Measuring device

Abstract

To provide a measuring device capable of precisely measuring a track and a height of a moving object by a simple method.SOLUTION: A measuring device includes: an acquisition section for acquiring an event signal from an imaging device having an event base vision sensor; a first image generation section for generating a first image on the basis of an event signal acquired during a first period; a determination section for determining whether a height of a moving object is less than a predetermined height on the basis of the first image generated for each first period; a second image generation section for generating a second image including a track region showing the track of a moving object on the basis of an event signal acquired during a second period between first timing after lapse of first time from a point of time when the height of a moving object becomes less than a predetermined height and second timing after lapse of second time from the point of time; and a calculation section for calculating a height of flip-back of a moving object on the basis of the second image. The second period is longer than the first period.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present disclosure relates to a measurement device. [Background technology]

[0002] Conventionally, a method for extracting the motion trajectory of an object (e.g., a ball) using a camera is known. For example, Japanese Patent Laid-Open Publication No. 2001-273500 (Patent Document 1) discloses a moving object measuring device. The moving object measuring device includes a TV camera and a world coordinate trajectory extraction set for extracting a world coordinate trajectory, which is a coordinate system based on a space in which the moving object exists. The world coordinate trajectory extraction set detects a moving object from an image captured by the camera, converts the trajectory of the moving object from a coordinate system based on the camera into world coordinates, and outputs the trajectory. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-273500 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the projected trajectory of the motion trajectory between world coordinates of the position of the ball touching the ground is regarded as a straight line or a predetermined curve, the two-dimensional motion trajectory of the ball is determined, and the height of the ball is calculated from the two-dimensional motion trajectory and the motion trajectory on the image. However, the method of calculating the height of the ball using a normal TV camera has a problem that the amount of information of the background other than the ball is large, and the algorithm becomes complicated in order to accurately calculate the motion trajectory (and height) of the ball.

[0005] An object in one aspect of the present disclosure is to provide a measurement device capable of measuring the trajectory and height of a moving object with high accuracy using a simple method. [Means for solving the problem]

[0006] A measuring device according to an embodiment includes: an acquisition unit that acquires an event signal including a coordinate of a pixel where a luminance change occurs and a time from an imaging device having an event-based vision sensor that detects a luminance change of a moving object dropping onto a receiving member; a first image generation unit that generates a first image based on the event signal acquired in a first period; a determination unit that determines whether or not the height of the moving object has become less than a predetermined height based on the first image generated for each first period; a second image generation unit that generates a second image including a trajectory area showing the trajectory of the moving object based on the event signal acquired in a second period between a first timing after a first time has elapsed since the height of the moving object became less than the predetermined height and a second timing after a second time has elapsed since the time; and a calculation unit that calculates a rebound height of the moving object when the moving object is dropped onto the receiving member based on the second image. The second period is longer than the first period. Effect of the Invention

[0007] According to the present disclosure, the trajectory and height of a moving object can be measured with high accuracy using a simple method. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram for explaining the overall configuration of a measurement system. [Diagram 2] FIG. 2 is a block diagram showing a hardware configuration of the measurement device. [Diagram 3] 4 is a flowchart illustrating an example of the operation of the measurement device. [Figure 4] FIG. 4 is a diagram showing an example of a frame image. [Diagram 5] 11 is a diagram for explaining an example of a fall determination processing method. FIG. [Figure 6] FIG. 2 is a diagram for explaining a method for measuring the rebound height of a ball. [Figure 7] FIG. 13 is a diagram showing an example of a frame image near the highest point of a ball's bounce. [Figure 8] FIG. 13 is a diagram for explaining a modified example of the measurement method. [Figure 9] 1 is a diagram for explaining a method for measuring the amount of lateral deviation before and after a ball bounces. [Figure 10] FIG. 2 is a block diagram showing an example of a functional configuration of a measurement device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the present embodiment will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[0010] <Overall composition> Fig. 1 is a diagram for explaining the overall configuration of a measurement system 1000. Referring to Fig. 1, the measurement system 1000 is a system for allowing a ball 30 to freely fall from a predetermined height (for example, a position 4 m above a receiving member 40) and measuring the maximum height (i.e., the rebound height) of the ball 30 after it rebounds from the receiving member 40. The measurement is performed to confirm the rebound performance of the ball 30. The ball 30 is, for example, a hard baseball. The receiving member 40 is, for example, marble, but may be another material.

[0011] Conventionally, the rebound height of the ball 30 that rebounds from the receiving member 40 has been measured visually. However, this measurement method has a large variation depending on the skill level and fatigue of the person taking the measurement, and requires a person dedicated to the measurement.

[0012] Another possible method is to capture an image of the ball 30 using a camera that uses an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), which are widely used in general, and measure the bounce height of the ball 30 from the captured image. However, this method has a problem in that the captured image contains a lot of information about the background other than the ball 30, making the process for obtaining the trajectory of the ball 30 with high accuracy (for example, the process for removing background information) complicated.

[0013] Therefore, the measurement system 1000 according to the present embodiment is configured to measure the bounce height of the ball 30 using the imaging device 20 equipped with an event-driven (based) vision sensor.

[0014] The imaging device 20 is an imaging device having an event-based vision sensor (hereinafter also referred to as "event sensor") that detects luminance changes of a moving object. The event sensor asynchronously detects luminance changes of each pixel as an event, and can operate at high speed with low power consumption compared to image sensors such as CCD and CMOS. Since pixel luminance changes occur when a subject moves, an image obtained by the event sensor contains only moving subjects and does not contain static background information. More specifically, the event sensor detects a luminance change of light captured by a pixel as an event when it exceeds a set threshold, and outputs an event signal containing the coordinates, time, and polarity of the pixel where the event occurred.

[0015] Typically, the imaging device 20 is fixed in advance so that the position of the rebound height of the ball 30 (i.e., the maximum height of the ball 30 after bouncing off the receiving member 40) is included in the imaging range 25 of the imaging device 20.

[0016] The measuring device 10 is configured as a laptop PC (Personal Computer). However, the measuring device 10 can be realized as any device regardless of type. For example, the measuring device 10 may be a smartphone, a tablet terminal, a desktop PC, etc. Typically, the measuring device 10 is connected to the imaging device 20 by a wired communication method, but may be configured to be connected to the imaging device 20 by a wireless communication method.

[0017] The measuring device 10 is configured to be able to communicate with the imaging device 20, and receives an event signal output from the imaging device 20. The measuring device 10 generates an image based on the event signal, and measures the bounce height of the ball 30 from the trajectory of the ball 30 included in the image. The measuring device 10 displays the measurement result on a display.

[0018] <Hardware configuration> Fig. 2 is a block diagram showing a hardware configuration of the measurement device 10. Referring to Fig. 2, the measurement device 10 includes, as main components, a processor 102, a memory 104, an input device 106, a display 108, and a communication interface (I / F) 110. These components are connected to each other via a bus.

[0019] Processor 102 reads out and executes a program stored in memory 104 to control the operation of each part of measuring device 10. Processor 102 is typically an arithmetic processing unit such as a CPU (Central Processing Unit) or an MPU (Multi Processing Unit). More specifically, processor 102 executes the program to realize the processing of measuring device 10, which will be described later.

[0020] The memory 104 is realized by a random access memory (RAM), a read-only memory (ROM), a hard disk, etc. The memory 104 stores programs executed by the processor 102, data used by the processor 102, etc.

[0021] The input device 106 accepts operation inputs for the measurement device 10. The input device 106 is realized, for example, by a keyboard, a button, a mouse, or the like. The input device 106 may also be realized as a touch panel. The display 108 displays images, text, and other information on a display screen based on a signal from the processor 102.

[0022] The communication interface 110 communicates signals with the imaging device 20. The communication interface 110 communicates with the imaging device 20 using a wired communication method such as USB (Universal Serial Bus) or a wireless communication method such as Bluetooth (registered trademark) or wireless LAN (Local Area Network).

[0023] <Example of operation> 3 is a flowchart for explaining an example of the operation of the measurement device 10. Typically, each step shown in FIG.

[0024] The measuring device 10 acquires (receives) each event signal output from the imaging device 20 (step S10). The event signal includes at least the position and time of the pixel where a luminance change has occurred.

[0025] The measuring device 10 generates a frame image based on the event signal corresponding to the period Da (e.g., 0.02 seconds) (step S12). Specifically, the measuring device 10 generates one frame image by synthesizing the event signals of each pixel for each period Da. For example, a frame image is generated in which pixels that have undergone a luminance change are represented by a binary value of "1" and pixels that have not undergone a luminance change are represented by a binary value of "0."

[0026] Fig. 4 is a diagram showing an example of a frame image. Referring to Fig. 4, a white region indicating the falling ball 30 is shown in the frame image 72. Specifically, the frame image 72 is generated by combining event signals acquired in a period Da1 (e.g., 0.02 seconds). Typically, the measurement device 10 recognizes the largest white region included in the frame image 72 as the region indicating the ball 30.

[0027] It should be noted that known image processing for removing noise has been performed on the frame image 72 shown in Fig. 3. For example, the image processing includes filtering, grayscaling, binarization, expansion, and the like.

[0028] In frame image 72, for example, the upper left pixel is defined as the origin (0,0), the horizontal direction is the X-axis direction, and the vertical direction is the Y-axis direction. In this case, the coordinates of the rightmost pixel on the X-axis in frame image 72 are (Xn,0), the coordinates of the bottommost pixel on the Y-axis in frame image 72 are (0,Yn), and the coordinates of the bottom rightmost pixel in frame image 72 are (Xn,Yn). Note that the X-axis direction indicates the horizontal direction, and the Y-axis direction indicates the vertical direction. More specifically, the negative direction of the Y-axis indicates the vertically upward direction, and the positive direction of the Y-axis indicates the vertically downward direction. This method of defining axes and coordinates is the same for each of the following images.

[0029] Referring again to FIG. 3, measurement device 10 executes a drop determination process for determining whether or not ball 30 has dropped to a height below a predetermined height, based on the frame images generated for each period Da (step S14).

[0030] FIG. 5 is a diagram for explaining an example of a drop determination processing method. Referring to FIG. 5, frame images 72, 74, and 76 show white regions indicating the falling ball 30. Specifically, the frame image 72 is generated by synthesizing each event signal acquired in a period Da1. Similarly, the frame image 74 is generated by synthesizing each event signal acquired in a period Da2 that is later than the period Da1, and the frame image 76 is generated by synthesizing each event signal acquired in a period Da3 that is later than the period Da2. The periods Da1 to Da3 are all the same period (for example, 0.02 seconds).

[0031] When the ball 30 reaches below the straight line L1, the measuring device 10 determines that the height of the ball 30 is below the predetermined height. For example, when the Y coordinates of all (or a part of) the pixels in the white area showing the ball 30 become larger than the Y coordinate of the straight line L1, the measuring device 10 determines that the height of the ball 30 is below the predetermined height. Hereinafter, the point in time when the measuring device 10 determines that the height of the ball 30 is below the predetermined height is also referred to as the "fall determination point in time." Note that the position of the straight line L1 shown in FIG. 5 is an example, and the straight line L1 may be set at another position.

[0032] Referring again to FIG. 3, the measurement device 10 generates an image for measuring the rebound height of the ball 30 (hereinafter also referred to as a “measurement image”) based on the event signal corresponding to the period Db after the drop determination point (step S16).

[0033] The period Db is set to the period between timing t1, which is the time T1 after the drop determination time, and timing t2, which is the time T2 after the drop determination time (where T2>T1). The period Db is set to include the period from when the ball 30 bounces off the receiving member 40 rises to when it falls.

[0034] For example, time T1 is 0.4 seconds, and time T2 is 1.0 seconds. In this case, period Db is 0.6 seconds. Times T1 and T2 are set by utilizing the fact that the time it takes for the ball 30 to freely fall and bounce off the receiving member 40 to reach its highest point falls within a certain time. In this way, it can be understood that period Db (e.g., 0.6 seconds) is a very long period compared to the above-mentioned period Da (e.g., 0.02 seconds).

[0035] Next, the measuring device 10 measures the bounce height of the ball 30 using the measurement image (step S18).

[0036] Fig. 6 is a diagram for explaining a method for measuring the ball's bounce height. Referring to Fig. 6, the measurement device 10 generates a measurement image 80 by synthesizing the event signals of each pixel acquired during the period Db. The measurement image 80 is an image in which images based on the event signals of each pixel acquired during the period Db are accumulated, and therefore includes a trajectory area showing the trajectory of the ball 30.

[0037] Typically, the measurement device 10 recognizes the largest white area included in the measurement image 80 (i.e., the parabolic area of ​​the measurement image 80) as the trajectory area of ​​the ball 30. Note that, like the frame images, the measurement image 80 is also subjected to known image processing for removing noise.

[0038] The measuring device 10 identifies the smallest Y coordinate among the Y coordinates of each pixel included in the trajectory area (for example, the Y coordinate of line L2 in Figure 6) and converts the identified Y coordinate into actual height information (for example, the height from the receiving member 40).

[0039] We will now explain in more detail why, when measuring the bounce height, we use measurement image 80 generated based on an event signal corresponding to period Db, rather than a frame image generated based on an event signal corresponding to period Da (e.g., 0.02 seconds).

[0040] 7 is a diagram showing an example of a frame image near the highest point of the ball's bounce. Referring to Fig. 7, a frame image 78 is an image generated based on each event signal acquired during a period Da near the highest point of the ball's bounce.

[0041] It can be seen from the frame image 78 that the white area representing the ball 30 is hardly observed. This is because the ball 30 is almost stationary near the highest point of the bounce, so no change in pixel brightness occurs and the event sensor does not detect an "event." Therefore, as described above, by setting the period Db to include the period from when the bouncing ball 30 rises to when it reaches the highest point and starts to fall, it is possible to obtain a single measurement image 80 in which the trajectory of the ball 30 as shown in FIG. 6 can be clearly observed. This allows the bounce height of the ball 30 to be measured with high accuracy.

[0042] 3, measuring device 10 outputs the measurement result of the bounce height of ball 30 (step S20). Typically, measuring device 10 displays the measurement result on display 108. Note that measuring device 10 may transmit the measurement result to another device, or may output the measurement result as sound via a speaker (not shown).

[0043] <Modification of the method for measuring bounce height> In the above, a method for calculating the bounce height of the ball 30 based on the minimum Y coordinate in the trajectory area has been described. However, according to this method, for example, if a white area indicating noise is superimposed on the edge of the trajectory area and the minimum Y coordinate is obtained in the white area, the bounce height of the ball 30 is calculated based on the minimum Y coordinate. In other words, the bounce height of the ball 30 is calculated based on noise, which causes measurement errors.

[0044] Therefore, in a modified measurement method, a method will be described in which the rebound height of the ball 30 is calculated based on the Y coordinate at the center of the trajectory area in order to avoid measurement errors due to noise as much as possible.

[0045] 8A and 8B are diagrams for explaining modified examples of the measurement method. Fig. 8A is a diagram showing a measurement image according to modified example (part 1). Fig. 8B is a diagram showing a measurement image according to modified example (part 2).

[0046] 8(a), the measurement image 91 is generated based on an event signal corresponding to the period Db. The measurement device 10 recognizes the largest white area included in the measurement image 91 (i.e., a parabolic area in the measurement image 91) as the trajectory area of ​​the ball 30. The measurement device 10 identifies the center of the trajectory area in the horizontal direction (i.e., the X-axis direction), and measures the bounce height of the ball 30 based on the vertical coordinate (i.e., the Y coordinate) of the center.

[0047] A method for identifying the center will now be described. The measurement device 10 acquires the coordinates (i.e., X coordinates) of the pixels at one end (e.g., the left end) and the other end (e.g., the right end) of the trajectory area in the horizontal direction. In the measurement image 91, it is shown that the X coordinate of the left end pixel is X1 (hereinafter also referred to as the "left end coordinate X1") and the X coordinate of the right end pixel is X2 (hereinafter also referred to as the "right end coordinate X2"). The measurement device 10 calculates the center coordinate X3 in the X-axis direction of the trajectory area based on the left end coordinate X1 and the right end coordinate X2. "X3=(X1+X2) / 2".

[0048] The measurement device 10 identifies a portion whose horizontal distance from the center coordinate X3 is within a predetermined range as the center. For example, the measurement device 10 identifies a portion in the trajectory region whose X coordinate is in the range from "X3-k" to "X3+k" (i.e., (X3-k)≦X≦(X3+k)) as the center. In this case, (2k+1) pixels including the pixel of the center coordinate X3 correspond to the center. k is, for example, 10.

[0049] The measuring device 10 measures the bounce height of the ball 30 based on the minimum Y coordinate among the Y coordinates of the pixels contained in the central portion identified as above.

[0050] As shown in FIG. 8(b), the following process may be added so that the center coordinate X3 becomes the center position of a parabola indicating the trajectory region.

[0051] The measuring device 10 generates a measuring image 93 by cutting out and deleting pixels in the measuring image 91 that have a Y coordinate equal to or greater than a predetermined value. The predetermined value is appropriately determined by empirical rules or the like. The measuring image 93 includes only the trajectory region near the highest point of the parabola. Therefore, when the central coordinate X3 in the X-axis direction of the trajectory region is calculated in the same manner as in FIG. 8(a), the central coordinate X3 is approximately the center position of the parabola. The measuring device 10 then identifies a portion that is within a predetermined range of horizontal distance from the central coordinate X3 as the central portion, and measures the bounce height of the ball 30 based on the Y coordinate of the central portion.

[0052] According to the above-mentioned configuration, the rebound height of the ball 30 can be calculated by limiting it to the central part of the track area, so that measurement errors due to noise can be prevented.

[0053] <Lateral deviation measurement method> Fig. 9 is a diagram for explaining a method for measuring the amount of lateral deviation before and after the rebound of the ball 30. Referring to Fig. 9, a frame image 95 is generated by combining event signals acquired during a certain period Da during the free fall of the ball 30 before it rebounds from the receiving member 40. A measurement image 97 is generated by combining event signals acquired during a period Db.

[0054] The measurement device 10 calculates the horizontal center coordinate Xa of the white area indicating the falling ball 30 in the frame image 95. The measurement device 10 calculates the horizontal center coordinate Xb of the white area indicating the trajectory area of ​​the ball 30 in the measurement image 97. The center coordinate Xb corresponds to the center coordinate X3 described in FIG. 8.

[0055] Based on the central coordinates Xa and Xb, the measuring device 10 measures the lateral deviation E, which indicates how much the ball 30 deviates horizontally before and after bouncing off the receiving member 40. Specifically, the lateral deviation E is calculated as the distance between the central coordinates Xa and Xb (i.e., |Xa-Xb|).

[0056] If the lateral deviation E is equal to or greater than the threshold, it is considered that the bounce height of the ball 30 has not been properly measured. Therefore, the measuring device 10 processes the measurement result of the bounce height of the ball 30 as an error. For example, the measuring device 10 assigns an error flag to the measurement result. The lateral deviation E is also used as an index for checking the quality of the ball 30.

[0057] <Functional configuration> Fig. 10 is a block diagram showing an example of a functional configuration of the measuring device 10. Referring to Fig. 10, the measuring device 10 includes an acquisition unit 202, a first image generation unit 204, a determination unit 206, a second image generation unit 208, a calculation unit 210, and an output unit 212. Typically, these functional configurations are realized by the processor 102 of the measuring device 10 or the like. Note that some or all of these functional configurations may be realized by hardware.

[0058] The acquisition unit 202 acquires an event signal from the imaging device 20 having an event sensor. The first image generation unit 204 generates frame images (e.g., frame images 72, 74, 76, etc.) based on the event signal acquired during a period Da. Specifically, the first image generation unit 204 generates one frame image for each period Da by synthesizing the event signals acquired during the period Da.

[0059] The determination unit 206 determines whether or not the height of the ball 30 is below a predetermined height, based on the frame images generated for each period Da. The determination unit 206 executes the drop determination process described with reference to FIG.

[0060] The second image generation unit 208 generates a measurement image (e.g., measurement image 80) including the trajectory area of ​​the ball 30 based on an event signal acquired during a period Db between timing t1, which is a time T1 after the point in time when the height of the ball 30 becomes less than a predetermined height (e.g., the point in time when the ball is determined to fall), and timing t2, which is a time T2 after the point in time when the ball 30 becomes less than a predetermined height (e.g., the point in time when the ball is determined to fall), and the timing t2, which is a time T2 after the point in time when the ball 30 becomes less than a predetermined height (e.g., the point in time when the ball is determined to fall).

[0061] The calculation unit 210 calculates the bounce height of the ball 30 when the ball 30 is allowed to freely fall onto the receiving member 40, based on the measurement image. In one aspect, the calculation unit 210 identifies the center of the trajectory area in the horizontal direction in the measurement image, and calculates the bounce height of the ball 30 based on the vertical coordinate (e.g., Y coordinate) of the center. Specifically, the calculation unit 210 acquires the coordinates of one end and the other end of the trajectory area in the horizontal direction, and calculates the center coordinate X3 in the horizontal direction based on the coordinate of the one end (e.g., left end coordinate X1) and the coordinate of the other end (e.g., right end coordinate X2). The calculation unit 210 identifies a portion whose horizontal distance from the center coordinate X3 is within a predetermined range as the center.

[0062] In another aspect, the calculation unit 210 calculates, based on the frame image, the horizontal center coordinate (e.g., center coordinate Xa) of the area showing the falling ball 30. The calculation unit 210 calculates the amount of lateral deviation of the ball 30 before and after the bounce, based on the center coordinate Xa and the horizontal center coordinate (e.g., center coordinate Xb) of the trajectory area based on the measurement image.

[0063] <Advantages> According to this embodiment, by utilizing an event sensor, the bounce height of the ball 30 can be measured with high accuracy without using a complicated algorithm. Measurement variability can be reduced compared to when a person measures it visually. In addition, since the bounce height of the ball 30 is measured automatically, the measurement time can also be shortened.

[0064] <Other embodiments> (1) In the above embodiment, the case has been described in which ball 30, which is the moving object, is a hard baseball ball, but ball 30 may be a soft baseball ball, a softball, a tennis ball, a basketball, a golf ball, or the like. Alternatively, ball 30 may be a metal ball or the like, and receiving member 40 may be a cushioning material or the like. In this case, the characteristics of receiving member 40 can be evaluated by calculating the rebound height of ball 30 using measuring device 10.

[0065] (2) It is also possible to provide a program that causes a computer to function and execute the control as described in the above embodiment. Such a program can be recorded on a non-transitory computer-readable recording medium such as a flexible disk, a CD-ROM (Compact Disc Read Only Memory), a ROM, a RAM, or a memory card that comes with the computer, and provided as a program product. Alternatively, the program can be recorded on a recording medium such as a hard disk built into the computer and provided. The program can also be provided by downloading it over a network.

[0066] (3) The configurations exemplified as the above-mentioned embodiments are merely examples of the configurations of the present invention, and may be combined with other known technologies. The present invention may also be modified, for example by omitting some parts, without departing from the gist of the present invention.

[0067] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0068] 10 Measuring device, 20 Imaging device, 25 Imaging range, 30 Ball, 40 Receiving member, 72, 74, 76, 78, 95 Frame image, 80, 91, 93, 97 Measurement image, 102 Processor, 104 Memory, 106 Input device, 108 Display, 110 Communication interface, 202 Acquisition unit, 204 First image generation unit, 206 Judgment unit, 208 Second image generation unit, 210 Calculation unit, 212 Output unit, 1000 Measurement system.

Claims

1. an acquisition unit that acquires an event signal including a coordinate of a pixel where a luminance change has occurred and a time from an imaging device having an event-based vision sensor that detects a luminance change of a moving object that has fallen onto a receiving member; a first image generating unit configured to generate a first image based on the event signal acquired during a first period; a determination unit that determines whether or not a height of the moving object is less than a predetermined height based on the first image generated for each first period; a second image generating unit that generates a second image including a trajectory area showing a trajectory of the moving object based on the event signal acquired during a second period between a first timing after a first time has elapsed since a time point when the height of the moving object becomes less than the predetermined height and a second timing after a second time has elapsed since the first timing; a calculation unit that calculates a rebound height of the moving object when the moving object is dropped onto the receiving member based on the second image, The second period of time is longer than the first period of time.

2. The measuring device according to claim 1 , wherein the second period includes a period from when the moving object bounces off the receiving member rises to when it falls.

3. The calculation unit is Identifying a center of the orbital region in a horizontal direction; 3. The measuring device according to claim 1, further comprising a measuring section for measuring a height of the moving object that bounces back based on a vertical coordinate of the central portion.

4. The calculation unit is Obtaining coordinates of one end and the other end of the trajectory region in a horizontal direction; Calculating a first center coordinate of the trajectory region in a horizontal direction based on the coordinates of the one end and the coordinates of the other end; The measuring device according to claim 3 , wherein a portion whose horizontal distance from the first center coordinate is within a predetermined range is identified as the central portion.

5. The calculation unit is calculating second horizontal center coordinates of an area representing the falling moving object based on the first image; The measuring device according to claim 4 , further comprising a step of calculating a lateral deviation of the moving object before and after the rebound based on the first center coordinate and the second center coordinate.

Images