JP2012233773A - Mobile body speed measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To concurrently measure moving speeds of a mobile body before and after the mobile body is hit and a speed of an object which hits the mobile body while securing a wide range of detecting a moving speed of a mobile body.SOLUTION: Doppler signals Sd are detected by using a Doppler sensor 14 for: transmitting transmission waves W1 to a ball 2 moving toward a hitting region from a front thereof, a bat 4 hitting the ball 2 in the hitting region and the ball 2 after being hit; and receiving reflection waves W2 reflected from the bat 4 and the ball 2. An accumulation section 30 accumulates intermediary data, the data which is converted from the Doppler signals Sd, for an amount equivalent to a predetermined accumulation period in the order of elapsed time. A measuring section 18 specifies a hitting time on the basis of the intermediary data accumulated in the accumulation section 30, and calculates an approach speed of the ball 2 moving in a direction of the ball approaching an antenna 12, a departing speed of the ball 2 moving in a direction of the ball 2 departing from the antenna 12, and an object speed which is a speed of the bat 4.

Description

  The present invention relates to a moving body speed measurement device.

An apparatus for detecting the swing speed of a golf club when a person swings a golf club and hits a golf ball has been proposed (see Patent Document 1). This device obtains the swing speed based on the image information of the golf club obtained by the imaging device.
There has also been proposed an apparatus for detecting the swing speed of a swing member when a person swings a swing member such as a baseball bat or a tennis racket and hits a ball (see Patent Document 2). This device calculates the swing speed based on the passage time of the swing member detected by the optical sensor.

JP 2002-90380 A Japanese Patent Laid-Open No. 02-249565

However, since the above-described conventional technique uses an imaging device or an optical sensor, the measurement range is limited. Therefore, it is necessary to hit a ball placed within a predetermined measurement range with a golf club or a swing member.
For this reason, measurement is difficult when the hit position varies and deviates from the measurement range of the imaging device or the optical sensor, such as hitting a ball thrown by a person or a pitching machine with a bat.
In addition, although it is possible to measure the moving speed of the ball based on the same principle as that for measuring the swing speed, conventionally, for example, only the speed of the thrown ball is measured or only the swing speed of the bat is measured. Only the velocity of the hit ball is measured.
The present invention has been made in view of such circumstances, and an object of the present invention is to ensure a large range in which the moving speed of the moving body can be detected, and the moving speed of the moving body before being hit. Another object of the present invention is to provide a moving body speed measuring device capable of simultaneously measuring the moving speed of the moving body and the speed of an object hitting the moving body.

  In order to achieve the above object, a moving body speed measuring device of the present invention includes a moving body that moves from the front of a striking area toward the striking area, an object that strikes the moving body in the striking area, and A transmission wave is transmitted from the rear of the hitting area toward the moving body after being hit, and a reflected wave reflected by the object and the moving body is received by the antenna, and a Doppler frequency is obtained. A Doppler sensor that generates a Doppler signal, a detection unit that converts the Doppler signal into intermediate data associated with the Doppler frequency, and samples the intermediate data at a predetermined sampling period; and the detection unit A storage unit that stores the intermediate data sampled at a predetermined storage period in order as time elapses, and the storage A striking time point identifying unit that identifies a striking time point at which the object strikes the moving body in the meantime, and from the start point of the accumulation period to the striking time point of the intermediate data accumulated in the accumulating unit An approach speed calculation unit that calculates an approach speed at which the moving body moves in a direction approaching the antenna based on the intermediate data stored in the first period T1 that is a period; and the intermediate data stored in the storage unit The separation speed for calculating the separation speed at which the moving body moves in the direction away from the antenna based on the intermediate data accumulated in the second period T2, which is the period from the impact time to the end of the accumulation period. A calculation unit, and an object speed calculation unit that calculates an object speed that is the speed of the object at the time of the hit based on intermediate data corresponding to the time of the hit. And butterflies.

  According to the present invention, the hit point at which the object hits the moving body is specified based on the Doppler signal obtained by the Doppler sensor, and the proximity speed, the separation speed, and the object speed of the object are determined using the specified hit point. Since each calculation is made, it is possible to secure a large range in which the moving speed of the moving object and the object can be detected, and the moving speed of the moving object before being hit, the moving speed of the moving object after being hit, the moving object It is possible to measure the speed of an object that strikes at the same time.

It is a block diagram which shows the structure of the speed measurement apparatus 10 of the moving body of 1st Embodiment. 3 is a functional block diagram of the speed measuring device 10. FIG. It is a figure which shows the result of having performed the wavelet analysis of the Doppler signal Sd. 3 is a flowchart showing the operation of the speed measuring device 10. It is a functional block diagram of speed measuring device 10 in a 2nd embodiment. It is a functional block diagram of speed measuring device 10 in a 3rd embodiment. FIG. 4 is a schematic diagram showing the frequency distribution of the Doppler signal Sd at a time point tA when both frequency distributions A and B exist in FIG. 3. It is a functional block diagram of speed measuring device 10 in a 4th embodiment. It is explanatory drawing which shows an example of the continuous FFT process of the Doppler signal Sd. It is explanatory drawing which shows the other example of the continuous FFT process of the Doppler signal Sd. It is a figure which shows an example of time series frequency distribution data.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a moving body speed measuring apparatus 10 (hereinafter referred to as speed measuring apparatus 10) according to the present embodiment, and FIG. 2 is a functional block diagram of the moving body speed measuring apparatus 10.

  In the present embodiment, the moving body is a baseball ball 2 and the speed measuring device 10 measures the moving speed of the ball 2 and the bat 4 when hit by a baseball bat (object) 4. explain. The moving body may be a ball for various ball games, as long as it moves in space by being hit by an object.

  As shown in FIG. 1, the speed measurement device 10 of the present embodiment includes an antenna 12, a Doppler sensor 14, a signal processing circuit 16, a measurement unit 18, a display unit 22, an operation unit 24, and the like. It is configured.

The antenna 12 transmits a microwave as a transmission wave W1 to the ball 2 and the bat 4 based on the transmission signal supplied from the Doppler sensor 14, and a reflected wave W2 reflected by the ball 2 and the bat 4. And the received signal is supplied to the Doppler sensor 14.
A space in which the ball 2 is hit with the bat 4 is defined as a hitting area, and the hitting area is set in front of the Doppler sensor 14.
Therefore, the antenna 12 is directed from the rear of the hitting area toward the ball 2 that moves from the front of the hitting area toward the hitting area, the bat 4 that hits the ball 2 in the hitting area, and the ball 2 that has been hit. While transmitting the transmission wave W1, the reflected wave W2 reflected by the bat 4 and the ball 2 is received, and the reception signal is supplied to the Doppler sensor 14.

The Doppler sensor 14 supplies the transmission signal to the antenna 12 and receives the reception signal supplied from the antenna 12 to detect the Doppler signal Sd.
The Doppler signal is a signal having a Doppler frequency Fd defined by a frequency F1-F2 that is a difference between the frequency F1 of the transmission signal and the frequency F2 of the reception signal.
Various commercially available Doppler sensors 14 can be used.
For example, a 24 GHz microwave can be used as the transmission signal, and the frequency of the transmission signal is not limited as long as the Doppler signal Sd can be obtained.

Here, the principle of speed detection using the Doppler sensor 14 will be described.
As is conventionally known, the Doppler frequency Fd is expressed by Expression (1).
Fd = F1-F2 = 2 · V · F1 / c (1)
V: speed of ball 2 or bat 4, c: speed of light (3 · 10 ⁸ m / s)
Therefore, when equation (1) is solved for V, equation (2) is obtained.
V = c · Fd / (2 · F1) (2)
Therefore, the speed V is proportional to the Doppler frequency Fd.
Therefore, the frequency component of the Doppler frequency Fd can be detected from the Doppler signal Sd, and the velocity V of the ball 2 can be obtained from the detected Doppler frequency component based on Expression (2).

Next, the measurement result of the Doppler frequency Fd when the ball 2 and the bat 4 are detected by the Doppler sensor 14 will be described.
FIG. 3 is a diagram illustrating a result of wavelet analysis of the Doppler signal Sd.
The horizontal axis represents time t (ms), and the vertical axis represents the Doppler frequency Fd (Hz) and the velocity V (m / s) of the moving object.
Such a diagram can be obtained, for example, by sampling the Doppler signal Sd, taking it into a digital oscilloscope and converting it into digital data, and then performing wavelet analysis or continuous FFT analysis on the digital data using a personal computer or the like. .

FIG. 3 shows a process before and after the ball 2 thrown toward a predetermined hitting area is hit by the swinged bat 4.
The frequency distribution (velocity distribution) indicated by the symbol A indicates the Doppler frequency Fd (velocity) corresponding to the reflected wave reflected by the ball 2 during the period in which the ball 2 moves toward the striking area (antenna 12). The detection result of V) is shown.
The frequency distribution (velocity distribution) indicated by the symbol B is the detection result of the Doppler frequency Fd (velocity V) corresponding to the reflected wave reflected by the bat 4 before and after the swinged bat 4 hits the ball 2. Is shown.
The frequency distribution (velocity distribution) indicated by the symbol C indicates that the Doppler corresponding to the reflected wave reflected by the ball 2 during the period in which the ball 2 hit by the bat 4 moves in a direction away from the hitting area (antenna 12). The detection result of the frequency Fd (speed V) is shown.
In the frequency distributions A, B, and C shown in FIG. 3, the portions indicated by hatching have a large intensity of the Doppler signal Sd, and the portions indicated by a solid line have a lower intensity than the portion indicated by the hatching. Is shown.

The frequency distribution A shows a process in which the ball 2 moving in the direction approaching the hitting area is measured from the time when it enters the detection area of the Doppler sensor 14 and moves at a substantially constant speed.
The frequency region B is a process in which the swung bat 4 is measured from the time when it enters the detection region of the Doppler sensor 14 and increases with time, and decelerates with time after the bat 4 strikes the ball 2. Is shown.
Further, the frequency distribution C shows a process in which the ball 2 hit with the bat 4 moves at a substantially constant speed in a direction away from the hitting area. In this example, the frequency of the frequency distribution C is higher than the frequency distribution A. Therefore, the moving speed 4 of the ball 2 after hitting with the bat 4 is higher than the moving speed of the ball 2 before hitting with the bat 4. high.
When the ball 2 and the bat 4 are moving at the same time as described above, since these multiple frequency distributions are detected together, it is possible to specify and measure the moving speed of the ball 2 and the bat 4. Have difficulty.

Therefore, the present inventors have obtained the following knowledge based on the measurement results shown in FIG.
(1) The moving speed V (Doppler frequency Fd) of the bat 4 is greatly decelerated by hitting the ball 2.
That is, the amount of change per unit time of the moving speed V (Doppler frequency Fd) of the bat 4 changes greatly when the ball 2 is hit.
The maximum speed of the bat 4 (so-called head speed) is the maximum speed of the moving speed V of the bat 4 in the period before hitting.
That is, the maximum speed of the bat 4 is a moving speed corresponding to the maximum frequency of the Doppler frequency Fd in the frequency distribution B of FIG.
That is, the moving speed corresponding to the portion where the rate of change of the Doppler frequency Fd is reversed from positive to negative is the maximum speed, and the bat 4 hits the ball 2 when this maximum speed occurs.
(2) On the other hand, the moving speed V (Doppler frequency Fd) of the ball 2 can be regarded as a substantially constant speed in the period before being hit by the bat 4 and in the period after being hit by the bat 4. it can.
Therefore, the moving speed of the ball 2 before being hit with the bat 4 is a moving speed corresponding to the Doppler frequency Fd in the frequency distribution A of FIG.
Further, the moving speed of the ball 2 after being hit with the bat 4 is a moving speed corresponding to the Doppler frequency Fd in the frequency distribution C of FIG.
(3) From the above, it is possible to determine the frequency distributions A, B, and C by specifying the hitting point “tim” when the bat 4 hits the ball 2.
By obtaining the maximum speed in the determined frequency distribution B, the maximum speed of the bat 4 can be measured.
In addition, by obtaining the average speed in the discriminated frequency distributions A and C, the moving speed before and after the ball 2 is hit can be measured.
Based on such knowledge, the present invention accurately measures the moving speed of the ball 2 and the bat 4 based on the fact that the changes in the moving speed of the ball 2 and the bat 4 have different tendencies and characteristics. It is.

Returning to FIG. 1, the description will be continued.
The signal processing circuit 16 amplifies the Doppler signal Sd supplied from the Doppler sensor 14.

The measuring unit 18 calculates the speed of the ball 2 and the bat 4 by inputting the amplified Doppler signal Sd supplied from the signal processing circuit 16 and performing various processes.
In the present embodiment, the measurement unit 18 is configured by a microcomputer 26.
The microcomputer 26 includes a CPU 26A, a ROM 26B, a RAM 26C, an interface 26D, a display driver 26E, and the like connected via an interface circuit (not shown) and a bus line.
The ROM 26B stores a speed measurement program executed by the CPU 26A, and the RAM 26C provides a working area.
The interface 26D receives the binarized signal supplied from the signal processing circuit 16 and supplies it to the CPU 26A, and receives the operation signal from the operation unit 24 and supplies it to the CPU 26A.
The display driver 26E drives the display unit 22 based on the control of the CPU 26A.

FIG. 5 is a block diagram of the speed measuring device 10 showing the configuration of the microcomputer 26 as functional blocks.
Functionally, the microcomputer 26 includes a detection unit 28, an accumulation unit 30, an impact point identification unit 32, an approach speed calculation unit 34, a separation speed calculation unit 36, an object speed calculation unit 38, and a flight distance. The calculation unit 40 and the control unit 44 are included.
The accumulating unit 30, the hit point specifying unit 32, the approach speed calculating unit 34, the separation speed calculating unit 36, the object speed calculating unit 38, the flight distance calculating unit 40, and the control unit 42 are provided by the CPU 26A. These parts are realized by executing the speed measurement program, but these parts may be constituted by hardware such as a circuit.

The detection unit 28 converts the amplified Doppler signal Sd supplied from the signal processing circuit 16 into a binarized signal that takes two values of a low level and a high level with a predetermined threshold as a reference, and binarizes the signal. The signal is converted into intermediate data associated with the Doppler frequency Fd, and the intermediate data is sampled at a predetermined sampling period.
The period of the Doppler signal Sd corresponds to the period of the binarized signal. In other words, the frequency of the Doppler signal Sd corresponds to the frequency of the binarized signal.
In the present embodiment, the detection unit 28 generates the cycle of the binarized signal as intermediate data by counting the cycle of the binarized signal using a counter. That is, the conversion of the intermediate data is performed by obtaining the period of the binarized signal obtained by binarizing the Doppler signal as the intermediate data.
In other words, the detecting unit 28 obtains periodic data as time series data by counting the period of the Doppler signal Sd, and generates this periodic data as intermediate data associated with the Doppler frequency Fd.
Therefore, the value of the intermediate data and the Doppler frequency Fd are inversely proportional.

In the present embodiment, the “detection unit that converts the Doppler signal into intermediate data associated with the Doppler frequency and samples the intermediate data at a predetermined sampling period” in the claims by the detection unit 28. It is configured.
In the present embodiment, the case where the intermediate data associated with the Doppler frequency Fd is periodic data will be described. However, the intermediate data may be frequency data representing the Doppler frequency Fd.
However, when frequency data is used as the intermediate data, there are disadvantages in that the configuration of the processing circuit becomes complicated and the processing time becomes long, such as FFT conversion as signal processing. On the other hand, when the period data is used as the intermediate data as in the present embodiment, the configuration of the processing circuit is simplified, which is advantageous for shortening the processing time.

The accumulating unit 30 accumulates the intermediate data sampled by the detecting unit 28 for a predetermined accumulating period in order as time elapses. In the present embodiment, the accumulating unit 30 is composed of a RAM 26C serving as a storage unit. The start and stop of the accumulation operation are controlled by the control.
More specifically, the accumulation unit 30 accumulates the intermediate data in a dripping manner when one measurement operation is started. Therefore, when intermediate data corresponding to a predetermined accumulation period is accumulated, the accumulation unit 30 accumulates new intermediate data while overwriting the already accumulated intermediate data. Thereby, the accumulation unit 30 always accumulates the latest intermediate data corresponding to the accumulation period.
The accumulating unit 30 determines whether or not the level of the Doppler signal Sd (intensity of the reflected wave) is equal to or higher than a predetermined value as the bat 4 enters the striking area (measurement area of the Doppler sensor 14). It is configured.
Then, the accumulation operation is stopped when the accumulation period ends, starting from the time when the level of the Doppler signal Sd is detected as a predetermined value. As a result, intermediate data corresponding to a predetermined accumulation period is accumulated in the accumulation unit 30.
The accumulation period is set in advance so that intermediate data sufficient to measure the separation speed of the bat 4 can be secured.

The hitting time specifying unit 32 specifies the hitting point tim, which is the time when the object hits the moving body in the accumulation period.
In the present embodiment, the hit point identifying unit 32 identifies the portion of the intermediate data accumulated in the accumulating unit 30 where the rate of change is reversed from positive to negative or from negative to positive, and the identified intermediate data The time point corresponding to the portion is identified as the impact time point tim.
That is, the peak of the frequency distribution B shown in FIG. 3, in other words, the time point corresponding to the portion of the frequency distribution B where the rate of change reverses from positive to negative or from negative to positive is specified as the impact time point timestamp.

The approach speed calculation unit 34 determines that the ball 2 is connected to the antenna 12 based on the intermediate data accumulated in the first period T1, which is the period from the start time of the accumulation period to the impact time point timp, among the intermediate data accumulated in the accumulation unit 30. It calculates the approach speed that moves in the direction approaching.
That is, the approach speed at which the ball 2 moves in the direction approaching the antenna 12 is calculated based on the frequency distribution A shown in FIG.
In addition, in order to remove the influence of the frequency distribution B, the approach speed calculation unit 34 sets a period retroactive to a predetermined first exclusion period ΔT1 from the impact time point tim so that the frequency distribution B is not included in the first period T1. Based on the intermediate data accumulated in the excluded period T1-ΔT1, the approach speed at which the ball 2 moves in the direction approaching the antenna 12 is calculated.
Such a first exclusion period ΔT1 is appropriately set based on the actual measurement result.

The separation speed calculation unit 36 determines that the ball 2 is connected to the antenna 12 based on the intermediate data stored in the second period T2, which is a period from the hitting time “tim” to the end of the storage period, among the intermediate data stored in the storage unit 30. The separation speed for moving in the direction away from the head is calculated.
That is, the approach speed at which the ball 2 moves in the direction away from the antenna 12 is calculated based on the frequency distribution C shown in FIG.
In order to eliminate the influence of the frequency distribution B, the separation speed calculation unit 36 sets a period after the second exclusion period ΔT2 that is predetermined from the impact time point tim so that the frequency distribution B is not included in the second period T2. Based on the intermediate data accumulated in the excluded period T2-ΔT2, the separation speed at which the ball 2 moves in the direction away from the antenna 12 is calculated.
Such a second exclusion period ΔT2 is appropriately set based on the actual measurement result.

  The object speed calculation unit 38 calculates an object speed that is the speed of the bat 4 at the hitting time point tim based on the intermediate data corresponding to the hitting time point tim.

The flight distance calculation unit 40 calculates the flight distance of the ball 2 based on the separation speed.
Calculation of the flight distance of the ball 2 by the flight distance calculation unit 40 is performed as follows.
Actually measure the separation speed and the flying distance of the ball 2 in advance, create a map showing the correlation between the separation speed and the flying distance, or create a correlation formula showing the correlation between the separation speed and the flying distance, A map or correlation equation is set in the calculation unit 40.
The flight distance calculation unit 40 calculates a flight distance from a map or a correlation equation based on the calculated separation speed.

The control unit 42 controls the measurement unit 18 according to the operation received by the operation unit 24.
In addition, the control unit 42 causes the display unit 22 to display information such as the approach speed, the separation speed, the object speed, and the flight distance calculated by the measurement unit 18.

The operation unit 24 is operated when setting the power switch and measurement operation of the speed measuring device 10.
The display unit 22 displays the operation state of the speed measuring device 10 and each piece of information calculated by the measuring unit 18.

Next, the operation of the speed measuring device 10 will be described with reference to the flowchart of FIG.
Hereinafter, a case where a user standing in the vicinity of the hitting area swings the bat 4 and hits the ball 2 thrown toward the hitting area from the pitching machine, such as a batting center, will be described.
The antenna 12 of the speed measuring device 10 is arranged in advance toward the striking area (toward the front) at a location behind the striking area.
Next, the antenna 12 may be placed on the ground, or may be installed via a fixture such as a tripod.

The user operates the operation unit 24 of the speed measurement device 10 to set the speed measurement device 10 to a measurement mode in which measurement is possible (step S10).
As a result, the measurement operation is started, and the transmission wave W1 transmitted from the antenna 12 hits the ball 2 and the bat 4, and the reflected wave W2 can be received by the antenna 12.
Therefore, after step S10, the transmission wave W1 is transmitted, and when the reflected wave W2 is generated, it is received by the Doppler sensor 14, and the Doppler sensor 14 generates the Doppler signal Sd. The Doppler signal Sd is amplified by the signal processing circuit 16. After that, the detection unit 28 converts the data into intermediate data associated with the Doppler frequency Fd, and the intermediate data is sampled and stored in the storage unit 30 as time-series data (steps S12 and S14).
That is, after the measurement operation of the speed measurement device 10 is started, the intermediate data is accumulated in the accumulation unit 30 in a dripping manner.

Next, the user swings and hits the bat 4 with the ball 2 thrown from the pitching machine (step S16).
Then, the ball 2 throws or the bat 4 swings to generate a reflected wave W2, and a Doppler signal Sb and intermediate data are generated.
As a result, intermediate data corresponding to the frequency distributions A, B, and C as shown in FIG.
If the intermediate data is generated, the hitting time specifying unit 32 specifies the hitting point tim, which is the time when the object hits the moving body during the accumulation period of the accumulating unit 30 (step S18).
The approach speed calculation unit 34 calculates an approach speed at which the ball 2 moves in a direction in which the ball 2 approaches the antenna 12 (step S20).
The separation speed calculation unit 36 calculates a separation speed at which the ball 2 moves in a direction away from the antenna 12 (step S22).
The object speed calculation unit 38 calculates an object speed that is the speed of the bat 4 at the impact time point tim (step S24).
The flight distance calculation unit 40 calculates the flight distance of the ball 2 based on the separation speed (step S26).
And the control part 42 displays the information of approach speed, separation speed, object speed, and flight distance on the display part 22 (step S28).
Thus, a series of measurement operations is completed.

As described above, according to the present embodiment, the hitting point “tim” at which the bat 4 hits the ball 2 is specified based on the Doppler signal obtained by the Doppler sensor, and the specified hitting point “tim” is used to determine the ball 2 The approach speed, the separation speed, and the object speed of the bat 4 are calculated.
Therefore, it is possible to secure a large range in which the moving speed of the ball 2 and the bat 4 can be detected, and the moving speed of the moving body before hitting, the moving speed of the moving body after hitting, and the object hitting the moving body. The speed can be measured at the same time, which is advantageous for improving the convenience of the user.
Conventionally, since an imaging device or an optical sensor is used, it is easily affected by changes in ambient light or illumination brightness in the measurement environment, and the calibration of the device is complicated, resulting in a disadvantage of increasing operational costs. .
On the other hand, in this embodiment, since a Doppler sensor is used, it is not affected by changes in ambient light or illumination brightness in the measurement environment, which is advantageous in reducing the operating cost of the apparatus.

(Second Embodiment)
Next, a second embodiment will be described.
In the first embodiment, a portion of the intermediate data stored in the storage unit 30 where the rate of change is inverted from positive to negative or from negative to positive is specified, and the portion corresponding to the specified intermediate data portion is specified. The case where the time point is specified as the impact time point tim has been described.
However, it is conceivable that the process of specifying the hitting point “timp” based on the change rate of the intermediate data is not always easy.
Therefore, in the second embodiment, focusing on the fact that the direction in which the ball 2 moves before and after being hit with the bat 4 is reversed, it is possible to specify the hit point tim with a simpler configuration. Is.
In the following embodiment, the same parts and members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simply performed.

FIG. 5 is a functional block diagram of the speed measuring device 10 according to the second embodiment.
In the second embodiment, a so-called dual type Doppler sensor (Doppler module) that outputs a first Doppler signal Sd1 and a second Doppler signal Sd2 whose phases are different by 90 degrees is used as the Doppler sensor. Such a dual-type Doppler sensor (Doppler module) is publicly known, for example, as described in 72p to 77p of "Low-power microwave application technology and device (Electric Shoin published on October 20, 2005)". And are commercially available.
In this dual type Doppler sensor, it is first determined whether the moving body that is the target of transmitting the transmission wave W1 is moving in the direction approaching the Doppler sensor (antenna 12) or in the direction separating it. The determination can be made based on whether the phase of the Doppler signal Sd1 is advanced or delayed by π / 2 with respect to the phase of the second Doppler signal Sd2.
Therefore, in the second embodiment, as shown in FIG. 5, the Doppler sensor 50 is configured to output a first Doppler signal Sd1 and a second Doppler signal Sd2.
Based on the phase relationship (phase difference) between the first and second Doppler signals Sd1 and Sd2, the ball 2 moves in the direction approaching the Doppler sensor 50, or the moving body moves in the direction away from the Doppler sensor 50. A direction discriminating unit 52 is provided for discriminating whether the vehicle is doing.
The hit time point specifying unit 32 is configured to specify the hit point time based on the determination result by the direction determining unit 52.
The signal processing circuit 16 generates intermediate data based on one of the first and second Doppler signals Sd1 and Sd2.
According to the second embodiment as described above, it is obvious that the same effect as the first embodiment can be obtained, and the impact time point tim can be specified by the first and second Doppler signals Sd1 and Sd2. Since it can be easily performed based on the phase relationship, the configuration can be simplified, which is advantageous for cost reduction.

(Third embodiment)
Next, a third embodiment will be described.
In the third embodiment, the hitting point “tim” is specified based on the hitting sound generated when the ball 2 is hit with the bat 4.
FIG. 6 is a functional block diagram of the speed measuring device 10 according to the third embodiment.
As shown in FIG. 6, in the third embodiment, a trigger signal is generated if a microphone 64 that picks up the hitting sound and the audio signal output from the microphone 64 exceeds a predetermined magnitude. And a trigger signal generation unit 66 to be supplied to the hitting time specifying unit 32.
The microphone 64 and the trigger signal generation unit 66 constitute an impact sound detection unit that detects an impact sound generated when an object in the claims hits a moving body.
The hitting time specifying unit 32 is configured to specify the hitting point tim based on the trigger signal supplied from the trigger signal generating unit 66.
In addition, since there is a time delay such as the transmission time of the sound wave after the hitting sound is generated until the trigger signal is generated, the hitting time specifying unit 32 considers such a delay time and Specify the tip.
According to the third embodiment as described above, it goes without saying that the same effect as that of the first embodiment is achieved, and it is easy to specify the impact time point tim based on the generation of the impact sound. Therefore, the configuration can be simplified, which is advantageous for cost reduction.

(Fourth embodiment)
Next, a fourth embodiment will be described.
In the fourth embodiment, it is possible to determine the presence or absence of a bat swing by using the fact that the moving speeds of the bat 2 and the bat 4 are different in a situation where the ball 2 and the bat 4 are moving simultaneously. It is a thing.

Hereinafter, the principle of determining the presence or absence of the bat swing will be described.
FIG. 7 is a schematic diagram showing the frequency distribution of the Doppler signal Sd at time tA when both frequency distributions A and B exist in FIG.
As shown in FIG. 7, there are two peaks, a frequency distribution peak corresponding to the velocity of the ball 2 and a frequency distribution peak corresponding to the velocity of the bat 4.
In this case, two objects having different speeds, that is, the ball 2 and the bat 4 are moving simultaneously.
If at least the ball 2 is always moving, the bat 4 is not swung if there is only one frequency distribution peak in FIG. On the other hand, if there are two peaks in the frequency distribution, the bat 4 is swung.
Therefore, the presence / absence of the swing of the bat 4 can be determined based on the number of peaks of such frequency distribution.

In order to determine the presence or absence of the bat swing based on the above principle, it is necessary to accurately obtain the frequency distribution of the Doppler frequency.
In the first to third embodiments, the cycle of the binarized signal obtained by binarizing the Doppler signal is handled as intermediate data. Therefore, it is conceivable to obtain a frequency distribution of Doppler frequencies as shown in FIG. 7 based on this intermediate data.
However, when the Doppler signal is binarized, it is difficult to specify each frequency when signals of two or more frequencies are mixed. In addition, when the Doppler signal is binarized, information on the frequency (period) of the signal having a small intensity is lost, and it is difficult to accurately obtain the frequency distribution of the Doppler frequency.

Therefore, in the fourth embodiment, time series frequency distribution data is obtained by performing continuous FFT processing on the Doppler signal Sd, and time series peak frequencies are specified from these time series frequency distribution data, and these peak frequencies are calculated. I got it as intermediate data.
In this way, even if intermediate data is used, two frequencies mixed in the Doppler signal Sd can be specified. Therefore, when the ball 2 and the bat 4 move simultaneously, as shown in FIG. It is possible to accurately detect a frequency distribution peak corresponding to the correct ball 2 and a frequency distribution peak corresponding to the bat 4.

FIG. 8 is a functional block diagram of the speed measuring device 10 according to the fourth embodiment.
As shown in FIG. 8, the fourth embodiment is different from the first to third embodiments in that the function of the detection unit 50 and a swing determination unit 52 are newly provided. .
The detection unit 50 obtains time-series frequency distribution data by performing continuous FFT processing on the Doppler signal Sd supplied from the signal processing circuit 16, and specifies time-series peak frequencies from these time-series frequency distribution data. The peak frequency is obtained as intermediate data.

9 and 10 are explanatory diagrams illustrating an example of continuous FFT processing of the Doppler signal Sd.
That is, the detection unit 50 divides the Doppler signal Sd obtained continuously for each predetermined section Δt, and repeats the FFT process for each section. In this case, as shown in FIG. 9, the sections Δt may be set without overlapping, or the sections Δt may be set to overlap as shown in FIG.
If the time series peak frequency is specified from the time series frequency distribution data as shown in FIG. 11 obtained by performing the continuous FFT processing as described above and these peak frequencies are set as intermediate data, the same result as in FIG. 3 is obtained. can get.
Thereafter, as in the first embodiment, the accumulating unit 30, the hit point specifying unit 32, the approach speed calculating unit 34, the separation speed calculating unit 36, the object speed calculating unit 38, the flight distance calculating unit 40, and the control unit. 42 functions.

The swing determination unit 52 determines whether or not the bat 4 swings based on the number of peaks representing the frequency distribution of the frequency as shown in FIG. 7 obtained by performing the frequency analysis of the intermediate data stored in the storage unit 30. Judgment.
That is, in FIG. 7, if there is only one frequency distribution peak, the bat 4 is not swung, and if there are two frequency distribution peaks, the bat 4 is swinging.
Therefore, by performing frequency analysis of the intermediate data stored in the storage unit 30 over the first and second periods T1 and T2, it is possible to determine the presence or absence of the swing of the bat 4 based on the number of peaks.
The control unit 42 causes the display unit 22 to display the determination result of the bat swing in addition to the information on the approach speed, the separation speed, the object speed, the presence / absence of the swing, and the flight distance of the ball 2.

According to the fourth embodiment, it is obvious that the same effects as those of the first embodiment can be obtained.
That is, time series frequency distribution data is obtained by performing continuous FFT processing on the Doppler signal, and time series peak frequencies are specified from these time series frequency distribution data, and these peak frequencies are obtained as intermediate data.
Therefore, when the ball 2 and the bat 4 move at the same time, a frequency distribution peak corresponding to the ball 2 and a frequency distribution peak corresponding to the bat 4 can be accurately detected based on the intermediate data. The speeds of both the moving body and the object hitting the moving body can be detected simultaneously.
In addition, since the swing determination unit 52 determines the presence or absence of the swing of the bat 4 based on the number of mountains, it is advantageous in improving the convenience of the user.

  In the embodiment described above, the case where the moving body is the baseball ball 2 and the object is the bat 4 has been described. However, the moving body is a tennis ball or a soccer ball, and the object is a racket or a human foot. The present invention may also be applied when various moving objects are hit with an object.

  DESCRIPTION OF SYMBOLS 10 ... Speed measurement apparatus of moving body, 12 ... Antenna, 14 ... Doppler sensor, 16 ... Signal processing circuit, 18 ... Measurement part, 22 ... Display part, 24 ... Operation part, 26 ... Micro Computer, 28... Detecting unit, 30... Accumulating unit, 32 .. hitting time specifying unit, 34 .. approaching speed calculating unit, 36 .. separation speed calculating unit, 38 .. object speed calculating unit, 40. Distance calculation unit 42... Control unit 50... Detection unit 52.

Claims (8)

Transmitting from the rear of the hitting area toward the moving body moving from the front of the hitting area toward the hitting area, the object hitting the moving body in the hitting area, and the moving object after being hit A Doppler sensor that transmits a wave from an antenna, receives a reflected wave reflected by the object and the moving body, and generates a Doppler signal having a Doppler frequency;
A detector that converts the Doppler signal into intermediate data associated with the Doppler frequency, and samples the intermediate data at a predetermined sampling period;
An accumulation unit that accumulates the intermediate data sampled by the detection unit for a predetermined accumulation period in order as time elapses;
A striking time point identifying unit that identifies a striking time point that is a time point when the object hits the moving body during the accumulation period;
A direction in which the moving body approaches the antenna based on the intermediate data stored in the first period T1, which is a period from the start time of the storage period to the impact time, among the intermediate data stored in the storage unit. An approach speed calculation unit for calculating the approach speed to move to,
A direction in which the moving body moves away from the antenna based on the intermediate data stored in the second period T2, which is a period from the impact time to the end of the storage period, of the intermediate data stored in the storage unit. A separation speed calculation unit for calculating a separation speed for moving to
An object speed calculation unit that calculates an object speed, which is the speed of the object at the time of hitting, based on intermediate data corresponding to the time of hitting;
A speed measurement apparatus for a moving body, comprising: The conversion of the intermediate data by the detection unit is performed by obtaining a period of a binarized signal obtained by binarizing the Doppler signal as the intermediate data.
The speed measurement apparatus for a moving body according to claim 1. The conversion of the intermediate data by the detection unit obtains time-series frequency distribution data by performing continuous FFT processing on the Doppler signal, specifies time-series peak frequencies from these time-series frequency distribution data, and detects these peak frequencies. Is obtained as intermediate data,
The speed measurement apparatus for a moving body according to claim 1. The hit point specifying unit specifies a portion of the intermediate data stored in the storage unit where the rate of change is reversed from positive to negative or from negative to positive, and corresponds to the specified intermediate data portion. Specify the time as the hitting time,
4. The moving body speed measuring device according to claim 1, wherein the moving body speed measuring device is a moving body speed measuring device. The Doppler sensor outputs a first Doppler signal and a second Doppler signal that are 90 degrees out of phase,
The phase of the first Doppler signal and the phase of the second Doppler signal indicate whether the moving body is moving in a direction approaching the Doppler sensor or whether the moving body is moving in a direction away from the Doppler sensor. A direction discriminating unit that discriminates based on the relationship of
The hit point specifying unit specifies the hit point based on a determination result by the direction determining unit,
5. The moving body speed measuring apparatus according to claim 1, wherein the moving body speed measuring apparatus is a moving body speed measuring apparatus. A striking sound detector for detecting a striking sound generated when the object strikes the moving body,
The hitting time specifying unit specifies the hitting point based on detection of the hitting sound by the hitting sound detection unit,
6. The moving body speed measuring device according to claim 1, wherein the moving body speed measuring device is a moving body speed measuring device. Provided a flight distance calculation unit for calculating the flight distance of the moving body based on the separation speed,
The moving body speed measuring device according to claim 1, wherein the moving body speed measuring device is a moving body speed measuring device. A swing determination unit that determines the presence or absence of a swing of the object based on the number of peaks representing a frequency distribution obtained by performing a frequency analysis of the intermediate data stored in the storage unit;
The apparatus for measuring a speed of a moving body according to claim 3.

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