Control method, projection device, and program product

Abstract

Control method, projection device, and program product. Color unevenness is properly corrected. The control method is a control method of at least one projection device capable of projecting a plurality of images different in luminance, the control method including: acquiring chromaticities that make luminances of a plurality of correction target points each become a target value; setting a target chromaticity as a chromaticity that minimizes a chromaticity difference between the plurality of correction target points; and correcting the chromaticity at each of the plurality of correction target points based on the target chromaticity.

Description

Technical Field

[0001] This disclosure relates to control methods, projection devices, and program products. Background Technology

[0002] Patent Document 1 discloses a color unevenness correction value creation system comprising a projector, a camera, and a color unevenness correction value creation device. The color unevenness correction value creation device sets the average XYZ value of the entire image or the central region of the image as the correction target value for color unevenness correction based on the shooting data obtained from the actual color unevenness state of the projected image captured by the camera.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2010-217644

[0004] In the technology described in Patent Document 1, since the average value is set as the correction target value when performing color unevenness correction, when correcting the color unevenness of images such as black images with the lowest brightness, the difference between the measured value of color unevenness and the average value, i.e. the correction amount, exceeds the adjustable range of color unevenness. As a result, color unevenness is sometimes not properly corrected. Summary of the Invention

[0005] A preferred embodiment of the control method disclosed herein is a control method for at least one projection device capable of projecting multiple images with different brightness levels. The control method includes: obtaining a chromaticity that makes the brightness of each of the multiple correction target points a target value; setting the chromaticity with the smallest chromaticity difference between the multiple correction target points as a target chromaticity for each of the multiple correction target points; and correcting the chromaticity of each of the multiple correction target points based on the target chromaticity.

[0006] A preferred embodiment of the projection device disclosed herein is a projection device capable of projecting multiple images with different brightness levels. The projection device includes one or more processors that perform the following processing: obtaining a chromaticity that makes the brightness of each of the multiple correction target points a target value; setting the chromaticity with the smallest chromaticity difference between the multiple correction target points as a target chromaticity for each of the multiple correction target points; and correcting the chromaticity of each of the multiple correction target points based on the target chromaticity.

[0007] A preferred embodiment of the program product disclosed herein is a program product that controls at least one projection device capable of projecting multiple images with different brightness levels. The program product causes a processor to perform the following processes: obtaining a chromaticity that makes the brightness of each of the multiple correction target points a target value; setting the chromaticity with the smallest chromaticity difference between the multiple correction target points as a target chromaticity for each of the multiple correction target points; and correcting the chromaticity of the multiple correction target points based on the target chromaticity. Attached Figure Description

[0008] Figure 1 This is a diagram showing the overall structure of the projection system used in the control method according to the embodiment.

[0009] Figure 2 This is a block diagram of the projection device involved in the implementation method.

[0010] Figure 3 This is an explanatory diagram of the correctable range of chromaticity between projection devices.

[0011] Figure 4 This is an explanatory diagram of chromaticity correction when the average chromaticity of multiple projection devices is set as the target chromaticity value.

[0012] Figure 5 This is an explanatory diagram of chromaticity correction when the arithmetic mean of the maximum and minimum values ​​of the chromaticity from multiple projection devices is set as the target value of the chromaticity.

[0013] Figure 6 This is a flowchart illustrating the control method involved in the implementation.

[0014] Figure 7 This is a diagram showing an example of multiple calibration target points.

[0015] Figure 8 This is a diagram showing an example of multiple calibration target points.

[0016] Figure 9 This is a diagram showing an example of multiple calibration target points.

[0017] Figure 10 This is an explanatory diagram of the projection device projecting the measurement pattern.

[0018] Figure 11 This is a flowchart showing the calculation of the correction value.

[0019] Figure 12 This is an example of a diagram showing the target value of brightness at the correction point in the overlapping area.

[0020] Figure 13 It is a graph showing the relationship between input grayscale and output brightness in overlapping and non-overlapping regions.

[0021] Figure 14 This is a diagram showing an example of the target brightness value at a correction point adjacent to an overlapping area in a non-overlapping correction point.

[0022] Figure 15 This is an explanatory diagram illustrating the calculation of the target brightness value at the correction target point in the non-overlapping region.

[0023] Figure 16 This is an explanatory diagram illustrating the calculation of the target brightness value at the correction target point in the non-overlapping region.

[0024] Figure 17 This is an explanatory diagram illustrating the calculation of the target brightness value at the correction target point in the non-overlapping region.

[0025] Figure 18 This is an illustration of the smoothing of the target value of brightness at the point of correction.

[0026] Figure 19 This is an explanatory diagram of the target chromaticity.

[0027] Label Explanation

[0028] 1: Projection system; 10: Projection device; 10A: Projection device; 10B: Projection device; 10C: Projection device; 11: Optical device; 12: Imaging device; 13: Processing device; 14: Storage device; 15: Communication device; 20: Image supply device; 131: Projection control unit; 132: Imaging control unit; 133: Image resolution unit; 134: Correction value calculation unit; 135: Image acquisition unit; 136: Correction unit; 137: Communication control unit; CM-1: Chromaticity; CM-2: Chromaticity; CT1: Target chromaticity; CT2: Target chromaticity; CTa: Target value; CTb: Target value; DP: Correction target point; DP1: Correction target point; DR: Overlapping area; LN: Communication line; LP: Correction target point; N P: Correction target point; NP1: Correction target point; NP17: Correction target point; NP18: Correction target point; NR: Non-overlapping region; PI: Projected image; PI1: Projected image; PI2: Projected image; PI3: Projected image; PI_A: Projected image; PP: Correction target point; PR1: Control procedure; PT1: Part; PT2: Part; PT3: Part; PT4: Part; PT5: Part; PT6: Part; PT7: Part; RC-1: Range; RC-2: Range; RL1: Region; RL2: Region; RL3: Region; RL4: Region; RL5: Region; S1: Step; S2: Step; S3: Step; S4: Step; S5: Step; SC: Projection surface; SS4: Step. Detailed Implementation

[0029] Hereinafter, the methods for implementing this disclosure will be described with reference to the accompanying drawings. Note that the dimensions and scales of the various parts in the drawings differ appropriately from the actual figures. Furthermore, the embodiments described below are preferred examples of this disclosure, and therefore various technically preferred limitations are included. However, unless otherwise specified in the following description, the scope of this disclosure is not limited to these methods.

[0030] 1: First Implementation Method

[0031] 1-1: Overall structure of the projection system used in the control method

[0032] Figure 1 This diagram illustrates the overall structure of the projection system 1 used in the control method according to the embodiment. The projection system 1 is a multi-projection system that projects a projected image PI_A onto a projection surface SC. The projection system 1 includes projection devices 10A, 10B, and 10C, as well as an image supply device 20. They are connected to each other via a communication line LN. Hereinafter, without distinguishing between projection devices 10A, 10B, and 10C, they will sometimes be referred to as projection devices 10. Furthermore, the number of projection devices 10 included in the projection system 1 is not limited to the example shown; it may be two or fewer, or four or more.

[0033] Projection devices 10A, 10B, and 10C are projectors that project images onto the projection surface SC based on image data from the image supply device 20. Projection devices 10A, 10B, and 10C have substantially the same function. Any one of the projection devices 10A, 10B, and 10C is the main unit, capable of controlling the operation of the other projection devices 10, which act as auxiliary units.

[0034] To explain more specifically, projection device 10A projects projection image PI1 onto projection surface SC. Projection device 10B projects projection image PI2 onto projection surface SC. Projection device 10C projects projection image PI3 onto projection surface SC. Furthermore, hereinafter, without distinguishing between projection images PI1, PI2, and PI3, they will sometimes be referred to as projection image PI.

[0035] Such projected images PI1, PI2, and PI3 have overlapping portions in the projection plane SC, thus displaying a single projected image PI_A. Here, projected image PI_A has regions RL1, RL2, RL3, RL4, and RL5.

[0036] In contrast, projected image PI1 includes a portion PT1 belonging to region RL1 of projected image PI_A and a portion PT2 belonging to region RL2 of projected image PI_A. Projected image PI2 includes a portion PT3 belonging to region RL1 of projected image PI_A, a portion PT4 belonging to region RL3 of projected image PI_A, and a portion PT5 belonging to region RL4 of projected image PI_A. Projected image PI3 includes a portion PT6 belonging to region RL4 of projected image PI_A and a portion PT7 belonging to region RL5 of projected image PI_A.

[0037] In this way, region RL1 of the projected image PI_A is the overlapping region (DR) of portions PT1 of the projected image PI1 and PT3 of the projected image PI2 in the projection plane SC. Similarly, region RL4 of the projected image PI_A is the overlapping region (DR) of portions PT5 of the projected image PI2 and PT6 of the projected image PI3 in the projection plane SC. On the other hand, regions RL2, RL3, and RL5 of the projected image PI_A are non-overlapping regions NR where only one of the projected images PI1, PI2, and PI3 is projected onto the projection plane SC.

[0038] The image supply device 20 is a device that performs the following functions: dividing image data representing one image into multiple image data that can be projected by multiple projection devices 10; and supplying each image data based on the division process to the corresponding projection device 10. The image supply device 20 may be, for example, a laptop or desktop computer, a smartphone or tablet terminal, or a video playback device, a DVD (Digital Versatile Disk) player, a Blu-ray disc player, a hard disk recorder, a television tuner device, a CATV (Cable Television) set-top box, a video game console, etc.

[0039] Furthermore, the image supply device 20 can supply image data to the projection devices 10A, 10B, and 10C respectively, or it can supply image data only to the main projection device 10. When the image supply device 20 supplies image data only to the main projection device 10, the main projection device 10 can appropriately distribute the image data from the image supply device 20 to the multiple secondary projection devices 10 respectively.

[0040] Alternatively, the image supply device 20 may be omitted if required. In this case, the image data may be pre-stored in each of the projection devices 10A, 10B, and 10C, or the image data for each of the projection devices 10A, 10B, and 10C may be stored in the projection device 10, which serves as the host.

[0041] 1-2: Structure of the projection device

[0042] Figure 2 This is a block diagram of the projection device 10A according to the embodiment. Furthermore, projection devices 10B and 10C each have substantially the same function as projection device 10A, but may have the same structure as projection device 10A or a different structure. For example, projection devices 10B and 10C each have the structure necessary for the projection function, but may also lack at least one of the following components: the imaging device 12, the imaging control unit 132, the image analysis unit 133, the correction value calculation unit 134, the image acquisition unit 135, and the correction unit 136 (described later).

[0043] The projection device 10A includes an optical device 11, an imaging device 12, a processing device 13, a storage device 14, and a communication device 15. These are interconnected via one or more buses. Furthermore, the various elements of the projection device 10A may be composed of one or more devices, or they may be integrated with other elements.

[0044] The optical device 11 is a device that projects a projected image PI onto a projection surface SC under the control of the processing device 13. The optical device 11 includes, for example, a light source, a projection lens, a dichroic mirror, a prism, and a liquid crystal panel. The liquid crystal panel, as an example of a light modulation element, modulates the light from the light source, and the modulated light is projected onto the projection surface SC via the projection lens. The light modulation element can also be a digital micromirror device.

[0045] The imaging device 12 is a device that captures a projected image PI projected onto the projection surface SC under the control of the processing device 13. The imaging device 12 is, for example, an image sensor.

[0046] The processing device 13 is a processor that controls the projection device 10A as a whole, and may be composed of one or more chips. The processing device 13 may be, for example, a central processing unit (CPU) that includes interfaces with peripheral devices, arithmetic units, and registers. Furthermore, some or all of the functions of the processing device 13 may be implemented using hardware such as a DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), or FPGA (Field Programmable Gate Array). The processing device 13 may also include a SoC (System on Chip). The processing device 13 executes various processes in parallel or sequentially.

[0047] Storage device 14 is a recording medium that can be read by processing device 13, storing multiple programs including control program PR1 executed by processing device 13. Additionally, storage device 14 stores a measurement pattern image projected from optical device 11 during calibration, as described later. Hereinafter, the measurement pattern image is sometimes referred to as a measurement pattern. Storage device 14 may be composed 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). Storage device 14 may also be referred to as a register, cache, main memory, or main storage device.

[0048] The communication device 15 is hardware that serves as a transceiver for communicating with other devices. The communication device 15 is also referred to as a network device, network controller, network interface card (NIC), communication module, etc. The communication device 15 may also include a connector for wired connection and an interface circuit corresponding to that connector. Additionally, the communication device 15 may also include a wireless communication interface. Examples of wired connectors and interface circuits that conform to wired LAN (Local Area Network), IEEE 1394, and USB (Universal Serial Bus) are examples. Examples of wireless communication interfaces that conform to wireless LAN or Bluetooth (registered trademark) are examples.

[0049] The processing unit 13 reads and executes the control program PR1 from the storage device 14, and functions as the projection control unit 131, the image capture 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. Furthermore, the control program PR1 can also be sent via a communication network from other devices such as a server that manages the projection device 10A.

[0050] The projection control unit 131 controls the operation of the optical device 11. More specifically, the projection control unit 131 causes the optical device 11 to project a measurement pattern onto the projection surface SC. In addition, the projection control unit 131 causes the optical device 11 to project an image acquired by the image acquisition unit 135 from the image supply device 20 (described later) onto the projection surface SC.

[0051] The imaging control unit 132 controls the operation of the imaging device 12. More specifically, the imaging control unit 132 causes the imaging device 12 to capture the reflected light of the measurement pattern projected onto the projection surface SC.

[0052] The image analysis unit 133 analyzes the captured image based on the imaging device 12. More specifically, the image analysis unit 133 analyzes the captured image obtained by the imaging device 12 capturing a measurement pattern, and calculates the measured values ​​of the color (RGB value) and brightness of the measurement pattern in the captured image.

[0053] The correction value calculation unit 134 calculates the correction value set by the correction unit 136 (described later) based on the measurement value calculated by the image analysis unit 133.

[0054] The image acquisition unit 135 acquires image data from the image supply device 20.

[0055] The correction unit 136 uses the correction value calculated by the correction value calculation unit 134 to correct the image data. Specifically, the correction unit 136 functions as a brightness correction circuit, using the correction value calculated by the correction value calculation unit 134 to correct the brightness of the image acquired by the image acquisition unit 135, or it functions as a color unevenness correction circuit, using the correction value calculated by the correction value calculation unit 134 to correct the color unevenness of the image acquired by the image acquisition unit 135.

[0056] The communication control unit 137 controls the operation of the communication device 15 to enable the communication device 15 to send and receive various information with external devices. More specifically, the communication control unit 137 enables the communication device 15 to send correction values ​​from the projection device 10A to the projection device 10B and the projection device 10C, respectively.

[0057] 1-3: Color Correction

[0058] In the past, in the calibration of chromaticity in projection devices, a preset value or a value calculated based on the measurement value of one of the multiple projection devices was used as the target value, and the same target value of color was used for calibration of all hues (chromaticities).

[0059] However, the color of black is different from that of other shades, from midtones to pure white. Therefore, if the target value of black in the correction is to be the same as that of other shades, the color of black must be changed significantly from its original color, thus requiring more assurance of the correction amount.

[0060] In addition, due to the individual differences in the black color and the large color unevenness within the projected image, when a target value is preset or determined based on the measurement value of a single projection device, the difference between the original black color and the target value becomes larger. Therefore, more calibration is required in this regard.

[0061] In this way, a larger amount of correction needs to be ensured beforehand in the correction of black. On the other hand, in order to suppress the reduction of contrast after correction, the correction amount of the hue on the black side is set to be less than that on the white side. Therefore, if the target color is set using the conventional method described above, the following problem exists: the correction amount of black is insufficient, and the chromaticity cannot be adequately corrected.

[0062] Therefore, the projection device 10 calculates the target color (chromaticity) for color correction of black as follows.

[0063] Specifically, first, the projection device 10 acquires the grayscale characteristics of the black side. These grayscale characteristics represent the relationship between the input grayscale and the output brightness. Then, based on these grayscale characteristics, the projection device 10 estimates the output brightness at a predetermined correction-expected grayscale as a target value for brightness for all the correction target points LP of the entire projection device 10 (described later). The correction-expected grayscale is determined through calibration, experimentation, etc. Afterward, the projection device 10 converts the estimated target value into u' and v', which are examples of chromaticity. Next, based on the maximum and minimum values ​​of u' and v' of all correction target points LP, the projection device 10 sets the target chromaticity for black to the chromaticity with the smallest chromaticity difference among the multiple correction target points LP. For example, the projection device 10 sets the target chromaticity for black as the arithmetic mean of the maximum and minimum values ​​of u' and v' of all correction target points LP. Furthermore, in this embodiment, chromaticity is defined by u' and v', but the type of chromaticity is not particularly limited. That is, chromaticity can also be defined by any one of u'v' obtained by synthesizing u' and v', u and v, uv obtained by synthesizing u and v, x and y, and xy obtained by synthesizing x and y.

[0064] Here, in estimating the target value of luminance, by determining a target value that is close to the chromaticity of the output luminance under the expected grayscale, rather than the original black, the amount of correction in chromaticity correction is suppressed. Furthermore, by targeting a grayscale greater than black, the chromaticity of the corrected black can be made close to that of a midtone.

[0065] Furthermore, in setting the target chromaticity for black, by setting the maximum and minimum values ​​of u' and v' based on all correction target points LP as the target chromaticity for black, the chromaticity difference after correction can be reduced if the correction amount is insufficient during chromaticity correction. Additionally, it can reduce the possibility that the correction amount for black will become insufficient.

[0066] To illustrate with a specific example, if there are 10 projection devices 10, and 9 of them have the same black chromaticity of (u', v') = (0.200, 0.400), while the remaining projection device 10 has a black chromaticity of (u', v') = (0.230, 0.430), then the chromaticity difference before correction is (Δu', Δv') = (0.030, 0.030). In contrast, as an example, the correctable chromaticity range for black is approximately (Δu', Δv') = (0.010, 0.010). The value of the correctable chromaticity range for black may vary depending on the performance of the projection device 10, the desired black color, contrast, etc.

[0067] Figure 3 This is an explanatory diagram of the correctable range of chromaticity between the projection devices 10. Figure 3 In the diagram, the horizontal axis represents the value of u', and the vertical axis represents the value of v'. Figure 3 In this context, the chromaticity of black for nine of the ten projection devices 10 is denoted as chromaticity CM-1, and the chromaticity of black for the remaining projection device 10 is denoted as chromaticity CM-2. Furthermore, in... Figure 3 In the projection setup, the range of correctable black chromaticity for nine out of ten projection devices 10 is shaded as range RC-1 centered on chromaticity CM-1, while the range of correctable black chromaticity for the remaining projection device 10 is shaded as range RC-2 centered on chromaticity CM-2. Furthermore, in... Figure 3 For ease of explanation, the shapes of RC-1 and RC-2 are respectively square, but in reality they can be various shapes.

[0068] The range of correctable chromaticity can be expanded by increasing the gray level selected as the correction value. However, in the correction of black, if the gray level selected as the correction value is increased excessively, the corrected black will become too bright. Therefore, the range of correctable chromaticity to the extent described above is limited. Furthermore, the range of correctable chromaticity described above is just one example; in reality, it varies according to each projection device 10 or according to each correction target point LP.

[0069] Figure 4 This is an explanatory diagram of chromaticity correction when the average chromaticity of multiple projection devices 10 is set as the target chromaticity value CTa. In this case, the average chromaticity of black of the 10 projection devices 10 is (u', v') = (0.203, 0.403). Therefore, although the target chromaticity value CTa in the chromaticity correction of the 10 projection devices 10 is within the range RC-1, it is outside the range RC-2. Therefore, when the chromaticity of each projection device 10 is corrected to the target value CTa, although the chromaticity of 9 projection devices 10 can be corrected to the target value CTa, the remaining projection device 10 becomes the correction limit. That is, although the corrected chromaticity of 9 projection devices 10 is (u', v') = (0.203, 0.403), the corrected chromaticity of the remaining projection device 10 is (u', v') = (0.220, 0.420). Therefore, the corrected chromaticity difference of the remaining projection device 10 becomes (Δu', Δv') = (0.017, 0.017).

[0070] Figure 5This is an explanatory diagram of chromaticity correction when the arithmetic mean of the maximum and minimum chromaticities among multiple projection devices 10 is set as the target chromaticity value CTb. In this case, the target CTb for the chromaticity correction of the aforementioned 10 projection devices 10 is (u', v') = (0.215, 0.415). Therefore, when the chromaticity of each projection device 10 is corrected to the target value CTa, although it becomes the correction limit among all 10 projection devices 10, the corrected chromaticity of 9 projection devices 10 is (u', v') = (0.210, 0.410), and the corrected chromaticity of the remaining 1 projection device 10 is (u', v') = (0.220, 0.420). Therefore, in any projection device 10, the corrected chromaticity difference is (Δu', Δv') = (0.010, 0.010), which is better than the above... Figure 4 The situation shown is small.

[0071] Furthermore, the above explanation of black correction was based on the problem of chromaticity difference between multiple projection devices 10, but the problem of chromaticity difference between multiple correction target points LP in one projection device 10 can also be solved.

[0072] 1-4: Control Methods

[0073] Figure 6 This is a flowchart illustrating the control method involved in the implementation. For example... Figure 6 As shown, the control method includes steps S1 to S5. Below, firstly, based on... Figure 6 A general description of each step will be provided. Furthermore, steps S1 to S5 are the same for projection devices other than projection device 10A; therefore, unless there are any particular differences, the operation of projection device 10A will be mentioned below.

[0074] First, in step S1, the projection device 10A calculates correction values ​​for brightness and color unevenness for grayscale values ​​other than black. Additionally, in step S1, the projection device 10A uses these correction values ​​to make adjustments so that the brightness and color of the projected images PI from the projection devices 10A, 10B, and 10C become uniform across the projection devices 10.

[0075] Following step S1, in step S2, the projection device 10A projects a measurement pattern for black correction onto the projection surface SC. Specifically, the processing device 13, which functions as the projection control unit 131, reads the measurement pattern from the storage device 14 and causes the optical device 11 to sequentially project multiple of the measurement patterns onto the projection surface SC.

[0076] Following step S2, in step S3, the processing unit 13 of the projection device 10A, which functions as the imaging control unit 132, causes the imaging device 12 to capture each measurement pattern projected onto the projection surface SC. Furthermore, the processing unit 13 of the projection device 10A, which functions as the image analysis unit 133, analyzes the measurement patterns captured by the imaging device 12 and calculates measurement values ​​representing the color (RGB values) and brightness of the measurement patterns in the captured image. Moreover, the number of times steps S2 and S3 are executed can be appropriately varied depending on the number of measurement patterns. In this embodiment, steps S2 and S3 are executed multiple times.

[0077] After step S3, in step S4, the processing device 13 of the projection device 10A, which functions as a correction value calculation unit 134, calculates the correction values ​​for the brightness of black and color unevenness.

[0078] After step S4, in step S5, the processing device 13 of the projection device 10A, which functions as a correction value calculation unit 134, sets the correction value calculated in step S4 as the set value.

[0079] By following steps S1 to S5, the brightness of black and color unevenness can be corrected. The following is a detailed description of each step.

[0080] Figures 7 to 9 This is a diagram illustrating an example of multiple calibration target points LP. In Figure 7 The image shown is an example of a correction target point LP corresponding to the projected image PI1 projected from the projection device 10A. Figure 8 The image shown is an example of a correction target point LP corresponding to the projected image PI2 projected from the projection device 10B. Figure 9 The image shown is an example of a correction target point LP corresponding to the projected image PI3 projected from the projection device 10C.

[0081] The correction target point LP is the point corresponding to the pixel among multiple pixels of the projected image PI that is the correction target for color unevenness. Figures 7 to 9 In the example, multiple correction target points LP are shown, corresponding to the grid points in row 11 and column 21.

[0082] like Figures 7 to 9As shown, multiple correction target points LP are divided into multiple correction target points DP, multiple correction target points NP, and multiple correction target points PP. Correction target point DP is the correction target point LP corresponding to a pixel belonging to the overlapping region DR, and is represented by a shaded circle in the figure. Correction target point NP is the correction target point LP corresponding to a pixel belonging to the non-overlapping region NR, and is represented by a white circle in the figure. Correction target point PP is the correction target point LP for which it cannot be determined whether it corresponds to the overlapping region DR or the non-overlapping region NR, and is represented by a dashed circle in the figure.

[0083] For each of the multiple correction target points LP as described above, there is a measurement value calculated by the image analysis unit 133.

[0084] The brightness correction in step S1 is as follows: For grayscale values ​​other than black, reduce the difference in brightness between the overlapping region DR and the non-overlapping region NR. The method used for this brightness correction is not particularly limited and can be any known method, for example, the following method: Figure 1 Any one of the regions RL1 to RL5 shown is taken as the target region. The captured values ​​obtained by shooting the target region are compared with the captured values ​​obtained by shooting other regions, thereby correcting brightness and color unevenness.

[0085] On the other hand, the color unevenness correction in step S1 is performed, for example, on each of the 11 rows × 21 columns of correction target points LP. This correction is performed, for example, based on the gray level of the boundary line obtained by dividing the 10-bit grayscale width, i.e., the grayscale width from grayscale 0 to grayscale 1023, into 8 equal parts.

[0086] Furthermore, in step S1, the processing device 13 determines whether the correction target point LP is contained in the overlapping region DR or the non-overlapping region NR. For example, before step S1, the processing device 13 projects a pure white image from the optical device 11 as the projected image and captures the pure white image using the imaging device 12 of the projection device 10A. Then, it projects a pure white image from the projection device 10B as the projected image and captures the pure white image using the imaging device 12 of the projection device 10A. Then, based on these capture results, the processing device 13 detects the right position of the pure white image projected from the projection device 10A and the left position of the pure white image projected from the projection device 10B, and determines the area from the right position to the left position as the overlapping region DR in the coordinate system of the captured image. Furthermore, based on the correspondence between the coordinate systems of the projection device 10A, the projection device 10B, and the captured image generated before step S1, the processing device 13 converts the overlapping region DR in the coordinate system of the captured image into the overlapping region DR in the coordinate systems of the projection device 10A and the projection device 10B. Furthermore, based on the captured image of the correction target point LP, the processing device 13 determines whether the correction target point LP belongs to the overlapping region DR in the coordinate systems of the projection device 10A and the projection device 10B, respectively. This correspondence can be calculated, for example, using a 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. Furthermore, the above determination method applies to both the projection device 10B and the projection device 10C.

[0087] Furthermore, the method described above for determining whether the correction target point LP is contained in the overlapping region DR or the non-overlapping region NR is just one example and can be modified appropriately.

[0088] Figure 10 This is an explanatory diagram of the projection measurement patterns projected by projection devices 10A and 10B. Furthermore, in Figure 10 For ease of explanation, only the projected image PI1 projected from the projection device 10A and the projected image PI2 projected from the projection device 10B are shown; the projection image PI3 projected from the projection device 10C is omitted. Hereinafter, the cases where the projected measurement patterns are the projected images PI1 and PI2 will be described representatively.

[0089] The measurement pattern used in step S2 is an image used to obtain the relationship between input grayscale and output brightness, for example, an image with a minimum grayscale of 4. Alternatively, the measurement pattern used in step S2 can also be an image with a grayscale of 0.

[0090] To brighten the measurement pattern, it is preferable that the measurement pattern is not a single color of any one of the R, G, and B components, but rather a color obtained by changing one of the color components of the R, G, and B components based on a reference gray. In this case, the reference gray is preferably set to a gray such that all the R, G, and B components are gray levels close to the output gray level after color non-uniformity correction of the overlapping area DR. As a result, the gray levels of the measurement pattern are the following 10 patterns. Furthermore, for ease of explanation, the values ​​of the R, G, and B components of measurement patterns (1) to (10) are labeled as (r, g, b). In addition, A, B, C, and D are different gray levels, in ascending order of A, B, C, and D. For example, gray level (A) is gray level (22), gray level (B) is gray level (34), gray level (C) is gray level (60), and gray level (D) is gray level (95).

[0091] Measurement pattern (1): (r, g, b) = (D, B, B)

[0092] Measurement pattern (2): (r, g, b) = (B, D, B)

[0093] Measurement pattern (3): (r, g, b) = (B, B, D)

[0094] Measurement pattern (4): (r, g, b) = (C, B, B)

[0095] Measurement pattern (5): (r, g, b) = (B, C, B)

[0096] Measurement pattern (6): (r, g, b) = (B, B, C)

[0097] Measurement pattern (7): (r, g, b) = (B, B, B)

[0098] Measurement pattern (8): (r, g, b) = (A, B, B)

[0099] Measurement pattern (9): (r, g, b) = (B, A, B)

[0100] Measurement pattern (10): (r, g, b) = (B, B, A)

[0101] When the measurement pattern also includes grayscale 0, the following measurement pattern is preferred.

[0102] Measurement pattern (11): (r, g, b) = (0, B, B)

[0103] Measurement pattern (12): (r, g, b) = (B, 0, B)

[0104] Measurement pattern (13): (r, g, b) = (B, B, 0)

[0105] By using the above measurement pattern, the projected measurement pattern can be made brighter, improving the S / N ratio of the imaging device 12 and reducing the error of the measurement value.

[0106] In step S2, the projected image PI1 projected by projection device 10A and the projected image PI2 projected by projection device 10B are the same measurement pattern. Furthermore, in step S2, the projection of image PI1 by projection device 10A and the projection of image PI2 by projection device 10B are synchronized. That is, image PI2 is projected onto the projection surface SC at the same timing as image PI1.

[0107] By projecting the measurement pattern as described above, compared to projecting the measurement pattern using a single projection device 10, the brightness of the overlapping area DR is more than twice that of the previous method, thereby improving the signal-to-noise ratio (S / N) of the imaging device 12. As a result, the projection device 10A of this embodiment can suppress errors in the measurement values ​​calculated by the image analysis unit 133. Furthermore, since at least two of the R, G, and B components of each measurement pattern have a gray level that is not zero, errors in the measurement values ​​using the imaging device 12 can be reduced.

[0108] In step S3, after the processing device 13, which functions as the shooting control unit 132, causes the shooting device 12 to capture each measurement pattern projected onto the projection surface SC, the processing device 13, which functions as the image analysis unit 133, analyzes the captured image obtained by the shooting device 12 capturing the measurement pattern, and thereby calculates the measured values ​​representing the color (RGB value) and brightness of the measurement pattern in the captured image.

[0109] In this analysis, firstly, the processing device 13 calculates the following correspondence at each point of the correction target point LP through interpolation calculation, namely, the correspondence between the gray value (r, g, b) (0 ≤ r, g, b ≤ 95) of the colored light of the measurement pattern projected by the optical device 11 and the measured value (R, G, B) representing the color of the colored light in the captured image, which is calculated by analyzing the colored light of the measurement pattern captured by the imaging device 12.

[0110] Here, the measurement data includes luminance values ​​representing the brightness of the reflected light corresponding to the R, G, and B components.

[0111] For ease of understanding, when grayscale values ​​(r, g, b) of colored light are projected as a measurement pattern through the optical device 11, the R component of the measured values ​​(R, G, B) representing the color of the colored light in the captured image, calculated by the processing device 13, is labeled as R.（r，g，b） The G component is labeled as G. （r，g，b） Component B is labeled as B. （r，g，b） .

[0112] Furthermore, when the R, G, and B components, representing the measured values ​​of the color of light in the captured image, are summarized, they are labeled as (R, G, B). （r，g，b） =(R （r，g，b） G （r，g，b） B （r，g，b） ).

[0113] The measured values ​​of the five measurement patterns, in which only the R component is changed, among the gray values ​​(r, g, b) of the colored light used as measurement patterns, are expressed as shown in Equations 1 to 5 below.

[0114]

[0115] The measured values ​​of these five measurement patterns are all known. Therefore, the processing device 13 can perform curve interpolation between the measured values ​​of the R component of these measured values ​​(R, G, B). The same applies to the G and B components. Known methods can be used for curve interpolation. For example, the processing device 13 can also perform curve interpolation using spline curves. Alternatively, the processing device 13 can also perform parabolic interpolation for every 3 of the 5 points corresponding to the 5 measured values. Alternatively, the processing device 13 can also perform cubic curve interpolation for every 4 of the 5 points corresponding to the 5 measured values. An example of cubic curve interpolation is cubic interpolation.

[0116] By changing only the r component, which is the R component, in the grayscale value (r, g, b) of the colored light used as the measurement pattern, interpolation curves R(r, 34, 34), G(r, 34, 34), and B(r, 34, 34) are obtained, which interpolate the measured values ​​of the R component in the measured values ​​(R, G, B) calculated by the processing device 13.

[0117] In step S3, the processing device 13 estimates the measured values ​​(R, G, B) when colored light with R component as arbitrary gray level r (0≤r≤95) is projected onto the projection surface SC by using the three interpolation curves R (r, 34, 34), interpolation curve G (r, 34, 34), and interpolation curve B (r, 34, 34). （r，34，34） =(R （r，34，34） G （r，34，34） B （r，34，34） ).

[0118] By changing only the g component of the grayscale value (r, g, b) of the colored light used as the measurement pattern, interpolation curves R(34, g, 34), G(34, g, 34), and B(34, g, 34) are obtained, which interpolate the measured values ​​of the R component in the measured values ​​(R, G, B) calculated by the processing device 13.

[0119] In step S3, the processing device 13 estimates the measured values ​​(R, G, B) when colored light with an arbitrary gray level g (0≤g≤95) of G is projected onto the projection surface SC by using the three interpolation curves R (34, g, 34), interpolation curve G (34, g, 34), and interpolation curve B (34, g, 34). （34，g，34） =(R （34，g，34） G （34，g，34） B （34，g，34） ).

[0120] By changing only the b component, which is the B component, in the grayscale value (r, g, b) of the colored light used as the measurement pattern, interpolation curves R(34, 34, b), G(34, 34, b), and B(34, 34, b) are obtained, which interpolate the measured values ​​of the R component in the measured values ​​(R, G, B) calculated by the processing device 13.

[0121] In step S3, the processing device 13 estimates the measured values ​​(R, G, B) when colored light with B component of arbitrary gray level b (0≤b≤95) is projected onto the projection surface SC by using the three interpolation curves R (34, 34, b), interpolation curve G (34, 34, b), and interpolation curve B (34, 34, b). （34，34，b） =(R （34，34，b） G （34，34，b） B （34，34，b） ).

[0122] Using the following equations 6 to 8, which are functions of the interpolation curves R(r, 34, 34), G(r, 34, 34), B(r, 34, 34), R(34, g, 34), G(34, g, 34), B(34, g, 34), R(34, 34, b), G(34, 34, b), and B(34, 34, b), it is possible to estimate the measured values ​​(R, G, B) when only one color component of the grayscale value (r, g, b) of the colored light projected from the optical device 11 is changed, while the other color components are fixed at grayscale 34. （r，g，b） =(R （r，g，b）G （r，g，b） B （r，g，b） ).

[0123]

[0124] In Equations 6 to 8 above, the only component that arbitrarily changes in the grayscale value (r, g, b) of the colored light projected from the optical device 11 is one of the components r (R component), g (G component), and b (B component), while the other two components remain fixed at grayscale 34. Therefore, by applying the properties of additive color mixing to Equations 6 to 8, the processing device 13 can estimate the measured value (R, G, B) of the grayscale value (r, g, b) (0 ≤ r, g, b ≤ 95) of the colored light when all components r (R component), g (G component), and b (B component) are arbitrarily changed, using Equation 9 below. （r，g，b） =(R （r，g，b） G （r，g，b） B （r，g，b） ).

[0125]

[0126] Furthermore, in Equation 9, the origin of the additive color mixing is not (r, g, b) = (0, 0, 0), but (r, g, b) = (34, 34, 34). If Equation 9 is expressed for each component, it becomes Equations 10 to 12 below.

[0127]

[0128] Image resolution unit 133 converts RGB values ​​to XYZ values ​​using Equation 13, where Equation 13 is the conversion of RGB values ​​calculated from Equations 10 to 12, i.e., R... （r，g，b） G （r，g，b） and B （r，g，b） The component matrix is ​​multiplied by the transformation matrix M inherent to the imaging device 12. As a result, the image resolution unit 133 is able to estimate the output values ​​XYZ for any gray level. The transformation matrix M is a matrix used to convert between RGB values ​​and output values ​​XYZ, and is determined by performing a known calibration on the imaging device 12 beforehand.

[0129]

[0130] Furthermore, the image analysis unit 133 converts the estimated XYZ values ​​into u' and v' using the following equation 14.

[0131]

[0132] Figure 11 This is a flowchart illustrating the calculation of the correction value in step S4. For example... Figure 11As shown, step S4 includes steps SS4[1] to SS4[8].

[0133] In detail, firstly, in step SS4[1], the processing device 13, which functions as the correction value calculation unit 134, assumes that the brightness of the target in the overlapping region DR has been determined by known methods, corrections or experiments, and sets the target value of the brightness at the correction target point DP contained in the overlapping region DR.

[0134] Figure 12 This is an example diagram showing the target brightness value at the correction target point LP, or correction target point DP, in the overlapping region DR. Figure 12 In this example, a target grayscale value (r, g, b) is shown as the target value for the brightness at the target point DP. In other words, by setting the grayscale value of the target point DP to the target grayscale value (r, g, b), the brightness of the target point DP becomes the target value for brightness. Furthermore, by setting the grayscale value of at least one pixel among the plurality of pixels of the liquid crystal panel corresponding to the target point DP to the target grayscale value (r, g, b), the brightness of the target point DP becomes the target value for brightness. In this embodiment, the target grayscale value (r, g, b) is approximately (30, 30, 30). However, the specific value of the target grayscale value (r, g, b) is appropriately changed according to the target value for the brightness of the target point DP. Furthermore, in... Figure 12 In the projected image PI2, for each correction target point DP, examples are shown of the values ​​of one of the r, g, and b components contained in the grayscale value (r, g, b). For convenience, the values ​​in the figure are integers, but decimals are also possible.

[0135] In addition, Figure 12 In this context, multiple correction target points LP are represented as multiple rectangular cells. Figure 12 In the diagram, the unit represented by a double-lined solid frame corresponds to the correction target point LP, or correction target point DP, belonging to the overlapping region DR. Figure 12 In the diagram, the unit represented by a frame composed of solid lines corresponds to the correction target point LP, or correction target point NP, belonging to the non-overlapping region NR. Figure 12 In the diagram, the cell represented by the double line consisting of solid and dashed lines corresponds to the correction target point LP, i.e., the correction target point PP, which cannot be determined to belong to either the overlapping region DR or the non-overlapping region NR.

[0136] exist Figure 11In step SS4[2], the processing device 13, which functions as the correction value calculation unit 134, determines the target gray value (r, g, b) at the correction target point NP in such a way that the correction target point DP belonging to the overlapping region DR and the correction target point NP belonging to the non-overlapping region NR, which are adjacent to each other across the boundary of the overlapping region DR and the non-overlapping region NR, have at least the same brightness.

[0137] Figure 13 This is a graph showing the relationship between input grayscale and output brightness in the overlapping region DR and the non-overlapping region NR. In step S3 above, the following is obtained: Figure 13 The grayscale characteristics of the black side are shown. Figure 13 The diagram illustrates the relationship between the input grayscale and output brightness at adjacent correction target points DP and NP. Figure 13 In this context, "overlapping area measurement value" represents the relationship between the input grayscale and output brightness at the calibration target point DP, while "non-overlapping area measurement value" represents the relationship between the input grayscale and output brightness at the calibration target point NP.

[0138] In order to calculate the target value of the brightness of the target point NP adjacent to the target point DP, the processing device 13 first calculates the brightness of the output value when the gray value of the target point DP is input as the target value of brightness. Then, the processing device 13 calculates the input value of the target point NP as the same as the calculated output value, and sets the calculated input value as the target value of brightness of the target point NP.

[0139] Thus, the target grayscale value (r, g, b) at the correction target point NP is calculated based on the target grayscale value (r, g, b) at the correction target point DP. The specific calculation method is explained below.

[0140] In step SS4[2], the processing device 13 applies Equations 10 to 12 above to the calculated grayscale values ​​(r, g, b), thereby estimating the RGB values ​​as measured by the imaging device 12. Furthermore, the processing device 13 applies the estimated measured values ​​(R, G, B) （r，g，b） By applying Equation 13 above, the RGB value, which is a measurement, is converted into an XYZ value. Furthermore, the processing device 13 applies Equation 14 above to the converted XYZ value, thereby further converting the converted XYZ value into u' and v'.

[0141] Thus, u' and v' of the correction target point DP1 are calculated. Then, the processing device 13 sets u' and v' as the target values ​​u' and v' of the correction target point NP1. Furthermore, the processing device 13 performs inverse operations on u' and v' as the target values ​​using Equations 6 to 14 described above, thereby calculating the target grayscale value (r, g, b) of the correction target point NP1.

[0142] When the brightness of the target point NP1 becomes the target value, the processing device 13 calculates the gray value t, where the r component, g component, and b component become (r, g, b) = (t, t, t), as the target gray value (r, g, b) of the target point NP. Specifically, when gray light is projected from the optical device 11, the processing device 13 calculates the gray value t that has the same brightness at the target points DP1 and NP1.

[0143] Figure 14 This is a diagram illustrating an example of the target brightness value at a correction target point NP adjacent to the overlapping region DR within the non-overlapping region NR. This target value is the target grayscale value t.

[0144] In addition, Figure 14 In the above calculation, the target gray value t at the correction target point NP is larger than the target gray value (r, g, b) at the correction target point DP. This is because the brightness of the correction target point DP is approximately twice that of the correction target point NP. Therefore, in order to make their brightness approximately equal, the target gray value t of the correction target point NP in the non-overlapping region NR needs to be increased.

[0145] In addition, without correction, the non-overlapping region NR is darker than the overlapping region DR. Therefore, in order to make the luminance component Y the same in the overlapping region DR and the non-overlapping region NR after correction, the target gray value t at the correction target point NP needs to be larger than the target gray value (r, g, b) at the correction target point DP.

[0146] exist Figure 11 In step SS4[3], the processing device 13 averages the target gray value t of the correction target point NP calculated in step SS4[2] with the target gray value t of the adjacent correction target point NP, thereby further calculating the target gray value t of the correction target point NP.

[0147] Specifically, regarding the correction target point NP whose target gray value t is undetermined, if there are more than one correction target point NP whose target gray value t has been determined among its adjacent correction target points NP (up, down, left, and right), then the processing device 13 calculates the average of the target gray values ​​t of these correction target points NP. The processing device 13 sets the calculated average as the target gray value t of the correction target point NP whose target gray value t is undetermined.

[0148] exist Figure 11 In step SS4[4], the processing device 13, which functions as the correction value calculation unit 134, determines whether the target gray value t has been calculated at all the correction target points NP in the non-overlapping region NR. If the target gray value t has been calculated at all the correction target points NP in the non-overlapping region NR ("Yes" in step SS4[4]), the processing device 13 performs the processing in step SS4[5]. On the other hand, if the target gray value t has not been calculated at all the correction target points NP in the non-overlapping region NR ("No" in step SS4[4]), the processing device 13 performs the processing in step SS4[3].

[0149] Thus, the processing device 13 extends the correction target point NP for calculating the target gray value t sequentially into the interior of the non-overlapping region NR.

[0150] Figures 15 to 17 This is an explanatory diagram illustrating the calculation of the target brightness value at the correction target point in the non-overlapping region. Figure 15 In, with Figure 14 Compared to the state shown, the following state is shown: the target gray value t of the correction target point NP adjacent to the inner side of the non-overlapping region NR is calculated relative to the correction target point NP adjacent to the boundary of the overlapping region DR and the non-overlapping region NR. Figure 16 The following states are shown: relative to Figure 15 For the correction target point NP in the state shown, the target gray value t of the correction target point NP adjacent to the inner side of the non-overlapping region NR was calculated. Figure 17 This shows the state after calculating the target grayscale value t for all the correction target points NP.

[0151] exist Figure 11 In step SS4[5], the processing device 13, which functions as the correction value calculation unit 134, repeatedly smooths the target gray value t of the calculated target gray value t for the correction target point NP that is adjacent to the boundary of the overlapping region DR and the non-overlapping region NR. Specifically, the processing device 13 smooths the target gray value t of the effective correction target point NP among the correction target points NP that are adjacent to the boundary mentioned above using the target gray value t of the correction target point NP in the upper, lower, left and right directions.

[0152] like Figure 17 As shown, when calculating the target grayscale value t of the target point NP, the processing device 13 calculates the target grayscale values ​​t of the target points NP adjacent to the inside (right side) of the non-overlapping region NR, starting from the overlapping region DR (region RL1) on one side. In parallel, the processing device 13 calculates the target grayscale values ​​t of the target points NP adjacent to the inside (left side) of the non-overlapping region NR, starting from the overlapping region DR (region RL4) on the other side. Therefore, in Figure 17 In the example shown, a large difference occurs between the target gray value t=45 of the correction target point NP17 and the target gray value t=41 of the adjacent correction target point NP18. In other words, a step difference occurs between the target gray value t=45 of the correction target point NP17 and the target gray value t=41 of the correction target point NP18.

[0153] The processing device 13 performs smoothing, eliminating the step difference in the interpolated target gray value t, so that the target gray values ​​t of the correction target point NP contained in the non-overlapping region NR are smoothly connected from one overlapping region DR (region RL1) to the other overlapping region DR (region RL4). As a result, the parameter defining the brightness of the non-overlapping region NR (region RL3), i.e., the target gray value t, becomes a continuous or staged distribution in the direction from region RL1 to region RL4.

[0154] exist Figure 11 In step SS4[6], the processing device 13, which functions as the correction value calculation unit 134, determines whether the change in the target gray value t of the correction target point NP before and after smoothing is below a threshold. More specifically, the processing device 13 determines whether the maximum value of the change in the target gray value t of all correction target points NP is below a threshold. If the maximum value of the change in the target gray value t of all correction target points NP is below the threshold ("Yes" in step SS4[6]), the processing device 13 performs the processing in step SS4[7]. On the other hand, if the maximum value of the change in the target gray value t of all correction target points NP exceeds the threshold ("No" in step SS4[6]), the processing device 13 performs the processing in step SS4[5]. In addition, the processing device 13 may also determine whether at least one of the average value, average value + 3σ, and sum of the change in the target gray value t of the correction target points NP before and after smoothing is below a threshold.

[0155] That is, the processing device 13 repeatedly performs smoothing until the maximum value of the change in the target gray value t of all the correction target points NP becomes below the threshold. The more times the smoothing process is performed, the smaller the overall difference in the target gray value t between adjacent correction target points NP becomes.

[0156] Figure 18 This is an illustration of the smoothing of the target brightness value at point NP. Figure 18 The image shows an example of the target grayscale value t after the 18th smoothing process. For example... Figure 18 As shown, smoothing is completed when the maximum value of the change in the target gray value t of all the correction target points NP is below the threshold.

[0157] exist Figure 11 In step SS4[7], the processing device 13, which functions as the correction value calculation unit 134, calculates the target chromaticity at the correction target point NP contained in the non-overlapping region NR and the target chromaticity at the correction target point DP contained in the overlapping region DR.

[0158] Specifically, the processing device 13 calculates the output brightness as the XYZ value for all valid correction target points LP when the target gray value (t, t, t) is input. Here, the target gray value (t, t, t) takes a different value for each correction target point NP. In addition, the target gray value (t, t, t) takes a different value for each correction target point DP. Furthermore, the target gray value (t, t, t) of the correction target point NP is different from the target gray value (t, t, t) of the correction target point DP.

[0159] In addition, the processing device 13 uses Equation 14 above to convert the calculated output brightness from XYZ values ​​into u' and v'.

[0160] Furthermore, the processing device 13 calculates the maximum value u' of the converted u' and v' values ​​for all the correction target points LP of all projection devices 10. max and minimum value u' min And the maximum value of v' v' max and minimum value v' min Thus, in step SS4[7], the processing device 13, which functions as the correction value calculation unit 134, calculates u' and v' based on the target brightness values ​​related to each of the multiple correction target points LP. After obtaining the set of u' and v', the maximum value u' is obtained from the obtained set of u' and v'. max Minimum value u' min Maximum value v' max and the minimum value v' min .

[0161] Then, the processing device 13 is based on the maximum value u' max Minimum value u' min Maximum value v' max and the minimum value v' min Calculate the target chromaticity (u') target ,v'target This calculation, for example, uses Equation 15 below.

[0162] Equation 7

[0163] Thus, in step SS4[7], the processing device 13, which functions as the correction value calculation unit 134, calculates the correction value for each of the multiple correction target points LP based on the maximum value u'. max Minimum value u' min Maximum value v' max and the minimum value v' min , target chromaticity (u' target ,v' target The chromaticity is set to the chromaticity with the smallest chromaticity difference among multiple correction target points LP.

[0164] Figure 19 It is the target chromaticity (u' target ,v' target (Explanation diagram). In Figure 19 In the u'v' coordinate system, the following points are shown: point A, where u' and v' values ​​are both minimum; point B, where u' is maximum and v' is minimum; point C, where v' is maximum; and the target chromaticity CT1 (u'...). a ,v' a ) and target chromaticity CT2 (u' a ,v' a ).

[0165] Target chromaticity CT1 (u' a ,v' a This is equivalent to using the target chromaticity (u') from Equation 15 above. target ,v' target That is, the target chromaticity CT1 (u' a ,v' a () is the point where Δu' and Δv' are minimized, equivalent to the center of the smallest rectangle containing all points A, B, and C. Here, the chromaticity of each point is set to (u') n ,v' n When Δu' and Δv' are Δu'=|u' n -u' a |、Δv'=|v' n -v' a | n is a natural number greater than 1 and less than N, where N is the number of measurement points, which in this embodiment is (21 points in the horizontal direction) × (11 points in the vertical direction). Furthermore, in Figure 19In this embodiment, three measurement points out of multiple measurement points are representatively represented as points A, B, and C. As in this embodiment, when the chromaticity is u' and v', the target chromaticity CT1 (u') is used. a ,v' a ) as target chromaticity (u' target ,v' target In the case of chromaticity u and v, x and y, the same target value as the target chromaticity CT1 is also used.

[0166] On the other hand, the target chromaticity CT2 (u' a ,v' a The point with the smallest chromaticity difference Δu'v' is equivalent to the center of the smallest circle containing all points A, B, and C. Specifically, find all circles with diameters of two points from among the multiple u' and v' that correspond one-to-one with the multiple correction target points LP, and circles passing through three points from among the multiple u' and v'. From these circles, select the circle with the smallest diameter that contains the u' and v' of each correction target point LP. The center of this circle is the chromaticity with the smallest chromaticity difference Δu'v', i.e., the target chromaticity CT2 (u'v'). a ,v' a Here, the chromaticity difference Δu'v' is... With chromaticity u'v', the target chromaticity CT2(u' a ,v' a ) used as target chromaticity (u' target ,v' target When the chromaticity is uv, xy, the same target value as the target chromaticity CT2 is also used.

[0167] As described above, in step SS4[7], the target chromaticity (u') is calculated. target ,v' target ).

[0168] exist Figure 11 In step SS4[8], the processing device 13, which functions as the correction value calculation unit 134, calculates the target value of the luminance and the target chromaticity (u') of the correction target point DP contained in the overlapping region DR. target ,v' target ), calculate the chromaticity correction value at the correction target point NP contained in the non-overlapping region NR and the chromaticity correction value at the correction target point DP contained in the overlapping region DR, so that the brightness of the non-overlapping region NR is substantially equal to the brightness of the overlapping region DR when the multi-projection system is constructed.

[0169] Specifically, the processing device 13 calculates the target chromaticity (u') according to the following steps. target ,v' target The correction value of the correction target point LP.

[0170] (Step 1) Calculate the XYZ values ​​for each calibration target point LP based on the target gray value of brightness and Equations 10-13. Here, the target gray value of brightness refers to the target gray value (r, g, b) of brightness as the target value of brightness at calibration target point DP and the target gray value (r, g, b) of brightness as the target value of brightness at calibration target point NP.

[0171] (Step 2) Based on Equation 14, calculate the Y value obtained in Step 1 and use it as the target chromaticity (u'). target ,v' target The X and Z values ​​of ).

[0172] (Step 3) Based on Equation 13, convert the XYZ values ​​calculated in Step 1 and Step 2 into RGB values, and set the RGB values ​​as the target RGB values.

[0173] (Step 4) Based on Figure 13 The relationship shown is used to calculate the input grayscale value as the target RGB value for each calibration target point LP. The input grayscale value in step 4 is the calibration value set for the calibration target point LP, which is the grayscale value directly or indirectly input to the pixel corresponding to the calibration target point LP among multiple pixels of the LCD panel.

[0174] Furthermore, regarding pixels other than the pixel corresponding to the correction target point LP among multiple pixels, for example, the processing device 13 sets the correction value of several pixels surrounding the pixel corresponding to the correction target point LP to the same value as the correction value of the pixel corresponding to the correction target point LP.

[0175] exist Figure 6 In step S5, the processing device 13, which functions as the correction value calculation unit 134, sets the correction value calculated in step S4 as the set value. As a result, in step S5, the processing device 13, which functions as the correction unit 136, sets the correction value based on the target chromaticity (u'). target ,v' target This corrects the chromaticity at each of the multiple correction target points LP.

[0176] exist Figure 2 In this process, the image acquired by the processing device 13, which functions as the image acquisition unit 135, is corrected based on a set correction value. As a result, the projected image PI, which corrects for black color unevenness and "black float" projected from the optical device 11 onto the projection surface SC, is obtained.

[0177] In the above control method, based on the maximum and minimum values ​​of the u' and v' groups, the target chromaticity (u') is... target ,v' targetIt is set as the chromaticity with the smallest chromaticity difference among multiple correction target points LP. Therefore, when the correction amount is insufficient during chromaticity correction, it can reduce the chromaticity difference after correction.

[0178] 2: Variation Example

[0179] The above methods can be modified in various ways. Specific modifications are illustrated below. The methods illustrated below and those shown in the above embodiments can be appropriately combined without contradiction. Furthermore, in the following illustrated modifications, elements with the same function and implementation method are represented by the same reference numerals as those used in the above description, and their detailed descriptions are appropriately omitted.

[0180] 2-1: Variation Example 1

[0181] In the above embodiment, the projection system 1 is illustrated as having multiple projection devices 10, but it is not limited to this embodiment. The number of projection devices 10 in the projection system 1 is not limited to multiple, and may also be a single device. When the projection system 1 has a single projection device 10, the multiple correction target points LP are points in the image projected from a single projection device 10. In this case, it is also possible to obtain an effect that allows for appropriate correction of the chromaticity of blacks within the image. The target value of brightness in this variation may be different from or the same as the target value of brightness in the above embodiment.

[0182] 2-2: Variation Example 2

[0183] In the above implementation, a smoothing method is illustrated by moving from one overlapping region DR, i.e., region RL1, toward the other overlapping region DR, i.e. region RL4, so that the gray values ​​(t, t, t) of the correction target point NP contained in the non-overlapping region NR are smoothly connected as the target value, but it is not limited to this method.

[0184] For example, it could also be smoothed by moving from one overlapping region DR (region RL1) to the other overlapping region DR (region RL4) in a way that the luminance component Y of the target value of the correction target point NP contained in the non-overlapping region NR is smoothly connected.

[0185] 3: Summary of this disclosure

[0186] The following is a summary published in this note.

[0187] Postscript 1

[0188] A first preferred embodiment of the control method disclosed herein is a control method for at least one projection device capable of projecting multiple images with different brightness levels. The control method includes: obtaining a chromaticity that makes the brightness of each of the multiple correction target points a target value; setting the chromaticity with the smallest chromaticity difference between the multiple correction target points as a target chromaticity for each of the multiple correction target points; and correcting the chromaticity of each of the multiple correction target points based on the target chromaticity.

[0189] In the above method, based on the maximum and minimum values ​​of the u' and v' groups, the target chromaticity is set to the chromaticity with the smallest chromaticity difference among multiple correction target points. Therefore, when the correction amount is insufficient during chromaticity correction, the chromaticity difference after correction can be reduced.

[0190] Appendix 2

[0191] A second preferred embodiment of the projection device disclosed herein is a projection device capable of projecting multiple images with different brightness levels. This projection device includes one or more processors that perform the following processing: obtaining a chromaticity that makes the brightness of each of the multiple correction target points a target value; setting the chromaticity with the smallest chromaticity difference between the multiple correction target points as a target chromaticity for each of the multiple correction target points; and correcting the chromaticity of each of the multiple correction target points based on the target chromaticity.

[0192] In the above method, based on the maximum and minimum values ​​of the u' and v' groups, the target chromaticity is set to the chromaticity with the smallest chromaticity difference among multiple correction target points. Therefore, when the correction amount is insufficient during chromaticity correction, the chromaticity difference after correction can be reduced.

[0193] Appendix 3

[0194] A third preferred embodiment of the program product disclosed herein is a program product that controls at least one projection device capable of projecting multiple images with different brightness levels. The program product causes a processor to perform the following processing: obtaining a chromaticity that makes the brightness of each of the multiple correction target points a target value; setting the chromaticity with the smallest chromaticity difference between the multiple correction target points as a target chromaticity for each of the multiple correction target points; and correcting the chromaticity of the multiple correction target points based on the target chromaticity.

[0195] In the above method, based on the maximum and minimum values ​​of the u' and v' groups, the target chromaticity is set to the chromaticity with the smallest chromaticity difference among multiple correction target points. Therefore, when the correction amount is insufficient during chromaticity correction, the chromaticity difference after correction can be reduced.

Claims

1. A control method for at least one projection device capable of projecting multiple images with different brightness levels. This control method includes: Obtain the chromaticity that makes the brightness of each of the multiple correction target points equal to the target value; For each of the plurality of correction target points, the chromaticity with the smallest chromaticity difference among the plurality of correction target points is set as the target chromaticity; and Based on the target chromaticity, the chromaticity of each of the plurality of correction target points is corrected.

2. A projection device capable of projecting multiple images with different brightness levels. The projection device has one or more processors. The processor performs the following processing: Obtain the chromaticity that makes the brightness of each of the multiple correction target points equal to the target value; For each of the plurality of correction target points, the chromaticity with the smallest chromaticity difference among the plurality of correction target points is set as the target chromaticity; and Based on the target chromaticity, the chromaticity of each of the plurality of correction target points is corrected.

3. A program product for controlling at least one projection device capable of projecting multiple images of different brightness. This program product causes the processor to perform the following processing: Obtain the chromaticity that makes the brightness of each of the multiple correction target points equal to the target value; For each of the plurality of correction target points, the chromaticity with the smallest chromaticity difference among the plurality of correction target points is set as the target chromaticity; and Based on the target chromaticity, the chromaticity of the plurality of correction target points is corrected.

Images