Adjustment method, computer program, and control device

Abstract

The present invention performs focus adjustment by acquiring a suitable pattern image. This adjustment method involves using an arithmetic circuit to adjust the focus of a projection device, the arithmetic circuit being connected to the projection device and an imaging device, and being able to access a storage device. The storage device stores pattern image information. With the arithmetic circuit: the pattern image information is read from the storage device; a composite pattern image in which there are arranged pattern images each having a different density for each area on the basis of the pattern image information is projected by the projection device; a captured image including the projected composite pattern image is acquired from the imaging device; and the focus is adjusted by using the composite pattern image included in the captured 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, first, a pattern image projected by the projection device is captured by a capturing 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 contained 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.

[0003] JP 2020-201365 A JP 2006-10791 A

[0004] Incidentally, it is preferable to acquire a suitable pattern image using an imaging device for focus adjustment, but optimization of the acquired pattern image is sometimes not taken into consideration.

[0005] The present disclosure provides an adjustment method, a computer program, and a control device for performing focus adjustment by acquiring a suitable pattern image.

[0006] The adjustment method disclosed herein adjusts the focus of the projection device using an arithmetic circuit connected to the projection device and the imaging device and capable of accessing a storage device. The storage device stores information related to a pattern image. The arithmetic circuit reads the information related to the pattern image from the storage device and generates a composite pattern image in which pattern images with different densities are arranged in different areas based on the information related to the pattern image. The projection device projects the composite pattern image. A captured image including the projected composite pattern image is obtained from the imaging device, and the focus is adjusted using the composite 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 acquire a suitable pattern image to achieve focus adjustment.

[0009] 6A is a conceptual diagram illustrating an example of the relationship between a screen, a projection direction, and a shooting direction in a projection system, and the relationship between a pattern image. FIG. 6B is a conceptual diagram illustrating another example of the relationship between a screen, a projection direction, and a shooting direction in a projection system, and the relationship between a pattern image. FIG. 6C is a conceptual diagram illustrating another example of the relationship between a screen, a projection direction, and a shooting direction in a projection system, and the relationship between a pattern image. FIG. 6D is a conceptual diagram illustrating another example of the relationship between a screen, a projection direction, and a shooting direction in a projection system, and the relationship between a pattern image. FIG. 6E is a diagram illustrating an example of the configuration of a projection system and a control device according to a first embodiment. FIG. 6F is an example of a pattern image used for focus adjustment by the control device of FIG. 2. FIG. 6G is another example of a pattern image used for focus adjustment by the control device of FIG. 2. FIG. 6H is another example of a pattern image used for focus adjustment by the control device of FIG. 2. FIG. 6I is a flowchart illustrating processing in a control device according to a first embodiment. FIG. 6I shows an example of an area set in the projection range used by the control device of FIG. 2. FIG. 6I shows an example of each area in the captured image of the capture device corresponding to each area of ​​FIG. 6A. FIG. 6I is an example of a composite pattern image generated by the control device of FIG. 2. FIG. 6F is an example of the configuration of a projection system and a control device according to a second embodiment. 9 is a flowchart showing processing in a control device according to a second embodiment. 10 shows an example of each area in a captured image used in the projection system of FIG. 8. 11 shows an example of calculating an average interval between feature points from a plurality of feature points in the area of ​​FIG. 8.

[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] <Pattern Image in Captured Image> First, the positional relationship between the projection device, the capture device, and the screen that poses a problem in adjusting the focus of the projection device using the adjustment method, computer program, and control device disclosed herein, and an example of a pattern image displayed on the screen will be described. Figure 1A shows an example of a captured image when the projection direction d1 from the projection device and the capture direction d2 from the capture device are perpendicular to the screen 50. As shown in Figure 1A, when the projection direction d1 and the capture direction d2 are perpendicular to the screen 50, the pattern image in the captured image is in an ideal state. Specifically, when the pattern of the pattern image is represented by a grid, the pitch of each grid is uniform.

[0012] In contrast, as shown in Figures 1B to 1D, when the projection direction d1 and the shooting direction d2 are not parallel, the pattern image in the captured image is not ideal. Specifically, when the pattern of the pattern image is represented by a grid, the pitch of the grid is not uniform. For example, the grid of the pattern in the captured image is divided into narrow and wide pitch areas on the left and right. In the narrow pitch areas, the grid may be crushed in the captured image. Therefore, the change in signal value on the captured image required for focus adjustment becomes small, making focus adjustment difficult.

[0013] The adjustment method, computer program, and control device according to the present disclosure achieve focus adjustment by acquiring a suitable pattern image regardless of the positional relationship between the projection device and the image capture device.

[0014] 2 , 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. When projecting content, the control device 10A can also adjust the focus by changing the position of a lens in the projection device 20.

[0018] 2, 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 such as for adjusting the focus.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] The pattern image 121 is data used for focus adjustment before content is projected by the projection device 20. The storage device 12 may store the pattern image 121 itself as information related to the pattern image. The storage device 12 may also store rules for generating the pattern image 121 as information related to the pattern image. FIGS. 3A to 3C show pattern images 121 with different degrees of density. The pattern images 121 shown in FIGS. 3A to 3C are lattice patterns. Specifically, FIGS. 3A to 3C show an example in which the degree of density varies depending on the lattice pitch.

[0024] 4, the grid spacing w1 in the x-axis direction of the image, the width of update w2 in the x-axis direction, the grid spacing h1 in the y-axis direction, and the width of update h2 in the y-axis direction may be changed to generate a pattern image 121 with different degrees of pattern density. However, the shape of the pattern shown by the pattern image 121 and the method of distinguishing between density and sparseness are not limited.

[0025] <Operation of Control Device> Processing executed by the control device 10A according to the first embodiment will be described with reference to the flowchart shown in FIG.

[0026] The arithmetic circuit 11 causes the projection device 20 to project indices that identify each area when the projection range is divided into a plurality of areas (S01).

[0027] For example, the arithmetic circuit 11 projects an index identifying each area, as shown in FIG. 6A . FIG. 6A illustrates an example in which each area is identified by a plurality of points serving as indices. In the example illustrated in FIG. 6A , one area is indicated by points P1 to P4. Also, in the example illustrated in FIG. 6A , the projection range is divided into nine areas, areas A to I. Note that the index identifying each area is not limited to the method illustrated in FIG. 6A . For example, a method of projecting a different color for each area may be used. Alternatively, a method of projecting a specific color for each area in sequence may be used. Also, although the example illustrated in FIG. 6A shows nine areas, the number of areas is not limited. For example, the control device 10A may divide the area into 100 or more areas, or 500 or more areas.

[0028] The arithmetic circuit 11 acquires a captured image including the indices projected in step S01 from the image capturing device 30 (S02).

[0029] For example, Fig. 6B shows an example of a captured image when the index shown in Fig. 6A is projected. When the projection direction of the projection device 20 and the capture direction of the capture device 30 are not parallel, the projection range is displayed distorted, as shown in Fig. 6B.

[0030] The arithmetic circuit 11 repeats the processing of steps S01 to S03 until the projection of the indices in all areas by the projection device 20 and the photographing by the photographing device 30 are completed (YES in S03).

[0031] When the projection and capture of the indices for all areas is completed, the arithmetic circuit 11 obtains the correspondence between the coordinates indicating each area in the projected image and the coordinates indicating each area in the captured image (S04).

[0032] For example, points P1, P2, P3, and P4 in the projected image in Fig. 6A correspond to points P1', P2', P3', and P4' in the captured image in Fig. 6B. Also, areas A to I in the projection region correspond to areas A' to I' in the captured image in Fig. 6B.

[0033] The arithmetic circuit 11 selects a pattern image to be applied to each area (S05). Specifically, the arithmetic circuit 11 selects a pattern image 121 with a dense pattern for an area with a large number of pixels in the captured image, and selects a pattern image 121 with a sparse pattern for an area with a small number of pixels.

[0034] For example, assume that areas A', B', and C' in a captured image have 600,000 pixels, areas D', E', and F' have 1,000,000 pixels, and areas G', H', and I' have 1,400,000 pixels. In this case, the coarsest pattern image 121 (e.g., FIG. 3A) is assigned to areas A' to B'. Furthermore, the densest pattern image 121 (e.g., FIG. 3C) is assigned to areas G' to I'.

[0035] The arithmetic circuit 11 may select a pattern image in which the number of pixels for each of w1, w2, h1, and h2 shown in FIG. 4 is determined using Table 1 below, depending on the number of pixels in the area in the captured image. Table 1 shows that, depending on the number of pixels in the area in the captured image, when the number of pixels in the area is large, the pattern becomes denser than when the number of pixels is small. Note that the following values ​​vary depending on the performance and installation environment of each device 20, 30. For example, the values ​​in Table 1 are an example when the resolution of the projection device 20 is 1920 x 1200 and the resolution of the capture device 30 is 4000 x 3000.

[0036] The arithmetic circuit 11 applies the pattern image 121 selected in step S05 to each area to generate a composite pattern image (S06).

[0037] 7 shows an example of a composite pattern image generated by allocating pattern images 121 to areas A to I in the state described above in FIGS. 6A and 6B. In the example of the composite pattern image shown in FIG. 7, pattern images 121 with a low degree of sparseness are allocated to areas with a small number of pixels on the captured image. Furthermore, pattern images 121 with a high degree of sparseness are allocated to areas with a large number of pixels on the captured image.

[0038] The arithmetic circuit 11 causes the projection device 20 to project the composite pattern image generated in step S06 (S07).

[0039] The arithmetic circuit 11 acquires a captured image from the image capture device 30, including the composite pattern image projected in step S06 (S08). The degree of pattern density in each area is determined according to the proportion of the area it occupies in the captured image. This reduces the difference in pattern density between areas with a low number of pixels and areas with a high number of pixels in the captured image obtained by capturing the projected composite pattern image. Furthermore, even if the pattern image appears reduced in size in the captured image, the pattern will not be crushed. Therefore, the pattern in each area appears in the captured image at a density that is easy to use for focus adjustment. This allows for improved focus accuracy during focus adjustment.

[0040] The arithmetic circuit 11 adjusts the focus of the projection device 20 based on the captured image acquired in step S08 (S08). Specifically, the arithmetic circuit 11 obtains a score value indicating each focus state from the captured image of the pattern image 121 projected in a plurality of different focus states by the projection device 20. The arithmetic circuit 11 determines the focus state with the highest score value as the in-focus state.

[0041] In this way, the arithmetic circuit 11 according to the first embodiment determines the pattern density of the pattern image in each area of ​​the projection range of the projection device according to the number of pixels in each area within the image captured by the image capture device, allowing the projection device to project the pattern image with a pattern density suitable for the focus adjustment of the control device.

[0042] Second Embodiment FIG. 8 shows a projection system 1 and a control device 10B according to a second embodiment. The control device 10B according to the second embodiment differs from the control device 10A according to the first embodiment described above with reference to FIG. 2 in that a feature point detection pattern 122 is stored in the storage device 12. Furthermore, the storage device 12 stores a control program P2 instead of the control program P1. The control device 10 according to the first embodiment determines the degree of density of the pattern image used for focus adjustment based on the number of pixels per area in the captured image. In contrast, the control device 10 according to the second embodiment calculates the spacing between the coordinates of each feature point from the captured image of the feature point detection pattern 122 projected onto the screen 50 and determines the degree of density of the pattern image based on each spacing.

[0043] The feature point detection pattern 122 indicates predetermined coordinates in the projection range as feature points. The feature point detection pattern 122 can identify coordinates at predetermined intervals in the projection range, for example, by using a regular shape. The feature point detection pattern 122 is not shown in the figure. FIG. 9 shows an example of feature points identified by the feature point detection pattern 122. Each point in FIG. 9 is the coordinate indicated by the feature point detection pattern 122. The control device 10B matches the coordinates of each feature point detected from the captured image when the feature point detection pattern 122 is projected onto the projection device 20 with the coordinates of the feature point in the projected image. This allows the control device 10B to determine the correspondence between the coordinate system of the imaging device 30 and the coordinate system of the projection device 20.

[0044] <Operation of Control Device> The process executed by the control device 10B according to the second embodiment will be described with reference to the flowchart shown in FIG.

[0045] The arithmetic circuit 11 causes the projection device 20 to project the feature point detection pattern 122 (S11).

[0046] The arithmetic circuit 11 acquires a captured image including the feature point detection pattern 122 projected in step S11 from the image capturing device 30 (S12).

[0047] The arithmetic circuit 11 acquires a correspondence relationship between the coordinates of the feature points in the projected image projected in step S11 and the coordinates of the feature points in the captured image acquired in step S12 (S13). This allows the arithmetic circuit 11 to identify the area to be set in the projection range. Fig. 11A shows an example of areas A' to I' corresponding to each area in the projection range in the captured image. Each area A' to I' in Fig. 11A corresponds to an area when areas A to I are set in the projection range as shown in Fig. 6A.

[0048] The arithmetic circuit 11 calculates the average spacing of feature points for each area set in the projection range in the captured image acquired in step S12 (S14). Fig. 11B shows the positional relationship of feature points detected in area G' in Fig. 11A. In the example shown in Fig. 11B, for feature point P10, the arithmetic circuit 11 calculates the average spacing L0 (= L1 (w11 + w12 + h11 + h12) / 4) between feature point P10 and feature points P11, P12, P13, and P14. The arithmetic circuit 11 also calculates average spacings L1 to Lm for all feature points in the area. The arithmetic circuit 11 then calculates the average of the average spacings calculated for all feature points in the area ((L1 + L2 + ... + Lm) / m) as the average spacing of feature points in the area.

[0049] The arithmetic circuit 11 determines the pattern pitch for each area based on the average interval determined for each area in step S14 (S15).

[0050] For example, the pattern pitch for each area is determined using Table 2 below, depending on the average spacing between feature points within the area in the captured image. In the example shown below, each pitch is distinguished by the grid spacing w1 in the x-axis direction, the update width w2 in the x-axis direction, the grid spacing h1 in the y-axis direction, and the update width h2 in the y-axis direction of the image shown in FIG. 4 . Table 2 shows that, depending on the average spacing between feature points within the area in the captured image, when the number of pixels in the area is large, the pattern becomes denser than when the number of pixels is small. Note that the following values ​​vary depending on the performance and installation environment of each device 20, 30, the number of feature points detected, etc. For example, the values ​​in Table 2 are an example when the resolution of the projection device 20 is 1920 x 1200, the resolution of the capture device 30 is 4000 x 3000, and 42 feature points are detected horizontally and 22 points vertically.

[0051] The arithmetic circuit 11 generates a pattern image for each area based on the pitch determined in step S15 (S16).

[0052] The arithmetic circuit 11 synthesizes the pattern images generated in step S16 to generate a composite pattern image (S17).

[0053] The arithmetic circuit 11 causes the projection device 20 to project the composite pattern image generated in step S17 (S18).

[0054] The arithmetic circuit 11 acquires a captured image including the composite pattern image projected in step S18 from the image capturing device 30 (S19).

[0055] The arithmetic circuit 11 adjusts the focus of the projection device 20 based on the captured image acquired in step S19 (S20).

[0056] In this way, the arithmetic circuit 11 according to the second embodiment determines the pattern density of the pattern image in each area of ​​the projection range of the projection device according to the distance interval between the feature points of each area in the image captured by the image capture device, allowing the projection device to project the pattern image with a pattern density suitable for the focus adjustment of the control device.

[0057] Overview of the embodiments (1) The adjustment method disclosed herein is an adjustment method that adjusts the focus of a projection device by an arithmetic circuit that is connected to a projection device and a photographing device and can access a storage device, wherein the storage device stores information related to a pattern image, the arithmetic circuit reads out information related to the pattern image from the storage device, causes the projection device to project a composite pattern image in which pattern images with different densities are arranged in each area based on the information related to the pattern image, obtains from the photographing device a photographed image that includes the projected composite pattern image, and adjusts the focus using the composite pattern image included in the photographed image.

[0058] This allows focus adjustment to be performed without being affected by the placement of the projection device and the image capture device.

[0059] (2) In the adjustment method of (1), the pattern corresponding to each area of ​​the composite pattern image included in the captured image may indicate a degree of density determined according to the proportion that each area occupies in the entire captured image.

[0060] By projecting the pattern image at a density level that corresponds to the proportion of each area, focus adjustment can be performed without being affected by the placement of the projection device and the image capture device.

[0061] (3) In the adjustment methods of (1) to (2), the arithmetic circuit may: cause the projection device to project an index that identifies each area when the projection range of the projection device is divided into multiple areas; acquire a captured image including the projected index from the capture device; correspond the coordinates of the image projected by the projection device to the coordinates of the image captured by the capture device according to the index included in the captured image; and determine a pattern image corresponding to each of the multiple areas of the image projected by the projection device according to the number of pixels on the captured image of the multiple areas.

[0062] By projecting a pattern image at a density that corresponds to the number of pixels in the area set in the projection range on the captured image, focus adjustment can be performed without being affected by the placement of the projection device and the capture device.

[0063] (4) In the adjustment method of (3), the pattern image may be such that a pattern image having a denser pattern is assigned to an area on the captured image having a larger number of pixels than an area on the captured image having a smaller number of pixels.

[0064] By allocating a dense pattern image to an area with a large number of pixels on the photographed image and allocating a sparse pattern image to an area with a small number of pixels, the difference in the degree of density of the patterns in each area on the photographed image can be reduced.

[0065] (5) In the adjustment method of (1), the storage device may have the arithmetic circuit project a feature point detection pattern that identifies feature points set at a predetermined interval within the projection range of the projection device, acquire a captured image including the projected feature point detection pattern from the capture device, match coordinates of the image projected by the projection device with coordinates of the image captured by the capture device according to feature points identified from the captured image, and determine a pattern image corresponding to the area of ​​the image projected by the projection device according to an average interval between feature points on the captured image of a plurality of areas.

[0066] By projecting a pattern image according to the average interval between feature points detected in the projection range on the captured image, focus adjustment can be performed without being affected by the arrangement of the projection device and the capture device.

[0067] (6) In the adjustment methods (1) to (5), the pattern image may be such that a pattern image with a denser pattern is assigned to an area on the captured image where the average interval is large, rather than to an area where the number of pixels is small.

[0068] By allocating a pattern image with a dense pattern to an area where the average interval between feature points on the captured image is large, and allocating a pattern image with a sparse pattern to an area where the average interval is small, focus adjustment can be performed without being affected by the arrangement of the projection device and the capturing device.

[0069] (7) In the adjusting methods (1) to (6), the shape representing the pattern may be a lattice shape, and the density of the pattern may be represented by the width of the lattice.

[0070] By utilizing the grid-shaped pattern, focus adjustment can be performed without being affected by the arrangement of the projection device and the image capture device.

[0071] (8) The computer program of the present disclosure may cause a control device to execute the adjustment methods (1) to (7).

[0072] This allows focus adjustment to be performed without being affected by the placement of the projection device and the image capture device.

[0073] (9) A control device of the present disclosure includes an arithmetic circuit that can access a storage device, is connected to a projection device and a photographing device, and adjusts the focus of the projection device, wherein the storage device stores information related to a pattern image, and the arithmetic circuit reads out information related to the pattern image from the storage device, causes the projection device to project a composite pattern image in which pattern images with different densities are arranged in each area based on the information related to the pattern image, obtains from the photographing device a photographed image including the projected composite pattern image, and adjusts the focus using the composite pattern image included in the photographed image.

[0074] This allows focus adjustment to be performed without being affected by the placement of the projection device and the image capture device.

[0075] 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.

[0076] 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. An adjustment method for adjusting the focus of a projection device by an arithmetic circuit connected to a projection device and a photographing device and capable of accessing a storage device, wherein the storage device stores information relating to a pattern image, the arithmetic circuit reads out the information relating to the pattern image from the storage device, causes the projection device to project a composite pattern image in which pattern images with different densities are arranged in each area based on the information relating to the pattern image, obtains from the photographing device a photographed image including the projected composite pattern image, and adjusts the focus using the composite pattern image included in the photographed image.

2. The adjustment method according to claim 1, wherein the pattern corresponding to each area of the composite pattern image included in the captured image indicates a degree of density determined according to the proportion that each area occupies in the entire captured image.

3. The adjustment method according to claim 1, wherein the arithmetic circuit: causes the projection device to project an index that identifies each area when the projection range of the projection device is divided into multiple areas; acquires a captured image including the projected index from the capture device; corresponds the coordinates of the image projected by the projection device to the coordinates of the image captured by the capture device according to the index included in the captured image; and determines a pattern image corresponding to each of the multiple areas of the image projected by the projection device according to the number of pixels on the captured image of the multiple areas.

4. The adjustment method according to claim 3, wherein the pattern image is assigned a pattern image with a denser pattern to an area on the captured image with a larger number of pixels than to an area with a smaller number of pixels.

5. The adjustment method according to claim 1, wherein the arithmetic circuit projects a feature point detection pattern that identifies feature points set at predetermined intervals within the projection range of the projection device, acquires a captured image including the projected feature point detection pattern from the capture device, matches the coordinates of the image projected by the projection device with the coordinates of the image captured by the capture device according to the feature points identified from the captured image, and determines a pattern image corresponding to the area of the image projected by the projection device according to the average interval between feature points on the captured image of a plurality of areas.

6. The adjustment method according to claim 2, wherein the pattern image is assigned a pattern image with a denser pattern to an area on the captured image where the average spacing is large, rather than an area where the number of pixels is small.

7. The adjustment method according to claim 1, wherein the shape representing the pattern of the pattern image is a lattice shape, and the density of the pattern is represented by the width of the lattice.

8. A computer program for causing a control device to execute the adjustment method according to any one of claims 1 to 7.

9. A control device comprising an arithmetic circuit that can access a storage device, connected to a projection device and a photographing device, and that adjusts the focus of the projection device, wherein the storage device stores information relating to a pattern image, and the arithmetic circuit reads out the information relating to the pattern image from the storage device, causes the projection device to project a composite pattern image in which pattern images with different densities are arranged in each area based on the information relating to the pattern image, obtains from the photographing device a photographed image that includes the projected composite pattern image, and adjusts the focus using the composite pattern image included in the photographed image.

Images