JPH0346138B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a head sway meter for measuring the balance state of a human being.

[Conventional technology]

BACKGROUND ART Conventionally, human equilibrium state has been measured in fields such as medicine and psychology. Conventionally, a center of gravity measuring device has been used to continuously measure the movement of a person's center of gravity to measure the balance state of the person. That is, this center of gravity measuring device is constructed by arranging a large number of pressure sensors in a matrix on a measuring table, and when a person stands upright on the measuring table,
Based on the person's weight, the pressure detection outputs received by each pressure sensor from both feet are processed to continuously measure the movement of the person's center of gravity. Then, based on the results of such arithmetic processing,
On the CRT screen of the monitor receiver, images of the soles of the human's feet and the movement of the projected point of the human's center of gravity on the measuring table were projected.

[Problem to be solved by the invention]

By the way, when measuring a human's equilibrium state using such a center of gravity measuring device, although it is possible to measure rough changes in the equilibrium state, it is difficult to measure minute changes in the equilibrium state.

In view of this, the present invention aims to improve the human equilibrium state by
The purpose is to provide a measuring device that can perform measurements with high precision.

[Means to solve the problem]

The head motion meter according to the present invention is used by being attached to a predetermined part of the head M of a subject, and includes a transmitter 1 {4x, 4y} that emits ultrasonic waves in a plurality of directions;
In order to receive the ultrasonic waves in each direction emitted from the transmitter 1 {4x, 4y}, a plurality of receivers 5x, 5y and a plurality of receivers 5 are attached to a fixed part.
It has a plurality of phase detection circuits 10x, 10y that separately detect the phase difference of each received signal from x, 5y with respect to each reference received signal at a common reference time, and from the plurality of phase detection circuits 10x, 10y. The state of head movement of the subject is measured based on the phase detection output.

[Operation] According to the present invention described above, ultrasonic waves emitted in a plurality of directions from the transmitters 4x and 4y that emit ultrasonic waves in a plurality of directions are attached to a predetermined part of the head M of the subject. , are received by a plurality of receivers 5x and 5y attached to a fixed part, and the phase difference of each received signal from the plurality of receivers 5x and 5y with respect to each reference received signal at a common reference time is calculated as follows: A plurality of phase detection circuits 10x and 10y detect each phase separately, thereby measuring the state of head movement of the subject.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. M indicates the head of a human subject, viewed from above. Reference numeral 1 denotes an ultrasonic transmitter, which is composed of a pair of ultrasonic transmitters 5x and 5y each having unidirectionality. Attach it to the center. Then, a fixed orthogonal coordinate system in a horizontal plane including the center of the forehead is set in space, and the directivity directions of the transmitters 5x and 5y are, for example, the +x axis (direction of the right ear) and the +y axis direction (direction of the nose), respectively. These transmitters 5x and 5y are arranged so that they match. Note that the mounting positions of the transmitters 5x and 5y are approximately the origin of the orthogonal coordinate system, but are not necessarily limited to this.

Then, on the +x axis and +y axis of this orthogonal coordinate system, respectively, at fixed positions at arbitrary distances from the origin,
An X-axis receiver 5x and a Y-axis receiver 5y are arranged to receive the ultrasonic waves transmitted from the above-mentioned transmitters 4x and 4y, respectively.

2 is a clock generation circuit, which, as shown in FIG. 2, divides the clock signal φ0 (see FIG. 4A) generated from a crystal oscillator 2a having an oscillation frequency of 12.8 MHz to 1/16 by dividing period 2b. By dividing the frequency, a clock signal φ1 (see FIG. 4B) having a frequency of 800 kHz and a phase of 0° is obtained, and the frequency divider 2c
Divide the frequency to 1/16, and similarly, the frequency is 800kHz,
A clock signal φ2 (see FIG. 4C) whose phase is 90° ahead of the clock signal φ1 is obtained. And furthermore,
The frequency of the clock signal φ1 is divided by 1/20 by a frequency divider 2d to obtain a 40 kHz clock signal F (see FIG. 4D). This clock signal F is then passed through the ultrasonic transducer driver 3 shown in FIG. 1 to the ultrasonic transmitter 4.
Supply to x, 4y. In addition, the clock signals φ0, φ
1 and φ2 are the X phase detection circuit 10x and Y
The signals are respectively supplied to the phase detection circuit 10y.

Received signals (sine wave signals) from the X- and Y-axis receivers 5x and 5y are supplied to pulse generators 7x and 7y through input amplifiers 6x and 6y, respectively, where they are converted into pulse signals and have a low input level. The signal is supplied to the detection circuit 8.

Then, the received pulse signals Px and Py from the pulse generators 7x and 7y are transmitted to the X and Y phase detection circuits 1, respectively.
Supplied to 0x, 10y.

x phase detection circuit 10x and Y phase detection circuit 10
y are each constructed of a circuit as shown in FIG. 3, which can detect the phase with high precision. Incidentally, to avoid redundant explanation, illustration and explanation of the Y phase detection circuit 10y will be omitted.

The X phase detection circuit 10x detects the amount of movement of the head in the left and right directions [the Y phase detection circuit 10y detects the amount of movement in the front and back of the head]. Below, according to Figure 3,
The X direction detection circuit 10x will be explained.

Reference numeral 10a designates a monostable multivibrator which, using the received pulse signal Px (see FIG. 41F) supplied from the pulse generation circuit 7x as a trigger, counts eight clock signals φ0 supplied from the clock generation circuit 2. One-shot pulse Ps having a pulse width of 8 cycles of clock signal φ0 (see Figure 4G)
to occur. The received pulse signal Px is generated in synchronization with the zero-crossing point of the received signal (see FIG. 4E and FIG. 5C).

10b and 10c are AND circuits, respectively. As shown in FIG. 6, the AND circuit 10b multiplies the clock signal φ1 and the one shot pulse Ps, and further multiplies this multiplication result by the clock signal φ0 to generate the clock signal φ1'. (see FIG. 41H) is generated, and the AND circuit 10c multiplies the clock signal φ2 and the one shot pulse Ps,
Further, this multiplication result is multiplied by the clock signal φ0 to generate the clock signal φ2' (see FIG. 41I). And Figure 5A
As shown in FIG.
It is assumed that the waveform of the received signal when the position x is at a certain position R is the solid line S ₀ in FIG. 5C. Then, as shown in FIG. 5A, the transmitter 4x is connected to the receiver 5.
x (the subject's head moves to the right in Figure 1), the subject's head moves to the left with respect to the received signal _S0 , as shown by the broken line _S1 in Figure 5C, and moves away (the subject's head moves to the right). The subject's head moves to the left in Figure 1) and Figure 5C.
As shown by the broken line S ₂ , it moves to the right with respect to the received signal S ₀ . The received pulse signal Px is a positive pulse generated at the zero cross position of this received signal. The one-shot pulse Ps is a positive pulse generated in synchronization with the falling edge of the received pulse signal. Therefore, the numbers of clock signals φ1' and φ2' supplied to the counters 10d and 10e, respectively, change as shown in FIGS. 7A to D when the transmitter 4x moves away from the receiver 5x. (Illustration of cases where the distance is short is omitted). The clock signals φ1' and φ2' from the AND circuits 10b and 10c are applied to the counters 10d and 1, respectively.
They are respectively supplied to clock signal input terminals CK of 0e. Then, the counters 10d and 10e are set when the received pulse signal Px supplied to the reset terminal R is "H".
Then, the clock signals φ1' and φ2' are counted respectively, and the counted values (see J and K in FIG. 4) are sent to the comparators 10h and 10i.
and input terminals A of comparators 10j and 10k, respectively.

Comparators 10h and 10j compare whether or not the count value is greater than a reference value "2" set by switch 10g supplied to input terminal B, respectively.
The comparison results are outputted from the "A>B" terminals (see FIG. 4L, however, the comparator 10j is not shown), and the count values of the comparators 10i and 10k are supplied to the input terminals B, respectively. A comparison is made to see if it is smaller than a reference value "4" set by the switch 10f, and the comparison results are output from the "A<B" terminals (none of which are shown). And comparator 10
The comparison results output from the “A>B” terminals of h and 10j, respectively, are sent to flip-flop circuits 10p and 10j.
are respectively supplied to the input terminal D of 0q, and
Comparator 10i via AND circuits 10l and 10n
and the comparison results output from the "A<B" terminals of 10k, respectively. That is, when the AND circuits 10l, 10n do not output a signal at the "H" level, the count values of the counters 10d, 10e are "3"(=4>A>2). and,
These multiplication results are multiplied by the received pulse signal Px via AND circuits 10m and 10o, respectively, and supplied to the clock input terminals CK of flip-flop circuits 10p and 10q, so that the counted values of counters 10d and 10e are calculated as described above. Except for the case of “3”, the direction signal P ₁ (Fig. 4 M
) and a speed signal P ₂ (not shown in FIG. 4, but at "L" level) are output, respectively.
Note that when the counter values of the counters 10d and 10e are "3", the direction signal _P1 and the speed signal _P2 are not output. That is, by providing a hysteresis width, this provides an insensitive area to noise and the like, thereby stabilizing the detection operation.

Therefore, in FIG. 7A, the clock signal φ
By counting 1', the count value of the counter 10d becomes "6", and by counting the clock signal φ2', the count value of the counter 10e becomes "2". The direction signal _P1 generated at the output terminal out1 becomes “H” level, and the output terminal
The speed signal _P2 generated at out2 becomes "L" level. In addition, in the case of FIG. 7B and C, the counter 10d,
Although the count value of 10e is different from that of Fig. 7A,
Again, the direction signal P ₁ becomes "H" level, and the speed signal P ₂ becomes "L" level. If the one-shot pulse Ps shown in Fig. 6 is further shifted to the right [the distance between the transmitter 4x and the receiver 5x is further increased] and becomes as shown in Fig. 7D, the clock pulse By counting the signal φ1', the counter 10
The count value of d becomes "7", and the clock signal φ2'
By counting , the count value of the counter 10e becomes "5", and in this case, the direction signal _P1 generated at the output terminal out1 becomes "H" level, and the direction signal P generated at the output terminal out2 becomes "H" level. ₂ becomes "H" level.

Then, as the distance between the ultrasonic transmitter 4x and the X-axis receiver 5x gradually decreases, the one-shot pulse Ps gradually shifts to the left and the number of clock signals φ1' decreases, as shown in FIG. , when the count value becomes smaller than "2", the direction signal _P1 generated at the output terminal out1 becomes "L" level. Therefore, when the subject's head M moves and the distance between the ultrasonic transmitters 4x, 4y and the receivers 5x, 5y becomes longer than the distance at the reference position, " The H" level direction signal _P1 is supplied to the movement amount counters 11x and 11y in FIG. 1, respectively, and when the distance becomes short, the phase detection circuits 10x,
Direction signal P ₁ of "H" level from 10y
The data are supplied to movement amount counters 11x and 11y in the figure, respectively.

Then, the movement amount counters 11x, 11y are reset by closing the counter reset switch 13, and then the phase detection circuits 10x, 10y are reset.
When the direction signal _P1 supplied from the
The speed signals _P2 supplied from 0x and 10y are counted up, respectively, and the phase detection circuits 10x and 10y
When the direction signal _P1 supplied from the
The speed signals _P2 supplied from 0x and 10y are counted down respectively.

In FIG. 1, the low input level detection circuit 8 is
If the positions of the transmitters 4x and 4y deviate significantly from the origin of the orthogonal coordinate system, or if their ultrasonic wave transmission directions have a significant angular deviation from the x-axis and y-axis, respectively, It is detected that the amplitudes of the received signals supplied from the input amplifier 6x and the Y input amplifier 6y are below a predetermined level, and a count prohibition signal NC is sent to the movement amount counter 11x and the Y movement amount counter 11y, which will be described later, respectively. At the same time, an indication signal is supplied to a reception failure indicator (for example, an LED) 9.

Further, the count outputs of the X and Y movement amount counters 11x and 11y are supplied to D/A converters 12x and 12y, respectively, and oscillation amount outputs converted into analog signals are obtained from output terminals outx and outy, respectively. Since the frequency of the clock signal F is 40 kHz, the wavelength of the ultrasonic waves transmitted from the transmitters 4x and 4y is approximately 9 mm. Since a change in phase is detected for each half wavelength of the 800 kHz clock signals φ1 and φ2, which have a frequency 20 times that of this clock signal F, the movement counters 11x and 1
One count of 1y corresponds to 0.225mm. Therefore, the amount of movement of the subject's head M is
It can measure with a resolution of 0.225mm. and,
By changing the number of bits in the movement counters 11x and 11y, the maximum measurement range can be varied.

Now, in order to measure the movement of the subject's head M using the above-mentioned head movement device, first, the ultrasonic transducer driver 3 receives a clock signal F (40kHz).
is supplied from the clock signal generation circuit 2 and amplified, and the amplified clock signal F is sent to the ultrasonic transmitter 4 fixed to the head M of the subject.
x, 4y to excite these transmitters 4x, 4y.
The ultrasonic wave transmitted from 4y is radiated toward receivers 5x and 5y respectively attached to the fixed part.
By closing the counter reset switch 13 at any time, the movement amount counter 11 is reset.
Initialize the count values of x and 11y, that is, set them to zero. At this time, one of the transmitters 4x and 4y is set as a reference position. Then, the receivers 6x and 6y attached to the fixed part receive the ultrasonic waves, respectively, and the received ultrasonic waves are sent to the input amplifiers 6x and 6 as reception signals.
The signals are supplied to the pulse forming circuits 7x, 7y and the low input level detection circuit 8 via the signal line y. Then, the low input level detection circuit 8 detects movement counters 11x and 11 in order to eliminate received signals with amplitudes that do not reach the reference value.
y count prohibition signal is supplied, and a reception impossible signal is supplied to the reception impossible display 9 to display the reception impossible state.

The received pulse signals Px and Py, which have been pulsed through the pulse generators 7x and 7y, are supplied to phase detection circuits 10x and 10y, respectively.

The phase detection circuits 10x and 10y generate one-shot pulses Ps in synchronization with the received pulse signals Px and Py, respectively, and the clock generation circuit 2
By multiplying and counting the clocks φ0, φ1, and φ2 supplied from φ0, φ1, and φ2, the moving direction and speed are respectively detected, and as a direction signal _P1 and a speed signal _P2 ,
It is supplied to movement amount counters 11x and 11y, respectively.
The digital count signals of the movement amount counters 11x, 11y are then converted into digital count signals of the D/A converters 12x, 1
2y are respectively converted into analog signals.

Furthermore, by supplying the analog counting signals output from the D/A converters 12x and 12y, respectively, to a plotter, the amount of oscillation can be depicted, and the digital counting signals of the movement amount counters 11x and 11y can be /A converter 12x, 12
It is also possible to perform diagnostic processing on the subject by transmitting the data to a computer or the like via an RS-232C interface, etc., without passing through the y.

In addition, in Fig. 1, the amount of head movement is set two-dimensionally, but as shown in Fig. 8, the amount of head movement is set two-dimensionally.
In the illustrated embodiment, Z
An ultrasonic transmitter 4 with additional axes to provide a three-axis orthogonal coordinate system of x, y, and z, and having a directivity direction in the z-axis direction.
It is also possible to perform three-dimensional measurements by adding a Z-axis wave receiver 5z to a fixed part on an extension of the Z-axis.

Furthermore, the subject may be standing or sitting on a chair.

Furthermore, four or more ultrasonic transmitters and four or more ultrasonic receivers may be provided.

〔Effect of the invention〕

According to the present invention described above, when measuring the agitation state of a subject, a transmitter that emits ultrasonic waves in multiple directions is attached to the head M of the subject, and the transmitter emits ultrasonic waves in multiple directions. In order to receive the ultrasonic waves emitted from the By separately detecting the phase difference using multiple phase detection circuits,
The state of head movement of the subject can be measured with high precision.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing its clock generation circuit, FIG. 3 is a block diagram showing its position detection circuit, and FIGS. 7 and 7 are timing charts for explaining the embodiment, FIG. 5 is a diagram for explaining the operation of the embodiment, and FIG. 8 is a diagram showing a part of another embodiment of the present invention. It is. 1 is an ultrasonic transmitter, 2 is a clock generation circuit, 3
is an ultrasonic transducer driver, 4x, 4y, 4z are ultrasonic transmitters, 5x is an X-axis receiver, 5y is a Y-axis receiver, 5z is a Z-axis receiver, 6x is an X-input amplifier,
6y is a Y input amplifier, 7x and 7y are pulsing circuits, 8 is a low input level detection circuit, 9 is a reception failure indicator, 10x is an X phase detection circuit, 10y is a Y phase detection circuit, 11x is an X movement amount counter, 11y is a Y movement amount counter, 12x and 12y are D/A converters, 13 is a counter reset switch, 2a
is a crystal oscillator, 2b and 2c are 1/16 frequency dividers, 2
d is a 1/20 frequency divider, 10a is a monostable multivibrator, 10b, 10c, 10l, 10m, 10n
and 10o are AND circuits, 10d and 10e are counters, 10f and 10g are switches, 10h,
10i, 10j and 10k are comparators, and 10p and 10q are flip-flop circuits.

Claims (1)

[Scope of Claims] 1. A transmitter that is used by being attached to a predetermined part of the subject's head and emits ultrasonic waves in multiple directions; and ultrasonic waves that are emitted from the transmitter in each direction. a plurality of receivers attached to a fixed part in order to receive the signal; and detecting the phase difference of each received signal from the plurality of receivers with respect to each reference received signal at a common reference time point. A head motion meter comprising: a plurality of phase detection circuits; and a head motion state of the subject is measured by phase detection outputs from the plurality of phase detection circuits.