Resolution measurement method, resolution measurement system, and program

Abstract

Provided is a resolution measurement method for a camera that generates distortion in a photographing field. The resolution measurement method for a camera executed by a computer device includes: a step of generating a distortion map representing a correspondence relationship of coordinates of all pixels of a first test pattern and coordinates of all pixels of the first test pattern in a captured image captured by the camera that generates distortion in a photographing field; a step of generating a distortion test pattern that is an image of distortion of a second test pattern for measuring resolution in a specific region within the first test pattern in the captured image, based on the correspondence relationship represented by the distortion map; and a step of performing resolution measurement by a contrast method in a portion of the photographing field of the camera corresponding to the specific region, using the distortion test pattern.

Description

Technical Field

[0001] This invention relates to camera resolution measurement technology. Background Technology

[0002] Traditional methods for measuring the MTF (Modulation Transfer Function) of digital cameras can be mainly classified into the tilted edge method and the contrast method. The tilted edge method, compared to the contrast method, allows for smaller test patterns and can handle cameras with distortion aberrations, such as fisheye cameras, making it applicable to various types of cameras. However, due to the application of image processing (edge ​​enhancement processing), reproducibility decreases, and the limiting resolution value becomes better than visually evaluated.

[0003] On the other hand, there are fewer problems with contrast methods, such as the tilted edge method. In MTF measurement using the contrast method, patterns with constant amplitude at different frequencies are captured, and the MTF is determined by measuring the brightness amplitude of each frequency of the captured image (e.g., Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-281626 Summary of the Invention

[0007] However, in the contrast method, when there is distortion in the test pattern, the waveform shape changes and higher harmonic components are generated, and the frequency interval changes, making it impossible to perform accurate MTF measurement. In other words, the contrast method is an MTF measurement method that assumes there is no distortion in the test pattern. Therefore, conventional contrast methods cannot handle cameras that produce distortion in the field of view, such as fisheye cameras.

[0008] The present invention was made in view of the following issues.

[0009] To address the aforementioned issues, one aspect of the present invention is a method for measuring camera resolution executed by a computer device, comprising: generating a distortion map representing the coordinates of all pixels in a first test image and a correspondence between the coordinates of all pixels in the first test image in an image captured by a camera that produces distortion in the field of view; generating a distorted image, i.e., a distortion test map, of a second test image for measuring resolution in a specific region within the first test image in the image captured, based on the correspondence represented by the distortion map; and performing a contrast-based resolution measurement in a portion of the camera's field of view corresponding to the specific region using the distortion test map.

[0010] Another aspect of the present invention is a computer device for performing the above-described resolution measurement method.

[0011] Another aspect of the present invention is a resolution measurement system, comprising: a computer device for executing the resolution measurement method described above; a camera for generating distortion in the field of view; and a display device, wherein the display device displays the distortion test image generated by the computer device, and the computer device performs the following steps: capturing the distortion test image displayed by the display device with the camera, and performing the resolution measurement.

[0012] Another aspect of the present invention is a program for causing a computer device to execute the above-described resolution measurement method.

[0013] Another aspect of the present invention is a computer-readable medium storing computer-executable commands, wherein, when the computer-executable commands are executed, a computer device performs the above-described resolution measurement method. Attached Figure Description

[0014] Figure 1 This is a diagram illustrating an example of the appearance of a resolution measurement system according to one embodiment of the present invention.

[0015] Figure 2 This is a diagram illustrating an example of the structure of a resolution measurement system according to one embodiment of the present invention.

[0016] Figure 3 This is a diagram illustrating an example of a camera's field of view.

[0017] Figure 4 This is an example diagram showing the correspondence between the pixels of a checkerboard image and the pixels of a distorted checkerboard image.

[0018] Figure 5 This is a diagram illustrating an example of data construction for distortion mapping.

[0019] Figure 6 This is an example of a test pattern image showing a white area corresponding to the chessboard image region in a captured image, and a distortion-free image of the test pattern used for measurement, which is then depicted.

[0020] Figure 7 This is a diagram illustrating an example of a distorted test chart image generated by backprojecting a distortion-free image of a test chart.

[0021] Figure 8 This is an example of a distorted step chart image generated by backprojecting a distortion-free step chart image.

[0022] Figure 9 This is a diagram illustrating an example of the field of view when taking a distorted test image using a camera.

[0023] Figure 10 This is a diagram showing an example of multiple measurement test patterns corresponding to multiple spatial frequencies.

[0024] Figure 11 This is a flowchart illustrating an example of processing in a computer device of a resolution measurement system according to an embodiment of the present invention.

[0025] Figure 12 This is a diagram illustrating an example of the hardware structure of a computer device for a resolution measurement system according to one embodiment of the present invention.

[0026] (Explanation of reference numerals in the attached diagram)

[0027] 1: Resolution measurement system; 10: Camera under test; 20: Display (test image); 30: Computer device; 302: Data input / output unit; 304: Distortion mapping generation unit; 306: Inverse projection image generation unit; 308: Resolution measurement unit; 40: Computer device; 41: Processor; 42: RAM; 43: ROM; 44: Hard disk device; 45: Removable memory; 46: Input / output user interface; 47: Communication interface; 48: Display. Detailed Implementation

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0029] (Structure of the resolution measurement system)

[0030] Figure 1This is an example of the appearance of the resolution measurement system according to this embodiment. The resolution measurement system 1 according to this embodiment is used to measure the resolution of a camera, such as a fisheye camera, that experiences distortion in its field of view. The resolution measurement system 1 of this embodiment employs a contrast method with good reproducibility, and performs distortion correction on the test image in a way that matches the camera under test. Figure 1 As shown, the camera 10, which is the object of resolution measurement, is configured to capture a test image 50 displayed on the display 20 within its field of view. More specifically, the camera 10 and the display 20 are configured such that any part of the field of view of the camera 10 from which the resolution to be measured is included within the screen area of ​​the display 20.

[0031] Figure 2 This is a diagram illustrating an example of the structure of the resolution measurement system according to this embodiment. (See diagram for example.) Figure 2 As shown, the resolution measurement system 1 is configured to include a camera 10, a display 20, and a computer device 30. The camera 10 is the camera under test that is the object of resolution measurement; it is a camera like a fisheye camera that experiences distortion in the field of view during shooting. Furthermore, in Figure 2 The dashed arrow extending from camera 10 represents an example of the field of view of camera 10. Display 20 displays images such as test charts, which are captured by camera 10. Computer device 30 acquires the image data captured by camera 10 and uses it together with the image data of the test chart displayed on the display to perform distortion correction processing on the test chart. Regarding display 20 (test chart), it can be configured to capture the test chart at any location within the field of view of camera 10 where the resolution to be measured is desired; it is not limited to a specific location. However, during the measurement of the resolution of that location, the relative positions of camera 10 and display 20 are kept fixed and do not change.

[0032] The computer device 30 includes a data input / output unit 302, a distortion mapping generation unit 304, a back projection image generation unit 306, and a resolution measurement unit 308.

[0033] The data input / output unit 302 performs various data input / output processing with the camera 10 or the display 20. For example, the data input / output unit 302 obtains image data captured by the camera 10 from the camera 10 via a wired or wireless network. Alternatively, the data input / output unit 302 can also obtain the captured image data via a removable, portable memory. Furthermore, the data input / output unit 302 outputs display data to the display 20 for displaying images such as test charts.

[0034] The distortion mapping generation unit 304 generates a distortion mapping that represents the correspondence between the coordinates of all pixels in the first test image (such as the chessboard image 50 described later) and the coordinates of all pixels in the captured image of the first test image (such as the distorted chessboard image 50d described later) obtained by the camera 10, which generates distortion in the field of view. Furthermore, the first test image is, for example, a grid-like image like the chessboard image 50 described later. The distortion mapping generation unit 304 calculates the coordinates of all pixels in the captured image of the distorted first test image based on the coordinates of each grid point in the captured image of the distorted chessboard image 50 (first test image) obtained by the camera 10, using interpolation processing such as cubic spline interpolation.

[0035] The inverse projection image generation unit 306 generates a distortion test image (such as the distortion measurement test image 62d described later) based on the correspondence represented by the distortion mapping generated by the distortion mapping generation unit 304. This distortion test image is a distorted image of the second test image (such as the distortion-free image 62 of the measurement test image described later) used to measure the resolution in a specific area within the first test image (within the image range) of the captured image. The generated distortion test image data is output to the display 20 and displayed on the display 20. Alternatively, the image data of the generated distortion test image can be output to a printer (not shown) and printed on paper.

[0036] The resolution measurement unit 308 uses the distortion test pattern generated in the back projection image generation unit 306 to perform a resolution measurement by contrast method within a portion of the field of view of the camera 10 corresponding to the specific area described above. Furthermore, during the resolution measurement, the distortion test pattern generated by the back projection image generation unit 306 is output to the display 20. In this embodiment, the distortion test pattern generated by the back projection image generation unit 306 is captured as a distortion-corrected (distortion-free) image when the camera 10 is used, so the resolution measurement by contrast method can be performed in the same manner as conventional contrast methods.

[0037] In addition, in the inverse projection image generation unit 306, a plurality of distorted images corresponding to a plurality of second test images corresponding to a plurality of spatial frequencies, i.e., a plurality of distorted test images, can be generated. In the resolution measurement unit 308, the plurality of distorted test images are used to perform the resolution measurement.

[0038] (Methods for generating distortion maps)

[0039] The following describes in detail a specific example of the distortion mapping generation method in the distortion mapping generation unit 304. In this embodiment, in order to generate the distortion mapping, an image of a chessboard displayed on the display 20 is captured at any position within the field of view of the camera 10 (including the area where the resolution is to be measured). Then, through interpolation processing, the distortion of all pixels in the chessboard image is calculated based on the coordinates of the captured image of the chessboard. Furthermore, as the interpolation processing, examples such as cubic spline interpolation can be used, but it is not limited to these. Other interpolation methods can also be used. Data representing the correspondence between the pixels of the original chessboard image and the pixels of the captured distorted chessboard image is stored as the distortion mapping. Moreover, a test map for measurement is generated based on this distortion mapping, so that even if the camera 10, which produces distortion in the field of view, produces distortion, the resolution can be measured by the contrast method.

[0040] Figure 3 This is a diagram illustrating an example of the field of view of camera 10. (See diagram for example.) Figure 3 As shown, firstly, a chessboard image 50 is displayed as a test image on the display 20. The relative positions of the display 20 and the camera 10 are adjusted so that the chessboard image 50 includes the area within the field of view of the camera 10 from which the resolution to be measured is displayed. Additionally, the data input / output unit 302 of the computer device 30 obtains data from the camera 10... Figure 3 Data of images captured by camera 10.

[0041] Next, refer to Figure 4 , Figure 4 This is a diagram illustrating an example of the correspondence between the pixels of the chessboard image 50 and the pixels of the distorted chessboard image 50d in the captured image obtained from the camera 10. Figure 4 In the example, the chessboard image 50 is set to a size of 2560 pixels × 1664 pixels.

[0042] Figure 5 This is a diagram illustrating an example of data construction for distortion mapping. (See diagram for example.) Figure 5As shown, in this embodiment, the distortion mapping data can be implemented as a two-dimensional arrangement of the coordinates (x, y) of all pixels in the test image 50 and the coordinates (x, y) of all pixels in the distorted test image 50d in the image captured by the camera 10. In this example, the test image (chessboard image) 50 is 2560 pixels × 1664 pixels, so the distortion mapping data can be represented as a two-dimensional arrangement of size 2560 (pixels) × 1664 (pixels) × 2 (x coordinates, y coordinates) (however, this example is just one example and is not limited thereto). More specifically, in this example, the coordinates of each grid point of the chessboard are measured. Moreover, the measured coordinates can be stored in a matrix for each xy coordinate. These processes can be performed using existing software. For example, the DetectCheckerboardPoints function of "MATLAB" (registered trademark), a product of MathWorks (registered trademark), can be used to calculate the coordinates of each grid point of the chessboard 50d in the image captured by the camera 10.

[0043] Furthermore, interpolation can be used to calculate the coordinates of all pixels in the chessboard image 50d based on the coordinates of each grid point. This process can be implemented, for example, by using the `griddedInterpolant` function of MATLAB (a product of MathWorks), where the x and y coordinates of the chessboard image 50d relative to all pixels are interpolated in two dimensions and saved as a distortion map.

[0044] (Methods for generating inverse projection images)

[0045] After the distortion mapping is generated in the distortion mapping generation unit 304, the inverse projection image of the test map used for measuring resolution is generated in the inverse projection image generation unit 306. Figure 6 This diagram illustrates an example of a white test image 50w corresponding to a chessboard image area in a camera-captured image, and a distortion-free image 62 of the measurement test image depicted thereafter. More specifically, in the white test image 50w representing the image range of the distorted chessboard image 50d, a user of a computer device 30 uses an input device such as a mouse to specify (draw) a rectangle 61 representing the area where the resolution to be measured. Furthermore, a distortion-free image 62 of the measurement test image is drawn at the location where this rectangle 61 is specified.

[0046] Next, based on the distortion mapping, the distortion-free image 62 of the measurement test map is inversely projected to generate a distorted measurement test map image. More specifically, the coordinates of all pixels in the distortion-free image 62 of the measurement test map correspond to... Figure 5The coordinates (x, y) of each pixel in the distortion-mapped chessboard image 50 are inversely transformed to the coordinates (x, y) of each pixel in the distortion-free image 62, thereby generating a distorted test image for measurement. Figure 7 This is a diagram showing an example of a distorted test pattern 62d generated by back-projecting a distortion-free image 62 of a test pattern for measurement.

[0047] Furthermore, in resolution measurement, the changes in brightness are transformed into frequency characteristics, thus requiring the linearity of the brightness data. However, the brightness characteristics of digital cameras are generally not linear for various reasons, so a test chart with known brightness (referred to here as a "step chart") is needed to correct the linearity of the brightness data. Therefore, similar to the test chart used for measurement, such as... Figure 8 As shown, the stair plot is also back-projected from its undistorted image 63 to generate a distorted stair plot 63d.

[0048] in addition, Figure 9 This diagram illustrates an example of a shooting field 10a when a distorted measurement test image 62d, generated as described above, is displayed on the display 20 and captured by the camera 10. It can be seen that in the shooting field 10a, the measurement test image 62d and... Figure 7 The distortion-free image 62 is also displayed in a distortion-free state. Therefore, the area in the field of view of the camera 10 where the test image 62a is displayed can be measured using a contrast method. This resolution measurement can be performed using a conventional contrast method. Furthermore, the resolution can also be measured similarly in other areas of the same white test image 50w. Furthermore, regarding the... Figure 8 The step diagram used to correct the linearity of luminance data, as described in the text, is also consistent with... Figure 9 Similarly, by displaying the distorted step chart image 63d on the display 20 and capturing the step chart image 63d with the camera 10, a distortion-free step chart is projected into the field of view 10a of the camera 10. Furthermore, when performing resolution measurement, the brightness data is corrected based on the brightness linearization LUT (Look-Up Table) generated from the step chart images 63 and 63d.

[0049] Furthermore, when measuring the resolution outside the range of the chessboard image 50 within the shooting field of view of the camera 10, the relative positions of the display 20 (test image) and the camera 10 are changed so that the chessboard image includes the area for resolution measurement, and the entire chessboard image 50 is contained within the shooting field of view of the camera 10. The above-described processing from the generation of the distortion map to the generation of the inverse projection image of the test image for measurement is repeated, thereby enabling the resolution to be measured at multiple locations within the shooting field of view of the camera.

[0050] Furthermore, in this embodiment, various test patterns are displayed on the display 20, but this is not a limitation. For example, the test pattern may also be a printed image on paper. For example, printing test patterns on paper is effective in environments with insufficient display brightness, such as outdoors. In either method, the test pattern (displayed on the display 20 or printed on paper) can be configured such that it includes any part of the field of view of the camera 10 from which the resolution to be measured. In addition, during the period from generating a distortion map based on the chessboard image 50 to generate a distorted test pattern 62d to measure the resolution, the relative position of the camera 10 and the test pattern needs to be fixed and not changed.

[0051] By generating a distortion map as described above and generating a distorted test image based on that distortion map, resolution can be measured at a specific location within the field of view of the camera 10 using the contrast method. Furthermore, in the resolution measurement method of this embodiment, only the relative positions of the camera 10 and the display 20 (test images 50, 50d, 62d, 62a) are required to remain unchanged during the period until the distortion map is generated to measure the resolution. The inspection distance between the camera 10 and the display 20 (test images 50, 50d, 62d, 62a), and the positions of the camera 10 and the display 20 (test images 50, 50d, 62d, 62a) are not particularly limited (they can be changed each time resolution is measured). Additionally, based on the correspondence between the coordinates of the pixels in the chessboard image 50 and the coordinates of the pixels in the distorted chessboard 50d in the camera image, a distorted test image image 62d is generated, and resolution measurement by the contrast method is performed. Therefore, even with a camera whose distortion characteristics are unknown, resolution can be measured.

[0052] However, conventional contrast methods typically use relatively large test patterns, such as test chart 62, which allows for the determination of resolution over multiple spatial frequencies. Therefore, conventional contrast methods make it difficult to determine resolution within a narrow range of the camera 10's field of view. In contrast, in this embodiment, as... Figure 10As shown, multiple measurement test charts (bar charts) 62d corresponding to multiple spatial frequencies are created. Distortion maps are also generated for these measurement test charts as described above, and distorted test charts 62d are generated based on these distortion maps. Furthermore, these distorted multiple measurement test charts 62d are displayed in a time-division manner at the same location on the display 20 (corresponding to the location within the field of view of the camera 10 where resolution measurement is desired), and the camera 10 captures images of them. Thus, in the captured images, the measurement test charts 62d are captured as distortion-free measurement test charts, enabling resolution measurement for multiple spatial frequencies. By using such measurement test charts 62d, the problem of difficulty in measuring resolution within a narrow range, as in conventional contrast methods, can be eliminated.

[0053] (Processing flow)

[0054] Figure 11 This is a flowchart illustrating an example of the processing in the computer device 30 of the resolution measurement system 1 according to this embodiment.

[0055] In step S100, the camera 10 and the display 20 are configured. The relative positions of the camera 10 and the display 20 are fixed until the end of this process.

[0056] In step S102, the data input / output unit 302 acquires image data of the distorted chessboard image 50d captured by the camera 10 with respect to the chessboard image 50 displayed on the display 20.

[0057] In step S104, the distortion mapping generation unit 304 generates a distortion mapping using the captured image data of the chessboard image 50 and the distorted chessboard image 50d obtained in step S102.

[0058] In step S106, the inverse projection image generation unit 306 generates a distortion-free image 62 of the measurement test pattern from a specific location (rectangle 61) specified by the user via a mouse or the like in the white test pattern image 50w. Alternatively, at this time, it is also possible to generate images such as... Figure 10 The images shown are distortion-free images of multiple test charts used for measurement. Similarly, in step S108, the inverse projection image generation unit 306 generates a distortion-free image 63 of a step chart for correcting the linearity of the brightness data. Furthermore, the processing order of steps S106 and S108 can be reversed, or they can be processed in parallel.

[0059] In step S110, the inverse projection image generation unit 306 inversely projects the distortion-free image 62 of the measurement test pattern according to the distortion mapping to generate a distorted measurement test pattern image 62d. Alternatively, at this time, it is also possible to generate an image such as... Figure 10Multiple test pattern images 62d for measurement are shown. Additionally, the image data of the generated distorted test pattern image 62d is output to the display 20. The display 20 acquires this image data and displays it. (Alternatively, the distorted test pattern image 62d can be printed on paper). Similarly, the back-projection image generation unit 306 performs back-projection on the undistorted image 63 of the step diagram to generate a distorted step diagram 63d. The image data of the generated distorted step diagram image 63d is output to the display 20.

[0060] In step S112, a resolution measurement using the contrast method is performed by capturing a distorted measurement test image 62d (displayed on the display 20 or printed on paper) with the camera 10, and then using the distortion-free measurement test image 62a. Furthermore, during the resolution measurement, luminance data is corrected based on a luminance linearization LUT generated from the step diagram images 63 and 63d. Alternatively, at this time, multiple measurement test images 62d can be displayed on the display 20 in a time-division manner to perform resolution measurements for multiple spatial frequencies.

[0061] Furthermore, when measuring the resolution in other parts of the image range of the distorted chessboard image 50d captured by camera 10, the processing steps S106 to S110 are repeated.

[0062] Furthermore, when measuring the resolution of areas outside the image range of the chessboard image 50d within the field of view of the camera 10, the processing in step S100 is performed such that the areas for resolution measurement are included in the chessboard image 50d. Moreover, the processing from step S102 onwards is performed regarding the areas for which the resolution measurement is performed.

[0063] Furthermore, the resolution measurement method based on this processing flow can also be implemented as a computer program for execution by a computer device. Additionally, such a computer program can be recorded onto a recording medium readable by the computer device.

[0064] (Hardware Structure)

[0065] The structure of the computer device 30 described above can be implemented using the same hardware structure as a general computer device. Figure 12 This is a diagram illustrating an example of the hardware structure of computer device 30. Figure 12The computer device 40 shown, as an example, includes a processor 41, RAM (Random Access Memory) 42, ROM (Read Only Memory) 43, a built-in hard disk drive 44, an external hard disk drive, a removable memory such as a CD, DVD, USB memory, memory stick, or SD card 45, an input / output user interface 46 (keyboard, mouse, touch panel, speaker, microphone, light, etc.) for exchanging data between the user and the computer device 40, a wired / wireless communication interface 47 for communicating with a camera 10, a display 20, or other devices, and a display 48 (which can be used in conjunction with the display 20). Regarding the functions of the computer device 30 according to this embodiment, for example, it can be implemented by the processor 41 reading programs pre-stored in the hard disk drive 44, ROM 43, removable memory 45, etc., into memory such as RAM 42, and simultaneously executing the program while appropriately reading the data required for processing from the hard disk drive 44, ROM 43, removable memory 45, etc. Furthermore, Figure 12 The hardware structure shown is only an example and is not limited to this.

[0066] This concludes the description of one embodiment of the present invention. However, the present invention is not limited to the above embodiment and can certainly be implemented in various different ways within the scope of its technical concept.

[0067] Furthermore, the scope of this invention is not limited to the illustrated and described exemplary embodiments, but also includes all embodiments that produce effects equivalent to those intended by the invention. Moreover, the scope of this invention is not limited to the combination of features described in the claims, but can be described by all desired combinations of specific features among all the disclosed features.

Claims

1. A method for measuring the resolution of a camera executed by a computer device, comprising: The step of acquiring image data is obtained by capturing the first test image in such a way that the image data is captured at any part of the field of view of the camera that produces distortion in the field of view, and the resolution of the target area is to be determined. The step of generating a distortion map through pixel interpolation, wherein the distortion map represents the correspondence between the coordinates of multiple pixels in the first test image and the coordinates of the multiple pixels in the first test image in the captured image composed of the captured image data; The step of generating a distortion test map based on the correspondence represented by the distortion mapping, wherein the distortion test map is a distorted image of a second test map used to determine the resolution in a specific region within the first test map in the captured image; as well as The relative positions of the camera and the distortion test image are made the same as those when the first test image was captured, and a resolution determination based on the contrast method is performed with the distortion test image captured in a portion of the camera's field of view corresponding to the specific region. The first test image is a grid-like image. In the step of generating the distortion map, based on the coordinates of each grid point in the first test image of the captured image, the coordinates of the plurality of pixels in the first test image of the captured image, excluding the grid points, are calculated by pixel interpolation. In the step of generating the distortion test map, multiple distortion images of the second test map corresponding to multiple spatial frequencies are generated, i.e., multiple distortion test maps. In the step of performing the resolution measurement, a resolution measurement based on the contrast method is performed while the plurality of distortion test images are captured in a time-divided manner at the same location as part of the field of view of the camera corresponding to the specific region.

2. The resolution measurement method according to claim 1, wherein, In the step of generating the distortion test map, the plurality of second test maps without distortion are drawn in the region of the captured image corresponding to the first test map, and the plurality of distortion test maps are generated according to the correspondence represented by the distortion mapping.

3. The resolution measurement method according to claim 1, wherein, In the step of performing the resolution measurement, the plurality of distortion test patterns are output to an external display device.

4. A computer device for performing the resolution measurement method according to any one of claims 1 to 3.

5. A resolution measurement system, comprising: A computer device that performs the resolution measurement method according to any one of claims 1 to 3; The camera produces distortion in the field of view during shooting; and display devices, wherein, The display device displays the plurality of distortion test patterns generated by the computer device. The computer device performs the step of measuring the resolution by taking pictures of the plurality of distortion test images displayed by the display device using the camera.

6. A computer-readable medium storing computer-executable commands, wherein, When the computer-executable command is executed, the computer device performs the resolution measurement method according to any one of claims 1 to 3.

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