Control method of projection device and program product

Abstract

A control method of a projection device and a program product. Correction of low gradation colors close to black is performed using a measurement pattern on which a selection method corresponding to gamma characteristics is applied. In a measurement pattern used for correction of low gradation colors close to black, a difference value between a lowest first gradation value among a plurality of first gradation values included in the plurality of gradation data and a second lower first gradation value is smaller than a difference value between a highest first gradation value among the plurality of first gradation values and a second higher first gradation value.

Description

Technical Field

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

[0002] Patent Document 1 discloses a method in which the projection device projects four measurement patterns, namely a first measurement pattern to a fourth measurement pattern, while correcting the white balance of an intermediate gray level. Here, the first measurement pattern is image data representing an intermediate gray level. The second to fourth measurement patterns are patterns in which the individual color components contained in the first measurement pattern have been changed.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2016-161918

[0004] In conventional techniques, when correcting low-grayscale colors close to black, the gamma characteristic, which represents the relationship between grayscale and output brightness, results in a small change in output brightness relative to changes in grayscale at low grayscale levels, thus reducing the accuracy of detecting the measurement pattern required for black correction. While using the first measurement pattern described above can improve accuracy, it requires setting a selection method corresponding to the gamma characteristic for the second to fourth measurement patterns. However, Patent Document 1 does not consider a selection method corresponding to the gamma characteristic. Summary of the Invention

[0005] The control method for the projection device according to the present invention includes the following steps: When multiple colored lights corresponding one-to-one with the multiple grayscale data are projected from the projection device onto a projection surface based on multiple grayscale data, multiple measurement data are obtained based on the output of a sensor measuring the reflected light of each of the multiple colored lights reflected by the projection surface; and based on the multiple grayscale data and the multiple measurement data, correction data for correcting the color of an image to be displayed on the projection surface is calculated, wherein the multiple grayscale data includes multiple first grayscale values ​​representing at least one grayscale related to a first color component, multiple second grayscale values ​​representing at least one grayscale related to a second color component, and multiple grayscale values ​​representing a third color component. A plurality of third gray values ​​relating to at least one gray level, the plurality of measurement data including a first luminance value representing the luminance of reflected light corresponding to the first color component having the first gray value, a second luminance value representing the luminance of reflected light corresponding to the second color component having the second gray value, and a third luminance value representing the luminance of reflected light corresponding to the third color component having the third gray value, wherein the difference between the lowest first gray value and the second lowest first gray value among the plurality of first gray values ​​included in the plurality of gray data is less than the difference between the highest first gray value and the second highest first gray value among the plurality of first gray values.

[0006] The program product according to the present invention controls a projection device to perform the following steps: when multiple colored lights corresponding one-to-one with the multiple grayscale data are projected from the projection device onto a projection surface, based on multiple grayscale data, multiple measurement data are obtained based on the output of a sensor measuring the reflected light of each of the multiple colored lights reflected by the projection surface; and based on the multiple grayscale data and the multiple measurement data, correction data for correcting the color of an image to be displayed on the projection surface is calculated, wherein the multiple grayscale data includes multiple first grayscale values ​​representing at least one grayscale related to a first color component, multiple second grayscale values ​​representing at least one grayscale related to a second color component, and... And a plurality of third gray values ​​representing at least one gray level related to the third color component, the plurality of measurement data including a first luminance value representing the luminance of reflected light corresponding to the first color component having the first gray value, a second luminance value representing the luminance of reflected light corresponding to the second color component having the second gray value, and a third luminance value representing the luminance of reflected light corresponding to the third color component having the third gray value, wherein the difference between the lowest first gray value and the second lowest first gray value among the plurality of first gray values ​​included in the plurality of gray data is less than the difference between the highest first gray value and the second highest first gray value among the plurality of first gray values. Attached Figure Description

[0007] Figure 1 This is a diagram showing the overall structure of the projection system 1.

[0008] Figure 2 This is a block diagram of the projection device 10A.

[0009] Figure 3 It is a graph showing the relationship between the γ curve in the overlapping region DR and the input gray level and the output brightness.

[0010] Figure 4 This is a graph showing the relationship between the γ curve and the input gray level and the output brightness in the non-overlapping region NR.

[0011] Figure 5 It is a graph showing the relationship between the input grayscale and the output brightness in the overlapping region DR and the non-overlapping region NR.

[0012] Figure 6 This is an explanatory diagram of the projection method of the measurement pattern based on the projection device 10A.

[0013] Figure 7 This is a functional block diagram of the calibration unit 136.

[0014] Figure 8 This is a flowchart illustrating an example of the operation of the projection device 10A according to the first embodiment.

[0015] Figure 9 This is a diagram showing an example of a lattice point LP.

[0016] Figure 10 This is a diagram showing an example of a lattice point LP.

[0017] Figure 11 This is a diagram showing an example of a lattice point LP.

[0018] Figure 12 This is a diagram showing an example of an interpolation curve R(r, 34, 34) for interpolating the measured values ​​of the R component in the measured values ​​(R, G, B) calculated by the processing device 13.

[0019] Figure 13 This is a diagram showing an example of an interpolation curve G(r, 34, 34) for interpolating the measured values ​​of the G component in the measured values ​​(R, G, B) calculated by the processing device 13.

[0020] Figure 14 This is a diagram showing an example of an interpolation curve B(r, 34, 34) for interpolating the measured values ​​of the B component in the measured values ​​(R, G, B) calculated by the processing device 13.

[0021] Figure 15 This is a graph showing an example of an interpolation curve R(34, g, 34) for interpolating the measured values ​​of the R component in the measured values ​​(R, G, B) calculated by the processing device 13.

[0022] Figure 16 This is a graph showing an example of an interpolation curve G(34, g, 34) for interpolating the measured values ​​of the G component in the measured values ​​(R, G, B) calculated by the processing device 13.

[0023] Figure 17 This is a graph showing an example of an interpolation curve B(34, g, 34) interpolated from the measured values ​​(R, G, B) calculated by the processing device 13, which is an interpolation curve for the B component.

[0024] Figure 18 This is a diagram showing an example of an interpolation curve R(34, 34, b) for interpolating the measured values ​​of the R component in the measured values ​​(R, G, B) calculated by the processing device 13.

[0025] Figure 19 This is a graph showing an example of an interpolation curve G(34, 34, b) for interpolating the measured values ​​of the G component in the measured values ​​(R, G, B) calculated by the processing device 13.

[0026] Figure 20 This is a graph showing an example of an interpolation curve B(34, 34, b) for interpolating the measured values ​​of the B component in the measured values ​​(R, G, B) calculated by the processing device 13.

[0027] Figure 21 The graphs of Equations 10 to 12 are shown in a space with R, G, and B components as the three axes.

[0028] Label Explanation

[0029] 1: Projection system; 10: Projection device; 10A: Projection device; 10B: Projection device; 10C: Projection device; 11: Projector; 12: Imaging device; 13: Processing device; 14: Storage device; 15: Communication device; 20: Image providing 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; DP: Grid point; DR: Overlap area; LC: Brightness correction circuit; LN: Communication line ; LP: Grid point; NP: Grid point; NR: Non-overlapping area; PI: Projected image; PI1: Projected image; PI2: Projected image; PI3: Projected image; PI_A: Projected image; PP: Grid point; PR1: Control program; PT1: Part; PT2: Part; PT3: Part; PT4: Part; PT5: Part; PT6: Part; PT7: Part; RL: Region; RL1: Region; RL2: Region; RL3: Region; RL4: Region; RL5: Region; SC: Projection surface; UL: Color unevenness correction circuit. Detailed Implementation

[0030] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. However, the dimensions and scales of the various parts in the drawings differ appropriately from the actual dimensions and scales. Furthermore, the embodiments described below are preferred examples of the present invention, and therefore various technically preferred limitations have been added. However, unless otherwise specified in the following description, the scope of the present invention is not limited to these embodiments.

[0031] 1: First Implementation Method

[0032] The following is for reference Figures 1 to 21 The projection system 1 according to the first embodiment will be described.

[0033] 1-1: Structure of the first embodiment

[0034] 1-1-1: Overall Structure

[0035] Figure 1 This diagram shows the overall structure of the projection system 1. The projection system 1 includes projection device 10A, projection device 10B, projection device 10C, and image providing device 20. Projection device 10A is an example of a "first projection device". Projection device 10B is an example of a "second projection device". Projection device 10C is an example of a "third projection device".

[0036] Projection device 10A, projection device 10B, projection device 10C and image providing device 20 are connected to each other via communication line LN in a manner that enables them to communicate with each other.

[0037] Projection devices 10A, 10B, and 10C project various images or videos onto the projection surface SC. As an example, projection device 10A is the main projection device relative to projection devices 10B and 10C. Projection devices 10B and 10C are secondary projection devices relative to projection device 10A. Specifically, projection device 10A sends various control signals to projection devices 10B and 10C respectively. As a result, projection device 10A controls projection devices 10B and 10C. These control signals include various correction values, which will be described later.

[0038] In addition, the image providing device 20 provides various images to the projection devices 10A, 10B, and 10C. The projection devices 10A, 10B, and 10C respectively project the images provided by the image providing device 20 onto the projection surface SC.

[0039] Alternatively, the image providing device 20 may only provide an image to the projection device 10A, while the projection device 10A provides the images to be projected by each projection device 10 to the projection devices 10B and 10C, respectively. Furthermore, in this embodiment, without distinguishing between projection devices 10A and 10C, they are referred to as projection device 10.

[0040] Alternatively, in projection system 1, projection devices 10A, 10B, and 10C can read the images to be projected from their respective storage devices 14 and project them onto the projection surface SC. Alternatively, projection device 10A can read the images to be projected from its own storage device 14 and provide the images to be projected by each projection device to projection devices 10B and 10C respectively. In this case, projection system 1 may not necessarily include an image providing device 20.

[0041] exist Figure 1 In the example shown, 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. By projecting projection images PI1, PI2, and PI3 onto projection surface SC in a way that partially overlaps each other, a single projection image PI_A is displayed as a whole on projection surface SC.

[0042] Specifically, projected image PI1 comprises portions of PT1 and PT2. Projected image PI2 comprises portions of PT3, PT4, and PT5. Projected image PI3 comprises portions of PT6 and PT7. Portions of PT1 from projected image PI1 and PT3 from projected image PI2 are projected onto the projection surface SC in an overlapping manner. Additionally, portions of PT5 from projected image PI2 and PT6 from projected image PI3 are projected onto the projection surface SC in an overlapping manner.

[0043] As a result, region RL1 of the projected image PI_A contains a portion PT1 of the projected image PI1 and a portion PT3 of the projected image PI2. Region RL2 of the projected image PI_A contains only a portion PT2 of the projected image PI1. Region RL3 of the projected image PI_A contains only a portion PT4 of the projected image PI2. Region RL4 of the projected image PI_A contains a portion PT5 of the projected image PI2 and a portion PT6 of the projected image PI3. Region RL5 of the projected image PI_A contains a portion PT7 of the projected image PI3.

[0044] In the projected image PI_A, regions RL1 and RL4 are overlapping regions DR. On the other hand, regions RL2, RL3, and RL5 are non-overlapping regions NR. The overlapping region DR is an example of "region 1". The non-overlapping region NR is an example of "region 2".

[0045] 1-1-2: Structure of the projection device

[0046] Figure 2 This is a block diagram of the projection device 10A. Furthermore, projection devices 10B and 10C may also have the same structure as projection device 10A. Alternatively, projection devices 10B and 10C may have the following structure: they have the necessary structure for a projection device, but on the other hand, they do not include at least one of the following: 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).

[0047] The projection device 10A includes a projector 11, a shooting device 12, a processing device 13, a storage device 14, and a communication device 15.

[0048] The various elements of the projection device 10A are interconnected via one or more buses for communication of information. Alternatively, the various elements of the projection device 10A may be composed of one or more devices, or some elements of the projection device 10A may be omitted.

[0049] Projector 11 is an optical device that projects various projected images PI onto a projection surface SC such as a screen or wall. Projector 11 projects various projected images PI under the control of processing unit 13. Projector 11 includes, for example, a light source, a projection lens, a dichroic mirror, a prism, and a liquid crystal panel. The liquid crystal panel modulates the light from the light source, and the modulated light is projected onto the projection surface SC via the projection lens. Furthermore, the light source, projection lens, dichroic mirror, and prism are examples of a projection optical system.

[0050] The imaging device 12 is a device for capturing a projected image PI that is projected onto the projection surface SC. The imaging device 12 captures various images under the control of the processing device 13. As an example, the imaging device 12 is an image sensor. The imaging device 12 is an example of a "sensor".

[0051] 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. Alternatively, 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), and 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.

[0052] Storage device 14 is a recording medium readable by processing device 13, storing multiple programs including control program PR1 executed by processing device 13. Additionally, during calibration (described later), storage device 14 stores a measurement pattern image projected from projector 11. 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.

[0053] The communication device 15 is hardware used for communicating with other devices as a transceiver. 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 have a connector for wired connection and an interface circuit corresponding to the connector. Additionally, the communication device 15 may have 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, Bluetooth (registered trademark), etc., are examples.

[0054] The processing unit 13 reads and executes the control program PR1 from the storage device 14, thereby functioning 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. Furthermore, the control program PR1 can also be sent from other devices, such as a server that manages the projection device 10A, via a communication network.

[0055] The projection control unit 131 causes the projector 11 to project the aforementioned measurement pattern onto the projection surface SC. Additionally, the projection control unit 131 causes the projector 11 to project the image acquired by the image acquisition unit 135 from the image providing device 20 onto the projection surface SC.

[0056] The shooting control unit 132 causes the shooting device 12 to capture the reflected light of the measurement pattern projected onto the projection surface SC.

[0057] The image analysis unit 133 analyzes the reflected light of the measurement pattern captured by the imaging device 12 and calculates a measurement value representing the color of the measurement pattern in the captured image. This measurement value is an example of "measurement data".

[0058] The correction value calculation unit 134 calculates the correction value set by the correction unit 136, which will be described later, based on the measurement value calculated by the image analysis unit 133.

[0059] Hereinafter, the measurement pattern projected by the projector 11 will be described in this embodiment.

[0060] As an example, a projection device with conventional color adjustment functions divides the color from the lowest gray level on the black side to the highest gray level on the white side into approximately equal segments, projects colored light having the gray level at each segmentation point, and calculates a correction value based on the imaging result obtained by photographing the colored light projected onto the projection surface. At this time, the projection device estimates the color of the intermediate gray level between the gray level of the first colored light and the gray level of the second colored light, for example, based on interpolation operations such as spline interpolation, and calculates the correction value based on the estimation result.

[0061] Alternatively, as another example, a projection device with conventional color adjustment functions projects colored light with a color based on a mid-grayscale gray, and a correction value is calculated based on the image obtained by photographing the colored light projected onto the projection surface. In this case, for colors other than gray, the properties of additive color mixing are used to estimate the color based on interpolation, and the correction value is calculated based on the result of this estimation.

[0062] However, the color of light near the low grayscale side (close to 0 grayscale) is obtained by gradually adding RGB-modulated light to the light output from a black liquid crystal panel with 0 grayscale (i.e., 0 transmittance). Therefore, the chromaticity u'v' changes significantly, leading to larger estimation errors in conventional measurement methods. Specifically, if the transmittance is increased from the 0 grayscale state of the liquid crystal panel, there is a tendency for a significant change in the ratio of RGB-modulated light (R, G, and B light). This change in ratio results in a change in chromaticity u'v'. Furthermore, the non-uniformity of chromaticity u'v' when the liquid crystal panel's transmittance is 0 can be caused, for example, by color non-uniformity in the projection optical system. Color non-uniformity in the projection optical system can be caused, for example, by chromatic aberration of the projection lens or the manufacturing precision of the prism.

[0063] Furthermore, in a typical projection device, for example, the input-output characteristics are adjusted to γ ​​= 2.2. Therefore, near the grayscale value of 0, the change in light intensity when the grayscale changes is small. Thus, to correct unevenness in black, the corrected output grayscale (correction value) needs to be increased to a level that ensures a certain degree of change in light intensity when the grayscale changes. Moreover, "output grayscale" refers to the grayscale of the colored light projected onto the projection surface SC, meaning the grayscale output from the correction unit 136 to the projector 11, as described later.

[0064] In addition, in order to correct the difference in brightness between the overlapping region DR and the non-overlapping region NR, i.e. "black floating", the corrected output grayscale (correction value) needs to be increased to make the brightness of the non-overlapping region NR the same as the brightness of the overlapping region DR.

[0065] When black light (0 grayscale) is projected onto the projection surface SC as a reference, and the measured value is calculated by analyzing the captured image of the reflected light from the projection surface SC, the measured grayscale value deviates significantly from the corrected grayscale value, resulting in a larger interpolation error. Consequently, it becomes impossible to calculate a highly accurate correction value. In short, as an example, when black correction is performed using projected light divided into eight equal parts by a grayscale width from grayscale 0 to grayscale 1023, the interpolation error becomes significant.

[0066] Furthermore, the brightness of the projected light on the low grayscale side, which is close to black, is low, thus increasing the influence of dark current noise, optical shot noise, etc. Therefore, when calculating the measurement value by projecting monochromatic light of R, G, and B onto the projection surface according to each projection device and analyzing the imaging results of the reflected light from the projection surface, there is a problem that the error contained in the measurement value increases.

[0067] Therefore, in this embodiment, the projection light on the near-black low grayscale side, which is projected as the measurement pattern, is set as projection light of multiple grayscales.

[0068] The grayscale of the measurement pattern used for overlapping region DR is set to at least 3 grayscale levels, including grayscale levels lower than the predicted output grayscale level corresponding to the output brightness (luminance) after color unevenness correction, and grayscale levels higher than the predicted grayscale level. The grayscale of the measurement pattern used for overlapping region DR is set to at least 3 grayscale levels because at least 3 grayscale levels are required when considering the curve fitting of the input-output characteristics, i.e., γ = 2.2. As an example, these 3 grayscale levels are defined as grayscale A, grayscale B, and grayscale C (A < B < C). Grayscale A is an example of the "first value". Grayscale B is an example of the "second value". Grayscale C is an example of the "third value". The projection device 10A of this embodiment, by setting the grayscale of the measurement pattern used for overlapping region DR to at least 3 grayscale levels, can measure in detail the grayscale required for color unevenness correction on the low grayscale side, which is close to black.

[0069] Figure 3 It is a graph showing the relationship between the γ curve in the overlapping region DR and the input gray level and the output brightness.

[0070] like Figure 3 As shown, grayscale A is a grayscale lower than the predicted output grayscale corresponding to the output brightness after color unevenness correction. On the other hand, grayscale C is a grayscale higher than the predicted output grayscale corresponding to the output brightness after color unevenness correction. Grayscale B is a grayscale between grayscale A and grayscale C.

[0071] As mentioned above, at gray levels close to 0 (black), such as Figure 3 As shown, a slight change in output brightness leads to a significant change in chromaticity. Therefore, if a light with a gray level lower than gray level A is used as the projection light, the correction error increases. Therefore, it is preferable to perform correction after brightening the black to an output brightness where the γ curve has a certain slope. A predicted gray level corresponding to the output brightness where the γ curve has a certain slope is predetermined. In order to improve the fitting accuracy when interpolating between gray levels A and C using the γ curve, the projection device 10A of this embodiment measures the output gray levels including the lowest three gray levels, including gray level B, which is the intermediate gray level between gray levels A and C. Gray level A is a gray level lower than the predicted gray level, and gray level C is a gray level higher than the predicted gray level.

[0072] The predicted grayscale is predetermined based on the degree of color unevenness that originally exists in the projection device 10. For example, if color unevenness can be suppressed with a small adjustment, the predicted grayscale is set to low grayscale. On the other hand, for example, if color unevenness is aggravated due to the quality of the components used in the projection device (projection lens, etc.), the predicted grayscale is set to high grayscale to ensure a minimum adjustment range.

[0073] Furthermore, grayscale A can be determined with the goal of sufficiently changing the light intensity when the grayscale changes by one step. "Sufficiently changing the light intensity" means a change to such an extent that, for example, when the image analysis unit 133 analyzes the image of the measurement pattern before and after the grayscale change by one step, the image analysis unit 133 can detect a light intensity difference greater than a specified value between the two. As an example, grayscale A is targeted to have a color difference Δu'v' of approximately 1 / 1000 when the grayscale changes by one step. For example, in the case of a projection device with a contrast ratio of 2000:1, when the maximum grayscale value is set to 1023, grayscale A becomes a grayscale value of 20 or higher. In the case of a projection device with a contrast ratio of 3000:1, when the maximum grayscale value is set to 1023, grayscale A becomes a grayscale value of 15 or higher.

[0074] On the other hand, grayscale C is a grayscale value of 127 or less, which is the maximum value of the first segment after dividing the grayscale width from grayscale 0 to grayscale 1023 into 8 segments. Alternatively, grayscale C can also be a grayscale value of 128 or less, which is the minimum value of the second segment after dividing the grayscale width from grayscale 0 to grayscale 1023 into 8 segments.

[0075] As a result, the difference between grayscale A and grayscale B is less than the difference between the highest grayscale value and the second highest grayscale value among the multiple input grayscale values ​​up to grayscale 1023. Here, as an example, the "highest grayscale value" is 1023, the highest grayscale value among the eighth segment after dividing the grayscale width from grayscale 0 to grayscale 1023 into eight parts. As an example, the "second highest grayscale value" is 896, the lowest grayscale value among the eighth segment after dividing the grayscale width from grayscale 0 to grayscale 1023 into eight parts.

[0076] In this embodiment, the grayscale width from grayscale 0 to grayscale 1023 is divided into 8 intervals, but this is not particularly limited. For example, the grayscale width from grayscale 0 to grayscale 1023 can also be divided into 7 intervals, or even 9 intervals. When the grayscale width from grayscale 0 to grayscale 1023 is divided into 7 intervals, for example, the maximum value of the grayscale width of the first segment is 146, and grayscale C can also be a grayscale value below 146.

[0077] The grayscale of the measurement pattern used for non-overlapping region NR is set to at least 3 grayscale levels, including grayscale levels lower than and higher than the grayscale level predicted to correspond to the output grayscale level after "black float" correction. The grayscale of the measurement pattern used for non-overlapping region NR is set to at least 3 grayscale levels because at least 3 grayscale levels are required when considering the curve fitting of the input-output characteristics, i.e., γ = 2.2. As an example, these 3 grayscale levels are set to grayscale B', grayscale C', and grayscale D (B' < C' < D). Grayscale B' is an example of a "fourth value." Grayscale C' is an example of a "fifth value." Grayscale D is an example of a "sixth value." The projection device 10A of this embodiment, by setting the grayscale of the measurement pattern used for non-overlapping region NR to at least 3 grayscale levels, can measure in detail the grayscale required for correcting "black float" on the low grayscale side close to black. The predicted grayscale is determined in advance, for example, through experiments or simulations.

[0078] Figure 4 This is a graph showing the relationship between the γ curve and the input gray level and the output brightness in the non-overlapping region NR.

[0079] like Figure 4 As shown, grayscale B' is a grayscale lower than the predicted output grayscale corresponding to the output brightness after "black floating" correction. On the other hand, grayscale D is a grayscale higher than the predicted output grayscale corresponding to the output brightness after "black floating" correction. Grayscale C' is a grayscale between grayscale B' and grayscale D.

[0080] The difference between grayscale B' and grayscale C' is less than the difference between the highest grayscale value and the second highest grayscale value among the multiple input grayscale values ​​up to grayscale 1023. Here, as an example, the "highest grayscale value" is 1023, the highest grayscale value among the eighth segment after dividing the grayscale width from grayscale 0 to grayscale 1023 into eight parts. As an example, the "second highest grayscale value" is 896, the lowest grayscale value among the eighth segment after dividing the grayscale width from grayscale 0 to grayscale 1023 into eight parts.

[0081] Figure 4 The grayscale B' ratio shown Figure 3 The grayscale A shown is high. In the overlapping region DR, the projected light from the projection device 10 overlaps by an amount of 2 units, so the brightness of the projected image PI in the overlapping region DR becomes the brightness of the projection device 10 by an amount of 2 units. In order to correct the "black float", it is necessary to project a projected light with a higher grayscale than that in the overlapping region DR into the non-overlapping region NR, so grayscale B' needs to be higher than grayscale A.

[0082] Furthermore, when bright gray light is projected onto the overlapping region DR beyond the range that can minimally eliminate color unevenness, the overall contrast deteriorates. Therefore, it is preferable to project gray light onto the overlapping region DR within the range that can minimally eliminate color unevenness.

[0083] In addition, through Figure 3 Gray levels A, B, and C in the data are... Figure 4 In the grayscale values ​​B', C', and D, making grayscale B equal to grayscale B' and grayscale C equal to grayscale C' enables the sharing of a portion of the measurement pattern in corrections related to the overlapping region DR and corrections related to the non-overlapping region NR.

[0084] Figure 5 It is a graph showing the relationship between the input grayscale and the output brightness in the overlapping region DR and the non-overlapping region NR.

[0085] Specifically, the projection control unit 131 may project the measurement pattern of the lowest four gray levels—gray level A, gray level B = gray level B', gray level C = gray level C', and gray level D—onto the overlapping region DR and the non-overlapping region NR. The image analysis unit 133 may then analyze the measurement pattern image captured by the imaging device 12 and calculate the measurement value. Alternatively, the projection control unit 131 may project a measurement pattern of gray level 0 onto the overlapping region DR and the non-overlapping region NR, and the image analysis unit 133 may analyze the measurement pattern image captured by the imaging device 12 and calculate the measurement value.

[0086] As a result, the number of measurement patterns can be reduced, and the measurement time can be shortened.

[0087] To brighten the measurement pattern, it is preferable that the measurement pattern is not set to a single color among the R, G, and B components, but rather to a color obtained by changing one of the color components of the R, G, and B components based on a reference gray. Furthermore, the R component is an example of a "first color component," the G component is an example of a "second color component," and the B component is an example of a "third color component." In this case, it is preferable that the reference gray is set to a gray of gray B that is close to the output gray of the overlapping area DR after color unevenness correction, where the R, G, and B components are all close to the gray of the overlapping area DR. As a result, the gray of the measurement pattern becomes 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, and b, respectively. r is an example of a "first gray value," g is an example of a "second gray value," and b is an example of a "third gray value."

[0088] Measurement Pattern 1: (r, g, b) = (D, B, B)

[0089] Measurement pattern 2: (r, g, b) = (B, D, B)

[0090] Measurement pattern 3: (r, g, b) = (B, B, D)

[0091] Measurement pattern 4: (r, g, b) = (C, B, B)

[0092] Measurement pattern 5: (r, g, b) = (B, C, B)

[0093] Measurement pattern 6: (r, g, b) = (B, B, C)

[0094] Measurement pattern 7: (r, g, b) = (B, B, B)

[0095] Measurement pattern 8: (r, g, b) = (A, B, B)

[0096] Measurement pattern 9: (r, g, b) = (B, A, B)

[0097] Measurement pattern 10: (r, g, b) = (B, B, A)

[0098] If the measurement pattern also includes grayscale 0, the following measurement pattern is also used.

[0099] Measurement pattern 11: (r, g, b) = (0, B, B)

[0100] Measurement pattern 12: (r, g, b) = (B, 0, B)

[0101] Measurement pattern 13: (r, g, b) = (B, B, 0)

[0102] Furthermore, the combination of (r, g, b) of these measurement patterns projected from projector 11 onto projection surface SC is an example of "grayscale data". The grayscale value of r in (r, g, b) is an example of "first grayscale value". The grayscale value of g in (r, g, b) is an example of "second grayscale value". The grayscale value of b in (r, g, b) is an example of "third grayscale value".

[0103] By using the above-mentioned measurement pattern, the measurement pattern can be brightened, the S / N ratio of the imaging device 12 can be improved, and the measurement error can be reduced.

[0104] In conventional methods, for example, when correcting the R component among the R, G, and B components, a measurement pattern is sometimes used where only the liquid crystal panel corresponding to the R component is driven, and a black color with a grayscale of 0 is output from the liquid crystal panels corresponding to the G and B components. In this embodiment, to improve the S / N ratio and to brighten the measurement pattern, measurement patterns that increase the R component, decrease the R component, increase the G component, decrease the G component, increase the B component, and decrease the B component are used compared to a gray pattern where all R, G, and B components are grayscale B.

[0105] Figure 6 This is an explanatory diagram of the projection method of the measurement pattern based on the projection device 10A.

[0106] In addition, to simplify the explanation, in Figure 6 In the middle, to and Figure 1 The same structural elements use the same labels. On the other hand, in Figure 6 In, with Figure 1 The difference is that only the projected image PI1 projected from the projection device 10A and the projected image PI2 projected from the projection device 10B are shown, while the projected image PI3 projected from the projection device 10C is omitted. Additionally, in Figure 6 In this diagram, the projected image PI3 is omitted. Therefore, the projected image PI2 only has a portion of PT3 and a portion of PT4, but not a portion of PT5. Consequently, the projected image PI2 includes regions RL1 and RL3, but not region RL4.

[0107] exist Figure 6 In this example, the projected image PI1 projected by the projection device 10A and the projected image PI2 projected by the projection device 10B are the same measurement pattern. As an example, both the projected image PI1 and the projected image PI2 are the aforementioned measurement pattern 1. However, the projected images PI1 and PI2 are not limited to measurement pattern 1; both can be any one of measurement patterns 2 to 13.

[0108] Furthermore, the projection of image PI1 by projection device 10A is synchronized with the projection of image PI2 by projection device 10B. That is, image PI2 is projected at the same timing as image PI1.

[0109] The combination of the R, G, and B components (r, g, b) of the first measurement pattern of the projected image PI1 projected from the projection device 10A is an example of "first grayscale data". Another example indicates that the color light of this first measurement pattern is "first color light". Another example indicates that the color light of the first measurement pattern of the projected image PI2 projected from the projection device 10B is "second color light". In the overlapping region DR, "first color light" and "second color light" overlap.

[0110] Furthermore, the combination of the R, G, and B components (r, g, b) of the second measurement pattern of the projected image PI1 projected from the projection device 10A is an example of "second grayscale data". Additionally, an example indicates that the color light of this second measurement pattern is "third color light". Furthermore, an example indicates that the color light of the second measurement pattern of the projected image PI2 projected from the projection device 10B is "fourth color light". In the overlapping region DR, "third color light" and "fourth color light" overlap.

[0111] By projecting the projected image PI using the above-described projection method, the brightness of the overlapping area DR is more than twice that of the case where the measurement pattern is projected using a single projection device 10, thereby improving the S / N ratio 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. In addition, the grayscale of any component among the R, G, and B components of each measurement pattern is not zero, thus reducing errors in the measurement values ​​obtained using the imaging device 12.

[0112] In conventional projection methods that project measurement patterns from multiple projection devices, for example, a non-zero grayscale color light is projected from one projection device as the measurement pattern, while a black measurement pattern with zero grayscale is projected from the other projection devices. In this case, the brightness of the overlapping area DR is less than half that of this embodiment. On the other hand, in order to achieve a good signal-to-noise ratio (S / N) for the imaging device 12, the projection system 1 of this embodiment projects the same color light from all projection devices 10 simultaneously as the measurement pattern. As a result, compared to conventional projection methods that project color light from only one projection device as the measurement pattern, the measurement pattern is more than twice as bright.

[0113] In another example of a method for projecting measurement patterns from multiple projection devices, consider the following approach: Colored light is projected as a measurement pattern from only one projection device, and a first measurement value is calculated by photographing the projected measurement pattern. Then, colored light is projected as a measurement pattern from only the other projection devices, and a second measurement value is calculated by photographing the projected measurement patterns. In this case, the first and second measurement values ​​are added together, but due to errors in both the first and second measurement values, the sum of the first and second measurement values ​​results in a 2x error. Specifically, measuring light with half brightness deteriorates the S / N ratio, thus the standard deviation of the error becomes √2x. Adding the two measurement values ​​results in the sum of the errors in both quantities, and the standard deviation of the error becomes √2x. Therefore, the final standard deviation of the error becomes the product of √2x and √2x, which is 2x. As a result, the noise in the S / N ratio becomes 2x. On the other hand, in this embodiment, the measurement is performed only once, thus reducing the noise in the S / N ratio.

[0114] Furthermore, in the above explanation, as an example, the effect was described when the projector 11 had three panels: a panel corresponding to the R component, a panel corresponding to the G component, and a panel corresponding to the B component. However, the same effect is achieved even when the liquid crystal panel has only one panel. This is because the brighter the light incident on the imaging device 12, which serves as the image sensor, the better the signal-to-noise ratio (S / N ratio) is.

[0115] The measurement pattern projected by the projector 11 has been described above in this embodiment.

[0116] Furthermore, a specific example of the method for calculating the correction value based on the correction value calculation unit 134 will be referred to... Figures 8 to 21 The operation of this embodiment will be described later in the explanation of the implementation method.

[0117] exist Figure 2 In this process, the image acquisition unit 135 acquires the image to be projected from the image providing device 20.

[0118] The correction unit 136 uses the correction value calculated by the correction value calculation unit 134 to correct the image acquired by the image acquisition unit 135.

[0119] Figure 7 This is a functional block diagram of the correction unit 136. The correction unit 136 includes a brightness correction circuit LC and a color unevenness correction circuit UC.

[0120] The brightness correction circuit LC uses 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. This correction includes the aforementioned correction of "black float".

[0121] The color unevenness correction circuit UC uses 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.

[0122] exist Figure 2 In the projection control unit 131, the projector 11 projects the image corrected by the correction unit 136 onto the projection surface SC as the projection image PI.

[0123] The communication control unit 137 enables the communication device 15 to send and receive various information with external devices. These various information include correction values ​​sent from the projection device 10A to the projection devices 10B and 10C respectively.

[0124] 1-2: Operation of the first embodiment

[0125] Figure 8 This is a flowchart illustrating an example of the operation of the projection device 10A according to the first embodiment.

[0126] In step S1, the projection device 10A calculates correction values ​​for grayscale (excluding black), brightness, and color unevenness. Then, 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 to 10C become uniform across the projection devices 10.

[0127] As an example, "black" here refers to the color contained in the first grayscale width, which includes grayscale 0, when the grayscale width is divided into N segments from the smallest grayscale value (grayscale 0) to the largest grayscale value (grayscale 1023). Here, N is an integer greater than or equal to 3. Furthermore, for ease of explanation, N is sometimes set to 8 below.

[0128] Furthermore, the aforementioned brightness correction targets grayscale values ​​other than black, reducing the difference in brightness between the overlapping region (DR) and the non-overlapping region (NR). Additionally, the methods used for color unevenness and brightness correction described above can also be existing techniques. As an example, this method could be as follows: Figure 1 In this process, any region RL from region RL1 to region RL5 is taken as the target region. The shooting value represented by the shooting value obtained by shooting the target region is compared with the shooting value obtained by shooting other regions RL, thereby correcting brightness and color unevenness.

[0129] At this time, the processing device 13 functions as a color unevenness correction circuit UC, thereby adjusting the point when correcting the projected image PI, for example, as the grid point LP in the 11 rows × 21 columns of the projected image PI. In addition, the gray level is based on the gray level of the boundary line obtained by dividing the gray level width from gray level 0 to gray level 1023 into 8 equal parts.

[0130] However, existing methods cannot correct for uneven color distribution of black near grayscale 0, therefore the correction value at grayscale 0 is not calculated.

[0131] Furthermore, in the processing of step S1, the processing device 13 determines whether the aforementioned grid points LP used as the color unevenness correction circuit UC are contained in the overlapping region DR or in the non-overlapping region NR.

[0132] Figures 9-11 This is a diagram showing an example of a lattice point LP. More specifically, Figure 9 This is an example of a grid point LP corresponding to the projected image PI1 projected from the projection device 10A. Figure 10 This is an example of a grid point LP corresponding to the projected image PI2 projected from the projection device 10B. Figure 11 This is an example of a grid point LP corresponding to the projected image PI3 projected from the projection device 10C.

[0133] exist Figures 9-11 In the diagram, grid point LP includes grid points DP, NP, and PP. In these diagrams, shaded circles represent grid point DP contained within the overlapping region DR. White circles represent grid point NP contained within the non-overlapping region NR. Circles with dashed outlines represent grid point PP whose inclusion in either the overlapping region DR or the non-overlapping region NR is uncertain. For... Figures 9-11 Each grid point LP shown has a measurement value calculated by the image analysis unit 133.

[0134] In step S2, the projection device 10A projects a black calibration measurement pattern. Specifically, the processing device 13 of 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 project the measurement pattern sequentially onto the projection surface SC.

[0135] The measurement pattern is any one of the measurement patterns 1 to 13 mentioned above. As described above, these measurement patterns are obtained by changing the gray level of one of the components R, G, and B, based on a grayscale value of B where all components R, G, and B are grayscale B.

[0136] Furthermore, as an example, in the first measurement pattern for color unevenness correction of black in the overlapping region DR, let gray level A be gray level 22, gray level B be gray level 34, and gray level C be gray level 60. This "first measurement pattern" corresponds to the "first gray level data" mentioned above.

[0137] Furthermore, in the second measurement pattern used for the correction of "black float" in non-overlapping NR regions and the correction of black color unevenness, let the aforementioned grayscale B' = grayscale B be grayscale 34, the aforementioned grayscale C' = grayscale C be 60, and grayscale D be grayscale 95. This second measurement pattern corresponds to the aforementioned "second grayscale data".

[0138] Furthermore, in the projection device 10A, the correction value for prioritizing contrast is also calculated simultaneously. Therefore, the processing device 13 functions as the projection control unit 131, thereby enabling the projector 11 to project a measurement pattern in which at least one of the R, G, and B components has a grayscale of 0.

[0139] In step S3, the processing unit 13 of the projection device 10A functions as an image capture control unit 132. The processing unit 13 causes the imaging device 12 to capture each measurement pattern projected onto the projection surface SC. Furthermore, the processing unit 13 functions as an image analysis unit 133. The processing unit 13 analyzes the measurement patterns captured by the imaging device 12 and calculates measurement values ​​representing the colors of the measurement patterns in the captured image.

[0140] In step S4, the processing unit 13 of the projection device 10A functions as a correction value calculation unit 134. The processing unit 13 calculates the correction values ​​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 when viewed from the imaging device 12, the color unevenness of the corrected black is suppressed, and the color becomes uniform when viewed from the imaging device 12.

[0141] First, the processing device 13 calculates the correspondence between the gray values ​​(r, g, b) (0≤r,g, b≤95) and the measured values ​​(R, G, B) at each grid point LP through interpolation. The gray values ​​(r, g, b) (0≤r, g, b≤95) are the gray values ​​of the colored light of the measurement pattern projected by the projector 11, and the measured values ​​(R, G, B) are the measured values ​​that represent the colors of the colored light in the captured image, calculated by analyzing the colored light of the measurement pattern captured by the imaging device 12.

[0142] Furthermore, as described above, for example, the gray values ​​of the R, G, and B components of the colored light projected by the projector 11 are set to 5 gray levels, ranging from gray level 0 to gray level 95.

[0143] Here, the grayscale value (r, g, b) is an example of "grayscale data".

[0144] In the grayscale values ​​(r, g, b) of the first measurement pattern, r is an example of the "first grayscale value", g is an example of the "second grayscale value", and b is an example of the "third grayscale value".

[0145] In the grayscale values ​​(r, g, b) of the second measurement pattern, r is an example of the "fourth grayscale value". g is an example of the "fifth grayscale value". b is an example of the "sixth grayscale value".

[0146] On the other hand, "measured value (R, G, B)" is an example of "measurement data". The "measured value (R, G, B)" corresponding to the first measurement pattern is an example of "first measurement data". The "measured value (R, G, B)" corresponding to the second measurement pattern is an example of "second measurement data".

[0147] The R component value in the measurement value (R, G, B) corresponding to the first measurement data is an example of a "first luminance value," representing the luminance of the reflected light corresponding to the "first color component" with a "first gray value." The G component value in the measurement value (R, G, B) corresponding to the first measurement data is an example of a "second luminance value," representing the luminance of the reflected light corresponding to the "second color component" with a "second gray value." The B component value in the measurement value (R, G, B) corresponding to the first measurement data is an example of a "third luminance value," representing the luminance of the reflected light corresponding to the "third color component" with a "third gray value."

[0148] The R component value in the measurement value (R, G, B) corresponding to the second measurement data is an example of a "fourth luminance value," representing the luminance of the reflected light corresponding to the "first color component" with a "fourth gray value." The G component value in the measurement value (R, G, B) corresponding to the second measurement data is an example of a "fifth luminance value," representing the luminance of the reflected light corresponding to the "second color component" with a "fifth gray value." The B component value in the measurement value (R, G, B) corresponding to the second measurement data is an example of a "sixth luminance value," representing the luminance of the reflected light corresponding to the "third color component" with a "sixth gray value."

[0149] Furthermore, for ease of understanding, when the projector 11 projects grayscale (r, g, b) colored light as a measurement pattern, the R component of the measured value (R, G, B) representing the color of the colored light in the captured image, calculated by the processing device 13, is expressed as R. （r, g, b） The G component is expressed as G （r, g, b） Component B is described as B （r, g, b） .

[0150] Additionally, when summarizing the R, G, and B components that represent the measurements of color light in the captured image, they are labeled as (R, G, B). （r, g, b） = (R)（r, g, b） G （r, g, b） B （r, g, b） ).

[0151] The measured values ​​of the five measurement patterns, in which only the R component is changed, in the grayscale (r, g, b) of the colored light used as the measurement pattern, are expressed as shown in Equations 1 to 5 below.

[0152]

[0153] All the measured values ​​of these five measurement patterns are known. Therefore, the processing device 13 can perform curve interpolation between the measured values ​​of the R component in 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 using every 3 points out of 5 points corresponding to the 5 measured values. Alternatively, the processing device 13 can also perform cubic curve interpolation using every 4 points out of 5 points corresponding to the 5 measured values.

[0154] Furthermore, in Equations 1 through 5 above, r = 22 is an example of the "first value". r = 34 is an example of the "second value". r = 60 is an example of the "third value". (R, G, B)(22, 34, 34) is an example of the "first measurement value". (R, G, B)(34, 34, 34) is an example of the "second measurement value". (R, G, B)(60, 34, 34) is an example of the "third measurement value".

[0155] Figure 12 This is a diagram illustrating an example of an interpolation curve R(r, 34, 34) that interpolates the measured values ​​of the R component in the measured values ​​(R, G, B) calculated by the processing device 13 when only r, which is the R component, is changed in the grayscale (r, g, b) of the colored light used as the measurement pattern. The interpolation curve R(r, 34, 34) is an example of a "curve representing the first characteristic".

[0156] Figure 13 This is a diagram showing an example of an interpolation curve G(r,34, 34) that interpolates the measured value of the G component in the measured value (R, G, B) calculated by the processing device 13 when only r, which is the R component, is changed in the grayscale (r, g, b) of the colored light as the measurement pattern.

[0157] Figure 14This is a diagram showing an example of an interpolation curve B(r,34, 34) for interpolating the measured value of the B component in the measured value (R, G, B) calculated by the processing device 13 when only r, which is the R component, is changed in the grayscale (r, g, b) of the colored light as the measurement pattern.

[0158] By using these three interpolation curves R(r, 34, 34), G(r, 34, 34), and B(r, 34, 34), the processing device 13 is able to estimate the measured values ​​(R, G, B) when colored light with an arbitrary gray level r (0≤r≤95) of R is projected onto the projection surface SC. （r, g, b） = (R) （r, g, b） G （r, g, b） B （r, g, b） ).

[0159] Figure 15 This is a diagram showing an example of an interpolation curve R(34, g, 34) for interpolating the measured values ​​of the R component in the measured values ​​(R, G, B) calculated by the processing device 13 when only g, which is the G component, is changed in the grayscale (r, g, b) of the colored light as the measurement pattern.

[0160] Figure 16 This is a diagram showing an example of an interpolation curve G(34, g, 34) that interpolates the measured values ​​of the G component in the measured values ​​(R, G, B) calculated by the processing device 13 when only g, which is the G component, is changed in the grayscale (r, g, b) of the colored light as the measurement pattern.

[0161] Figure 17 This is a diagram showing an example of an interpolation curve B(34, g, 34) for interpolating the measured value of the B component in the measured value (R, G, B) calculated by the processing device 13 when only g, which is the G component, is changed in the grayscale (r, g, b) of the colored light as the measurement pattern.

[0162] By using these three interpolation curves R(34, g, 34), G(34, g, 34), and B(34, g, 34), the processing device 13 is able to estimate 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. （r, g, b） = (R) （r, g, b） G （r, g, b） B （r, g, b） ).

[0163] Figure 18This is a diagram showing an example of an interpolation curve R(34, 34, b) for interpolating the measured values ​​of the R component in the measured values ​​(R, G, B) calculated by the processing device 13 when only b, which is the B component, is changed in the grayscale (r, g, b) of the colored light as the measurement pattern.

[0164] Figure 19 This is a diagram showing an example of an interpolation curve G(34, 34, b) that interpolates the measured value of the G component in the measured value (R, G, B) calculated by the processing device 13 when only b, which is the B component, is changed in the grayscale (r, g, b) of the colored light as the measurement pattern.

[0165] Figure 20 This is a diagram showing an example of an interpolation curve B(34, 34, b) for interpolating the measured values ​​of the B component in the measured values ​​(R, G, B) calculated by the processing device 13 when only b, which is the B component, is changed in the grayscale (r, g, b) of the colored light as the measurement pattern.

[0166] By using these three interpolation curves R(34, 34, b), G(34, 34, b), and B(34, 34, b), the processing device 13 is able to estimate 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. （r, g, b） = (R) （r, g, b） G （r, g, b） B （r, g, b） ).

[0167] As a result, as shown in Equations 6 to 8 below, which use 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 value (R, G, B) when only one color component of the grayscale value (r, g, b) of the colored light projected from the projector 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） ).

[0168]

[0169] In Equations 6 to 8 above, the grayscale values ​​(r, g, b) of the colored light projected from the projector 11 are arbitrarily varied only by one of the components r (R component), g (G component), and b (B component), while the other two components are fixed at a grayscale of 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) when all components r (R component), g (G component), and b (B component) of the grayscale values ​​(r, g, b) (0 ≤ r, g, b ≤ 95) of the colored light are arbitrarily varied using Equation 9 below. （r, g, b） = (R) （r, g, b） G （r, g, b） B （r, g, b） ).

[0170]

[0171] 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. Figure 21 The graphs of Equations 10 to 12 are shown in a three-dimensional space with the R component, G component, and B component as the three axes.

[0172]

[0173] When the projector 11 projects any correction value, i.e., any output grayscale (r, g, b) light output from the correction unit 136 to the projector 11, onto the projection surface SC, the processing device 13 can estimate the measurement values ​​(R, G, B) calculated by the image analysis unit 133 by using the above-described formulas 10 to 12. （r, g, b） = (R) （r, g, b） G （r, g, b） B （r, g, b） ).

[0174] The processing device 13 calculates the corrected output grayscale (r, g, b) corresponding to each grid point LP as the correction value (adjustment value), so that the brightness of the corrected black becomes the target brightness when observed from the imaging device 12, the color unevenness of the corrected black is suppressed, and it becomes a uniform color when observed from the imaging device 12.

[0175] Specifically, for each grid point LP, the processing device 13 can calculate the following: when the correction unit 136 outputs a certain output grayscale (r, g, b) to the projector 11, what color the reflected light from the projector 11 projected onto the projection surface SC will appear when observed by the imaging device 12. The processing device 13 can also perform the inverse operation of this calculation. As a result, the processing device 13 calculates the corrected output grayscale (r, g, b) as a correction value (adjustment value) by matching the brightness of the corrected black and the color unevenness of the corrected black.

[0176] Furthermore, projection devices 10A, 10B, and 10C have the same γ characteristic. As a result, if the processing unit 13 of projection device 10A calculates the corrected output grayscale (r, g, b) corresponding to each grid point LP in the projected image PI1, then in the overlapping region DR of the projected images PI1 and PI2, the same corrected output grayscale (r, g, b) can be applied to the grid points LP in the projected image PI2 located near the grid points LP in the projected image PI1 as to the grid points LP in the projected image PI1.

[0177] exist Figure 8 In step S5, the processing unit 13 of the projection device 10A functions as a correction value calculation unit 134. The processing unit 13 sets the correction values ​​calculated in step S4 for the brightness correction circuit LC and the color unevenness correction circuit UC.

[0178] exist Figure 2 In this process, the image acquired by the processing device 13, which functions as the image acquisition unit 135, is corrected by the brightness correction circuit LC and the color unevenness correction circuit UC, which are set with the aforementioned correction values. As a result, a projected image PI, with corrected black color unevenness and "black floating", is projected from the projector 11 onto the projection surface SC.

[0179] 2: Variation Example

[0180] The above methods can be varied. Specific variations are illustrated below. The methods illustrated below and those shown in the above embodiments can be appropriately combined without contradiction. Furthermore, in the variations illustrated below, elements with the same function and implementation method are omitted with reference to the reference numerals used in the above description.

[0181] 2-1: Variation Example 1

[0182] In the above embodiment, the projection system 1 includes projection devices 10A, 10B, and 10C. Based on this, the projected image PI1 projected from projection device 10A, the projected image PI2 projected from projection device 10B, and the projected image PI3 projected from projection device 10C are stitched together while overlapping in a portion of their areas, thereby forming a projected image PI_A. The correction for uneven black color and "black floating" in the above embodiment are corrections in this projected image PI_A.

[0183] However, the correction of uneven black color can also be achieved when the projection system 1 has only one projection device 10A.

[0184] 3: Summary of this disclosure

[0185] The following is a summary published in this note.

[0186] Postscript 1

[0187] A method for controlling a projection device includes the following steps: When projecting multiple colored lights, each corresponding one-to-one with the multiple grayscale data, from the projection device onto a projection surface based on multiple grayscale data, acquiring multiple measurement data based on the output of a sensor measuring the reflected light of each of the multiple colored lights reflected by the projection surface; and calculating correction data for correcting the color of an image to be displayed on the projection surface based on the multiple grayscale data and the multiple measurement data, wherein the multiple grayscale data includes multiple first grayscale values ​​representing at least one grayscale related to a first color component, multiple second grayscale values ​​representing at least one grayscale related to a second color component, and multiple grayscale values ​​representing a third color component... A plurality of third gray values ​​relating to at least one gray level, the plurality of measurement data including a first luminance value representing the luminance of reflected light corresponding to the first color component having the first gray value, a second luminance value representing the luminance of reflected light corresponding to the second color component having the second gray value, and a third luminance value representing the luminance of reflected light corresponding to the third color component having the third gray value, wherein the difference between the lowest first gray value and the second lowest first gray value among the plurality of first gray values ​​included in the plurality of gray data is less than the difference between the highest first gray value and the second highest first gray value among the plurality of first gray values.

[0188] The control method described in Appendix 1, with the structure described above, enables the correction of low-grayscale colors approaching black using a measurement pattern with a selection method corresponding to the gamma characteristics applied to the first grayscale value. As a result, the correction accuracy of low-grayscale colors approaching black is improved.

[0189] Appendix 2

[0190] According to the control method of the projection device described in Appendix 1, the difference between the lowest second gray value and the second lowest second gray value among the plurality of second gray values ​​contained in the plurality of gray data is less than the difference between the highest second gray value and the second highest second gray value among the plurality of second gray values, and the difference between the lowest third gray value and the second lowest third gray value among the plurality of third gray values ​​contained in the plurality of gray data is less than the difference between the highest third gray value and the second highest third gray value among the plurality of third gray values.

[0191] The control method in Appendix 2, by having the structure described above, can also correct low-grayscale colors that are close to black using a measurement pattern with a selection method corresponding to the gamma characteristics applied to the second and third grayscale values. As a result, the correction accuracy of low-grayscale colors that are close to black is improved.

[0192] Appendix 3

[0193] According to the control method of the projection device described in Appendix 1, wherein the plurality of grayscale data includes a plurality of first grayscale values ​​comprising a first value, a second value larger than the first value, and a third value larger than the second value; the plurality of measurement data includes a plurality of first luminance values ​​comprising a first measurement value, a second measurement value larger than the first measurement value, and a third measurement value larger than the second measurement value; the first value and a first group of the first measurement values, the second value and a second group of the second measurement values, and the third value and a third group of the third measurement values ​​satisfy a curve representing a first characteristic of a plurality of first luminance values ​​relative to the plurality of first grayscale values; and calculating the correction data comprises the following steps: determining a function representing the curve based on the first group, the second group, and the third group; and determining a correction value for correcting the color of the image based on the function.

[0194] The control method in Appendix 3, having the structure described above, interpolates the discrete values ​​based on a plurality of discrete first gray values ​​and a plurality of discrete first brightness values ​​represented by measurement data corresponding to the first gray values, thereby enabling correction even when the first gray value has values ​​between these discrete values.

[0195] Appendix 4

[0196] According to the control method of the projection device described in Appendix 3, the gray values ​​of the first color component are divided into N ranges from the first gray value representing the minimum gray value to the first gray value representing the maximum gray value. The first value, the second value, and the third value belong to the interval to which the first gray value representing the minimum gray value belongs in the N ranges, where N is an integer greater than or equal to 3.

[0197] The control method in Appendix 4, with the structure described above, enables extremely fine correction of low-grayscale colors that are close to black, compared to relatively high-grayscale colors.

[0198] Appendix 5

[0199] According to the control method of the projection device described in Appendix 1, the plurality of grayscale data includes grayscale data in which the first grayscale value, the second grayscale value, and the third grayscale value are equal to each other.

[0200] The control method described in Appendix 5, having the structure described above, enables the use of a gray pattern as a measurement pattern.

[0201] Appendix 6

[0202] According to the control method of the projection device described in Appendix 1, wherein the projection device is a first projection device, the plurality of grayscale data are a plurality of first grayscale data, the plurality of measurement data are a plurality of first measurement data, the plurality of colored lights are a plurality of first colored lights, and a second projection device, based on the plurality of first grayscale data, projects a plurality of second colored lights corresponding one-to-one with the plurality of first grayscale data onto the projection surface, thereby causing the plurality of first colored lights and the plurality of second colored lights to overlap in a first region of the projection surface. The control method of the projection device includes the following steps: based on the plurality of second grayscale data, the projection device projects a plurality of second colored lights corresponding one-to-one with the plurality of first grayscale data onto the projection surface, thereby causing the plurality of first colored lights and the plurality of second colored lights to overlap in a first region of the projection surface. When multiple third-color lights, corresponding one-to-one with multiple second grayscale data, are projected from the first projection device onto the projection surface, multiple second measurement data are obtained based on the output of the sensor measuring the reflected light of the multiple third-color lights reflected by the projection surface; when multiple fourth-color lights, corresponding one-to-one with the multiple second grayscale data, are projected from the second projection device onto the projection surface based on the multiple second grayscale data, multiple second measurement data are obtained based on the output of the sensor measuring the reflected light of the multiple fourth-color lights reflected by the projection surface; and on the projection surface... In the first region, the plurality of third-color lights overlap with the plurality of fourth-color lights. In addition to the plurality of first-color data and the plurality of first-color measurements, correction data for correcting the color of the image to be displayed on the projection surface is calculated based on the plurality of second-color data and the plurality of second-color measurements. The plurality of second-color data respectively include a plurality of fourth-color values ​​representing at least one gray level related to the first-color component, a plurality of fifth-color values ​​representing at least one gray level related to the second-color component, and a plurality of sixth-color values ​​representing at least one gray level related to the third-color component. The plurality of second-color measurements... Each of the plurality of grayscale values ​​includes a fourth brightness value representing the brightness of reflected light corresponding to the first color component having the fourth grayscale value, a fifth brightness value representing the brightness of reflected light corresponding to the second color component having the fifth grayscale value, and a sixth brightness value representing the brightness of reflected light corresponding to the third color component having the sixth grayscale value. The difference between the lowest fourth grayscale value and the second lowest fourth grayscale value among the plurality of fourth grayscale values ​​included in the plurality of second grayscale data is less than the difference between the highest first grayscale value and the second highest first grayscale value among the plurality of first grayscale values.

[0203] The control method in Appendix 6, with the above-described structure, is able to simultaneously correct the colors of multiple projected images displayed in a spliced ​​manner.

[0204] Appendix 7

[0205] According to the control method of the projection device described in Appendix 6, only the plurality of first-color lights are projected onto the second region of the projection surface, and the color correction of the image refers to correcting it in a way that reduces the color unevenness in the first region and makes the brightness of the second region equal to the brightness of the first region.

[0206] The control method in Appendix 7, with the above-described structure, is able to simultaneously correct uneven black color and "black float" in multiple projected images displayed in a spliced ​​manner.

[0207] Postscript 8

[0208] According to the control method of the projection device described in Appendix 6, the plurality of first grayscale values ​​included in the plurality of first grayscale data include a first value, a second value larger than the first value, and a third value larger than the second value; the plurality of fourth grayscale values ​​included in the plurality of second grayscale data include a fourth value, a fifth value larger than the fourth value, and a sixth value larger than the fifth value; the second value and the fourth value are equal to each other; and the third value and the fifth value are equal to each other.

[0209] The control method described in Appendix 8, by having the above-described structure, enables the use of measurement patterns with a common grayscale in the overlapping region DR and the non-overlapping region NR. As a result, the processing load is reduced. Furthermore, the control method of this embodiment can improve the S / N ratio in the imaging device 12.

[0210] Postscript 9

[0211] According to the control method of the projection device described in Appendix 6, the projection of the plurality of first-color lights from the first projection device and the projection of the plurality of second-color lights from the second projection device are synchronized with each other.

[0212] The control method described in Appendix 9, by having the structure described above, can improve the S / N ratio in the imaging device 12.

[0213] Postscript 10

[0214] A program product controls a projection device to perform the following steps: when projecting multiple colored lights, corresponding one-to-one with the multiple grayscale data, from the projection device onto a projection surface, acquiring multiple measurement data based on the output of a sensor measuring the reflected light of each of the multiple colored lights reflected by the projection surface; and calculating correction data for correcting the color of an image to be displayed on the projection surface based on the multiple grayscale data and the multiple measurement data, wherein the multiple grayscale data includes multiple first grayscale values ​​representing at least one grayscale related to a first color component, multiple second grayscale values ​​representing at least one grayscale related to a second color component, and a plurality of grayscale values ​​representing... A plurality of third gray values ​​relating to at least one gray level, the plurality of measurement data including a first luminance value representing the luminance of reflected light corresponding to the first color component having the first gray value, a second luminance value representing the luminance of reflected light corresponding to the second color component having the second gray value, and a third luminance value representing the luminance of reflected light corresponding to the third color component having the third gray value, wherein the difference between the lowest and the second lowest of the plurality of first gray values ​​included in the plurality of gray data is less than the difference between the highest and the second highest of the plurality of first gray values.

[0215] The program product in Appendix 10, having the aforementioned structure, can correct low-grayscale colors approaching black using a measurement pattern with a selection method corresponding to the gamma characteristic, with respect to the first grayscale value. As a result, the correction accuracy for low-grayscale colors approaching black is improved.

Claims

1. A method for controlling a projection device, comprising the following steps: In a scenario where multiple colored lights, each corresponding one-to-one with one of the multiple grayscale data, are projected from a projection device onto a projection surface, multiple measurement data are obtained based on the output of a sensor measuring the reflected light of each of the multiple colored lights reflected by the projection surface; and Based on the multiple grayscale data and the multiple measurement data, correction data is calculated to correct the color of the image to be displayed on the projection surface. The plurality of grayscale data includes a plurality of first grayscale values ​​representing at least one grayscale value related to the first color component, a plurality of second grayscale values ​​representing at least one grayscale value related to the second color component, and a plurality of third grayscale values ​​representing at least one grayscale value related to the third color component. The plurality of measurement data includes a first luminance value representing the luminance of reflected light corresponding to the first color component having the first gray value, a second luminance value representing the luminance of reflected light corresponding to the second color component having the second gray value, and a third luminance value representing the luminance of reflected light corresponding to the third color component having the third gray value. The difference between the lowest and the second lowest of the multiple first gray values ​​contained in the plurality of gray values ​​is less than the difference between the highest and the second highest of the multiple first gray values.

2. The control method for the projection device according to claim 1, wherein, The difference between the lowest and the second lowest second grayscale value among the plurality of second grayscale values ​​contained in the plurality of grayscale data is less than the difference between the highest and the second highest second grayscale value among the plurality of second grayscale values. The difference between the lowest third gray value and the second lowest third gray value among the plurality of third gray values ​​contained in the plurality of gray data is less than the difference between the highest third gray value and the second highest third gray value among the plurality of third gray values.

3. The control method for the projection device according to claim 1, wherein, The plurality of grayscale data includes a plurality of first grayscale values, which include a first value, a second value that is larger than the first value, and a third value that is larger than the second value. The plurality of first brightness values ​​included in the plurality of measurement data include a first measurement value, a second measurement value that is larger than the first measurement value, and a third measurement value that is larger than the second measurement value. The first value and the first group of the first measured values, the second value and the second group of the second measured values, and the third value and the third group of the third measured values ​​satisfy a curve representing a first characteristic of a plurality of first brightness values ​​relative to the plurality of first grayscale values. Calculating the correction data involves the following steps: Based on the first group, the second group, and the third group, determine the function representing the curve; and Based on the function, a correction value is determined for correcting the colors of the image.

4. The control method for the projection device according to claim 3, wherein, The gray values ​​of the first color component are divided into N values, from the first gray value representing the minimum gray value to the first gray value representing the maximum gray value. The first value, the second value, and the third value belong to the interval to which the first gray value, representing the minimum gray level, belongs among the N intervals. N is an integer greater than or equal to 3.

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

6. The control method for the projection device according to claim 1, wherein, The projection device is the first projection device. The multiple grayscale data are multiple first-level grayscale data. The multiple measurement data are multiple first measurement data. The plurality of colored lights are plurality of first-color lights. The second projection device projects a plurality of second colors, each corresponding to one of the plurality of first grayscale data, onto the projection surface based on the plurality of first grayscale data. Thus, in a first region of the projection surface, the plurality of first colors overlap with the plurality of second colors. The control method for the projection device includes the following steps: When multiple third-color lights, which correspond one-to-one with the multiple second-color lights, are projected from the first projection device onto the projection surface based on multiple second-color lights, multiple second-color measurement data are obtained based on the output of the sensor that measures the reflected light reflected by the projection surface of the multiple third-color lights. When multiple fourth-color lights, which correspond one-to-one with the multiple second-color lights, are projected from the second projection device onto the projection surface based on the multiple second-color lights, multiple second measurement data are obtained based on the output of the sensor that measures the reflected light reflected by the projection surface of the multiple fourth-color lights. as well as In the first region of the projection surface, the plurality of third-color lights overlap with the plurality of fourth-color lights. In addition to the plurality of first grayscale data and the plurality of first measurement data, correction data for correcting the color of the image to be displayed on the projection surface is calculated based on the plurality of second grayscale data and the plurality of second measurement data. The plurality of second grayscale data each includes a plurality of fourth grayscale values ​​representing at least one grayscale value related to the first color component, a plurality of fifth grayscale values ​​representing at least one grayscale value related to the second color component, and a plurality of sixth grayscale values ​​representing at least one grayscale value related to the third color component. The plurality of second measurement data respectively include a fourth brightness value representing the brightness of reflected light corresponding to the first color component having the fourth gray value, a fifth brightness value representing the brightness of reflected light corresponding to the second color component having the fifth gray value, and a sixth brightness value representing the brightness of reflected light corresponding to the third color component having the sixth gray value. The difference between the lowest fourth gray value and the second lowest fourth gray value among the plurality of second gray values ​​is less than the difference between the highest first gray value and the second highest first gray value among the plurality of first gray values.

7. The control method for the projection device according to claim 6, wherein, Only the plurality of first-color lights are projected onto the second region of the projection surface. The color correction of the image refers to the correction in a manner that reduces color unevenness in the first region and makes the brightness of the second region equal to the brightness of the first region.

8. The control method for the projection device according to claim 6, wherein, The plurality of first grayscale data includes a plurality of first grayscale values, which include a first value, a second value that is larger than the first value, and a third value that is larger than the second value. The plurality of fourth grayscale values ​​contained in the plurality of second grayscale data include a fourth value, a fifth value larger than the fourth value, and a sixth value larger than the fifth value. The second value and the fourth value are equal to each other. The third value is equal to the fifth value.

9. The control method for the projection device according to claim 6, wherein, The projection of the plurality of first-color lights from the first projection device and the projection of the plurality of second-color lights from the second projection device are synchronized with each other.

10. A program product that controls a projection device to cause the projection device to perform the following steps: In a scenario where multiple colored lights, each corresponding one-to-one with one of the multiple grayscale data, are projected from a projection device onto a projection surface, multiple measurement data are obtained based on the output of a sensor measuring the reflected light of each of the multiple colored lights reflected by the projection surface; and Based on the multiple grayscale data and the multiple measurement data, correction data is calculated to correct the color of the image to be displayed on the projection surface. The plurality of grayscale data includes a plurality of first grayscale values ​​representing at least one grayscale value related to the first color component, a plurality of second grayscale values ​​representing at least one grayscale value related to the second color component, and a plurality of third grayscale values ​​representing at least one grayscale value related to the third color component. The plurality of measurement data includes a first luminance value representing the luminance of reflected light corresponding to the first color component having the first gray value, a second luminance value representing the luminance of reflected light corresponding to the second color component having the second gray value, and a third luminance value representing the luminance of reflected light corresponding to the third color component having the third gray value. The difference between the lowest and the second lowest of the multiple first gray values ​​contained in the plurality of gray values ​​is less than the difference between the highest and the second highest of the multiple first gray values.

Images