Adjustment method, computer program, and control device

Abstract

The present invention adjusts focusing for preventing deviation of content being projected. This adjustment method adjusts focusing of a projection device, the adjustment being executed by a control device connected to the projection device for projecting content. In the adjustment method, the arithmetic circuit of the control device causes the projection device to project a pattern image reflecting the APL of the content, acquires, from a connected photographing device, a photographed image including the pattern image projected by the projection device, and adjusts focusing according to the state of the pattern image included in the photographed image.

Description

Adjustment method, computer program and control device

[0001] The present disclosure relates to an adjustment method, a computer program, and a control device for adjusting focus when an image is projected by a projection device.

[0002] Conventionally, a predetermined pattern image has been used when adjusting the focus of a projection device (see, for example, Patent Documents 1 and 2). For example, in focus adjustment using a pattern image, a camera first captures the pattern image projected by the projection device while changing the focus state. Next, using an existing algorithm, multiple score values ​​indicating each focus state are calculated based on the pattern image portion included in the captured image. The focus state with the largest score value among the multiple score values ​​is determined to be the in-focus state. However, even if the focus of the projection device is adjusted to the in-focus state in advance based on the pattern image, the focus may shift when the actual content is projected. Specifically, the above-mentioned focus shift may occur when the APL (average picture level) of the pattern image differs from the APL of the content actually projected by the projection device.

[0003] JP 2005-283952 A JP 2010-130224 A

[0004] As described above, conventional focus adjustment methods may not be suited to the projection of actual content.

[0005] The present disclosure provides an adjustment method, a computer program, and a control device that realize focus adjustment that prevents deviation when content is projected.

[0006] The adjustment method disclosed herein adjusts the focus of a projection device that projects content, and is executed by a control device connected to the projection device. The adjustment method involves causing the projection device to project a pattern image that reflects the APL of the content using an arithmetic circuit in the control device, acquiring a captured image that includes the pattern image projected by the projection device from a connected image capture device, and adjusting the focus according to the state of the pattern image included in the captured image.

[0007] These general and specific aspects may be realized by a system, a method, and a computer program, as well as combinations thereof.

[0008] The adjustment method, computer program, and control device disclosed herein can achieve focus adjustment that prevents deviation when content is projected.

[0009] FIG. 1 is a conceptual diagram showing a projection system according to a first embodiment. FIG. 2 is a schematic diagram showing the configuration of a projection device included in the projection system of FIG. 1. FIG. 3 is an example of a pattern image used for focus adjustment by the control device according to the first embodiment. FIG. 4 is another example of a pattern image used for focus adjustment by the control device according to the first embodiment. FIG. 5 is a flowchart showing processing in the control device according to the first embodiment. FIG. 6 is an example of content projected by the projection device. FIG. 7 is an example of a pattern image used for focus adjustment by the control device according to the second embodiment. FIG. 8 is a flowchart showing processing in the control device according to the second embodiment. FIG. 9 is a conceptual diagram showing a projection system according to a third embodiment. FIG. 10 is an example of correspondence data used for focus adjustment by the control device according to the third embodiment. FIG. 11 is another example of correspondence data used for focus adjustment by the control device according to the third embodiment. FIG. 12 is a schematic diagram showing the timing of focus adjustment by the control device according to the third embodiment. FIG. 13 is an example of a pattern image used as a reference for generating a pattern image by the control device according to Modification 1. FIG. 14 is an example of a pattern image generated by the control device according to Modification 2. FIG. 15 is another example of a pattern image generated by the control device according to Modification 2.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as appropriate. However, in the detailed description, unnecessary parts of the description of the prior art and substantially identical configurations may be omitted. This is for the sake of simplicity. Furthermore, the following description and the accompanying drawings are disclosed to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter of the claims.

[0011] <Focus Drift> First, we will explain the focus deviation between when adjusting focus and when actually projecting content, which is an issue in the focus adjustment of a projection device performed by the adjustment method, computer program, and control device according to the present disclosure. This phenomenon of focus deviation between when adjusting focus in a projection device and when actually projecting content is called focus drift. Generally, focus drift is classified into "switch-on drift" and "APL drift."

[0012] Switch-on drift is a phenomenon that occurs when the temperature of a projection device rises immediately after it is turned on. The switch-on drift disappears once a certain amount of time has passed since the power was turned on and the temperature of the projection device has stabilized.

[0013] On the other hand, APL drift is a phenomenon that occurs when the brightness of each frame that constitutes the content changes during content projection. Specifically, differences in brightness result in different heat being applied to the lens of the projection device. This can cause distortions such as expansion or contraction in the lens of the projection device. This lens expansion or contraction can occur over a period of several seconds. If content is formed from multiple consecutive frames and all APLs are the same, such distortions will not occur in the lens. However, different content projected by a projection device typically has different APLs depending on the content. The adjustment method, computer program, and control device disclosed herein enable focus adjustment that is compatible with the APL of the content to be projected.

[0014] 1, a projection system 1 according to the first embodiment includes a control device 10A, a projection device 20, and an image capturing device 30. The control device 10A is connected to the projection device 20 and the image capturing device 30 via a network 40.

[0015] The projection device 20 is a projector. The projection device 20 projects content onto a screen 50, which is a projection surface. The content may be, for example, a moving image made up of a series of multiple frames. Alternatively, the content may be a still image.

[0016] The image capturing device 30 is a camera. The image capturing device 30 captures an image of the screen 50. By capturing an image of the screen 50, the image capturing device 30 can capture an image of the projection area of ​​the projection device 20.

[0017] The control device 10A may be, for example, an information processing device such as a media server or a personal computer. The control device 10A controls the projection of content by the projection device 20. Furthermore, when projecting content, the control device 10A can adjust the focus by changing the position of a lens in the projection device 20. As will be described later using Figures 3A and 3B, the control device 10A according to the first embodiment selects and uses a pattern image from a plurality of pattern images according to the APL of the content to be projected by the projection device 20 during focus adjustment.

[0018] <Configuration of Projection Device> As shown in FIG. 2 , the projection device 20 includes a light source 21, a first optical element 22, an image forming element 23, a beam splitter 24, a second optical element 25, and the like. The light source 21 may be a semiconductor laser or the like that emits red, green, and blue light used to project an image. The first optical element 22 may include a lens or the like that guides light from the light source 21 to the beam splitter 24. The image forming element 23 may be a digital micromirror device (DMD) or the like that forms an image to be projected. The second optical element 25 may include a lens or the like that receives the content image formed by the image forming element 23 via the beam splitter 24 and projects it onto the screen 50. Specifically, the second optical element 25 includes a focus adjustment lens that adjusts the focus by varying its position on the optical path from the beam splitter 24 to the screen 50. This focus adjustment lens is made of resin, glass, or the like, and expands and contracts in response to the heat of the light that forms the content to be projected. This causes APL drift in the projection device 20. 2 shows only the main components of the projection device 20 that are used to disclose the projection system 1 according to the present disclosure.

[0019] 1, the control device 10A may include an arithmetic circuit 11, a storage device 12, an input device 13, an output device 14, and a communication circuit 15. When the projection device 20 projects content, the control device 10A transmits various control signals for adjusting focus and the like.

[0020] The arithmetic circuit 11 is a controller that controls the entire control device 10A. For example, the arithmetic circuit 11 reads and executes a control program P1 stored in the storage device 12. This allows the control device 10A to perform various processes including adjusting the focus of the projection device 20. The arithmetic circuit 11 may be various processors such as a CPU, an MPU, a GPU, an FPGA, a DSP, an ASIC, or a dedicated hardware circuit.

[0021] The input device 13 may be an operation button, a keyboard, a mouse, a touch panel, a microphone, etc., which are used for inputting operations and data. The output device 14 may be a display, a speaker, etc., which are used for outputting processing results and data.

[0022] The communication circuit 15 enables data communication with external devices (e.g., the projection device 20 and the image capture device 30). The above-mentioned data communication may be wired and / or wireless and may be performed according to known communication standards. For example, wired data communication is performed by using a communication controller of a semiconductor integrated circuit that operates in accordance with the Ethernet (registered trademark) standard and / or the USB (registered trademark) standard as the communication circuit 15. Wireless data communication is performed by using a communication controller of a semiconductor integrated circuit that operates in accordance with the IEEE 802.11 standard for LANs (Local Area Networks) and / or the fourth-generation / fifth-generation mobile communication systems, known as 4G / 5G, for mobile communications, as the communication circuit 15.

[0023] The storage device 12 is a recording medium for recording various information. The storage device 12 is realized by, for example, a RAM, a ROM, a flash memory, an SSD (Solid State Drive), a hard disk drive, or other storage devices, or an appropriate combination thereof. The storage device 12 stores a control program P1, which is a computer program executed by the arithmetic circuit 11, and various data such as a pattern image 121 used in focus adjustment.

[0024] The pattern image 121 is data used for focus adjustment before content is projected by the projection device 20. Pattern images 121 with different APLs are shown in FIGS. 3A and 3B . As shown in FIGS. 3A and 3B , the storage device 12 stores a plurality of pattern images 121 with different APLs. The storage device 12 associates each pattern image 121 with information related to the respective APLs. For example, each pattern image 121 may be associated with an APL value. Alternatively, each pattern image 121 may be associated with a predetermined APL range indicated by an upper limit and a lower limit of the APL.

[0025] The pattern image 121 shown in Figures 3A and 3B is a grid pattern. Specifically, Figures 3A and 3B show an example in which differences in APL are represented by grid thickness. However, the shape of the pattern shown in the pattern image 121 and the method for distinguishing APL are not limited.

[0026] <Operation of Control Device> The process executed by the control device 10A according to the first embodiment will be described with reference to the flowchart shown in FIG.

[0027] The arithmetic circuit 11 acquires information about the APL of content to be projected by the projection device 20 (S01). The arithmetic circuit 11 may acquire information about the APL of the content by accepting the APL value itself via the input device 13 or the like. Alternatively, the arithmetic circuit 11 may acquire information about the APL by accepting the content itself via the communication circuit 15 or the like and calculating the accepted content. Furthermore, the information about the APL acquired by the arithmetic circuit 11 does not have to be the APL value of the content itself. For example, the arithmetic circuit 11 may acquire information about the APL of the content by using a level indicating the APL of the content.

[0028] For example, when the content is a still image, the information regarding the APL of the content may be the average value of the signal value of the entire content. Furthermore, when the content is a moving image composed of multiple frames, the average value of the signal values ​​of the frames over a predetermined period may be the APL of the content. The predetermined period may be the entire period of the content, or a partial period. The predetermined period may be a period specifying one frame specified by the user, or a period specifying multiple frames specified by the user. Furthermore, when the content is a moving image, the information regarding the APL of the content may be the APL value or APL level specified by the user.

[0029] The arithmetic circuit 11 selects a pattern image 121 corresponding to the APL acquired in step S01 from the pattern images 121 stored in the storage device 12 (S02). For example, the arithmetic circuit 11 may select a pattern image 121 associated with an APL in a range closest to the APL acquired in step S01. Alternatively, the arithmetic circuit 11 may select a pattern image 121 associated with a range of APLs that includes the APL acquired in step S01.

[0030] The arithmetic circuit 11 causes the projection device 20 to project the pattern image 121 selected in step S02 (S03). Specifically, the arithmetic circuit 11 transmits the selected pattern image 121 to the projection device 20 via the communication circuit 15 and causes the projection device 20 to project the pattern image 121. This allows the projection device 20 to project D1 the pattern image that reflects the APL of the content.

[0031] After projecting the pattern image 121 in step S03, the arithmetic circuit 11 acquires, from the image capturing device 30, a captured image including the pattern image 121 projected onto the screen 50 by the projection device 20 (S04).

[0032] The arithmetic circuit 11 adjusts the focus according to the state of the pattern image included in the captured image acquired in step S04 (S05). Specifically, the arithmetic circuit 11 obtains a score value indicating each focus state from the captured image of the pattern image 121 projected by the projection device 20 in a plurality of different focus states. The arithmetic circuit 11 determines the focus state with the highest score value as the in-focus state and moves the focus position of the projection device to achieve that state. Note that the operation of setting the projection device 20 to a plurality of different focus states may be performed by a control signal transmitted from the arithmetic circuit 11. Alternatively, the projection device 20 may be manually operated by an operator.

[0033] In this way, the control device 10A according to the first embodiment selects, from a plurality of pattern images 121, a pattern image 121 that corresponds to the APL of the content to be projected by the projection device 20. The control device 10A also adjusts the focus using the pattern image 121 selected according to the APL of the content. Therefore, the focus adjustment is performed to reflect the APL of the content, and therefore it is possible to project content that matches the APL of the actual content.

[0034] Second Embodiment The configurations of a projection system and a control device according to a second embodiment are the same as those of the projection system 1 described above with reference to FIG. 1. Therefore, FIG. 1 will be referred to in the description of the projection system according to the second embodiment. The control device 10A according to the first embodiment selected and used a pattern image according to the APL of the content. In contrast, the control device 10A according to the second embodiment superimposes a pattern image having an image size smaller than the content to be projected on part of the content, and generates a new pattern image to use for focus adjustment.

[0035] For example, assume that there is content, an example of which is shown in FIG. 5A . In the control device 10A according to the second embodiment, a pattern image 121 used for focus adjustment is superimposed on the content to create a new pattern image, as shown in FIG. 5B . The example shown in FIG. 5B shows an example of a new pattern image in which the pattern image 121 is superimposed on a central portion of the content. However, the position at which the pattern image 121 is superimposed on the content is not limited. For example, the position at which the pattern image 121 is superimposed on the content may be other positions, such as the left side, upper side, right side, or lower side of the content. The user can perform a suitable focus adjustment by superimposing the pattern image 121 on the position at which the user most wants to focus. Furthermore, the shape of the pattern image 121 is not limited as long as it is a shape that allows for focus adjustment.

[0036] The size of the pattern image 121 to be superimposed on the content is within a predetermined range (e.g., 5 to 10%) of the projection range of the projection device 20. For example, if the range of the pattern image 121 is larger than, for example, 10% of the projection range of the projection device 20, there is a risk of a large discrepancy between the APL after the pattern image 121 is superimposed on the content and the APL of the content itself. On the other hand, if the range of the pattern image 121 is smaller than, for example, 5% of the projection range of the projection device 20, there is a risk of an inability to perform appropriate focus adjustment. Therefore, it is necessary to determine the size of the pattern image 121 to be superimposed within a range that does not result in a large discrepancy between the APL of the new pattern image and the actual content and allows appropriate focus adjustment. The size of the pattern image 121 to be superimposed is affected by various factors, such as the performance of the projection device 20, the performance of the lens used by the projection device 20, the performance of the image capture device 30, such as resolution, and the distance from the image capture device 30 to the screen 50.

[0037] Even if a pattern image 121 is superimposed on a portion of the content, a difference will occur between the APL of the content and the APL of the new pattern image. Therefore, pattern images 121 with a plurality of different APL levels may also be used as the pattern image 121 to be superimposed on the content. For example, the arithmetic circuit 11 generates a new pattern image by superimposing a pattern image 121 selected from a plurality of pattern images 121 that are matched to brightness levels, such as light, medium, and dark, on the content. This makes it possible to further reduce the difference between the APL of the content and the APL of the new pattern image.

[0038] <Operation of Control Device> The process executed by the control device 10A according to the second embodiment will be described using the flowchart shown in Fig. 6. In the frame of Fig. 6, an example will be described in which a pattern image 121 to be superimposed on content is selected from a plurality of pattern images 121 for each level and used as information related to the APL.

[0039] The arithmetic circuit 11 acquires the APL level of the content to be projected by the projection device 20 (S11). For example, the APL level is designated by the user via the input device 13.

[0040] The arithmetic circuit 11 selects, from the pattern images 121 stored in the storage device 12, a pattern image 121 associated with the APL level obtained in step S11 (S12).

[0041] The arithmetic circuit 11 generates an image by superimposing the pattern image 121 selected in step S12 on the content to be projected by the projection device 20, as a new pattern image, an example of which is shown in FIG. 5B (S13).

[0042] When the pattern image 121 is superimposed on the content in step S13, (1) first, the proportion (e.g., 80%) of the projection range of the projection device 20 in the shooting range of the shooting device 30 is calculated. (2) Next, in order to project the pattern image 121 onto 7% of the area on the shot image, the proportion of 7% of the shot image on the projected image is calculated (e.g., 7% × 100 / 80 = 8.75%). (3) Finally, the pattern image 121 with the proportion calculated in (2) is superimposed on the content to generate a new pattern image. Note that, when the proportion on the projected image is calculated, the arithmetic circuit 11 may reduce the original pattern image 121 to the calculated proportion (e.g., 8.75%) and superimpose it on the content. Alternatively, the arithmetic circuit 11 may cut out a portion of the original pattern image 121 determined to fit the calculated proportion (e.g., 8.75%) and superimpose it on the content to generate a new pattern image.

[0043] The arithmetic circuit 11 causes the projection device 20 to project the new pattern image generated in step S13 (S14).

[0044] After projecting the new pattern image in step S14, the arithmetic circuit 11 acquires, from the image capturing device 30, a captured image including the new pattern image projected onto the screen 50 by the projection device 20 (S15).

[0045] The arithmetic circuit 11 adjusts the focus in accordance with the state of the pattern image included in the photographed image acquired in step S15 (S16).

[0046] As described above, the image size of the pattern image 121 to be superimposed on the content is smaller than the image size of the content. Therefore, the new pattern image does not obscure the entire content behind the original pattern image 121. For example, as shown in FIG. 5B , only a small area of ​​the content is obscured by the pattern image 121. Therefore, even if steps S11 and S12 are omitted in the processing of the control device 10A according to the second embodiment, focus adjustment that reflects the APL of the content is possible. In other words, the APL of the entire new pattern image is an APL that is relatively close to the APL of the content itself.

[0047] In this way, the control device 10A according to the second embodiment uses a new pattern image obtained by superimposing the pattern image 121 on the actual content for focus adjustment. As a result, the new pattern image is affected by the APL of the content. Therefore, the focus adjustment is performed reflecting the APL of the content, so that content that matches the APL of the actual content can be projected.

[0048] Third Embodiment A projection system 1 according to a third embodiment will be described with reference to FIG. 7 . The configuration of a control device 10B according to the third embodiment is similar to that of the control device 10A described above with reference to FIG. 1 . However, the storage device 12 of the control device 10B according to the second embodiment stores correspondence data 122 in addition to a pattern image 121. The control device 10B according to the third embodiment stores, in advance, a plurality of predetermined APLs and information used for focus control corresponding to each APL as the correspondence data 122. The control device 10B adjusts the focus using such correspondence data 122 when projecting content.

[0049] 8A and 8B show examples of the correspondence data 122. The correspondence data 122 shown in FIG. 8A associates multiple APLs with values ​​indicating the lens position at which the lens is focused when projecting an image at the corresponding APL. FIG. 8B associates multiple APLs with the amount of movement of the lens position for each APL, with the lens position for APL 20 being set as the reference (0). Note that the example of the correspondence data 122 shown in FIGS. 8A and 8B associates information used for focus control in 10% increments of the APL from 0 to 100%. However, the correspondence data 122 may associate information in any increment, not limited to 10% increments.

[0050] <Operation of Control Device> Processing executed by the control device 10B according to the third embodiment will be described with reference to the flowchart shown in FIG.

[0051] The arithmetic circuit 11 selects a pattern image 121 of a predetermined APL stored in the storage device 12, and causes the projection device 20 to project it (S21).

[0052] After projecting the pattern image 121 in step S21, the arithmetic circuit 11 acquires, from the image capturing device 30, a captured image including the pattern image 121 projected onto the screen 50 by the projection device 20 (S22).

[0053] The arithmetic circuit 11 adjusts the focus in accordance with the state of the pattern image included in the photographed image acquired in step S22 (S23).

[0054] Furthermore, in step S23, the arithmetic circuit 11 adds information used for focus control to achieve an in-focus state to the correspondence data 122 in association with the APL of the pattern image 121 projected in step S21 (S24). For example, the arithmetic circuit 11 adds, as information used for focus control, values ​​indicating the positions of the lens to achieve an in-focus state to the correspondence data 122 in association with each APL. The in-focus state is the state resulting in the highest score value among the score values ​​calculated from the pattern image 121 photographed in a plurality of different focus states, as described in step S05 of the flowchart in FIG. 4 .

[0055] The arithmetic circuit repeats the processes of steps S21 to S25 until information used for focus control for all predetermined APLs is added to the correspondence data 122 (YES in S25).

[0056] When new content is projected, the arithmetic circuit 11 acquires the APL of the content (S26).

[0057] The arithmetic circuit 11 refers to the correspondence data 122 and adjusts the focus using information used for focus control associated with the APL acquired in step S26 (S27).

[0058] The arithmetic circuit 11 repeats the processes of steps S26 to S28 while content projection continues (NO in step S28). This allows the control device 10B according to the third embodiment to perform focus adjustment in accordance with changes in APL within a single piece of content, even if the APL changes across multiple frames that form the single piece of content. Note that in the example shown in FIG. 9 , the control device 10A generates the correspondence data 122 and then projects the content, but this is not limiting. For example, the generation of the correspondence data 122 and the projection of the content do not necessarily have to be performed consecutively.

[0059] For example, as shown in FIG. 8A and other figures, the correspondence data 122 has focus positions at predetermined intervals. Therefore, focus positions with an APL value identical to the content APL value are not included in the correspondence data 122. For example, the values ​​between the elements of the correspondence data 122 may be considered to change linearly, and control may be performed in accordance with the content APL. In the example using FIG. 8A, assume that 17 is acquired as the content APL. The focus position at this time may be calculated as 4389 + (4432 - 4389) x (17 - 10) / (20 - 10) = 4419.

[0060] 10 shows an example of the timing of control when focus control is performed in response to changes in the APL of content. For example, when the arithmetic circuit 11 acquires APL1 for period 1 at the end of period 1 immediately after the start, it refers to the correspondence data 122 and performs focus adjustment 1 in response to APL1. When the arithmetic circuit 11 acquires APL2 for period 2 at the end of period 2, it refers to the correspondence data 122 and performs focus adjustment 2 in response to APL2. In this way, the control device 10B according to the second embodiment can adjust the focus in response to changes in the APL of each frame during the period in which content that is a moving image is projected.

[0061] In the case of content with 60 frames per second, the number of frames in 30 seconds is 1,800. However, even if focus adjustment is performed every 30 seconds, it is considered possible to perform focus adjustment sufficiently without calculating the average APL of 1,800 frames each time. In other words, images of consecutive frames are generally similar. Therefore, for example, when focus adjustment is performed every 30 seconds, the control device 10B may acquire the APL of only one frame out of the multiple frames in the 30 seconds and perform focus adjustment. For example, in the example shown in FIG. 10 , the control device 10B may acquire the last frame of period 1 as APL1 and the last frame of period 2 as APL2.

[0062] Here, if the difference between the focus positions is large, and focus adjustment is performed based on that difference, the user viewing the projected content may feel uncomfortable. Therefore, an upper limit may be set for the adjustment range. For example, if the difference between the focus positions before and after the calculated adjustment is less than 20, the control device 10B performs an adjustment equivalent to the calculated difference. On the other hand, if the difference between the focus positions before and after the calculated adjustment is 20 or more, the control device 10B performs an adjustment equivalent to 20.

[0063] Furthermore, content with large changes in brightness will cause drastic fluctuations in the APL. In this case, the focus adjustment of the control device 10B may not be able to keep up. Therefore, in such a case, the control device 10B may perform focus control using information related to the APL specified by the user.

[0064] Furthermore, the APL to be adjusted may be specified in advance. For example, if the APL to be adjusted is 130 to 225, the control device 10B may not perform focus adjustment on images with an APL outside the range of 130 to 255.

[0065] <Variation 1> In the above-described embodiment, an example was described in which the storage device 12 pre-stores pattern images 121 associated with information related to multiple different APLs. However, if the arithmetic circuit 11 can create a suitable pattern image from the reference pattern image 200 based on the information related to the APL, the arithmetic circuit 11 may generate the pattern image. For example, the storage device 12 stores rules for generating a corresponding pattern image based on information related to the APL. Furthermore, upon acquiring information related to the APL of content to be projected, the arithmetic circuit 11 generates a pattern image using the rules. Specifically, the rules are rules for adjusting the thickness of the grid based on the reference pattern image 200 to generate a pattern image suitable for the content.

[0066] Fig. 11 shows an example of a pattern image 200 used by the control device according to Modification 1. A reference pattern image 200 such as that shown in Fig. 11 is stored in the storage device 12. The storage device 12 also stores, in association with each other, the range of APL and values ​​h1, h2, w1, and w2 indicating the spacing and width of the grid of the pattern image for the range of APL.

[0067] When the arithmetic circuit 11 acquires the APL of the content to be projected, it extracts values ​​h1, h2, w1, and w2 associated with the range included in the acquired APL. The arithmetic circuit 11 also generates a suitable pattern image by changing the thickness of each grid in the reference pattern image 200 using the extracted values. Thus, the control device according to the first modification can generate a suitable pattern image by using the reference pattern image 200 and values ​​indicating the grid spacing and width, rather than storing multiple pattern images.

[0068] <Modification 2> A control device according to Modification 2 will be described using Figures 12A to 12C. In Modification 2, a pattern image is generated using rules different from those of the control device according to Modification 1. The arithmetic circuit 11 according to Modification 2 superimposes a pattern 203 on a portion of a color image 202 determined according to the APL of the content to be projected, to generate a pattern image 201 that conforms to the APL of the content to be projected. Here, the image size of the predetermined color image 202 is the same as that of the pattern image 201. Furthermore, the image size of the pattern 203 is smaller than that of the pattern image 201. Figure 12A shows an example in which the predetermined color image 202 is white. Figure 12B shows an example in which the color image 202 is intermediate between white and black. Figure 12C shows an example in which the color image 202 is black.

[0069] For example, when the APL of the content to be projected is X, the APL X2 of the color image 202 may be calculated by the following formula (1): X = X1 x R1 + X2 x R2 (1) where each value represents the following: X: APL of the content to be projected X1: APL of the pattern X2: APL of the color image R1: Ratio of the area of ​​the pattern 203 in the generated pattern image 201 R2: Ratio of the area of ​​the color image 202 in the generated pattern image 201

[0070] Specifically, for example, if the area ratio of the pattern 203 in the generated pattern image 201 is 1 / 9, the APL of the pattern 203 is 50%, and the APL of the content to be projected is X, the APL of the color image 202 can be calculated by applying the above formula (1): (50%) x (1 / 9) + (X2%) x (8 / 9) = (X%). Assume that the APL (X2%) of the color image is calculated to be 30% by the above calculation. In this case, the signal value of the color image 202 is calculated as 255 x 30% = 77, which is 77. Therefore, the arithmetic circuit 11 generates the pattern image 201 by superimposing the pattern 203 on the color image 202 with a signal value of 77. As a result, the control device according to the second modification can generate the pattern image 201 using the pattern 203 and the above formula (1) without storing multiple pattern images.

[0071] Overview of the embodiment (1) The adjustment method disclosed herein is an adjustment method for adjusting the focus of a projection device that projects content, executed by a control device connected to the projection device, and includes the steps of: causing the projection device to project a pattern image that reflects the APL of the content using an arithmetic circuit of the control device; acquiring a captured image that includes the pattern image projected by the projection device from a connected capture device; and adjusting the focus depending on the state of the pattern image included in the captured image.

[0072] This makes it possible to achieve focus adjustment that reflects the APL of the content.

[0073] (2) In the adjustment method of (1), the arithmetic circuit may be accessible to a storage device, and the storage device may store corresponding pattern images in association with information about a plurality of APLs, and the arithmetic circuit may select a pattern image associated with information about the APL of the content from the storage device, and project the selected pattern image onto the projection device.

[0074] This makes it possible to achieve focus adjustment that reflects the APL of the content.

[0075] (3) In the adjustment method of (1), the arithmetic circuit is accessible to a storage device, the storage device stores a predetermined pattern image, the arithmetic circuit generates a new pattern image by superimposing the pattern image stored in the storage device on the content, and projects the new pattern image on the projection device, and the image size of the pattern image superimposed on the content may be smaller than the image size of the content.

[0076] This allows a pattern image to be superimposed on the content, and makes it possible to achieve focus adjustment that reflects the APL of the actual content.

[0077] (4) In the adjustment method of (3), the storage device may store a corresponding pattern image for each level of a predetermined APL, and the arithmetic circuit may select from the storage device a pattern image associated with the level selected according to the APL of the content, and superimpose the selected pattern image on the content to generate the new pattern image.

[0078] This allows a pattern image corresponding to the APL of the content to be superimposed on the content, thereby realizing focus adjustment that more accurately reflects the APL of the actual content.

[0079] (5) In the adjustment methods of (1) to (4), the arithmetic circuit can access a storage device, and the arithmetic circuit causes the projection device to project pattern images previously reflected in a plurality of different APLs instead of a pattern image reflecting information about the APL of the content, and stores values ​​related to focus control to achieve an in-focus state when the pattern image of each APL is displayed in association with information about each APL as corresponding data in the storage device, and when new content is projected, the focus may be adjusted using the value in the corresponding data that is associated with information about the APL of the new content.

[0080] This allows focus adjustment to be achieved using correspondence data that has been generated in advance. Because correspondence data is generated in advance, focus adjustment is possible even while content that is a moving image is being projected.

[0081] (6) In the adjustment methods (1) to (5), when the content is a moving image composed of a plurality of frames, the average value of the APL of a plurality of frames over a predetermined period may be used as information about the APL of the content.

[0082] This allows for adjustment of focus on successive frames of content.

[0083] (7) In the adjustment methods (3) to (6), when the content is a moving image composed of multiple frames, the information regarding the APL of the content may be the APL of one frame specified by the user, the average value of the APLs of multiple frames specified by the user, or the APL specified by the user.

[0084] This allows the focus to be adjusted to match the APL of the selected frame.

[0085] (8) The computer program of the present disclosure may cause a control device to execute the adjustment methods (1) to (7).

[0086] This makes it possible to achieve focus adjustment that reflects the APL of the content.

[0087] (9) The control device of the present disclosure is a control device that is connected to a projection device that projects content and a photographing device, and adjusts the focus of the projection device, and includes an arithmetic circuit that causes the projection device to project a pattern image that reflects the APL of the content, obtains a photographed image from the photographing device that includes the pattern image projected by the projection device, and adjusts the focus depending on the state of the pattern image included in the photographed image.

[0088] This makes it possible to achieve focus adjustment that reflects the APL of the content.

[0089] The projection apparatus, correction apparatus, projection system, and correction method according to all claims of the present disclosure are realized by hardware resources, such as a processor, a memory, and cooperation with a computer program.

[0090] The projection device, correction device, projection system, correction method, and computer program of the present disclosure are useful for adjustments when projecting an image using a projection device.

Claims

1. A method for adjusting the focus of a projection device that projects content, executed by a control device connected to the projection device, comprising the steps of: causing the projection device to project a pattern image that reflects the APL of the content using an arithmetic circuit in the control device; acquiring a captured image that includes the pattern image projected by the projection device from a connected image capture device; and adjusting the focus according to the state of the pattern image included in the captured image.

2. The adjustment method according to claim 1, wherein the arithmetic circuit is accessible to a storage device, the storage device stores corresponding pattern images in association with information relating to a plurality of APLs, and the arithmetic circuit selects, from the storage device, a pattern image associated with information relating to the APL of the content, and causes the projection device to project the selected pattern image.

3. The adjustment method according to claim 1, wherein the arithmetic circuit is accessible to a storage device, the storage device stores rules for generating a corresponding pattern image based on information relating to an APL, the arithmetic circuit uses the rules read from the storage device to generate a corresponding pattern image based on information relating to the APL of the content, and the generated pattern image is projected by the projection device.

4. The adjustment method according to claim 1, wherein the arithmetic circuit is accessible to a storage device, the storage device stores a predetermined pattern image, the arithmetic circuit generates a new pattern image by superimposing the pattern image stored in the storage device onto the content, and projects the new pattern image onto the projection device, and the image size of the pattern image superimposed on the content is smaller than the image size of the content.

5. The adjustment method according to claim 4, wherein the storage device stores a corresponding pattern image for each predetermined APL level, and the arithmetic circuit selects from the storage device a pattern image associated with the level selected according to the APL of the content, and superimposes the selected pattern image on the content to generate the new pattern image.

6. The adjustment method according to claim 1, wherein the arithmetic circuit is accessible to a storage device, and the arithmetic circuit causes the projection device to project pattern images previously reflected in a plurality of different APLs instead of a pattern image reflecting information related to the APL of the content, associates values related to focus control to achieve an in-focus state when the pattern image of each APL is displayed with information related to each APL and stores them in the storage device as correspondence data, and when new content is projected, adjusts the focus using the value in the correspondence data that is associated with information related to the APL of the new content.

7. The adjustment method according to claim 1, wherein when the content is a moving image made up of a plurality of frames, the average value of the APL of a plurality of frames over a predetermined period is used as information relating to the APL of the content.

8. The adjustment method according to claim 1, wherein when the content is a moving image composed of multiple frames, the information relating to the APL of the content is either the APL of one frame specified by the user, the average APL of multiple frames specified by the user, or the APL specified by the user.

9. A computer program for causing a control device to carry out the adjustment method according to any one of claims 1 to 8.

10. A control device connected to a projection device that projects content and a photographing device, and that adjusts the focus of the projection device, comprising an arithmetic circuit, which causes the projection device to project a pattern image that reflects the APL of the content, obtains from the photographing device a photographed image that includes the pattern image projected by the projection device, and adjusts the focus according to the state of the pattern image included in the photographed image.

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