of is the brightness correction value C0 = C for all grid points NP in Figure 26. NonLap It will be set as follows. As shown in Figure 26, when substep SS4[4] is completed, the brightness correction value C0 and the ideal output value A are i Regarding the color unevenness correction value S1, values ​​have been calculated for all grid points DP and NP. Furthermore, regarding the color unevenness correction value S0, values ​​have been calculated for grid points DP included in the superimposed region DR, and for grid points NP adjacent to grid point DP among the grid points NP included in the non-superimposed region NR.

[0102] In substep SS4[5] of Figure 18, the processing unit 13 calculates the brightness correction value C0 = C at the grid point NP of the entire non-overlapping region NR, which was calculated in substep SS4[4]. NonLap Therefore, color unevenness correction value S 0= S0 NonLap’ The following is calculated. Note that the processing in substep SS4[5] is performed in substep SS4[3] where the brightness correction value C0=C NonLapThe calculation is performed for grid points NP adjacent to grid points DP included in the superimposed region DR, across the boundary between the non-superimposed region NR and the superimposed region DR. This is because the brightness correction value C0 = C at the grid point NP. NonLap This is because it changed after processing in substep SS4[4].

[0103] Ideal output value A i =A NonLap Color unevenness correction value S1 = S1 in 146 gradations NonLap , and brightness correction value C0=C NonLap The values ​​of are known, and substituting these values ​​into Equation 2 gives Equation 7. By transforming Equation 7 into Equation 8, we obtain the color unevenness correction value S0 = S0 NonLap’ The value is calculated. Note that the color unevenness correction value S0 = S0 for non-overlapping region NR NonLap’ This is an example of a "second color unevenness correction value".

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[0104] Figure 27 shows the color uniformity correction value S0, brightness correction value C0, and ideal output value A in substep SS4[5]. i This figure shows an example of the calculation status of the color unevenness correction value S1. In Figure 27, the ideal output value A of a lattice point NP adjacent to lattice point DP, which is included in the non-superposition region NR. i However, the ideal output value A mentioned above i =A NonLap Therefore, the color unevenness correction value S1 for a grid point NP adjacent to grid point DP among the grid points NP included in the non-overlapping region NR is the above color unevenness correction value S1 = S1. NonLap Therefore, the brightness correction value C0 at the grid point NP included in the non-overlapping region NR is given by the above C=S0 NonLap Therefore, using these values ​​and equation 17, the color unevenness correction value S is obtained. 0= S0 NonLap’ This is calculated. As shown in Figure 27, when substep SS4[5] is completed, the color uniformity correction value S0, the brightness correction value C0, and the ideal output value A arei Furthermore, regarding the color unevenness correction value S1, the value has been calculated for all grid points DP and NP.

[0105] Figure 28 is a flowchart showing the substeps SS4[1] to SS4[8'] that constitute step S4, when the second parameter prioritizes brightness flatness.

[0106] Note that the flowchart shown in Figure 28 differs from the flowchart shown in Figure 18 in that it includes substep SS4[5'] instead of substep SS4[5], and also includes substeps SS4[6'] to SS4[8']. For the sake of simplicity, the following will explain the differences between the flowchart shown in Figure 28 and the flowchart shown in Figure 18, specifically substeps SS4[5'] to SS4[8'].

[0107] In substep SS4[5'] of Figure 28, the processing unit 13 calculates the color unevenness correction value S of the G component at the grid points NP of the entire non-overlapping region NR. 0= Calculate S0_G.

[0108] Figure 29 shows the color uniformity correction value S0_G, brightness correction value C0, and ideal output value A in substep SS4[5']. i This figure shows an example of the calculation process for _G and the color unevenness correction value S1_G. The processing unit 13 first calculates the color unevenness correction value S of the G component at the grid point NP adjacent to the grid point DP, across the boundary between the superimposed region DR and the non-superimposed region NR. 0= S0_G is the color unevenness correction value S for the G component at the relevant grid point DP. 0= The value is the same as S0_G. Then, the processing unit 13 sets the color unevenness correction value S of the G component set for the grid point NP adjacent to the grid point DP. 0= S0_G is applied to all grid points NP included in the non-overlapping region NR. As a result, in the example shown in Figure 29, the color uniformity correction value S for the G component at all grid points NP is obtained. 0= The value of S0_G is the color unevenness correction value S of the G component of the grid points DP included in the superimposed region DR.0= This value is the same as the value of S0_G. In substep SS4[5'], the color unevenness correction value S for the G component of all grid points LP is determined. 0= The value of S0_G is determined. Note that S is the color unevenness correction value for the G component at the grid point NP adjacent to the grid point DP. 0= S0_G is the color uniformity correction value S for multiple grid point DPs that are subject to this processing. 0= It may also be used as the average value of S0_G. As shown in Figure 29, when substep SS4[5'] is completed, the color uniformity correction value S0, the brightness correction value C0, and the ideal output value A are determined. i Furthermore, regarding the color unevenness correction value S1, the value has been calculated for all grid points DP and NP.

[0109] In substep SS4[5'], the processing device 13 sets the R component color unevenness correction value S 0= S0_R and the color unevenness correction value S for component B. 0= Discard S0_B. This is because, as a characteristic of human vision, the contours of an image seen by the human eye are determined almost entirely by the G component among the R, G, and B components.

[0110] In substep SS4[6'] of Figure 28, the processing device 13 sets the color unevenness correction value S for the G component. 0= From S0_G and the brightness correction value C0=C0_G for the G component, the ideal output value A for the G component is obtained. i Recalculate _G. Specifically, the processing device 13 adds the color unevenness correction value S for the G component to Equation 2. 0= S0_G, the brightness correction value C0=C0_G for the G component, and the color uniformity correction value S for the G component. 1= Substituting S1_G into the following equation 9, the ideal output value A of the G component is obtained. i Calculate _G.

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[0111] Figure 30 shows the color uniformity correction value S0_G, brightness correction value C0, and ideal output value A in substep SS4[6'].i It is a diagram showing an example of the calculation status of the color unevenness correction value S1_G and _G. In FIG. 30, the ideal output value A i _G has changed from the initial value, and the corrected brightness in the overlapping region DR and the corrected brightness in the non-overlapping region NR are different from each other. As shown in FIG. 30, at the stage when the sub-step SS4[5‘] is completed, for the color unevenness correction value S0, the brightness correction value C0, the ideal output value A i and the color unevenness correction value S1, values are calculated for all the grid points DP and grid points NP.

[0112] In the sub-step SS4[7’] of FIG. 28, the processing device 13 calculates the ideal output value A i _R of the R component and the ideal output value A i _B of the B component again.

[0113] Specifically, the processing device 13 fixes the ideal output value A i [[ID=2I]]as the Yu’v’ value or RGB value, fixes the ideal output value A i _G calculated in the sub-step SS4[6’], and then recalculates the ideal output value A i _R and the ideal output value A i _B.

[0114] In the sub-step SS4[8’] of FIG. 28, the processing device 13 executes the same processing as the sub-steps SS4[3] to SS4[5] shown in FIG. 18 for the ideal output value A i _R calculated in the sub-step SS4[7’], and divides the ideal output value A i _R into the color unevenness correction value S0_R and the brightness correction value C0_R. The processing device 13 divides the ideal output value A i _B into the color unevenness correction value S0_B and the brightness correction value C0_B in the same way.

[0115] In step S5 of FIG. 4, the processing device 13 selects one set of correction values from the plurality of sets of correction values calculated in step S4.

[0116] For example, the processing unit 13 selects a set of correction values ​​based on information input by the user to the information processing unit 20. This information is, for example, first information indicating whether to prioritize the contrast ratio or the accuracy of correction of black color unevenness in the projected image PI_A. In this case, this information corresponds to the first parameter described above. Furthermore, as another example, the information provided in response to user input to the information processing device 20 may include second information indicating whether to prioritize brightness uniformity between the superimposed region DR and the non-superimposed region NR in the projected image PI_A, or to prioritize brightness flatness in each of the superimposed region DR and the non-superimposed region NR. In this case, this information corresponds to the second parameter described above. Note that the information provided in response to user input to the information processing device 20 may include both the first and second information.

[0117] Figure 31 shows an example of an operation screen OP1 displayed on an unshown display device that is provided with or communicated with the information processing device 20. For example, a touch panel is superimposed on the display device as an input device.

[0118] The operation screen OP1 includes radio buttons RB1 and RB2, selection buttons SB1 through SB4, first gauge GG1 and second gauge GG2, selection list SL1, display button DB1, and display button DB2. Users operate these controls by touching or clicking them using a touch panel or mouse. Hereafter, touching or clicking may be referred to as "operating."

[0119] Radio buttons RB1 and RB2 are buttons that select whether to display a preview image of the uncorrected projected image PI or a preview image of the corrected projected image PI. When radio button RB1 is selected, if the user touches or clicks display button DB2, the preview image PR of the uncorrected projected image PI is displayed on the projection surface SC. On the other hand, when radio button RB2 is selected, if the user operates display button DB1, the preview images PR of the nine corrected projected image PIs are displayed in a list on the projection surface SC. Also, when radio button RB2 is selected, if the user operates display button DB2, the preview image PR of the corrected projected image PI according to the correction method selected by selection buttons SB1 to SB4 is displayed individually on the projection surface SC. When radio button RB1 is selected, display button DB2 may be disabled, and the preview image PR of the uncorrected projected image PI may be displayed individually on the projection surface SC regardless of whether display button DB1 or display button DB2 is operated.

[0120] When display button DB1 or display button DB2 is operated, the processing unit 13 acquires information to select which projection image PI_A to display on the projection surface SC, either the projection image PI_A before correction or the projection image PI_A after correction, according to the selection results of radio buttons RB1 and RB2. The information indicating the selection results of radio buttons RB1 and RB2 is an example of "fifth information".

[0121] The selection buttons SB1 and SB2 are used to select the amount of "black level" in the projected image PI. When the user operates the selection button SB1, the identifier moves to the left in the first gauge GG1. When the user operates the selection button SB2, the identifier moves to the right in the first gauge GG1. The further left the identifier is positioned in the first gauge GG1, the less "black level" there is. The further right the identifier is positioned in the first gauge GG1, the more "black level" there is. In this embodiment, the identifier can take on three positions in the first gauge GG1: both ends and the center. The selection results from the selection buttons SB1 and SB2 correspond to the first parameter described above.

[0122] Based on the selection results from selection buttons SB1 and SB2, one set of correction values ​​is selected from a plurality of sets of correction values ​​for correcting the projected image PI_A. This set of correction values ​​is an example of "correction information".

[0123] As described above, the processing unit 13 determines the brightness of the black in the projected image PI1 in the superimposed region DR based on the first information.

[0124] The selection buttons SB3 and SB4 are used to select the degree to which the boundary between the superimposed region DR and the non-superimposed region NR is noticeable in the projected image PI. When the user operates the selection button SB3, the identifier moves to the left in the second gauge GG2. When the user operates the selection button SB4, the identifier moves to the right in the second gauge GG2. The further left the identifier is positioned in the second gauge GG2, the less pronounced the contour enhancement, resulting in a less noticeable boundary between the superimposed region DR and the non-superimposed region NR. The further right the identifier is positioned in the second gauge GG2, the greater the contour enhancement, resulting in a more noticeable boundary between the superimposed region DR and the non-superimposed region NR. In this embodiment, the identifier can take on three positions in the second gauge GG2: both ends and the center. The selection results from the selection buttons SB3 and SB4 correspond to the second parameter described above.

[0125] Based on the selection results from selection buttons SB3 and SB4, one set of correction values ​​is selected from a set of multiple correction values ​​to correct the projected image PI_A. This correction value is an example of "correction information".

[0126] As described above, the processing unit 13 performs corrections based on the first and second information to reduce the difference in black brightness between the superimposed region DR and the non-superimposed region NR, and to reduce color unevenness in the projected image PI_A.

[0127] As described above, when the user selects the amount of "black level" using selection buttons SB1 and SB2, and selects the degree to which the boundary between the superimposed area DR and the non-superimposed area NR is noticeable using selection buttons SB3 and SB4, and then operates the display button DB2, the first and second information are transmitted from the information processing device 20 to the projection device 10A. The processing device 13 acquires the first and second information. The processing device 13 generates a preview image PR of the projected image PI according to the first and second information and outputs it to the projector 11 and the information processing device 20. As a result, the preview image PR of the projected image PI corrected by the correction method selected by selection buttons SB1 to SB4 is displayed independently on the display device and the projection surface SC.

[0128] The selection list SL1 is a list for selecting the pattern image to be projected by the projection device 10. The selection list SL1 includes a white pattern, a black pattern, a gray bar, and a brown pattern. Here, the white pattern is a pattern for correcting color unevenness on the higher gradation side. The black pattern is an image that is entirely black and is used to perform the above correction. If nothing is selected in the selection list SL1, the image supplied by the information processing device 20 as an image supply device to the projection device 10A, or the black pattern, is projected. The multiple pattern images shown in the selection list SL1 are multiple candidates for the projected image PI_A. The information processing device 20 accepts the user's operation to select one pattern image from the selection list SL1. The information indicating that one pattern image is an example of "fourth information". The processing device 13 obtains the fourth information from the information processing device 20. The processing device 13 generates a preview image PR using the pattern image indicated by the fourth information.

[0129] Figure 32 shows an example of the operation screen OP2 displayed on the display device when the user operates the display button DB1 on the operation screen OP1 shown in Figure 31. The operation screen OP2 displays a list of preview images PR1 to PR9, which are displayed on the projection surface SC. The operation screen OP2 also includes a selection button DB3. Preview images PR1 to PR9 are also displayed on the projection surface SC in the same arrangement as in Figure 32. When displaying preview images PR1 to PR9 in a list, each of the preview images PR1 to PR9 may be generated using a single pattern image selected from the selection list SL1. As long as the user can recognize the visual differences between them, a schematic diagram that simply represents the differences between preview images PR1 to PR9 may also be used.

[0130] In Figure 32, comparing preview images PR1 to PR3, the boundary between the superimposed region DR and the non-superimposed region NR is most prominent in preview image PR1, and the boundary between the superimposed region DR and the non-superimposed region NR is least prominent in preview image PR3. The degree to which the boundary between the superimposed region DR and the non-superimposed region NR is prominent in preview image PR2 is intermediate between that of preview image PR1 and preview image PR3. Comparing preview images PR4 to PR6, the boundary between the superimposed region DR and the non-superimposed region NR is most prominent in preview image PR4, and least prominent in preview image PR6. The degree to which the boundary between the superimposed region DR and the non-superimposed region NR is prominent in preview image PR5 is intermediate between that of preview image PR4 and preview image PR6. Comparing preview images PR7 to PR9, the boundary between the superimposed region DR and the non-superimposed region NR is most prominent in preview image PR7, and the boundary between the superimposed region DR and the non-superimposed region NR is least prominent in preview image PR9. The degree to which the boundary between the superimposed region DR and the non-superimposed region NR is prominent in preview image PR8 is intermediate between that of preview image PR7 and preview image PR9.

[0131] Furthermore, comparing preview images PR1, PR4, and PR7 in Figure 32, the amount of "black level shift" is lowest in preview image PR1 and highest in preview image PR7. The amount of "black level shift" in preview image PR4 is intermediate between that of preview image PR1 and preview image PR7. Comparing preview images PR2, PR5, and PR8, the amount of "black level shift" is lowest in preview image PR2 and highest in preview image PR8. The amount of "black level shift" in preview image PR5 is intermediate between that of preview image PR2 and preview image PR8. Comparing preview images PR3, PR6, and PR9, the amount of "black level shift" is lowest in preview image PR3 and highest in preview image PR9. The amount of "black level shift" in preview image PR6 is intermediate between that of preview image PR3 and preview image PR9.

[0132] On the operation screen OP2, the user selects one preview image PR from preview images PR1 to PR9 and touches or clicks the selection button DB3. Then, as shown in Figure 33 below, the selected preview image PR is displayed alone. Furthermore, when the user operates the selection button DB3, the processing unit 13 obtains information to select one preview image PR from preview images PR1 to PR9. This information is an example of "sixth information".

[0133] Figure 33 shows an example of the operation screen OP3 displayed on the display device when the user operates the display button DB2 while radio button RB2 is selected on the operation screen OP1 shown in Figure 31. The operation screen OP3 displays the preview image PR10 of the projected image PI, which has been corrected as a result of the selections made by selection buttons SB1 to SB4 on the operation screen OP1, independently. The operation screen OP3 also includes a confirmation button DB4. The preview image PR10 is also displayed independently on the projection surface SC.

[0134] The user operates the confirmation button DB4 while the preview image PR10 is displayed. As a result of this operation, the correction method indicated by the preview image PR10 is confirmed. In this case, the processing unit 13 acquires information indicating that the confirmation button DB4 has been operated, and uses the above-mentioned first and second information as setting information to confirm when displaying the projected image PI_A. This information is an example of "third information". As a result, in step S5 of Figure 4, the brightness correction value C0 and color unevenness correction value S0 corresponding to the correction method are selected. The preview image PR10 displayed when radio button RB2 is selected is the corrected projected image PI. By displaying the corrected projected image PI before acquiring the third information, the user can confirm the correction result and then confirm the correction method.

[0135] Furthermore, as described above, if the user operates the display button DB2 on the operation screen OP1 shown in Figure 31, the operation screen OP3 shown in Figure 33 will also be displayed.

[0136] Furthermore, when preview images PR1 to PR10 shown in Figures 32 and 33 are projected onto the projection surface SC, it is preferable that images different from preview images PR1 to PR10, such as OSD (On Screen Display) images from projection devices 10A to 10C, are not superimposed on the preview images PR1 to PR10 on the projection surface SC. Note that these OSD images are images generated by projection devices 10A to 10C.

[0137] In this case, as an example, the information processing device 20 sends a control signal to the projection devices 10A to 10C instructing them not to superimpose the OSD images onto the preview images PR1 to PR10. Furthermore, it is preferable that the information processing device 20 sends the same control signal to the projection devices 10A to 10C as a trigger when the operation screen OP1 is displayed. Alternatively, the information processing device 20 may send a control signal to the projection devices 10A to 10C instructing them not to send any notifications to the projection surface SC.

[0138] Furthermore, when the OSD image is displayed on the projection surface SC, it is preferable that it is displayed darker than preview images PR1 to PR10. More specifically, as an example, it is preferable that the average brightness of the entire OSD image is lower than the average brightness of the entire preview images PR1 to PR10.

[0139] Furthermore, when projection devices 10A to 10C display a preview image PR on the projection surface SC, it is preferable to display the preview image PR with the same size and shape as the projected image PI_A. This allows the user to more accurately perceive the appearance of the projected image PI_A than when a smaller preview image PR is displayed. When a smaller preview image PR is displayed, it is preferable to lower the brightness of the area of ​​the projected image PI_A other than the preview image PR, and it is even preferable to set the brightness to 0.

[0140] In step S6 of Figure 4, the processing unit 13 provided in the projection device 10A functions as a correction value calculation unit 134. The processing unit 13 sets the brightness correction value C0 selected in step S5 to the brightness correction circuit LC and the color uniformity correction value S0 to the color uniformity correction circuit UC.

[0141] In Figure 2, when the brightness correction circuit LC receives the grayscale value of each pixel in the image acquired by the image acquisition unit 135, it calculates a grayscale value to output to the color unevenness correction circuit UC using the brightness correction value C0. When the color unevenness correction circuit UC receives the grayscale value calculated by the color unevenness correction circuit UC, it outputs the color unevenness correction circuit A based on the color unevenness correction value S0. u Output. Output value A u This is the grayscale value and is input to the projection control unit 131. The projection control unit 131 outputs value A u The signal is converted into a control signal to drive the LCD panel and output to the projector 11. As a result, the projector 11 projects a projected image PI onto the projection surface SC, with corrections made for black color unevenness and "black floating".

[0142] In the above embodiment, however, only the correction value for black is calculated as one of several sets of correction values.

[0143] 1-3: Appendix (Method for calculating ideal output values) Figure 34 is a flowchart of substeps SS4[1]_1 to SS4[1]_7 that constitute substep SS4[1]. In the flowchart shown in Figure 34, the processing unit 13 first sets the ideal output value A of the superimposed region DR. i After calculating the above, the processing unit 13 calculates target values ​​for brightness and chromaticity of the non-overlapping region NR. Then, based on the calculated target values, the processing unit 13 calculates the ideal output value A in the non-overlapping region NR. i Calculate. For the sake of simplicity, the following explanation assumes an ideal output value A at grid point LP contained in the projected image PI2. i Only the calculation method will be explained. However, the ideal output value A at grid point LP included in projected images PI1 and PI3 will not be explained. i The calculation method is basically the same.

[0144] In substep SS4[1]_1, the processing unit 13 assumes that the target brightness and chromaticity in the superimposed region DR have already been determined by a known method, and sets an ideal output value A at the grid point DP included in the superimposed region DR. i The processing unit 13 calculates the ideal output value A. i Known methods may be used to calculate this.

[0145] Specifically, the processing unit 13 predetermines the target gradation value for the superimposed region DR. For each grid point DP of the superimposed region DR shown in Figures 5 to 7, the processing unit 13 calculates the brightness component Y as a target value from the determined gradation value. This "brightness component Y as a target value" is the brightness component Y used to correct the "black level lift" mentioned above.

[0146] The processing unit 13 calculates a target brightness component Y for each grid point DP. Specifically, even if brightness unevenness originally exists within the superimposed region DR, the processing unit 13 does not uniformly adjust the brightness unevenness within the superimposed region DR, but rather calculates a target brightness component Y for each grid point DP. If the processing unit 13 were to uniformly adjust the brightness unevenness, it would be necessary to lower the brightness at each grid point DP, which would reduce the number of gradation steps that can be corrected at each grid point DP. The reason the processing unit 13 pre-determines a target brightness component Y for each grid point DP is to ensure that the minimum correction amount is sufficient to uniformly remove color unevenness at each grid point DP as described above.

[0147] Furthermore, the processing unit 13 predetermines the chromaticity component u'v' as the target chromaticity value for the superimposed region DR. This "target chromaticity component u'v'" is the chromaticity component u'v' used as the target value for correcting the color unevenness mentioned above. The processing unit 13 determines the same target chromaticity component u'v' for all superimposed regions DR based on the average chromaticity among the three projectors 10 (projector 10A, projector 10B, and projector 10C), the average chromaticity in each projector 10, the chromaticity design value of each projector 10 at the time of product shipment, etc. In this case, after correction, all superimposed regions DR will have the same chromaticity. Alternatively, the processing unit 13 determines the chromaticity component u'v' as the same target value within each superimposed region DR based on the above parameters. In this case, after correction, the chromaticity will be the same within each superimposed region DR. As a result, color unevenness in the superimposed DR region is corrected.

[0148] The processing unit 13 converts the target value Yu'v' value, which consists of the brightness component Y and the chromaticity component u'v', at each grid point DP within the superimposed region DR, into an RGB value. Furthermore, the processing unit 13 inversely calculates the target gradation value (r,g,b) to be output from the correction unit 136 to the projector 11 using the converted RGB value. The processing unit 13 then determines this to be the ideal output value A that should be output from the correction unit 136 to the projector 11. i Therefore, in this section, the ideal output value Ai represents the target grayscale values ​​(r, g, b).

[0149] Figure 35 shows an example of the target grayscale value (r,g,b) at the grid point DP calculated by the processing unit 13. In Figure 35, an example of the value of one of the r, g, and b components included in the grayscale value (r,g,b) is shown. Figure 35 corresponds to the projected image PI2 shown in Figure 6. Furthermore, each rectangle shown in Figure 35 represents a portion PT of the projected image PI, including each grid point LP shown in Figure 6. Region RL1 includes multiple portions PT11. Region RL3 includes multiple portions PT31. Region RL4 includes multiple portions PT41. The numerical values ​​inside the rectangle above represent the values ​​of one of the r, g, and b components included in the target grayscale value (r, g, b). For the sake of simplicity, the values ​​in Figure 35 are shown as integers, but in reality, they may be decimals. The same applies to the values ​​shown below.

[0150] Furthermore, among the rectangles shown in Figure 35, those with double borders correspond to lattice point DP. As described above, lattice point DP is lattice point LP included in the superposition region DR. Rectangles with single borders correspond to lattice point NP. As described above, lattice point NP is lattice point LP included in the non-superposition region NR. Rectangles with double borders, one of which is a dotted line, correspond to lattice point PP. As described above, lattice point PP is lattice point LP that could not be determined to belong to either the superposition region DR or the non-superposition region NR.

[0151] In substep SS4[1]_2 of Figure 34, the processing unit 13 determines the target gradation values ​​(r,g,b) at the grid point NP such that the brightness and color are matched between the grid point DP belonging to the superimposed region DR and the grid point NP belonging to the non-superimposed region NR, which are adjacent to each other across the boundary between the superimposed region DR and the non-superimposed region NR.

[0152] The target grayscale value (r,g,b) at the grid point NP is calculated based on the target grayscale value (r,g,b) at the grid point DP. The specific calculation method is described below.

[0153] In Figure 35, lattice point DP1 is an example of lattice point DP. Similarly, lattice point NP1 is an example of lattice point NP. Lattice points DP1 and NP1 are adjacent to each other, separated by the boundary between the superposition region DR and the non-superposition region NR.

[0154] In Figure 35, the grayscale values ​​(r,g,b) of grid point DP1 have already been calculated. The processing unit 13 estimates the RGB values ​​as measured values ​​by the imaging device 12 based on these grayscale values ​​(r,g,b). The processing unit 13 also converts the estimated RGB values ​​as measured values ​​into XYZ values. Furthermore, the processing unit 13 applies the above equation 1 to the converted XYZ values ​​to further convert the converted XYZ values ​​into Yu'v' values.

[0155] As a result, the Yu'v' value of grid point DP1 is calculated, and the processing unit 13 uses this Yu'v' value as the target Yu'v' value for grid point NP1. Furthermore, the processing unit 13 calculates the grayscale values ​​(r, g, b) of the target value for grid point NP1 based on this target Yu'v value.

[0156] In Figure 35, region RL3 includes multiple intermediate portions CP between the first adjacent portion GP1 and the second adjacent portion GP2.

[0157] For the sake of simplicity, the following explanation will focus on the brightness target value among the target values ​​for grid point NP1. Since the method for calculating the chromaticity target value is the same as that for the brightness target value, the explanation regarding the brightness target value also applies to the chromaticity target value.

[0158] When the brightness of grid point NP1 reaches the target value, the processing unit 13 calculates a grayscale value t as the target grayscale value (r,g,b) for grid point NP such that the r, g, and b components are (r,g,b)=(t,t,t). Specifically, the processing unit 13 calculates a grayscale value t such that when gray light is projected from the projector 11, the brightness at grid point DP1 and grid point NP1 are the same.

[0159] Figure 36 shows an example of the target grayscale value (r,g,b) at grid point DP and the target grayscale value t at grid point NP adjacent to the boundary between the superimposed region DR and the non-superimposed region NR. Furthermore, without correction, the non-overlapping region NR will be darker than the overlapping region DR. Therefore, in order to make the brightness component Y the same for both the overlapping region DR and the non-overlapping region NR after correction, it is necessary to make the target tonal value t at grid point NP larger than the target tonal value (r,g,b) at grid point DP.

[0160] In substep SS4[1]_3 of Figure 34, the processing unit 13 calculates a further target grayscale value t for a grid point NP by averaging the target grayscale value t of a grid point NP calculated in substep SS4[1]_2 with the target grayscale value t of an adjacent grid point NP.

[0161] Specifically, for a grid point NP whose target grayscale value t is undetermined, the processing unit 13 calculates the average value of the target grayscale values ​​t of at least one of the adjacent grid points NP (up, down, left, or right) whose target grayscale value t is determined. The processing unit 13 then sets the calculated average value as the target grayscale value t for the grid point NP whose target grayscale value t is undetermined.

[0162] Figures 37 and 38 show examples of methods for determining the target grayscale value t for a grid point NP whose target grayscale value t is undetermined.

[0163] In Figure 37, grid point NP2, whose target grayscale value t is undetermined, is located at the edge of the non-overlapping region NR. In this case, there are five grid points NP adjacent to grid point NP2: grid points NP3 to NP7. Of these grid points NP3 to NP7, grid point NP3 is set to a target grayscale value t=52. Grid point NP4 is set to a target grayscale value t=51. On the other hand, grid points NP5 to NP7 do not have a target grayscale value t set. Therefore, the processing unit 13 sets the average value of the target grayscale value t=52 of grid point NP3 and the target grayscale value t=51 of grid point NP4 as the target grayscale value t of grid point NP2.

[0164] In Figure 38, grid point NP8, whose target tone value t is undetermined, is located inside the non-overlapping region NR. In this case, there are eight grid points NP adjacent to grid point NP8: grid points NP9 to NP16. Of these eight grid points NP, grid point NP9 is set to a target tone value t=52. Grid point NP10 is set to a target tone value t=51. Grid point NP11 is set to a target tone value t=52. On the other hand, grid points NP12 to NP16 do not have a target tone value t set. Therefore, the processing unit 13 sets the average value of the target tone value t=52 for grid point NP9, the target tone value t=51 for grid point NP10, and the target tone value t=52 for grid point NP11 as the target tone value t for grid point NP8.

[0165] In substep SS4[1]_4 of Figure 34, the processing unit 13 determines whether the target grayscale value t has been calculated for all grid points NP included in the non-overlapping region NR. If the target grayscale value t has been calculated for all grid points NP in the non-overlapping region NR ("YES" in substep SS4[1]_4), the processing unit 13 executes the process in substep SS4[1]_5. On the other hand, if the target grayscale value t has not been calculated for all grid points NP in the non-overlapping region NR ("NO" in substep SS4[1]_4), the processing unit 13 executes the process in substep SS4[1]_4.

[0166] As a result, the processing unit 13 sequentially extends the grid points NP used to calculate the target grayscale value t into the interior of the non-overlapping region NR.

[0167] Figures 39 to 41 show examples of the calculation status of the target tone value t. More specifically, Figure 39 shows the calculation status of the target tone value t for grid points NP adjacent to the boundary between the superimposed region DR and the non-superimposed region NR, in the direction inward of the non-superimposed region NR, compared to the state in Figure 38. Figure 40 shows the calculation status of the target tone value t for grid points NP adjacent to the direction inward of the non-superimposed region NR, for grid points NP for which the target tone value t has been newly calculated in Figure 39. Figure 41 shows the state in which the target tone value t has been calculated for all grid points NP.

[0168] In substep SS4[1]_5 of Figure 34, the processing unit 13 repeatedly smooths the target grayscale values ​​t of the calculated target grayscale values ​​t of grid points NP other than those adjacent to the boundary between the superimposed region DR and the non-superimposed region NR. Specifically, for grid points NP other than those adjacent to the boundary, the processing unit 13 smooths using the target grayscale values ​​t of valid grid points NP among the grid points NP adjacent to it in the upper, lower, left, and right directions.

[0169] As shown in Figure 41, when the processing unit 13 calculates the target tone value t of a grid point NP, it sequentially calculates the target tone value t of adjacent grid points NP to the right, starting from the first superimposed region DR, region RL1, inside the non-superimposed region NR. In parallel with this, the processing unit 13 sequentially calculates the target tone value t of adjacent grid points NP to the left, starting from the second superimposed region DR, region RL4, inside the non-superimposed region NR. As a result, in Figure 41, as an example, a large difference occurs between the target tone value t=45 of grid point NP17 and the target tone value t=41 of grid point NP18, which is adjacent to grid point NP17. In other words, there is a step between the target tone value t=45 of grid point NP17 and the target tone value t=41 of grid point NP18.

[0170] The processing unit 13 eliminates the step difference in the interpolated target values ​​and performs the smoothing described above so that the target values ​​of the grid points NP included in the non-overlapping region NR are smoothly connected from region RL1, which is the first superimposed region DR, to region RL4, which is the second superimposed region DR. As a result, as described later, the distribution of the grayscale value t, which is a parameter that defines the brightness of region RL3, a non-overlapping region NR, becomes a continuous or stepped distribution in the direction from region RL1 to region RL4.

[0171] Figures 42 and 43 show examples of smoothing. Figure 42 corresponds to Figure 37. Figure 43 corresponds to Figure 38.

[0172] In Figure 42, the processing unit 13 smooths the target gradation value t=51 at grid point NP2 using the target gradation values ​​t=52 at grid point NP3, t=51 at grid point NP4, t=51 at grid point NP5, t=50 at grid point NP6, and t=50 at grid point NP7.

[0173] In Figure 43, the processing unit 13 smooths the target tone value t=51 at grid point NP8 using the target tone value t=52 at grid point NP9, the target tone value t=51 at grid point NP10, the target tone value t=52 at grid point NP11, the target tone value t=51 at grid point NP12, the target tone value t=50 at grid point NP13, the target tone value t=50 at grid point NP14, the target tone value t=50 at grid point NP15, and the target tone value t=51 at grid point NP16.

[0174] In substep SS4[1]_6 of Figure 34, the processing unit 13 determines whether the range of change in the target grayscale value t of the grid point NP is below a threshold before and after smoothing. More specifically, the processing unit 13 determines whether the sum of the ranges of change in the target grayscale value t of all grid points NP is below a threshold. If the sum of the ranges of change in the target grayscale value t of all grid points NP is below a threshold ("YES" in substep SS4[1]_6), the processing unit 13 executes the process in substep SS4[1]_7. On the other hand, if the sum of the ranges of change in the target grayscale value t of all grid points NP exceeds a threshold ("NO" in substep SS4[1]_6), the processing unit 13 executes the process in substep SS4[1]_5.

[0175] In other words, the processing unit 13 repeats the smoothing process until the sum of the changes in the target grayscale value t for all grid points NP falls below a threshold.

[0176] Figures 44 to 46 show examples of the smoothing process of the target tone value t. More specifically, Figure 44 shows an example of the target tone value t after the first smoothing process. Figure 43 shows an example of the target tone value t after the second smoothing process. Figure 44 shows an example of the target tone value t after the 18th smoothing process. Note that smoothing is considered complete after the 18th smoothing process shown in Figure 44.

[0177] As is clear from comparing Figures 44 to 46, the more times the smoothing process is performed, the smaller the difference in target grayscale values ​​t between adjacent grid points NP becomes overall.

[0178] Figure 47 shows a three-dimensional representation of the target grayscale value t for each grid point NP before smoothing. Figure 48 shows a three-dimensional representation of the target grayscale value t for each grid point NP after smoothing is complete. In both Figures 47 and 48, the x-axis indicates the column position of the grid point NP, the y-axis indicates the row position of the grid point NP, and the z-axis indicates the target grayscale value t. As is clear from comparing Figure 47 and Figure 48, after smoothing is complete, the steps in the target grayscale value t are eliminated compared to before smoothing.

[0179] In substep SS4[1]_7 of Figure 34, the processing unit 13 functions as a correction value calculation unit 134. The processing unit 13 calculates the target gradation values ​​(r,g,b) at the grid point NP included in the non-overlapping region NR.

[0180] As described above, the processing unit 13 determines the target gradation value (t,t,t) of brightness at the grid point NP after smoothing is completed by processing up to substep SS4[1]_6. Based on the gradation value (t,t,t), the processing unit 13 calculates the target gradation value (r,g,b) at the grid point NP. The processing unit 13 may use a known method as the method for calculating the target gradation value (r,g,b).

[0181] Specifically, the processing unit 13 calculates the brightness component from the grayscale value (t,t,t). The processing unit 13 sets the calculated brightness component as the brightness component Y of the target value.

[0182] Furthermore, the processing unit 13 determines the chromaticity component u'v' of the target value in the same manner as the brightness component Y of the target value at the grid point NP, as described above.

[0183] The processing unit 13 converts the Yu'v' value, which is the target value at each grid point NP in the non-overlapping region NR, into RGB values. Furthermore, the processing unit 13 inversely calculates the target gradation values ​​(r,g,b) that are output from the correction unit 136 to the projector 11 using the converted RGB values.

[0184] The processing unit 13 outputs the target grayscale values ​​(r, g, b) at each grid point DP and each grid point NP to an ideal output value A. i Let's assume that.

[0185] 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.

[0186] 2-1: Variation 1 In the above embodiment, the processing unit 13 corrected the black color in the projected image PI_A when tiling display was performed using multiple projection devices 10, from projection devices 10A to projection devices 10C. However, the processing unit 13 may also perform the correction method included in the above embodiment when projecting the image PI1 from only a single projection device 10A.

[0187] Specifically, when the processing unit 13 projects the projected image PI1 from only a single projection device 10A, it may execute a correction method other than the correction method for correcting the difference in brightness between the superimposed region DR and the non-superimposed region NR, which is included in the above embodiment.

[0188] 2-2: Variation 2 In the above embodiment, operation screens OP1 to OP3 were displayed on a display device provided with the information processing device 20, or connected to the information processing device 20 in a communicative manner. However, operation screens OP1 to OP3 may also be displayed on the projection surface SC by the projection device 10A. In this case, it is preferable for the user to perform the above operations using, for example, a remote control attached to the projection device 10A.

[0189] In this case, the following displays and controls may also be performed. First, the projection device 10A displays the selection list SL1 and accepts the user's selection of one pattern image. Once one pattern image is selected, projection devices 10A to 10C project only that one pattern image onto the projection surface SC. The case of displaying an OSD image is as described above. Next, when the processing device 13 receives an operation of the directional keys on the remote control, the projection devices 10A to 10C sequentially display preview images PR1 to PR9 on the projection surface SC according to the operation of the directional keys. For example, the processing device 13 may sequentially display preview images PR1 to PR9 according to the operation of the left and right keys. Also, as an example, the processing device 13 may change the first parameter with the up and down keys and change the second parameter with the left and right keys. When the processing device 13 receives an operation of the OK button on the remote control, it confirms that it will apply the correction value indicated by the preview image PR that was displayed when the OK button was pressed. Furthermore, if the back button on the remote control is pressed while the preview image PR is displayed, the processing unit 13 displays the selection list SL1.

[0190] 2-3: Variation 3 In the above embodiment, the first information specifying whether to prioritize correction of the contrast ratio of the projected image PI_A or the color unevenness of the projected image PI_A was information corresponding to user input using the information processing device 20. However, the first information may also be based on the brightness of the environment in which the projected image PI_A is projected, and at least one of the brightness or chromaticity of the projected image PI_A. In this case, the processing device 13 autonomously determines whether to prioritize correction of the contrast ratio of the projected image PI_A or the color unevenness of the projected image PI_A based on this information, and automatically selects one set of correction values ​​from a plurality of sets of correction values. The method by which the processing device 13 automatically selects one set of correction values ​​will be described below.

[0191] The processing unit 13 may automatically select a set of correction values ​​only once, depending on the environment in which the projection device 10A is installed.

[0192] First, regarding whether to prioritize the accuracy of color unevenness correction or the contrast ratio, the processing unit 13 prioritizes the accuracy of color unevenness correction and selects a set of correction values ​​when the ambient light is bright. This is because when the ambient light is bright, the contrast ratio is already reduced due to the influence of the ambient light, so even if the degree of "black level distortion" is high, it will not be noticeable. On the other hand, when the ambient light is dark, the processing unit 13 prioritizes the contrast ratio and selects a set of correction values. In the above example, if the ambient light is 1 lux or more, it will be considered that "the ambient light is bright."

[0193] Furthermore, regarding whether to prioritize brightness uniformity between the superimposed region DR and the non-superimposed region NR, or brightness flatness in each of the superimposed region DR and the non-superimposed region NR, the processing unit 13 prioritizes brightness flatness when the luminance at the boundary between the superimposed region DR and the non-superimposed region NR differs depending on the location. Specifically, if the difference between the maximum and minimum values ​​of the brightness correction value C0 is greater than or equal to a threshold, the processing unit 13 prioritizes brightness flatness. On the other hand, in all other cases, the processing unit 13 prioritizes brightness uniformity.

[0194] Alternatively, the processing unit 13 may automatically select a set of correction values ​​only once, based on at least one of the brightness or chromaticity of the projected image PI_A of the input image.

[0195] First, regarding whether to prioritize the accuracy of color unevenness correction or the contrast ratio, the processing unit 13 prioritizes the accuracy of color unevenness correction when the distribution of statistical values ​​of the brightness or chromaticity of the input image is narrow, that is, when the input image is uniform content. This is because when the input image is uniform content, brightness differences and color unevenness at the boundaries mentioned above tend to be more noticeable. On the other hand, when the distribution of statistical values ​​of the brightness or chromaticity of the input image is wide, the processing unit 13 prioritizes the contrast ratio. This is because when the input image is non-uniform content, brightness differences and color unevenness at the boundaries mentioned above tend to be less noticeable.

[0196] In addition, when calculating the above statistical values, the measurement target is the entire projection image PI_A as the input image, but the part where the output value is from gradation 0 to gradation 146 is focused on. Also, specific examples of the statistics that are the basis of the statistical values are the luminance histogram or the chrominance histogram. When using the luminance histogram as the statistic, the above "the distribution of the statistical values of luminance is narrow" means that there are 50% or more pixels whose output value is less than gradation 146. On the other hand, "the distribution of the statistical values of luminance is wide" means that there are less than 50% pixels whose output value is less than gradation 146. Regarding the distribution of the statistical values of chrominance, it is preferable to classify single-color patterns and black-and-white images as uniform contents, and landscape paintings and the like as non-uniform contents.

[0197] Also, regarding whether to prioritize the brightness uniformity between the overlapping region DR and the non-overlapping region NR or prioritize the flatness of the brightness in each of the overlapping region DR and the non-overlapping region NR, when the distribution of the statistical values of the luminance or chrominance of the input image is narrow, that is, when the input image has uniform content, the processing device 13 prioritizes the flatness of the brightness. On the other hand, when the distribution of the statistical values of the luminance or chrominance of the input image is wide, that is, when the input image has non-uniform content, the processing device 13 prioritizes the brightness uniformity.

[0198] 2-4: Modified Example 4 In the above embodiment, the processing device 13 provided in the projection device 10A operates as the projection control unit 131, the imaging control unit 132, the image analysis unit 133, the correction value calculation unit 134, the image acquisition unit 135, the correction unit 136, and the communication control unit 137. However, instead of the projection device 10A, the information processing device 20 may execute the above correction method by operating as at least one or more of these components.

[0199] 2-5: Modified Example 5 In the above embodiment, the operation screen OP1 included the display button DB1. However, the operation screen OP1 may not include the display button DB1. In this case, a list display of the preview images PR1 to PR9 such as the operation screen OP2 is not performed. Each time the display button DB2 is operated, the processing device 13 projects a preview image PR corresponding to the selection results of the radio button RB1, the radio button RB2, the selection buttons SB1 to SB4, and the selection list SL1 onto the projection surface SC alone.

[0200] 2-6: Modification Example 6 In the above embodiment, the operation screen OP1 included the display button DB1 and the display button DB2. However, the operation screen OP1 may not include the display button DB1 and the display button DB2. In this case, each time any one of the radio button RB1, the radio button RB2, the selection buttons SB1 to SB4, and the selection list SL1 is operated, the information processing device 20 transmits information corresponding to the operation to the processing device 13. Each time the processing device 13 acquires information corresponding to the operation from the information processing device 20, it displays one preview image PR corresponding to the information on the projection surface SC. The operation screen OP1 includes an OK button DB4 as shown in FIG. 45. When the user operates the OK button DB4, the processing device 13 determines to apply the correction value indicated by the preview image PR displayed when the OK button DB4 was operated.

[0201] 3: Summary of the Present Disclosure Hereinafter, a summary of the present disclosure will be appended.

[0202] (Note 1) An image correction method comprising: acquiring one of a plurality of correction pieces of information for correcting a third image based on first information indicating which of the following should be prioritized: the contrast ratio of a third image having a first region in which a first image projected by a first projection device onto a projection surface and a second image projected by a second projection device onto the projection surface overlap, and a second region in which the first image and the second image do not overlap, and the color unevenness of the third image; and performing correction based on the one correction piece of information to reduce the difference in brightness of black on the projection surface between the first region and the second region, and the color unevenness in the third image.

[0203] The image correction method described in Appendix 1 performs correction using one of several correction pieces of information, based on first information indicating whether to prioritize the contrast ratio of the third image or the color unevenness of the third image. Compared to the case where there is only one way to correct, this method allows for the display of images of preferred quality depending on the operating environment of the projection device and the type of projected content.

[0204] More specifically, the image correction method of this embodiment determines the correction value based on the selection results of multiple options with different black brightness levels and multiple options with different prominence of the boundary between the superimposed region DR and the non-superimposed region NR in tiling display, thereby enabling the display of images with better quality.

[0205] Furthermore, according to the image correction method described in Appendix 1, when the appropriate algorithm for calculating the correction value differs depending on the user's usage environment and purpose, the user can select the optimal correction value. In particular, the user can select the optimal correction value depending on whether they prioritize contrast ratio or accuracy in correcting black color unevenness.

[0206] (Note 2) The first information is information corresponding to user input, and the image correction method is as described in Note 1.

[0207] The image correction method described in Appendix 2, having the above configuration, allows the user to choose whether to prioritize the contrast ratio or the accuracy of correcting black color unevenness, depending on their input.

[0208] (Note 3) The first information is the brightness of the environment on which the third image is projected, and the chromaticity, which is information based on at least one of the brightness or chromaticity of the third image, and the image correction method described in Note 1 or 2.

[0209] The image correction method described in Appendix 3, having the above configuration, allows the projection device 10 to automatically select whether to prioritize the contrast ratio or the accuracy of correcting black color unevenness.

[0210] (Appendix 4) An image correction method according to any one of Appendix 1 to 3, further comprising: determining the brightness of black in the first image in the first region corresponding to the first information; calculating a first color unevenness correction value for the first image in the first region for correcting the color unevenness based on the brightness of black in the first image; calculating a brightness correction value for the first image in the second region for reducing the difference in the brightness of black based on the first color unevenness correction value, and a second color unevenness correction value for the first image in the second region for correcting the color unevenness, wherein the correction includes correcting the first image based on the first color unevenness correction value, the brightness correction value, and the second color unevenness correction value.

[0211] The image correction method described in Appendix 4, having the above configuration, can correct the difference in brightness between the superimposed region DR and the non-superimposed region NR within the projected image PI_A, as well as color unevenness within the projected image PI_A.

[0212] (Note 5) The image correction method according to any one of Notes 1 to 4, wherein acquiring the correction information includes acquiring one of the plurality of correction information based on the first information and second information indicating the degree to which the boundary between the first region and the second region is noticeable in the third image.

[0213] By having the above configuration, the image correction method of Supplementary Note 5 can correct the brightness difference between the overlapping region DR and the non-overlapping region NR in the projection image PI_A and the color unevenness in the projection image PI_A according to the degree to which the boundary between the overlapping region DR and the non-overlapping region NR is prominent.

[0214] (Supplementary Note 6) Further including acquiring third information for determining the first information and the second information as setting information when displaying the third image, and the correction includes displaying the third image that has been corrected before acquiring the third information. The image correction method of Supplementary Note 5.

[0215] By having the above configuration, the image correction method of Supplementary Note 6 can display the preview image PR before determining the correction method.

[0216] (Supplementary Note 7) Displaying the third image that has been corrected before acquiring the third information includes not overlapping an image different from the third image with the third image. The image correction method of Supplementary Note 6.

[0217] By having the above configuration, the image correction method of Supplementary Note 7, as an example, the OSD image is not overlapped with the preview image PR. As a result, the visibility of the preview image PR is enhanced.

[0218] (Supplementary Note 8) Displaying the third image that has been corrected before acquiring the third information is to display an image that is entirely black. The image correction method of Supplementary Note 6 or Supplementary Note 7.

[0219] By having the above configuration, the image correction method of Supplementary Note 8 allows the user of the projection device 10A to confirm the black correction using the black pattern.

[0220] (Note 9) An image correction method according to Note 6 or Note 7, further comprising obtaining fourth information for selecting one image from a plurality of candidates for the third image, wherein displaying the corrected third image before obtaining the third information means displaying the corrected single image.

[0221] The image correction method described in Appendix 9, having the above configuration, allows the user to select one preview image PR from multiple preview images PR.

[0222] (Note 10) The image correction method according to any one of Notes 1 to 9, further comprising obtaining fifth information for selecting which of the third image before correction and the third image after correction to display, wherein the correction includes displaying one of the third image before correction and the third image after correction based on the fifth information.

[0223] The image correction method described in Appendix 10, having the above configuration, allows the user of the projection device 10A to select either the projected image PI_A before correction or the projected image PI_A as a preview image PR after correction.

[0224] (Note 11) A program that causes a processor to perform the following actions: firstly,

[0225] The program described in Appendix 11, having the above configuration, can display images of a desirable quality depending on the operating environment of the projection device and the type of projected content.

[0226] More specifically, the program of this embodiment determines a correction value based on the selection results of multiple options with different black brightness levels and multiple options with different prominence of the boundary between the superimposed region DR and the non-superimposed region NR in tiling display, thereby enabling the display of images with better quality.

[0227] Furthermore, according to the program described in Appendix 11, when the appropriate algorithm for calculating the correction value differs depending on the user's usage environment and purpose, the user can select the optimal correction value. In particular, the user can select the optimal correction value depending on whether they prioritize the accuracy of black color unevenness correction or the contrast ratio. [Explanation of Symbols]

[0228] 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...Information processing device, 131...Projection control unit, 132...Imaging control unit, 133...Image analysis unit, 134...Correction value calculation unit, 135...Image acquisition unit, 136...Correction unit, 137...Communication control unit, BD...Boundary line, C0...Brightness correction value, C0_B...Brightness correction value, C0_R...Brightness correction value, CP...Intermediate part, DB1...Display button, DB2...Display button, DB3...Selection button, DB4...Confirm button, DD...Step, DP...Grid Point, DR...Superimposed area, GG1...First gauge, GG2...Second gauge, GP1...First adjacent area, GP2...Second adjacent area, LA...Brightness correction value, LC...Brightness correction circuit, LN...Communication line, LP...Grid point, NP...Grid point, NR...Non-superimposed area, OP1...Operation screen, OP2...Operation screen, OP3...Operation screen, PG1...Control program, PI...Projected image, PP...Grid point, PR...Preview image, PT...Part, RB1...Radio button, RB2...Radio button, RL...Area, S0...Correction value, S1...Correction value, SC...Projection surface, SL1...Selection list, UA...Correction value, UC...Color unevenness correction circuit, XYZ...Output value, Y...Brightness component

Claims

1. Based on first information indicating which of the following should be prioritized for correcting the third image, which has a first region where the first image projected by the first projection device onto the projection surface and the second image projected by the second projection device onto the projection surface overlap, and a second region where the first image and the second image do not overlap, one correction information is obtained from among a plurality of correction information for correcting the third image. This includes performing a correction based on the aforementioned correction information to reduce the difference in brightness of black on the projection surface between the first region and the second region, and the color unevenness in the third image, Image correction methods.

2. The aforementioned first information is information that corresponds to the user's input. The image correction method according to claim 1.

3. The first information is information based on the brightness of the environment on which the third image is projected, and at least one of the brightness or chromaticity of the third image. The image correction method according to claim 1.

4. To determine the brightness of the black in the first image in the first region, corresponding to the first information, Based on the brightness of the black in the first image, a first color unevenness correction value is calculated for the first image in the first region to correct the color unevenness. Based on the first color unevenness correction value, A brightness correction value for the first image in the second region, for performing brightness correction to reduce the difference in brightness of the black area, A second color unevenness correction value of the first image in the second region for correcting the aforementioned color unevenness, This includes calculating and further including, Making the aforementioned correction means This includes correcting the first image based on the first color unevenness correction value, the brightness correction value, and the second color unevenness correction value. The image correction method according to claim 1.

5. Acquiring the correction information includes, in the third image, acquiring one of the plurality of correction pieces of information based on second information indicating the degree to which the boundary between the first region and the second region is noticeable, and the first information. The image correction method according to claim 1.

6. The process further includes obtaining a third piece of information which determines the first piece of information and the second piece of information as setting information for displaying the third image, Performing the correction includes displaying the corrected third image before acquiring the third information. The image correction method according to claim 5.

7. Displaying the corrected third image before acquiring the third information includes not superimposing an image different from the third image onto the third image. The image correction method according to claim 6.

8. Displaying the corrected third image before acquiring the third information means displaying an image that is entirely black. The image correction method according to claim 6 or claim 7.

9. The process further includes obtaining fourth information for selecting one image from a plurality of candidates for the third image, Displaying the corrected third image before acquiring the third information is equivalent to displaying the corrected single image. The image correction method according to claim 6 or claim 7.

10. The method further includes obtaining fifth information for selecting which of the third image before the correction is made and the third image after the correction is made to display, The correction includes, based on the fifth information, displaying either the third image before the correction or the third image after the correction has been made. The image correction method according to claim 1.

11. Based on first information indicating which of the following should be prioritized for correcting the third image, the third image has a first region where the first image projected by the first projection device onto the projection surface and the second image projected by the second projection device onto the projection surface overlap, and a second region where the first image and the second image do not overlap, first information is obtained to select one of a plurality of correction pieces of information for correcting the third image. Based on the aforementioned correction information, the processor is instructed to perform corrections to reduce the difference in brightness of black on the projection surface between the first and second regions, and to reduce color unevenness in the third image. program.

Images