Target system

Abstract

The present disclosure relates to a target system that makes it possible to detect an impact position on the basis of an image. The target system comprises: an imaging device that images a target; and a collision position identification unit that, on the basis of an image captured by the imaging device of a flying object which has reached a state of slowed movement or a substantially stopped state after flying toward the target and colliding with a flexible sheet, identifies the collision position of the flying object on the target. When the imaging device is disposed in front of the target, the collision position identification unit uses an image captured in a certain amount of time starting from when, upon impact of the flying object on the flexible sheet, the flying object collides with the flexible sheet to when the flexible sheet absorbs energy and the flying object is bounced back. The present technology can be applied, for example, to a target system for an airsoft gun that can fire BB bullets.

Description

Target System

[0001] The present disclosure relates to a targeting system, and more particularly to a targeting system that is capable of detecting a bullet impact position based on an image.

[0002] Shooting competitions have been held in which participants shoot at targets using soft air guns, which are toy guns equipped with a mechanism for firing plastic bullets (hereinafter referred to as BBs (ball bullets)) using low-pressure compressed air or the like, and compete for scores based on the position at which the BBs hit the target. In such shooting competitions, it is important to accurately detect the position at which the BBs hit.

[0003] Therefore, the applicant of the present application has proposed a target system that can accurately calculate the impact position, impact speed, energy, etc. of a BB bullet that hits a target board by detecting the shock wave generated when the BB bullet hits the target board (see, for example, Patent Document 1).

[0004] JP 2014-25677 A

[0005] Incidentally, as proposed in the above-mentioned Patent Document 1, it is possible to detect the impact position of a BB bullet based on shock waves, but there are cases where it is required to detect the impact position of a BB bullet based on an image.

[0006] The present disclosure has been made in consideration of such circumstances, and makes it possible to detect the impact position based on an image.

[0007] A target system according to one aspect of the present disclosure includes an imaging device that images a target, and a collision position identification unit that identifies the collision position of a flying object with respect to the target based on an image captured by the imaging device of the flying object flying toward the target colliding with a soft sheet and becoming slowed down or substantially stationary.

[0008] In one aspect of the present disclosure, a target is imaged by an imaging device, and the collision position of the flying object with the target is identified based on an image of the flying object flying toward the target colliding with a soft sheet and becoming slowed down or nearly stationary.

[0009] According to one aspect of the present disclosure, the impact position can be identified based on the image.

[0010] The effects described here are not necessarily limited to those described herein, and may be any of the effects described in this disclosure.

[0011] Fig. 1 is a diagram showing a configuration example of a first embodiment of a target system to which the present technology is applied; Fig. 2 is a diagram showing a configuration example of an impact mitigation unit; Fig. 3 is a diagram explaining a method for detecting the impact position of a BB bullet; Fig. 4 is a diagram showing a configuration example of a second embodiment of the target system; Fig. 5 is a diagram showing a configuration example of a third embodiment of the target system; Fig. 6 is a diagram explaining a method for detecting the impact position of a BB bullet; Fig. 7 is a diagram showing a configuration example of a fourth embodiment of the target system.

[0012] Hereinafter, specific embodiments to which the present technology is applied will be described in detail with reference to the drawings.

[0013] <First Configuration Example of Target System> FIG. 1 is a diagram showing a configuration example of a first embodiment of a target system to which the present technology is applied.

[0014] 1, the target system 11 is configured to include a display device 12, an impact absorbing unit 13, an imaging device 14, and a notebook personal computer (hereinafter referred to as a notebook PC (Personal Computer)) 15. The display device 12 and the notebook PC 15 are connected via a video cable 16, and the imaging device 14 and the notebook PC 15 are connected via a communication cable 17. It is also possible to adopt a configuration in which these are connected wirelessly.

[0015] For example, in the target system 11, the display device 12 is placed at a predetermined distance (e.g., about 10 to 30 meters) from a user who is shooting using a soft air gun 21, and the laptop PC 15 is placed near the user. In addition, an impact absorbing unit 13 is attached to the front of the display device 12, and a collection tray 22 is placed below and in front of the impact absorbing unit 13.

[0016] The imaging device 14 can be positioned in front of the display device 12 and out of the line of fire of the soft air gun 21 held by the user (e.g., above, below, to the left, or right of the line of fire of the soft air gun 21, but not in the way of the user's shooting) so as to capture an image of the display device 12 through the impact mitigation unit 13. Specifically, for example, when the user is in a standing shooting position, the imaging device 14 is preferably positioned within approximately 40 cm below the user's viewpoint. Even if the imaging device 14 is positioned in this way, by providing a distance of 10 m or more from the imaging device 14 to the display device 12, the imaging device 14 can capture an image of the display device 12 from approximately the front, thereby avoiding obstruction to the user's shooting. Alternatively, the imaging device 14 may be mounted on a tripod or the like and positioned closer than 10 m from the display device 12, but not in the user's line of fire. It is also possible to configure the imaging device 14 to be fixed along the barrel of the soft air gun 21, but in this configuration it is necessary to correct blurring and tilt that occurs in the image captured by the imaging device 14 in response to the vibration of the soft air gun 21.

[0017] In the target system 11, when a user operates the laptop PC 15 to display a target image 23 representing a target to be shot on the display unit of the laptop PC 15, the target image 23 is also displayed on the display device 12 via the video cable 16. When the user points the muzzle of the soft air gun 21 at the display device 12 and fires at the target image 23, a BB bullet 24 fired from the soft air gun 21 flies along the dashed line shown in Fig. 1 and then hits and rebounds from the impact cushioning unit 13. As will be described later with reference to Fig. 2, a soft sheet 32 ​​is provided on the surface of the impact cushioning unit 13. The BB bullets 24, whose impact upon impact is cushioned by the soft sheet 32, fall in front of the impact cushioning unit 13 and are collected by the collection tray 22 without scattering.

[0018] The target system 11 detects the impact position of the BB bullet 24 on the impact absorbing unit 13 based on the image captured by the imaging device 14, and displays an impact mark P indicating the impact position superimposed on the target image 23. The user can confirm the impact position of the BB bullet 24 by looking at the impact mark P on the target image 23 displayed on the display device 12 and the impact mark P on the target image 23 displayed on the display unit of the notebook PC 15.

[0019] The target system 11 is configured in this manner and has a detection function for detecting the impact position of the BB bullet 24 fired from the soft air gun 21 relative to the target image 23, and a recovery function for recovering the BB bullet 24 that has impacted the impact absorbing unit 13 in a collection tray 22.

[0020] The target system 11 may be configured to include a tablet terminal, a smartphone, or the like instead of the laptop PC 15, and operations for the laptop PC 15 may be performed on the tablet terminal, the smartphone, or the like. Furthermore, the target system 11 may be configured to include a computer module, such as a board-type computer module, that has the necessary processing capabilities. As the imaging device 14, a camera mounted on the laptop PC 15, a tablet terminal, a smartphone, or the like, or a camera module connectable to a board-type computer module, may be used, as long as it can be arranged as described above and is capable of being utilized in terms of performance. For example, a board-type computer module equipped with a camera may be used, or the required number of cameras may be connected to a board-type computer module.

[0021] <Configuration Example of Impact Absorbing Unit> A configuration example of the impact absorber unit 13 and the position of the image capturing device 14 relative to the display device 12 will be described with reference to FIG.

[0022] FIG. 2 shows a schematic configuration example of the target system 11 in plan view, and the notebook PC 15, video cable 16, communication cable 17, etc. are not shown.

[0023] 2, in the targeting system 11, an impact absorbing unit 13 is attached to the front of the display device 12, and an imaging device 14 is disposed a predetermined distance D, for example, about 10 to 30 meters, from the impact absorbing unit 13, directly in front of the display device 12. Note that the range of 20 degrees to the left, right, top, and bottom as viewed from the front of the display device 12 is defined as the front direction, and the coordinates of the impact position of the BB bullet 24 can be calculated by applying correction according to the inclination within this range.

[0024] The impact absorbing unit 13 is configured to include a frame member 31, a soft sheet 32, a protective plate 33, and fixing plates 34-1 to 34-3.

[0025] The frame member 31 is a frame-shaped member for fixing either the upper and lower edges and / or the left and right edges of the soft sheet 32 ​​and the protective plate 33, and is configured to have approximately the same size as the outer shape of the display device 12. Of course, the frame member 31 may be larger than the outer shape of the display device 12. The soft sheet 32 ​​is fixed to the front side of the frame member 31 (the imaging device 14 side), and the protective plate 33 is fixed to the back side of the frame member 31 (the display device 12 side).

[0026] The soft sheet 32 ​​is a transparent, soft, sheet-like member that can deflect to receive the impact of the BB pellets 24 fired by the soft air gun 21. For example, the soft sheet 32 ​​is preferably made of a material that has a slow recovery rate after deformation due to impact, such as a soft vinyl chloride resin with a thickness of 3.0 mm. The soft sheet 32 ​​is fixed to the frame member 31 at either its top and bottom edges or its left and right edges, or both of its top and bottom edges and its left and right edges, so that the sheet is generally flat when stretched substantially vertically in front of the display device 12 and does not deflect.

[0027] The protective plate 33 is a transparent, hard, plate-like member for protecting the display screen of the display device 12. It is preferable to use, for example, a 2 mm-thick polyethylene terephthalate (PET) resin. For example, even if a BB bullet 24 strikes the soft sheet 32, causing the soft sheet 32 ​​to bend significantly more than the thickness of the frame member 31 (the distance between the soft sheet 32 ​​and the protective plate 33), the protective plate 33 can protect the display device 12. If such a large bending does not occur in the soft sheet 32, the shock-absorbing unit 13 may be configured without the protective plate 33. The protective plate 33 also serves as a brace for the frame member 31 and is effective in preventing distortion of the frame member 31, for example.

[0028] The fixing plates 34-1 to 34-3 are used to attach the shock absorbing unit 13 to the display device 12. For example, the fixing plates 34-1 to 34-3 are fixed to the upper surface of the frame member 31 so as to extend rearward from the upper surface of the frame member 31. The fixing plate 34-1 is fixed to the center of the upper surface of the frame member 31, and the fixing plates 34-2 and 34-3 are fixed near the left and right ends of the upper surface of the fixing plate 34-1, respectively. For example, as shown in FIG. 4 , which will be described later, the shock absorbing unit 13 is attached to the display device 12 by abutting the lower surfaces of the fixing plates 34-1 to 34-3 against the upper surface of the display device 12 and engaging the display device 12 with the fixing plates 34-1 to 34-3.

[0029] The impact absorbing unit 13 is configured in this manner, and absorbs the impact when the BB bullet 24 hits the soft sheet 32. In the targeting system 11, the imaging device 14 disposed in front of the display device 12 captures an image of the BB bullet 24 hitting the soft sheet 32, and the impact position of the BB bullet 24 can be detected based on the image obtained by capturing the image.

[0030] A method for detecting the impact position of the BB bullet 24 in the targeting system 11 will be described with reference to FIG.

[0031] For example, by using an imaging device 14 with a frame rate of 120 fps and a distance D from the impact mitigation unit 13 of 10 m to capture a telephoto image of the entire display device 12 through the impact mitigation unit 13, it was possible to confirm, frame by frame, the BB bullets 24 flying toward the target image 23, colliding with the soft sheet 32, and bouncing off. It was confirmed that the BB bullets 24 began to appear in the image approximately 5 m before impacting the soft sheet 32, and that the BB bullets 24 that had impacted the soft sheet 32 ​​fell in various directions due to the influence of their own rotation, etc. It was also confirmed that the BB bullets 24 flew at a speed of approximately 70 m / s before impacting the soft sheet 32, and then fell at a speed of approximately 1 to 2 m / s after impacting the soft sheet 32.

[0032] 3 shows a schematic representation of the center of the target image 23 extracted from five frames (times t: 1 to 5) taken before and after the BB bullet 24 hits the soft sheet 32, among the multiple frames captured as described above. In the images of frames t1 to t5, the BB bullet 24 appears as an elongated, blurred shape (a rounded rectangle with approximately semicircular front and rear ends) depending on the direction of travel of the BB bullet 24. Hereinafter, the area in which the BB bullet 24 is captured in this shape will be referred to as a BB bullet image 51.

[0033] First, in order to identify the impact position of the BB bullet 24, the notebook PC 15 performs image processing, for example, by examining the color of the entire image area of ​​each frame pixel by pixel and detecting pixels that are close to the color (RGB values) of the BB bullet 24, thereby identifying the BB bullet image 51. For example, the notebook PC 15 examines the RGB values ​​of just one pixel in each area slightly smaller than the size of the BB bullet image 51 (for example, if the BB bullet image 51 is 6 mm in size, a square area with one side measuring 4 mm), and then further narrows the square area within the detected area and continues examining it, thereby accurately identifying the center of the BB bullet image 51.

[0034] For example, if the BB bullets 24 are white and the RGB color code indicating white is #FFFFFF, the accuracy of detecting the white BB bullet image 51 can be ensured by determining whether the BB bullet image 51 is within the range by determining that the BB bullet image 51 is white when all RGB color codes are #F0 or greater. Note that in the process of identifying the BB bullet image 51 based on color, the color of the target image 23 that forms the background of the BB bullet image 51 must be a color different from the color of the BB bullet 24 (for example, if white BB bullets 24 are used, each RGB color code must be a color less than #F0). Additionally, illuminating the display device 12 with illumination light can be effective in improving the accuracy of detecting the BB bullet image 51.

[0035] Alternatively, the laptop PC 15 can use an image processing library or the like to perform background difference processing to detect changed areas and easily identify the BB bullet image 51. Alternatively, if a high-speed camera or the like is used as the imaging device 14 and circular images of the BB bullet image 51 can be captured at a high frame rate, the laptop PC 15 can detect the BB bullet image 51 using image processing techniques such as the Hough transform and pattern matching.

[0036] The notebook PC 15 then identifies multiple frames in which the BB bullet image 51 is captured, and performs image processing for each of those frames to chronologically recognize the BB bullet image 51. As a result, the notebook PC 15 determines the traveling direction of the BB bullet image 51 and determines the image of the frame immediately before the traveling direction of the BB bullet image 51 changes as the image for identifying the impact position of the BB bullet 24.

[0037] In the example shown in Fig. 3, the images of frames t1, t2, and t3 display BB bullet images 51 (approximately horizontally oriented rectangles with rounded corners) of BB bullets 24 flying toward the soft sheet 32. That is, the BB bullet images 51 are displayed in the order of frames t1, t2, and t3, with the direction of travel from right to left. The images of frames t4 and t5 display BB bullet images 51 (approximately vertically oriented rectangles with rounded corners) of BB bullets 24 bouncing off the soft sheet 32 ​​and falling. That is, the BB bullet images 51 are displayed in the order of frames t4 and t5, with the direction of travel from top to bottom.

[0038] Therefore, the notebook PC 15 determines the image of frame t3, which is taken immediately before the direction of travel of the BB bullet image 51 changes, as the image for identifying the impact position of the BB bullet 24. For example, in the images of frames t1 to t4, the center coordinates (x, y) of the BB bullet image 51 change from (320, 240) in the image of frame t1 to (310, 242) in the image of frame t2, to (305, 244) in the image of frame t3, and to (300, 230) in the image of frame t4. Therefore, based on the change in the y coordinate of the center coordinate of the BB bullet image 51 from frame t3 to frame t4, the image of frame t3 can be determined as the image for identifying the impact position of the BB bullet 24.

[0039] Next, the notebook PC 15 measures the vertical length h and horizontal length w of the BB bullet image 51 in the image of frame t3 determined in this manner. The notebook PC 15 then determines the longitudinal direction of the measured length as the direction of travel of the BB bullet image 51, and can identify the center position of a circle (the two-dot chain circle within the BB bullet image 51 shown on the right side of FIG. 3 ) with a semicircle formed by an arc ahead of the BB bullet image 51 in that direction of travel as the impact position of the BB bullet 24. Here, of the arcs ahead and behind the BB bullet image 51 in the image of frame t3, for example, the arc closest to the BB bullet image 51 in the next frame t4 is determined to be the arc ahead of the BB bullet image 51 in the image of frame t3.

[0040] Alternatively, the image of frame t4, in which a change in the traveling direction of the BB bullet image 51 is detected, may be determined as the image for identifying the impact position of the BB bullet 24. In this case, the center of a semicircle formed by an arc above the BB bullet image 51 (i.e., rearward of the traveling direction of the BB bullet image 51) in the image of frame t4 can be identified as the impact position of the BB bullet 24. Even if the traveling direction does not change in frame t4, the speed of the BB bullet image 51 decreases after impact (to a speed of approximately 1 to 2 m / s, as described above). Therefore, by simultaneously checking this change in the speed of the BB bullet image 51, the impact position of the BB bullet 24 can be reliably identified. For example, in this case, the center of a semicircle formed by an arc closer to the BB bullet image 51 in frame t3, which is the arc in front of and behind the BB bullet image 51 in the image of frame t4, can be identified as the impact position of the BB bullet 24.

[0041] While it is possible to reduce the blur of the BB bullet image 51 by increasing the shutter speed of the imaging device 14, this results in a longer period of time when the BB bullet 24 is not captured. Therefore, by using the blurred BB bullet image 51 without increasing the shutter speed of the imaging device 14 (e.g., at a frame rate of 1 / second) to identify the impact position of the BB bullet 24 as described above, the accuracy of detecting the impact of the BB bullet 24 can be increased and the error in the impact position of the BB bullet 24 can be reduced. Of course, as the frame rate increases, the BB bullet image 51 becomes closer to a perfect circle rather than a rounded rectangle. Therefore, it is sufficient to identify the frame at the moment of impact of the BB bullet 24 based solely on the change in the direction of travel of the BB bullet 24 (or solely on the change in the velocity of the BB bullet 24, or both the direction of travel and the velocity of the BB bullet 24). In this way, when the BB bullet image 51 is captured as a circle, the center of the circle can be identified as the impact position of the BB bullet 24.

[0042] <Second Configuration Example of Target System> Fig. 4 is a diagram showing a configuration example of a second embodiment of a target system to which the present technology is applied. In the target system 11A shown in Fig. 4, components common to the target system 11 in Fig. 1 are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0043] FIG. 4 shows a schematic configuration example of the target system 11A as viewed from the side.

[0044] As shown in Fig. 4, the target system 11A has a configuration similar to that of the target system 11 in Fig. 1 in that an impact absorbing unit 13 is attached to the display device 12. Note that the notebook PC 15, video cable 16, communication cable 17, etc. shown in Fig. 1 are omitted from Fig. 4. Also, as shown in the figure, the target system 11A (and the other configuration examples are similar) is configured so that its own weight is supported by legs with an adjustable function, and the stopper of the fixing plate 34 engages with the upper end of the display device 12.

[0045] The target system 11A has a different configuration from the target system 11 of FIG. 1 in that it includes a support member 41 that supports the imaging device 14.

[0046] The support member 41 is fixed to approximately the center of the upper edge of the frame member 31 of the impact cushioning unit 13 so as to extend forward (to the right in FIG. 4 ) from the impact cushioning unit 13. For example, the support member 41 is configured so that the base of the support member 41 is fixed to the upper surface of the impact cushioning unit 13 and the imaging device 14 is attached to the tip of the support member 41. In other words, the support member 41 can support the imaging device 14 so as to capture an image of the display device 12 from diagonally above.

[0047] That is, in the target system 11 of FIG. 1, the imaging device 14 is positioned directly in front of the display device 12, whereas in the target system 11A, the imaging device 14 is positioned diagonally above the display device 12.

[0048] In the target system 11A configured in this manner, the imaging device 14, positioned diagonally above the display device 12, captures an image of the BB bullets 24 impacting the soft sheet 32, and the impact position of the BB bullets 24 can be detected based on the image obtained by the image capture. The imaging device 14 may also be positioned below the display device 12. In this case, it is assumed that the BB bullets 24 will fall toward the display device 12, and the impact position of the BB bullets 24 can be detected based on the image of the BB bullets 24 captured from below as they decelerate. Of course, in this case, it is necessary to protect the display device 12 from the BB bullets 24. In this case, instead of using the support member 41, the imaging device 14 can be placed on a stand or tripod facing diagonally upward and angled to the floor.

[0049] <Third Configuration Example of Target System> Fig. 5 is a diagram showing a configuration example of a third embodiment of a target system to which the present technology is applied. In the target system 11B shown in Fig. 5, components common to the target system 11 in Fig. 1 are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0050] FIG. 5 shows a schematic configuration example of the target system 11B in plan view.

[0051] As shown in Fig. 5, the target system 11B has a configuration common to the target system 11 in Fig. 1 in that an impact absorbing unit 13 is attached to a display device 12. Note that Fig. 5 does not show the notebook PC 15, video cable 16, communication cable 17, etc. shown in Fig. 1.

[0052] The target system 11B has a different configuration from the target system 11 of FIG. 1 in that it includes a support member 42 that supports the imaging device 14.

[0053] The support member 42 is fixed to approximately the center of the right side (the right side when viewing the impact cushioning unit 13 from the front) of the frame member 31 of the impact cushioning unit 13 so as to extend forward (to the right in FIG. 5 ) from the impact cushioning unit 13. For example, the support member 42 is an L-shaped member bent at 90 degrees, and is configured so that the base of the support member 42 is fixed to the right side surface of the impact cushioning unit 13 and the imaging device 14 is attached to the tip of the support member 42.

[0054] That is, in the target system 11 of FIG. 1, the imaging device 14 is positioned directly in front of the display device 12, whereas in the target system 11B, the imaging device 14 is positioned diagonally to the side of the display device 12.

[0055] In the target system 11B configured in this manner, the imaging device 14 disposed diagonally to the display device 12 captures an image of the BB bullets 24 impacting the soft sheet 32, and the impact position of the BB bullets 24 can be detected based on the image obtained by capturing the image. Note that, although Fig. 5 shows an example configuration in which the imaging device 14 is disposed diagonally to the right of the display device 12, the imaging device 14 may alternatively be disposed diagonally to the left of the display device 12.

[0056] In the targeting systems 11A and 11B, it is preferable to position the imaging device 14 so that it captures an image of the display device 12 from a 45° diagonal angle, as shown in FIG. 5 . However, the angle at which the imaging device 14 captures the image of the display device 12 is not limited to 45° and may be any angle between 20° and 80°. For example, the coordinates of the impact position of the BB bullets 24 can be calculated by correcting for the inclination within this range. Even if a short support member 41 or 42 is used, resulting in a larger inclination, the coordinates of the impact position of the BB bullets 24 can be calculated as long as the imaging device 14 can capture the image of the BB bullets 24 impacting the soft sheet 32. On the other hand, using a long support member 41 or 42 allows the imaging device 14 to capture the image of the BB bullets 24 impacting the soft sheet 32 ​​from a position closer to the front.

[0057] Note that target system 11A may be configured to capture an image of display device 12 from an obliquely upward direction using imaging device 14 fixed to the ceiling without using support member 41. Similarly, target system 11B may be configured to capture an image of display device 12 from an obliquely lateral direction using imaging device 14 mounted on a base such as a tripod without using support member 42. Furthermore, target systems 11A and 11B can improve convenience by configuring support members 41 and 42 to be detachable from frame member 31 or by configuring support members 41 and 42 to be foldable from frame member 31.

[0058] A method for detecting the impact position of the BB bullet 24 in the targeting system 11B will be described with reference to FIG.

[0059] 3, when an image is captured by the imaging device 14 from the front of the display device 12, the BB bullets 24 are captured in multiple frames, including before they hit the soft sheet 32. In contrast, when an image is captured by the imaging device 14 from a diagonal side of the display device 12, the BB bullets 24 are not captured before they hit the soft sheet 32, but rather after they have decelerated after hitting the soft sheet 32 ​​(unless a high-speed camera is used as the imaging device 14, even if the BB bullets 24 are captured, only faint streaks remain). In this embodiment, an imaging device 14 capable of capturing moving images at a frame rate of greater than 60 fps is referred to as a high-speed camera.

[0060] Therefore, in the target system 11B, the impact position of the BB bullet 24 can be identified based on the first frame image in which the BB bullet 24 is captured, among images captured by the imaging device 14 from a diagonal lateral direction of the display device 12. Depending on the angle at which the imaging device 14 is positioned, the BB bullet 24 may appear as a streak before impacting the soft sheet 32. However, for example, as shown in Figure 5, when an image is captured by the imaging device 14 from a diagonal lateral direction of 45° with respect to the display device 12, the BB bullet 24 before impacting the soft sheet 32 ​​is hardly captured.

[0061] 6, the images of frames t1 and t2 do not show the BB bullets 24. The image of frame t3 shows a BB bullet image 51 of the BB bullet 24 after it has impacted the soft sheet 32 ​​and decelerated, and the images of frames t4 and t5 show a BB bullet image 51 of the BB bullet 24 in a falling state.

[0062] Therefore, the notebook PC 15 performs image processing to detect changes from the previous frame, for example, and determines the image of frame t3, in which the BB bullet 24 is first captured, as the image for identifying the impact position of the BB bullet 24.

[0063] Here, as in the target system 11B, when an image is captured by the imaging device 14 from a diagonal lateral direction to the right of the display device 12, the BB bullet 24 will almost certainly appear to move toward the left side of the image after impacting the soft sheet 32. Therefore, in this case, the notebook PC 15 can identify the impact position of the BB bullet 24 as the center position of a circle (the two-dot chain circle in the BB bullet image 51 shown on the right side of FIG. 6 ) of the right and left arcs of the BB bullet image 51 in the image of frame t3, with the right arc being a semicircle.

[0064] In other words, when an image is taken from the front of the display device 12, the BB bullets 24 scatter in various directions, up, down, left, and right, after hitting the soft sheet 32 ​​due to factors such as the rotation of the BB bullets 24 themselves, so there is a high probability that they will move downward, but the BB bullets 24 will not be captured in the image as moving in a specific direction. In contrast, when an image is taken from a diagonal lateral direction on the right side of the display device 12, the BB bullets 24 will be captured in the image as moving toward the left after hitting the soft sheet 32. Of course, conversely, when an image is taken from a diagonal lateral direction on the left side of the display device 12, the BB bullets 24 will be captured in the image as moving toward the right after hitting the soft sheet 32.

[0065] Therefore, compared to an image captured from the front of the display device 12, an image captured from a diagonal side of the display device 12 makes it possible to almost certainly identify the direction in which the BB bullet 24 moves after impacting the soft sheet 32. The notebook PC 15 can then identify, as the impact position of the BB bullet 24, the center position of a semicircle formed by an arc on the same side as the side on which the imaging device 14 is disposed diagonally to the right of the display device 12, out of the right and left arcs of the BB bullet image 51 (the right side when the imaging device 14 is disposed diagonally to the right of the display device 12, and the left side when the imaging device 14 is disposed diagonally to the left of the display device 12).

[0066] 4, like the targeting system 11B, the image in which the BB bullet 24 is first captured is determined as the image for identifying the impact position of the BB bullet 24, and the center position of the circle in which the upper arc of the BB bullet image 51 forms a semicircle can be identified as the impact position of the BB bullet 24. Conversely, if the imaging device 14 is disposed below the display device 12, the center position of the circle in which the lower arc forms a semicircle can be identified as the impact position of the BB bullet 24.

[0067] 1, the target systems 11A and 11B allow the imaging device 14 to be positioned closer to the soft sheet 32. Furthermore, by fixing the imaging device 14 to the impact absorbing unit 13, the target systems 11A and 11B eliminate the need to adjust the direction or position of the imaging device 14, making them easier to handle, and also facilitates the process of determining an image for identifying the impact position of the BB bullets 24. Furthermore, by configuring the imaging device 14 to capture an image of the display device 12 from an oblique direction, it is possible to capture only the BB bullets 24 that have bounced off the soft sheet 32 ​​and become slower, and the XY coordinates of the impact position of the BB bullets 24 can be identified with a single imaging device 14.

[0068] <Fourth Configuration Example of Target System> Fig. 7 is a diagram showing a configuration example of a fourth embodiment of a target system to which the present technology is applied. In the target system 11C shown in Fig. 7, components common to the target system 11 in Fig. 1 are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0069] FIG. 7 shows a schematic configuration example of the target system 11C in plan view.

[0070] As shown in Fig. 7, the target system 11C has a configuration common to the target system 11 in Fig. 1 in that an impact absorbing unit 13 is attached to a display device 12. Note that the notebook PC 15, video cable 16, communication cable 17, etc. shown in Fig. 1 are omitted in Fig. 7.

[0071] The target system 11C has a different configuration from the target system 11 in FIG. 1 in that it includes a stereo camera 61.

[0072] The stereo camera 61 is configured with two image capturing devices 14L and 14R, and is disposed in front of the display device 12 at a predetermined distance (for example, approximately 10 m to 30 m) from the shock absorbing unit 13. The stereo camera 61 supplies images captured by the image capturing devices 14L and 14R to the notebook PC 15, and the notebook PC 15 can measure the distance to a subject captured in the pair of images captured simultaneously based on the parallax between the image capturing devices 14L and 14R.

[0073] For example, the notebook PC 15 measures the distance from the stereo camera 61 to the soft sheet 32 ​​and also measures the distance from the stereo camera 61 to the BB bullets 24, and determines the image of the frame when these distances become equal (i.e., when the BB bullets 24 hit the soft sheet 32) as the image for identifying the impact position of the BB bullets 24. Note that because the soft sheet 32 ​​is transparent, the distance from the stereo camera 61 to the display device 12 is actually measured, and the distance from the stereo camera 61 to the soft sheet 32 ​​is calculated by subtracting the distance between the display device 12 and the soft sheet 32 ​​from that distance.

[0074] However, at a typical high frame rate of around 60 fps, for example, a bullet traveling at a speed of 90 m / s can only be imaged once every 1.5 m, making it difficult to accurately detect the impact position of the BB bullet 24. Therefore, the targeting system 11C, for example, begins measuring the distance to the BB bullet 24 and the time at at least two locations after the BB bullet 24 is fired, and calculates the predicted impact time of the BB bullet 24 on the soft sheet 32 ​​based on the measurement results. Then, by having the stereo camera 61 capture images at a shutter speed of 1 / 60 second starting just before the predicted impact time, it is possible to capture an image of the BB bullet 24 at the moment it impacts the soft sheet 32.

[0075] Specifically, in the target system 11C, the stereo camera 61 continuously captures images at 60 fps to continuously detect the BB bullets 24, and the notebook PC 15 starts measuring the distance and time to the BB bullets 24 every 1 / 60 seconds when the BB bullets 24 are detected. The notebook PC 15 then calculates the speed of the BB bullets 24 based on the distance and time difference from the previous measurements, and calculates the predicted time at which the BB bullets 24 will hit the soft sheet 32.

[0076] In the targeting system 11C, when the distance between the BB bullets 24 and the flexible sheet 32 ​​becomes short (e.g., 2.5 m or less), the stereo camera 61 temporarily suspends continuous imaging and resumes continuous imaging immediately before the predicted impact time to capture the moment the BB bullets 24 hit the flexible sheet 32. For example, if the shutter timing of the two imaging devices 14L and 14R is synchronized, a faster shutter speed can improve the accuracy of measuring the distance to the receding BB bullets 24. With a shutter speed of 1 / 250 seconds, the shutter is open for 4 ms, so releasing the shutter 2 ms before the predicted impact time can capture images of the BB bullets 24 before and after impact. In particular, because the speed of the BB bullets 24 slows to approximately 1 m / s to 3 m / s after impacting the flexible sheet 32, capturing images from the front with the stereo camera 61 almost ensures that the BB bullet image 51 is circular. It is also possible to increase the shutter speed of the stereo camera 61, for example to 1 / 500 seconds, and release the shutter 1 ms before the BB bullet 24 hits the soft sheet 32. This makes it possible to capture a clearer image of just the moment the BB bullet 24 hits the soft sheet 32, and to measure the impact position more accurately.

[0077] In reality, the time it takes for the BB bullets 24 to bounce back from the moment they come to rest on the soft sheet 32 ​​is several times longer than the time it takes for the BB bullets 24 to come to rest on the soft sheet 32. Therefore, as long as there is no significant measurement error in the stereo camera 61, the shutter may be released at the predicted impact time. Alternatively, as described above, the predicted impact time may be calculated using the stereo camera 61, and the moment the BB bullets 24 hit the soft sheet 32 ​​may be captured by either the imaging device 14L or the imaging device 14R of the stereo camera 61, or by a camera other than the stereo camera 61, in accordance with the predicted impact time.

[0078] However, if the measurement error of the stereo camera 61 is large, it is necessary to prioritize increasing the reliability of detecting the impact of the BB bullets 24 by setting the shutter speed slower than the above-mentioned 1 / 250 second and releasing the shutter at a timing that ensures that the moment the BB bullets 24 impact falls within the image capture time. Alternatively, as usual, images can be taken while measuring the distance with the stereo camera 61 at a shutter speed of 1 / 60 second or the like, and when the BB bullets 24 impact, the impact position can be measured using the above-mentioned method in the frame at which the BB bullets 24 have reached the distance to the soft sheet 32 ​​(and, if necessary, in frames before and after that). In this case, the BB bullet image 51 will be almost a rectangle with rounded corners.

[0079] In this way, the target system 11C can detect the impact position of the BB bullet 24 with higher accuracy without using a high-speed camera or the like.

[0080] The reliability of detecting the impact of BB bullets 24 can be increased by irradiating illumination light toward the display device 12 from a location that does not reflect the user's view of the flexible sheet 32 ​​or the display device 12. For example, in the configuration in which the imaging device 14 is installed as shown in FIGS. 4 and 5, an ideal method would be to provide an illumination device that shines in the same direction as the imaging device 14, thereby irradiating illumination light so that the BB bullets 24 form a perfect circle. On the other hand, from the standpoints of preventing the illumination device from being reflected on the screen of the flexible sheet 32 ​​or the display device 12 and of uniformity of illumination light, it is more reasonable to irradiate illumination light from a slender illumination device, such as a row of LED (Light Emitting Diode) illumination devices, along the surface of the display device 12 from directly above or to the side. Note that for all of the illumination light described here, using an illumination device that emits infrared illumination light (e.g., a light source other than visible light, such as an infrared LED) can reduce the illumination light from being reflected on the screen as viewed by the user, allowing the imaging device 14 to function solely as illumination light for capturing images of the BB bullets 24. In this case, if the imaging device 14 has an IR cut filter, it is necessary to remove the IR cut filter from the imaging device 14. Of course, an infrared camera may be used as the imaging device 14.

[0081] Therefore, in the configurations shown in Figures 4 and 5, it is preferable to irradiate the screen of the display device 12 with illumination light from above, below, or from the left and right sides using this method. However, if the illumination device does not reflect on the screen of the display device 12, it is more effective to irradiate with illumination light from the diagonal front. This prevents the shadow of the BB bullets 24 from being reflected within a necessary range, improving the reliability of detecting the impact of the BB bullets 24 and enabling the target system 11 to be used, for example, in dark places. Furthermore, in the configuration shown in Figure 2, it is preferable to irradiate the soft sheet 32 ​​with illumination light from above, below, or from the left and right sides (including diagonal front sides). In this case, it is necessary to irradiate with illumination light from both sides so that they are symmetrical. Note that in a configuration in which illumination light is irradiated from the position of the imaging device 14 to the soft sheet 32, the amount of light decreases due to the distance to the soft sheet 32, but illumination light can always be irradiated to the BB bullets 24 in the same manner, and this configuration can also be applied to the target system 11C shown in Figure 7.

[0082] However, in a use case where multiple BB bullets 24 land at the same time, a targeting system that detects the impact position of the BB bullets 24 based on shock waves, such as that disclosed in the above-mentioned Patent Document 1, is unable to detect the impact positions of the BB bullets 24. For example, a use case can be envisioned in which a soft air gun 21 capable of firing multiple BB bullets 24 at once is used, or multiple people fire BB bullets 24 from the soft air gun 21 together.

[0083] In contrast, the targeting system 11 detects the impact position of the BB bullets 24 based on the image, so even in a use case where multiple BB bullets 24 impact at the same time, it can detect the impact positions of those BB bullets 24. In other words, even if multiple BB bullet images 51 are displayed in the image captured by the imaging device 14, it is possible to determine the impact position from each individual BB bullet image 51.

[0084] Of course, a configuration may be used that combines a targeting system that detects the impact position of BB bullets 24 based on shock waves with targeting system 11 that detects the impact position of BB bullets 24 based on images. For example, in a use case where BB bullets 24 impact one by one, the impact position of the BB bullets 24 can be detected based on shock waves, and in a use case where multiple BB bullets 24 impact simultaneously, the impact position of the BB bullets 24 can be detected based on images. This makes it possible to detect the impact position of the BB bullets 24 with high accuracy based on shock waves and to detect the impact positions of multiple BB bullets 24 based on images.

[0085] Furthermore, the present invention is not limited to target systems 11 that are targets for BB bullets 24 fired from a soft air gun 21. For example, the present invention may be applied to any sport or game in which a projectile hits a target, specifically, target systems such as darts and blowguns. In this case, the impact position of the dart or blowgun can be accurately detected, and the dart or blowgun arrow can be displayed at the impact position on the target image instead of the impact mark. Naturally, the tip of the dart or blowgun arrow, which replaces the BB bullets 24, must be rounded to prevent it from piercing the soft sheet 32. Furthermore, by increasing the strength of the soft sheet 32, the present invention can also be applied to target systems for air rifles (real air guns), which have greater impact energy than toy guns (soft air guns).

[0086] It is also possible to attach a piece of paper with a similar target drawn on it to the flexible sheet 32 ​​or the protective plate 33, or to draw a similar target on the flexible sheet 32 ​​or the protective plate 33, without using the display device 12 that displays the target image 23. Alternatively, the flexible sheet 32 ​​or the protective plate 33 may be made opaque (for example, white or gray), and the target image 23 may be projected onto the flexible sheet 32 ​​or the protective plate 33 by a projector. When using a projector in this way, cloth may be used as the flexible sheet 32. In this case, it is necessary to provide a mounting stand that serves as a substitute for the display device 12, or to provide legs on the frame member 31 of the impact absorbing unit 13 so that it can stand on its own.

[0087] <Modifications of the Target System> As a first modification of the target system 11, a configuration can be adopted in which two imaging devices 14 that capture images in directions parallel to the screen are arranged above and to the side of the screen of the display device 12. Then, of the X and Y coordinates when the BB bullet 24 hits the soft sheet 32, the X coordinate is measured by the imaging device 14 arranged above the display device 12, and the Y coordinate is measured by the imaging device 14 arranged to the side of the display device 12, thereby making it possible to detect the impact position of the BB bullet 24.

[0088] In this way, even in the target system 11 of the first modification, only the BB bullets 24 after they have impacted the soft sheet 32 ​​and decelerated can be imaged by the two imaging devices 14. In the target system 11 of the first modification, it is preferable to synchronize the shutter timing of the two imaging devices 14. However, because only the BB bullets 24 after they impact the soft sheet 32 ​​and decelerate are imaged, detection of the impact position of the BB bullets 24 is not significantly hindered even if the timing is not synchronized at a typical frame rate (e.g., approximately 30 to 60 fps). Furthermore, the target system 11 of the first modification can avoid a structure in which the imaging device 14 protrudes significantly forward from the soft sheet 32, as in the configuration examples shown in FIGS. 4 and 5 above.

[0089] Instead of the two imaging devices 14 of the targeting system 11 of the first modified example, for example, two sets of LiDAR (Light Detection and Ranging) or radar may be arranged above and to the side of the display device 12. Alternatively, a configuration in which a light-emitting element and a light-receiving element are arranged opposite each other, or a configuration employing a touch panel system that senses surface contact using a light-emitting element, a reflector, and a camera, may be used. These configurations allow for detection of high-speed BB bullets 24 not from the side, but from the moment they hit the soft sheet 32 ​​and become substantially stationary, and after that moment, after they have sufficiently decelerated. Furthermore, if the elements and control systems are inexpensive, it is easy to measure using small LiDAR (semiconductor laser and optical sensor) or antenna elements arranged in a row. On the other hand, if the elements and control systems are expensive, a configuration that rapidly changes the irradiation direction and scans using a small number of elements and sensors is preferable.

[0090] As a second modification of the targeting system 11, a configuration can be adopted in which electromagnetic waves are emitted and the distance to the BB bullets 24, as well as the position and speed of the BB bullets 24, are measured by measuring the reflected waves. For example, by replacing the imaging device 14 shown in FIG. 2 with a LiDAR or radar, illumination light or the like can be eliminated even when the targeting system 11 is used in a dark place. Furthermore, all colors can be used on the screen of the display device 12, regardless of the color of the BB bullets 24.

[0091] For example, in the second variant of the target system 11, when LiDAR is used, the situation can be captured over a wide area by emitting (scanning) laser light in various directions, and when a phased array radar is used as the radar, a wide area can be measured quickly, making it compatible with a large-screen display device 12.

[0092] Furthermore, in the second variant of the targeting system 11, if a millimeter-wave radar device with a built-in antenna or the like is used, the distance to and speed of the BB bullets 24 can be measured. By arranging these devices with the antennas spaced apart to form a multi-channel configuration, the direction of the reflected waves can be determined, making it possible to pinpoint the location of the BB bullets 24. Of course, if a millimeter-wave radar device with multiple integrated transmitting and receiving antennas or even a submillimeter-wave radar device could be used, pinpointing the location of the BB bullets 24 would be even easier. Even in this case, the BB bullets 24 can be detected from the moment they hit the soft sheet 32 ​​and become substantially stationary, and after that moment, after they have sufficiently decelerated, ensuring reliable detection of the location of the BB bullets 24.

[0093] As a third variant of the target system 11, instead of the display device 12, a configuration can be adopted in which the target image 23 is displayed using an AR (Augmented Reality), MR (Mixed Reality), or XR (Extended Reality / Cross Reality) device, such as a goggle-type or eyeglass-type device. For example, in the target system 11 of the third variant that does not use the display device 12, a protective plate 33 for protecting the display device 12 is not required, and an impact mitigation unit 13 can be used in which a soft target sheet 32 ​​is fixed to a frame member 31. However, even in this case, it is effective to provide the protective plate 33 as a brace to prevent distortion of the frame member 31. Furthermore, the target system 11 of the third variant may need to be provided with an installation stand in place of the display device 12, or the frame member 31 of the impact mitigation unit 13 may need to be provided with legs to enable it to stand on its own. Alternatively, the target system 11 of the third variant may be configured as a wall-mounted system.

[0094] For example, in a VR shooting game performed while wearing VR (Virtual Reality) goggles, virtual shooting can be performed anywhere because BBs 24 are not fired. In contrast, in a shooting game using a soft air gun 21 that fires BBs 24, an impact absorbing unit 13 is required to protect walls and the like from the BBs 24 and to collect the BBs 24 (it is also advisable to have a collection unit, such as a collection tray 22 or a microfiber towel, that can limit the range in which the BBs 24 roll without repelling them), and shooting can only be performed within a fixed range.

[0095] Therefore, the target system 11 of the third modified example uses a camera, distance sensor, inertial sensor, gyroscope, etc. to track the movements of the user's body, head, eyes, etc. and recognizes the user's position, posture, line of sight, etc., and also recognizes the position and tilt of the target soft sheet 32, thereby grasping the spatial relationship between the user and the soft sheet 32. Then, similar to a configuration in which the display device 12 is disposed behind the impact absorbing unit 13 or a configuration in which an image is projected by a projector, the target system 11 of the third modified example displays a target image 23 in real time using an AR / MR / XR device, superimposed on the soft sheet 32, according to the position and size of the soft sheet 32 ​​as actually seen by the user.

[0096] Furthermore, as described above, the target system 11 of the third modified example can display a hit mark P on the target image 23 or display a score, etc., in accordance with the detection of the impact position when the BB bullet 24 hits the soft sheet 32. Additionally, the target system 11 of the third modified example may be configured to provide actions such as images and sounds according to the impact time and impact position of the BB bullet 24 using an AR / MR / XR device.

[0097] Furthermore, in the target system 11 of the third modified example, the soft sheet 32 ​​can be used as a marker for AR, MR, and XR, and may be used as a clear marker for AR, MR, and XR by, for example, providing a black or other band around the periphery of the soft sheet 32 ​​or providing marks at the four corners of the soft sheet 32. Note that the markers for AR, MR, and XR provided on the soft sheet 32 ​​may be a color, a border, or marks at the four corners (or at least three places around the periphery).

[0098] In the target system 11 of the third modification, particularly when a transmission type (optical see-through type) AR / MR / XR device is used, it is desirable to use an opaque soft sheet 32. Also, in the target system 11 of the third modification, when a video transmission type (video see-through type) AR / MR / XR device is used, it is preferable to use an opaque soft sheet 32 ​​that is a conspicuous color such as a single color of green so that the BB bullets 24 can be easily identified.

[0099] Furthermore, in the target system 11 of the third modification, the use of an opaque soft sheet 32 ​​in a color such as green, red, or black can improve the identification of the BB bullets 24, making it suitable for use in a video-transparent AR / MR / XR device in which the impact position of the BB bullets 24 is detected based on the image captured by the imaging device 14, as described above. Furthermore, it is most reasonable to configure the AR / MR / XR device to detect the impact position of the BB bullets 24 using its own camera, provided that such a configuration can provide accurate detection of the impact position.

[0100] It is anticipated that with the transparent soft sheet 32, the visibility of the internal structure or the area behind the impact mitigation unit 13 will change depending on the angle, regardless of whether a see-through or video-see-through AR / MR / XR device is used, and regardless of whether an AR marker is used. For this reason, in the target system 11 of the third modified example, it is preferable to use a soft sheet 32 ​​that is uniformly opaque (for example, when a see-through AR / MR / XR device is used, a single color such as gray or light blue that does not obstruct the image and allows the BB bullets 24 to be identified; when a video-see-through AR / MR / XR device is used, a single color such as green or red that prioritizes the ease of identifying the BB bullets 24).

[0101] In the target system 11 of the third modification, in addition to the method of detecting the impact position of the BB bullets 24 based on an image captured by the imaging device 14 as described above, other methods such as detecting the impact position of the BB bullets 24 based on shock waves or detecting the impact position of the BB bullets 24 based on reflected waves from a laser or the like can be employed, and cloth may be used as the soft sheet 32. Furthermore, in the methods of detecting the impact position of the BB bullets 24 based on an image captured by the imaging device 14 and the methods of detecting the impact position of the BB bullets 24 based on reflected waves from a laser or the like, an opaque soft sheet 32 ​​makes it easier to confirm the timing at which the BB bullets 24 contact the soft sheet 32 ​​(i.e., the moment the BB bullets 24 hit the soft sheet 32). For example, an image of the moment the BB bullets 24 contact the soft sheet 32 ​​can be captured from an oblique or sideways angle. Therefore, in a configuration in which optical detection is performed without installing the display device 12 behind the impact absorbing unit 13, it is preferable to use an opaque soft sheet 32 ​​(but of a different color from the BB bullets 24).

[0102] In addition, in the target system 11 of the third modification, a program is executed to display a target image 23 in real time by the AR / MR / XR device at the position of the soft sheet 32 ​​of the impact absorbing unit 13, acquire information indicating the impact position detected when a BB bullet 24 hits the soft sheet 32 ​​by the AR / MR / XR device, detect the impact position using a camera in the AR / MR / XR device, and display an impact mark P on the target image 23, change the image, or change the score display according to the impact position, thereby providing the user with an action using images, sounds, etc. Only the desired area of ​​the target image 23 may be displayed in a solid color or opaque so as to be superimposed on the soft sheet 32, or a marker indicating that area may be drawn on the soft sheet 32. This makes it easier for the AR / MR / XR device to create a program that displays the target image 23 only in that area, and is considered to be effective even in a markerless type. For example, when using a video-transparent AR / MR / XR device, if it is superimposed on the soft sheet 32 ​​and completely replaced with the target image 23, there is no adverse effect whatsoever regardless of the color of the target image 23. On the other hand, if the soft sheet 32 ​​is transparent and the inside of the impact mitigation unit 13 can be seen, it is thought that there may be adverse effects such as an unnecessary increase in the amount of information to be processed due to changes in appearance depending on the angle and light reflection on the surface of the soft sheet 32.

[0103] Furthermore, in any of the above-described embodiments and modifications, the present technology is extremely effective in detecting the impact position of a BB bullet 24 that has momentarily come to a near standstill (or has been sufficiently decelerated to, for example, about 1 to 3 m / s) on a soft sheet 32, cloth, etc. Furthermore, even in a targeting system 11 configured with a hard plate instead of the soft sheet 32, the above-described detection method is effective because the direction and speed of the BB bullet 24 (for example, the amount of position change between frames) change before and after it impacts the plate.

[0104] <Other Methods for Identifying the Impact Position of BB Bullets> In the above-described embodiment, a method for identifying the impact position of the BB bullets 24 based on an image captured of the BB bullets 24 flying toward the target image 23, impacting the soft sheet 32, and bouncing off has been described. However, another method is to identify the impact position of the BB bullets 24 based on an image captured of the BB bullets 24 that have impacted the soft sheet 32 ​​and become slower or substantially stationary. Note that, while the following describes imaging the BB bullets 24 that have impacted the soft sheet 32 ​​and become stationary, the impact position of the BB bullets 24 can also be identified by imaging the BB bullets 24 that have impacted the soft sheet 32 ​​and become slower.

[0105] For example, in a configuration in which the imaging device 14 images the soft sheet 32 ​​from the front (or rear), the target system 11 can capture an image in which the BB bullet 24 appears to remain at the impact position for a certain period of time from when the BB bullet 24 hits the soft sheet 32 ​​until the BB bullet 24 is rebounded as its energy is absorbed by the soft sheet 32. In this way, when an image of the BB bullet 24 that has landed on the soft sheet 32 ​​and is in a stationary state can be captured, for example, when there are at least two consecutive frames of images in which the BB bullet 24 is stationary, the notebook PC 15 can determine that the BB bullet 24 has hit the soft sheet 32 ​​based on the image.

[0106] In an image of the BB bullet 24 in a stationary state after it has impacted the soft sheet 32 ​​and before its energy is absorbed by the soft sheet 32 ​​and it is rebounded, a substantially circular BB bullet image 51 is captured, rather than the rounded rectangular shape described above. Therefore, the notebook PC 15 can more easily identify the center position of the substantially circular BB bullet image 51 as the impact position of the BB bullet 24 than by identifying the impact position of the BB bullet 24 from the arc of the BB bullet image 51, as described above. In other words, the method of identifying the impact position of the BB bullet 24 based on an image of the BB bullet 24 that has impacted the soft sheet 32 ​​and is in a stationary state can identify the impact position of the BB bullet 24 more quickly.

[0107] For example, it has been confirmed that when the frame rate of the imaging device 14 is 120 fps, the BB bullets 24 are captured in a stationary state for approximately 30 ms (i.e., approximately four frames) until they hit the soft sheet 32 ​​and bounce off. In this way, an imaging device 14 with a frame rate of 120 fps can capture four consecutive frames of the BB bullets 24 in a stationary state, and therefore an imaging device 14 with a frame rate of 60 fps or higher can capture two or more consecutive frames of the BB bullets 24 in a stationary state.

[0108] Therefore, the method of identifying the impact position of the BB bullets 24 based on an image of the BB bullets 24 that have landed on the soft sheet 32 ​​and come to rest can more quickly and easily identify the impact position of the BB bullets 24 without having to wait for the BB bullets 24 to rebound. This method can also easily handle, for example, high-speed continuous firing by the soft air gun 21 or multiple simultaneous impacts.

[0109] Here, the state in which the BB bullet 24 is stationary in two consecutive frames does not necessarily have to be the same position, but may be, for example, a position within an acceptable range that does not exceed the required accuracy. For example, it is sufficient if the BB bullet 24 is imaged at a position (either the same position or a position within an acceptable range) where the energy is absorbed upon impact with the soft sheet 32 ​​and the BB bullet 24 remains stationary for a certain period of time. In this way, the impact of the BB bullet 24 can be determined based on the image in which the BB bullet 24 remains stationary for a certain period of time. By recognizing that the BB bullet 24 is stationary in two (or more) frames of image, the impact position of the BB bullet 24 can be identified.

[0110] For example, if an imaging device 14 with a high frame rate is used to continuously capture images of the BB bullets 24 at a stationary position (either the same position or a position within an acceptable range) when the BB bullets 24 impact the target object, the impact position of the BB bullets 24 may be identified using images captured every other frame or every two frames. Furthermore, if it is known in advance that the BB bullets 24 will be stationary for 30 ms, the impact position of the BB bullets 24 can be identified by confirming that the BB bullets 24 are captured in a stationary position (either the same position or a position within an acceptable range) in two frames, one at the beginning (e.g., 0-5 ms) and one at the end (e.g., 25-30 ms) of that time. In other words, the impact position of the BB bullets 24 can be identified based on two or more frames of images in which the BB bullets 24 are captured in a stationary position.

[0111] Alternatively, a detection means such as an acoustic sensor or vibration sensor may be placed on the front or rear side of the soft sheet 32 ​​or in the vicinity of the soft sheet 32 ​​(for example, within a distance where the propagation time of sound or vibration does not exceed the time it takes for the BB bullet 24 to bounce back after hitting the target), and the exact time of impact may be measured from the signal output from the detection means. The frame closest to that time of impact may then be determined to be the image captured when the BB bullet 24 hits the target, and the impact position may be identified based on that image.

[0112] For example, in all of the above-described embodiments, the notebook PC 15 may estimate the impact position by tracing the path of the BB bullet 24 from previously captured frames, thereby calculating the impact position. While the inability to determine the impact time of the BB bullet 24 is a problem with configurations other than the target system 11C, which includes a stereo camera 61, the impact time of the BB bullet 24 can be determined by identifying the frame in which the BB bullet 24 impacts the soft sheet 32. Furthermore, the higher the frame rate (e.g., 240 fps or higher; although 120 fps or higher is also acceptable, although this results in lower accuracy), the more clearly the time at which the path or velocity of the BB bullet 24 changes can be determined. This means that the impact time can be accurately determined simply from frames before and after the change in the path or velocity of the BB bullet 24, making it even easier to determine the impact time of the BB bullet 24. This makes it possible to estimate the impact position of the BB bullet 24 with high accuracy based on the path and impact time of the BB bullet 24 without using an image of a frame in which the BB bullet 24 impacts the soft sheet 32.

[0113] Furthermore, the speed of the BB bullets 24 can be measured by capturing images using a camera installed at a fixed distance and angle relative to the impact position of the BB bullets 24 and based on the number of frames captured while the BB bullets 24 pass through a certain range. For example, the speed of the BB bullets 24 can be measured based on the number of frames capturing the BB bullets 24 from the time they first appear in the camera's field of view (or a specified range within the field of view) until they hit the soft sheet 32. The fewer frames captured, the faster the bullet speed. For example, the number of frames capturing the BB bullets 24 increases or decreases depending on the impact position of the BB bullets 24 and conditions (e.g., the camera's installation position and angle). Therefore, by correcting this increase or decrease according to the impact position of the BB bullets 24, the accuracy of measuring the speed of the BB bullets 24 can be improved. Furthermore, the higher the frame rate of a camera, the more accurately the speed of the BB bullets 24 can be measured. In addition, regardless of the impact position of the BB bullet 24, the bullet speed of the BB bullet 24 may be measured based on the number of frames captured while the BB bullet 24 passes through a certain range (unit distance) on the path until it impacts the soft sheet 32.

[0114] In addition, since the target system 11C equipped with the stereo camera 61 can determine the distance to the BB bullets 24, the impact of the BB bullets 24 may be determined at the timing when the distance to the BB bullets 24 reaches the position of the soft sheet 32. For example, even if a stereo camera 61 with a frame rate of 240 fps is used, the distance can only be measured every 37.5 cm. Therefore, the impact position of the BB bullets 24 may be identified based on the frame captured at the timing when the distance to the BB bullets 24 is closest to the distance to the soft sheet 32.

[0115] Incidentally, in the above-described target system 11C, even in a method in which measurement of the distance and time to the BB bullet 24 is started at at least two locations after the BB bullet 24 is fired and the predicted impact time of the BB bullet 24 on the soft sheet 32 ​​is calculated based on the measurement results, errors in the impact position can occur. In contrast, in a method in which the impact position of the BB bullet 24 is determined based on an image of the BB bullet 24 that has landed on the soft sheet 32 ​​and come to a standstill, there is almost no error in the impact position. Furthermore, in a method in which the impact position of the BB bullet 24 is determined based on an image of the BB bullet 24 that has landed on the soft sheet 32 ​​and come to a standstill, there is no need to measure the distance using the stereo camera 61.

[0116] Furthermore, even in a configuration in which images are captured from an oblique direction or a lateral direction as described above with reference to Figures 4 and 5, the impact position of the BB bullet 24 can be identified by using an imaging device 14 with a higher frame rate and confirming that the BB bullet 24 is captured in two frames in a stationary state (at the same position or within an acceptable range) before it hits the soft sheet 32 ​​and bounces off.

[0117] In this configuration, in which images are captured from an oblique or lateral direction, the BB bullets 24 are hardly captured until they hit the soft sheet 32, and then, almost simultaneously with the BB bullets 24 hitting the soft sheet 32, the BB bullets 24 begin to be captured as their energy is absorbed and they slow down. Therefore, the impact position of the BB bullets 24 can be identified based only on the image in the first frame in which the BB bullets 24 begin to be captured. In this case, if an imaging device 14 with a frame rate of approximately 60 fps is used, for example, the BB bullets 24 will appear as a circle in less than half of the frames, and the rest will appear as a rounded rectangle.

[0118] Therefore, in a configuration in which imaging is performed from an oblique direction or a lateral direction, it is necessary to use an imaging device 14 with a frame rate of about 120 fps or more in order to capture an image of the BB bullet 24 in a stationary state (at the same position or within an allowable range) before it hits the soft sheet 32 ​​and bounces off. Therefore, in a configuration in which imaging is performed from an oblique direction or a lateral direction, it is preferable to use a target system 11 equipped with an imaging device 14 with a frame rate of, for example, 70 fps or more.

[0119] In images captured from an oblique or lateral direction, the BB bullets 24 appear to move a few millimeters left and right as they impact the soft sheet 32. Therefore, it is estimated that the time from when the BB bullets 24 impact the soft sheet 32 ​​until the energy is absorbed and the BB bullets 24 come to rest is within 1 ms. On the other hand, it takes approximately 10 ms or more for the stationary BB bullets 24 to separate from the soft sheet 32. Furthermore, when soft vinyl chloride resin is used as the soft sheet 32, it has been confirmed that the soft sheet 32 ​​is depressed by approximately 5 mm and does not return to its original shape immediately, due to its slow recovery time.

[0120] For this reason, in a configuration in which images are taken from an oblique direction or a lateral direction, the BB bullet 24 appears circular only while it is stationary and has absorbed most of its energy. When the energy of the BB bullet 24 is about 0.4 joules, the dent in the soft sheet 32 ​​is about 5 mm. Therefore, by calculating the impact position of the BB bullet 24 by applying position correction based on the dent caused by impact on the soft sheet 32, it is possible to more accurately identify the impact position.

[0121] Furthermore, in a configuration where images are captured from an oblique or lateral direction, as the frame rate increases, the movement of the BB bullet 24 slows down before it stops, resulting in the BB bullet 24 being captured in a circular shape over multiple frames. Therefore, the impact position of the BB bullet 24 can be calculated by applying position adjustment such that the position of the BB bullet 24 when it reaches its deepest point is recessed by 5 mm.

[0122] However, because the amount of dent made in the soft sheet 32 ​​changes slightly depending on the increase or decrease in the energy of the BB bullets 24, it is necessary to correct the impact position according to the amount of dent. Note that when the surface of the soft sheet 32 ​​is imaged from the side using a high frame rate imaging device 14, the movement of the BB bullets 24 slows down and the depth to which the BB bullets 24 sink when they begin to be captured (the amount of dent made in the soft sheet 32) can be measured, so the impact position of the BB bullets 24 can be accurately corrected even when imaging from an oblique direction or the side.

[0123] Furthermore, if a high-frame-rate imaging device 14 captures an image of the surface of the flexible sheet 32 ​​from above or below the flexible sheet 32, the BB bullets 24 can be constantly captured if the frame rate is sufficiently high, making it possible to determine the exact impact position even shortly before the bullets hit the ground. Accurate measurement is also possible even when multiple BB bullets 24 hit the ground at approximately the same time. In this case, the imaging device 14 does not need to be perfectly oriented in the direction along the surface of the flexible sheet 32; it may be oriented diagonally forward, for example, as long as the flexible sheet 32 ​​is within the field of view of the imaging device 14.

[0124] When multiple BB bullets 24 hit the soft sheet 32 ​​at approximately the same time, such as when using a soft air gun 21 that can fire multiple shots simultaneously, if attention is paid to a specific BB bullet 24 among them and it is confirmed that the focused BB bullet 24 hits at approximately the same position for two frames, it is possible to determine the impact results for all BB bullets 24 that were captured at the time of image capture as having hit all of them.

[0125] Alternatively, in a configuration in which the imaging device 14 captures images from the front (at an angle nearly straight ahead), the BB bullets 24 are always captured, making it possible to continuously track changes in the position of the BB bullets 24. In the first frame in which the BB bullets 24 hit the soft sheet 32 ​​and begin to remain in that position, the amount of change in position from the previous frame becomes small, so it is possible to determine that the BB bullets 24 have hit the soft sheet 32 ​​at the moment when the amount of change in position between frames suddenly becomes small (i.e., when the speed drops), and identify the impact position from the image captured at that moment.

[0126] Furthermore, in a configuration in which imaging is performed from the front using the imaging device 14, it is preferable to use a telephoto lens. Furthermore, when imaging is performed from the front using the imaging device 14 (at an angle close to the front), if the resolution is sufficiently high, the distance to the BB bullet 24 can be estimated based on the size of the captured BB bullet 24, and the frame in which the BB bullet 24 hits can be determined.

[0127] It is assumed that capturing an image of the BB bullets 24 from directly behind the flexible sheet 32 ​​would capture images of the BB bullets 24, which do not move until they hit the target. However, in reality, capturing an image of the BB bullets 24 from directly behind the flexible sheet 32 ​​is difficult. Because the BB bullets 24 do not fly in a perfectly straight line, images of the BB bullets 24 moving left and right or up and down are captured. If the BB bullets 24 are not moving, the impact position of the BB bullets 24 can be identified based on the image of the frame immediately before the BB bullets 24 land on the flexible sheet 32 ​​and fall. Furthermore, when the BB bullets 24 land on the flexible sheet 32, the flexure caused by the impact of the BB bullets changes the amount of light reflected from the surface of the flexible sheet 32, sometimes resulting in a wave pattern or streaks. Therefore, the impact of the BB bullets 24 can be determined based on the change in the amount of light reflected from the surface as the flexible sheet 32 ​​flexes.

[0128] For example, if a projector is used to display the target image 23 instead of the display device 12, the target image 23 is projected onto the opaque soft sheet 32. In this case, when the BB bullet 24 hits the soft sheet 32, it is possible to determine whether the BB bullet 24 has hit the soft sheet 32 ​​based on the change in the target image 23 that accompanies the bending of the soft sheet 32 ​​caused by the impact of the bullet.

[0129] It should be noted that the present embodiment is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist of the present disclosure. Furthermore, the effects described in this specification are merely examples and are not intended to be limiting, and other effects may also be obtained.

[0130] For example, in a target system that uses an adhesive sheet instead of the soft sheet 32 ​​and detects the impact position by the BB bullet 24 that lands on and sticks to the adhesive sheet, there is a limitation in that the next shot cannot be aimed at the impact position of the BB bullet 24 until the BB bullet 24 falls from the adhesive sheet (generally around 10 seconds), but the target system 11 in this embodiment can shoot continuously without such limitations.

[0131] REFERENCE SIGNS LIST 11 target system, 12 display device, 13 impact mitigation unit, 14 imaging device, 15 notebook PC, 16 video cable, 17 communication cable, 21 soft air gun, 22 collection tray, 23 target image, 24 BB bullet, 31 frame member, 32 soft sheet, 33 protective plate, 34 fixing plate, 41 and 42 support member, 51 BB bullet image, 61 stereo camera

Claims

1. A target system comprising: an imaging device that images a target; and a collision position identification unit that identifies the collision position of a flying object with respect to the target based on an image captured by the imaging device of the flying object flying toward the target colliding with a soft sheet and becoming slowed down or substantially stationary.

2. The target system according to claim 1, wherein the collision position identification unit identifies the center position of the flying object, which is captured in a substantially circular shape while remaining substantially stationary, as the collision position of the flying object.

3. The target system according to claim 1, wherein the collision position identification unit determines that the flying object has collided with the soft sheet when there are at least two consecutive frames of images in which the flying object is substantially stationary.

4. The targeting system of claim 1, wherein the imaging device is positioned in a front direction of the target.

5. The target system described in claim 4, wherein the collision position identification unit uses images captured during a certain period of time from when the flying object lands on the soft sheet until the flying object is bounced off as a result of energy being absorbed by the soft sheet.

6. The targeting system of claim 1, wherein the imaging device is positioned obliquely above, below, or laterally with respect to the front of the target.

7. The target system according to claim 6, wherein the frame rate of the imaging device is 70 fps or more.

8. A target system comprising: a target; a transparent soft sheet that is placed in front of the target and that a flying object flying toward the target collides with; a photographing device that is placed in front of the target and that photographs the collision position where the flying object collides with the soft sheet; and a collision position identifying unit that identifies the collision position based on the image taken by the photographing device.

9. The target system described in claim 8, wherein the photographing device photographs the collision position from an oblique direction within a predetermined range when viewed from the front of the target, and the collision position identification unit applies correction according to the inclination at the oblique position where the photographing device is placed, and identifies the collision position based on the images taken before and after the flying object collides with the soft sheet and changes its path or speed.

Images