JP3427084B2 - Motion detection method and apparatus using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion detection method for detecting a moving object and specifying the movement of the object and an apparatus using the same, and more particularly to a variable for measuring a motion (movement distance, reciprocating motion). The present invention relates to a motion detection method and a device using the same, which are capable of accurately capturing (cycle, speed, etc.).

[0002]

2. Description of the Related Art A conventional motion detecting apparatus detects a temporal change from a phase difference between a high frequency signal of a single wavelength radiated from a transmitting and receiving antenna and a part of a high frequency signal reflected by a moving object and received. When capturing the movement of the object,
The distance (movement amount) and the way of movement of the object are limited to an extremely narrow range, and there is a drawback that the reliability of the detection result is low.

One of the reasons for this is that when the amount of movement of the object is sufficiently small for one wavelength of the high frequency signal, the output level of the phase comparator for detecting the phase difference is relatively low, resulting in high gain. When the amount of movement of the object is one wavelength or more of the high frequency signal, the output level of the phase comparator has the maximum amplitude, and therefore an amplifier having a wide dynamic range is required.

As a countermeasure for this, there is a method of changing the amplification factor of the amplifier according to the output level of the phase comparator, but there is a drawback that the circuit configuration becomes complicated and the noise of the amplifier itself becomes large.

On the other hand, when the amount of movement of the object is sufficiently small for one wavelength of the high frequency signal, the temporal change in the detected phase difference is proportional to the period of movement of the object. When the movement amount of the object is one wavelength or more, the temporal change of the detected signal becomes a very wide frequency band in proportion to the moving speed of the object. Phase comparators, amplifiers, etc. are required to have wide band characteristics.

As a countermeasure for this, there is a method of combining some phase comparators and amplifiers, but there is a drawback that the circuit configuration becomes complicated and it causes deterioration of detection accuracy.

[0007]

In the conventional motion detecting device described above, since the high frequency signal radiated from the transmitting / receiving antenna has a single wavelength, the moving amount and the moving manner of an arbitrary object are limited to a narrow range. The detection result has the drawback of low reliability.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks by selecting an oscillator having an appropriate wavelength from one or more oscillators which output a high frequency signal.
It is an object of the present invention to provide a motion detection device that expands the detectable range of the movement amount and the movement method of a moving object and improves the reliability of the detection result.

[0009]

According to the motion detecting method of the present invention, an oscillator having an appropriate output frequency (wavelength) is selected from two or more oscillators which output a high frequency signal, and the selected oscillator output signal is transmitted and received. The transmission signal radiated from the antenna to the space, the transmission signal radiated to the space and the reception signal reflected by the moving object and received by the transmission / reception antenna are phase-compared, and the phase comparison phase comparison signal is compared. Is the maximum amplitude value or less than the maximum amplitude value.
Determine the maximum output frequency or maximum
It is characterized by detecting a moving object and specifying the movement of the object based on the temporal change of the value less than the width .

In the phase comparison signal, the phase difference between the transmission signal and the reception signal is 0 to 180 degrees or 0.
It is characterized in that the maximum amplitude is obtained every time the angle changes from 360 degrees to 360 degrees.

Further, when the moving object reciprocates in a certain cycle, the oscillator output signal having a wavelength at which the phase comparison signal is less than the maximum amplitude is selected, and the time comparison of the phase comparison signal is performed. It is characterized in that the cycle is obtained from the change and the cycle in which the moving object reciprocates is specified.

Further, when the moving object is reciprocating within a certain movement width, the oscillator output signal having a wavelength at which the phase comparison signal is less than the maximum amplitude is selected, and the time of the phase comparison signal is selected. The amount of phase change is obtained from the dynamic change, and the moving width of the reciprocating motion of the moving object is specified from the amount of phase change and the selected wavelength of the oscillator output signal.

Further, when the moving object is moving at a certain speed, the oscillator output signal having a wavelength at which the phase comparison signal has a maximum amplitude is selected, and the phase change signal is cycled from a temporal change. Is obtained, and the speed at which the moving object is moving is specified from this cycle and the selected wavelength of the oscillator output signal.

Further, when the moving object is moving at a certain acceleration, the oscillator output signal having the wavelength at which the phase comparison signal has the maximum amplitude is selected, and the phase comparison signal is approached from the temporal change. It is characterized in that two acceleration cycles are obtained, and the acceleration of the moving object is specified from the two cycles and the selected wavelength of the oscillator output signal.

Further, the motion detecting apparatus of the present invention includes two or more oscillators that output a high frequency signal, a selector that selects one of these oscillators, and an oscillator output signal that is output from this selector as a phase reference signal. And a power distributor that distributes the transmission signal, a circulator that transmits the transmission signal in one direction, and a part of the transmission signal that is connected to the circulator and radiates the transmission signal into space and is reflected by a moving object. And a transmitting and receiving antenna to receive the received signal received by the transmitting and receiving antenna through the circulator to perform a phase comparison with the phase reference signal, and a phase comparison signal of the phase comparator output frequency band of the phase comparison signal. A limiting filter, an amplifier that amplifies the output of this filter, a signal processing unit that processes the output of this amplifier, and And a display unit for displaying the output of No. processor, for one of the oscillator but to identify the detected motion how the object of the object of the motion, the phase comparison signal
Is selected so that it has a maximum amplitude value or a value less than the maximum amplitude value .

Further, a control type oscillator having a variable output frequency used as the oscillator, a level detector for detecting the level of the phase comparison signal on the output side of the filter, and the output of the level detector are compared with a reference voltage. A control unit is provided, and the control unit controls the output frequency of the controlled oscillator so that the output voltage of the phase comparator can take a maximum amplitude value.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a motion detecting device of the present invention.

In the present embodiment shown in FIG. 1, first to nth oscillators 1 consisting of n (a positive integer) which outputs a high frequency signal, and a selector 2 for selecting one of these oscillators 1 are provided.
A power distributor 3 for distributing the oscillator output signal output from the selector 2 into a phase reference signal and a transmission signal; a circulator 4 for transmitting the transmission signal in one direction; and a transmission signal connected to the circulator 4 for radiating the transmission signal into space. Then, a transmitting / receiving antenna 5 for receiving a part of the transmitting signal reflected by a moving object, and a phase comparator 6 for inputting the receiving signal received by the transmitting / receiving antenna 5 through a circulator 4 and for phase comparison with a phase reference signal. A filter 7 that limits the frequency band of the phase comparison signal output from the phase comparator 6, an amplifier 8 that amplifies the output of the filter 7, a signal processing unit 9 that processes the output of the amplifier 8, and a signal processing unit. It is composed of a display unit 10 for displaying the output of 9.

Next, the motion detecting device of this embodiment is shown in FIG.
Will be described in detail with reference to.

Referring to FIG. 1, the n-th first to n-th oscillators 1 output high-frequency signals having different oscillator output frequencies (wavelengths).

The selector 2 selects the i-th oscillator output signal having a wavelength suitable for capturing the movement of an arbitrary object from the 1st to nth oscillators 1. If the oscillation frequency band of the oscillator is wide enough, one oscillator is enough,
At this time, the selector 2 is unnecessary.

The power distributor 3 distributes the oscillator output signal selected by the selector 2 into a transmission signal and a phase reference signal, and supplies the transmission signal to the transmission / reception antenna 5 and the phase reference signal to the phase comparator 6. .

The circulator 4 transmits the transmission signal distributed by the power distributor 3 and the reception signal received by the transmission / reception antenna 5 in opposite directions to ensure isolation.

The transmission / reception antenna 5 radiates the transmission signal passing through the circulator 4 into the space and receives a part of the transmission signal reflected by a moving object and sends it to the circulator 4.

The phase comparator 6 compares the phase reference signal distributed by the power distributor 3 with the reception signal received by the transmitting / receiving antenna 5 and passed through the circulator 4, and outputs a phase comparison signal.

The output of the phase comparator 6 has a phase difference determined by the distance from the transmitting / receiving antenna 5 to the moving object and the wavelength of the transmission signal (oscillator output signal) as a central value, and if there is a moving object, that Since the phase change amount proportional to the ratio of the movement width of the object and the wavelength of the transmission signal is added, it is desirable to correct the center value of this phase difference by selecting the wavelength of the transmission signal.

Further, the phase comparator 6 generally obtains a value in the range of maximum amplitude ± 1 at the output when the phase difference changes from 0 degree to 180 degrees or from 0 degree to 360 degrees.

The filter 7 is composed of a low-pass filter or a band-pass filter, and a frequency band for passing a frequency component based on the motion of the object is selected. For example, when an object reciprocates, the signal band is determined by its cycle, and when the object moves at a constant speed or acceleration, the signal band changes depending on the wavelength of the transmission signal. Therefore, the pass band of the filter 7 is determined in relation to the ratio of the distance (movement amount) the object has moved per unit time and the wavelength of the transmission signal.

The amplifier 8 amplifies the phase comparison signal passed through the filter 7 to a level that the signal processing section 9 can handle.

The signal processing unit 9 performs signal processing for displaying the phase comparison signal amplified by the amplifier 8 on the time axis or the frequency axis, and outputs the result.

The display unit 10 displays the result of signal processing by the signal processing unit 9.

Next, the relationship between the motion of the object and the time axis output waveform of the phase comparison result will be described.

FIG. 3 is a diagram showing the relationship between the phase difference between the transmission signal and the reception signal and the output of the phase comparator. Figure 3 (a)
Is the case where the distance between the transmitting and receiving antenna and the object is constant,
FIG. 3B shows the case where the distance is displaced in one direction,
FIG. 3C shows the case of reciprocating motion in a minute range.
(D) is a case where the object is moving at a certain constant velocity or acceleration.

Here, the wavelength of the transmission signal is λ, the distance from the transmitting / receiving antenna 5 to an arbitrary object is d, and the phase comparator 6 is a phase comparator having a cosine wave characteristic shown in FIG.
The electrical phase length from the emitting surface of the transmitting / receiving antenna 5 to the input end of the phase comparator 6 is ignored.

First, in the case where the position of the object that reflects the transmission signal does not change, such as a wall, as shown in FIG. 3A, the position of the transmission signal (phase reference signal) and the reception signal is changed. The phase difference θ is determined by the relationship between the distance d from the transmitting / receiving antenna 5 to the reflecting object and the wavelength λ of the transmission signal, and the output (phase comparison signal) of the phase comparator 6 corresponds to the phase difference θ between the transmission signal and the reception signal. The output level (indicated by Δ in the figure) is always constant.

Next, assuming that the position of the object that reflects the transmission signal is slightly closer to the transmitting / receiving antenna 5 side by Δd (Δd << λ << d), as shown in FIG.
The phase difference θ is twice the distance traveled by the object, 2Δ
The phase change amount Δθ corresponding to d is added to obtain θ + Δθ.

On the contrary, if the position of the object that reflects the transmission signal is slightly away from the transmitting / receiving antenna 5 by Δd, the phase difference θ is 2Δd, which is twice the distance traveled by the object. Δθ is subtracted and θ−
Δθ.

From the above, if the object reflecting the transmission signal moves continuously from the transmitting / receiving antenna 5 within the range of distance d ± Δd, the phase difference between the transmission signal and the reception signal is within the range of θ ± Δθ. Changes continuously. Therefore, as the output of the phase comparator 6 on the time axis, as shown in FIG. 3C, a repetitive waveform having an amplitude corresponding to the phase difference θ ± Δθ is obtained.

By detecting this repetitive waveform, it is found that there is a moving object within the radiation area of the transmitting / receiving antenna 5, and further, if the moving object moves periodically within the range of the distance d ± Δd, It is possible to obtain t1 as the movement cycle of the object.

Here, the following expression holds between the phase change amount Δθ associated with the movement of the object and the wavelength λ of the transmission signal.

[0041]

[Equation 1]

In equation (1), from the phase change amount Δθ obtained from the output of the phase comparator 6 and the wavelength λ of the transmission signal,
Δd, that is, the amount of movement of the moving object can be obtained.

At this time, when the phase comparator 6 has the cosine wave characteristic shown in FIG. 2, the wavelength of the transmission signal at which the central value of the phase difference change between the transmission signal and the reception signal is, for example, θ = 90 degrees. By selecting λ, the center value of the output of the phase comparator 6 becomes zero and the output dynamic range can be maximized. Further, it is also possible to select the wavelength λ of the transmission signal that allows the output of the phase comparator 6 to be larger, based on the condition that the output of the phase comparator 6 becomes zero.

As described above, in order to specify the movement amount of the moving object and its period, the wavelength λ of the transmission signal is appropriately selected, whereby the detection sensitivity of the phase comparator 6 is high and the detection accuracy is improved.

Next, an arbitrary object that reflects the transmitted signal is
A case will be described in which the movement amount Δd of one wavelength λ or more of the transmission signal is moved in a certain direction.

The amount of movement of the object is Δd = nλ / 2 (n:
In the case of (integer), the change amount Δθ of the phase difference between the transmission signal and the reception signal is an integral multiple of 360 degrees according to equation (1). That is, each time the object moves a distance of one half wavelength, the phase change amount Δθ advances by 360 degrees. Therefore, FIG.
(D), the output of the phase comparator 6 changes with the maximum amplitude.

If the period of time change of the phase difference is always constant, it is found that the object is moving at a constant velocity, and at this time, the object moves by a half wavelength. It took time. Assuming that this period is t2, the moving speed υ of the object is given by equation (2).

[0048]

[Equation 2]

Further, when the period is changing with time, it is found that the object is accelerating, and if two time-proximate periods are t3 and t4, respectively, the object is Acceleration and average velocity of (3)
Equation (4) is approximated.

[Equation 3]

[Equation 4]

From the above, by detecting the temporal change in the phase difference between the transmission signal and the reception signal, it is possible to detect a moving object and specify its movement.

That is, the method of selecting the wavelength λ of the transmission signal that is appropriate for the movement amount Δd and the movement speed υ of the object and the method of determining the movement of the object are different as follows.

First, when the object reciprocates in a certain cycle, the wavelength λ at which the phase comparator output is less than the maximum amplitude is selected, and the temporal change of the phase comparator output obtained at this time is selected. If the cycle t1 of is calculated, the cycle of reciprocating motion of the object can be obtained.

When the object reciprocates within a certain movement width, the wavelength λ at which the phase comparator output is less than the maximum amplitude is selected, and the phase comparator output temporally obtained at this time is selected. If the phase change amount Δθ is obtained from the change, the movement width of the reciprocating motion of the object can be obtained from the equation (1).

Here, the phase comparator output has an appropriate wavelength λ.
By selecting, the center value of the output can be corrected to the optimum level of zero and the maximum amplitude can be obtained. As a result, the signal can be detected without requiring an excessive amplification degree in the latter stage of the phase comparator, and the influence of saturation and noise of the amplifier can be minimized, so that the detection sensitivity is improved. Further, the range of movement width of the detectable object becomes wide.

Next, when the object is moving at a certain speed, the wavelength λ at which the phase comparator output has the maximum amplitude is selected, and the cycle of the temporal change of the phase comparator output obtained at this time is selected. If t2 is obtained, the moving speed of the object can be obtained from the equation (2).

When the object is moving at a certain acceleration, the wavelength λ at which the phase comparator output has the maximum amplitude is selected, and the time change of the phase comparator output obtained at this time is close to that. If the two cycles t3 and t4 are obtained, the acceleration of the object can be obtained from the equation (3).

Here, when the object is moving at a constant velocity or acceleration, the output of the phase comparator can be set to a band that is easy to read. That is, the phase comparator output becomes a signal in the high frequency region when the wavelength λ is sufficiently small with respect to the amount of movement of the object per unit time, and when the wavelength λ is sufficiently large with respect to the amount of movement of the object per unit time. Is a signal in the low frequency region.

In the conventional motion detecting device using a single wavelength, when the output of the phase comparator is a signal of several Hz, the frequency is not enough to pass through the capacitor, so special correction is made. Although circuit processing was required, by selecting an appropriate wavelength λ for the velocity υ or acceleration α of the moving object, the signal in the band where the filter and amplifier after the phase comparator can be easily set It can be handled, the configuration of the circuit connected after the phase comparator can be simplified, and detection sensitivity and detection accuracy can be improved.

FIG. 4 is a block diagram showing a second embodiment of the motion detecting device of the present invention.

Referring to FIG. 4, the second embodiment is as follows.
The first to nth oscillators 1 shown in FIG. 1 are replaced with first to nth controlled oscillators 11 having variable oscillation frequencies such as voltage controlled oscillators, and level detection is performed on the output side of a filter 7 for band limitation. And a control unit 13 for comparing the output of the level detector with a reference voltage and controlling the output frequency of the first to nth controlled oscillators 11.

In the second embodiment, the output of the phase comparator 6 is set at an optimum level by finely adjusting or selecting the wavelength λ of the transmission signal, and the detection sensitivity of the phase comparator 6 is high and the detection accuracy is high. Is improved.

[0062]

As described above, the motion detecting method of the present invention and the device using the same include a plurality of oscillators or frequency-variable oscillators, and transmit signals (oscillator output signals) are provided.
Since the frequency (wavelength) is selected, it is possible to expand the range in which a moving object is detected and how the object moves can be expanded, and the reliability of the detection result can be improved.

Further, since the frequency (wavelength) of the transmission signal (oscillator output signal) is selected, it is possible to handle the signal in a band in which the filter and amplifier in the latter stage of the phase comparator can be easily set, and the detection sensitivity is high. And the detection accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a motion detection device of the present invention.

FIG. 2 is a diagram showing an example of a phase comparator having a cosine wave characteristic.

FIG. 3 is a diagram showing a relationship between a phase difference between a transmission signal and a reception signal and a phase comparator output.

FIG. 4 is a block diagram showing another embodiment of the motion detection device of the present invention.

[Explanation of symbols]

1st to nth oscillators 2 selector 3 Power distributor 4 circulator 5 transmitting and receiving antenna 6 Phase comparator 7 filters 8 amplifier 9 Signal processing unit 10 Display 11 First to nth controlled oscillators 12 level detector 13 Control unit

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01S ^7/ 00-17/88

Claims (8)

(57) [Claims] 1. An oscillator having an appropriate output frequency (wavelength) is selected from two or more oscillators for outputting a high frequency signal, the selected oscillator output signal is radiated from a transmitting / receiving antenna into a space, and is radiated into this space. Phase comparison between the transmitted signal and the received signal reflected by a moving object and received by the transmitting / receiving antenna, and the phase comparison signal obtained by the phase comparison has the maximum amplitude value or the maximum amplitude.
Find the output frequency that is less than this value, and
Alternatively , a motion detection method characterized by detecting a moving object and identifying a moving method of the object based on a temporal change of a value less than the maximum amplitude . 2. The maximum amplitude of the phase comparison signal is obtained each time the phase difference between the transmission signal and the reception signal changes from 0 degree to 180 degrees or from 0 degree to 360 degrees. The described motion detection method. 3. When the moving object reciprocates in a certain cycle, the oscillator output signal having a wavelength at which the phase comparison signal is less than the maximum amplitude is selected, and the time comparison of the phase comparison signal is performed. 3. The motion detection method according to claim 1, wherein a cycle is obtained from the change, and a cycle in which the moving object reciprocates is specified. 4. The oscillator output signal having a wavelength at which the phase comparison signal is less than the maximum amplitude is selected when the moving object reciprocates with a certain movement width, and the time of the phase comparison signal is selected. 2. The phase change amount is obtained from the dynamic change, and the moving width of the reciprocating motion of the moving object is specified from the phase change amount and the selected wavelength of the oscillator output signal. 2. The motion detection method described in 2. 5. When the moving object is moving at a certain speed, the oscillator output signal having a wavelength at which the phase comparison signal has the maximum amplitude is selected, and a cycle is selected from a time change of the phase comparison signal. And determining the speed at which the moving object is moving from this cycle and the wavelength of the selected oscillator output signal.
The described motion detection method. 6. When the moving object is moving at a certain acceleration, the oscillator output signal having a wavelength at which the phase comparison signal has the maximum amplitude is selected, and the phase comparison signal is approximated from a temporal change. 3. The motion detection according to claim 1 or 2, characterized in that the acceleration of the moving object is specified from the two cycles and the wavelength of the selected oscillator output signal. Method. 7. An oscillator for outputting a high frequency signal, two or more oscillators, a selector for selecting one of these oscillators, and an electric power distribution for distributing an oscillator output signal output from the selector to a phase reference signal and a transmission signal. A circulator for transmitting the transmission signal in one direction, a transmitting / receiving antenna connected to the circulator for receiving the transmission signal in space and receiving a part of the transmission signal reflected by a moving object, A phase comparator for inputting a received signal received by a transmission / reception antenna through the circulator for phase comparison with the phase reference signal, a filter for limiting a frequency band to a phase comparison signal output from the phase comparator, and this filter An amplifier that amplifies the output of the amplifier, a signal processing unit that processes the output of the amplifier, and a display that displays the output of the signal processing unit. The phase comparison signal has a maximum amplitude value or a maximum oscillation value in order to detect one of the moving objects and specify how the object moves.
A motion detection device characterized by being selected to be a value less than the width . 8. A control type oscillator having a variable output frequency used as said oscillator, a level detector on the output side of said filter for detecting the level of said phase comparison signal, and the output of this level detector is compared with a reference voltage. 8. The motion detecting apparatus according to claim 7, further comprising a control unit, which controls the output frequency of the controlled oscillator so that the output voltage of the phase comparator can take a maximum amplitude value.