JP2014048049A - Movement detection device - Google Patents

Abstract

An object of the present invention is to realize a device for detecting a fine movement of a moving object in a non-contact manner.
A radiator has a transmitting antenna that radiates microwaves, and a phase difference detector has receiving antennas that receive microwaves. A change in multipath due to the movement of the fingertip of the hand located between the transmitting antenna 13 and the receiving antennas 20A and 20B causes a phase difference in signals received by the receiving antennas 20A and 20B. The phase difference detector 2 detects the movement of the fingertip of the hand by detecting the phase difference. The reason why the motion detection apparatus according to the first embodiment has a high resolution is that even if a minute multipath change due to a fine movement is performed using a microwave, the phase difference is a large value.
[Selection] Figure 1

Description

  The present invention relates to a motion detection device that detects a motion of a moving body in a non-contact manner, and more particularly to a device that has a high motion resolution and can detect, for example, the motion of a fingertip of a hand.

  Conventionally, there are devices such as a mouse and a touch panel display as devices for measuring the position of a specific part of the human body, for example, the position of the hand, but these all require contact with the human body. It cannot be measured.

  As a device for detecting a specific position of a human body in a non-contact manner, a musical instrument called a theremin is well known. Theremin has an antenna connected to an oscillation circuit. The oscillation frequency is changed by changing the capacitance due to the relative distance between the antenna and the human body, and the beat of the frequency between the oscillation frequency and the reference frequency is converted into sound. It is a musical instrument.

  Patent Documents 1 and 2 are examples of position measuring devices that use the principle of theremin. In Patent Document 1, a plurality of first antennas arranged in parallel along a first direction and a plurality of second antennas arranged in parallel along a second direction orthogonal to the first direction are configured. A sensor device having an antenna panel is shown. The sensor device is provided with one oscillation circuit that is connected to the first and second antennas with a switch, and when the fingertip of the person approaches the antenna panel, the first antenna and the oscillation circuit are connected. Then, the coordinates in the first direction are determined from the change in the oscillation frequency, and the second direction coordinates are determined from the change in the oscillation frequency by switching to the connection between the second antenna and the oscillation circuit. The position of a human fingertip can be detected without contact. Patent Document 2 discloses a non-contact sensor having an operation principle similar to that of Theremin, in which an antenna is spherical. By making the antenna spherical, fluctuations in capacitance due to differences in hand position can be suppressed, and the oscillation frequency is stabilized, so that the distance between the hand and the antenna can be detected with high accuracy.

  Further, humans communicate with each other using hand gestures, and attempts have been made to apply such hand gestures to operations of electronic devices and the like. As a method for detecting a difference in hand gesture, in other words, a difference in the shape of a human hand (for example, a difference between goo and par), there is a technique of Non-Patent Document 1. Non-Patent Document 1 describes that a hand shape is detected by photographing a hand shape with a camera, extracting the hand shape from an image, and comparing it with pre-registered teacher data. .

JP 2010-139280 A JP 2011-118156 A

Kenichi Fukaya, “Operating a Mobile Robot Using Hand Gestures”, Hokkai Gakuen University Faculty of Engineering Research Report, 2010-02-22

  When an operation of an electronic device or the like is performed using a hand gesture, it is necessary to detect the position of the hand and the movement of the fingertip. However, the hand gesture detection method described in Non-Patent Document 1 requires an image sensor such as a camera, and there is a problem that the hand gesture cannot be detected depending on the surrounding brightness and the background image. Also, the sensor cannot be covered with plastic or cloth so that it cannot be touched by human eyes, and the aesthetic appearance cannot be impaired.

  Further, in the hand position detection according to Patent Documents 1 and 2, even if it is desired to measure the hand position of a specific person, the specific person cannot be distinguished from other persons, and the person can be selectively selected. You can't measure the position of your hand. Further, it is not possible to detect fine movements such as finger movements.

  Accordingly, the present invention is to provide a motion detection device that can detect the motion of a moving body in a non-contact manner and has a high resolution for motion detection.

  According to a first aspect of the present invention, there is provided a motion detection device that detects a motion of a moving body in a non-contact manner, from a transmission antenna that radiates microwaves and a transmission antenna that is spaced apart from each other and spaced from the transmission antenna. Having two receiving antennas for receiving microwaves and a detector for receiving the microwaves by the two receiving antennas and detecting a phase difference between the two received signals. A motion detection device that detects motion of a moving object in a motion detection region between a transmission antenna and a reception antenna from a phase difference.

  According to a second aspect of the present invention, in the motion detection device that detects the motion of the moving body in a non-contact manner, the two transmission antennas that are spaced apart from each other that radiate microwaves are disposed apart from the transmission antenna. A reception antenna that receives the microwave from the transmission antenna, and receives the signal reflecting the phase difference between the microwave from one transmission antenna and the microwave from the other transmission antenna by the reception antenna; The motion detection device detects motion of a moving object in a motion detection region between a transmission antenna and a reception antenna from the phase difference.

  In the invention according to claims 1 and 2, the microwave is an electromagnetic wave having a frequency of 300 MHz to 3 THz. A desirable frequency is 2.0 to 6.0 GHz from the viewpoint of availability of an oscillator that oscillates at a high frequency.

  The signal received by the receiving antenna may be down-converted so that the phase difference can be easily detected, or the phase may be expanded using a PLL circuit.

The detector in the invention according to claim 1 can be configured as in the inventions according to claims 3 and 4 below, for example. If comprised like 4th invention, offset will be stabilized and the measurement precision of a position can be improved. Further, if configured as in the third invention, the position measurement accuracy is lowered, but the configuration is simplified, so that the cost of the apparatus can be reduced.
Moreover, in the invention which concerns on Claim 2, it comprises like the invention which concerns on the following Claim 6, for example, and can extract a phase difference.

  According to a third aspect of the present invention, the detector includes a multiplier that multiplies and outputs the two received signals, and a first low-pass filter that outputs a high-frequency component cut out of the output of the multiplier. The motion detection device according to claim 1.

  Each receiving antenna and the multiplier need not be directly connected, and may be configured to be indirectly connected by inserting an amplifier, a band-pass filter, or the like.

  According to a fourth aspect of the present invention, the detector includes a first phase shifter to which a signal from one of the receiving antennas is input, and a signal from the other of the receiving antenna to which the phase shift amount is the first phase shifter. A first phase shifter that is equal to and a first multiplier that multiplies a signal received by one of the receiving antennas and a signal received by the other of the receiving antennas and phase-shifted by the second phase shifter, and outputs A second multiplier that multiplies a signal received by one of the receiving antennas and phase-shifted by the first phase shifter and a signal received by the other of the receiving antenna, and an output of the first multiplier; A first subtractor that takes a difference from the output of the second multiplier, and a first low-pass filter that outputs a high frequency component out of the output of the first subtractor. 1. The motion detection device according to 1.

  One of the receiving antennas and the first phase shifter or the first multiplier, the other of the receiving antennas and the second phase shifter or the second multiplier, the first phase shifter and the second multiplier, the second phase shifter and the first The sections of the first multiplier, the first and second multipliers, and the subtractor need not be directly connected, and may be configured to be indirectly connected by inserting an amplifier, a bandpass filter, or the like.

  The invention according to claim 5 is the motion detection device according to claim 4, wherein the amount of phase shift of the first phase shifter and the second phase shifter is 90 °.

  The invention according to claim 6 further includes: a non-linear element that squares and outputs a signal from the receiving antenna; and a first low-pass filter that outputs a high-frequency component out of the output of the non-linear element. The motion detection device according to claim 2, wherein

  The receiving antenna and the nonlinear element do not need to be directly connected, and may be configured to be indirectly connected by inserting an amplifier, a bandpass filter, or the like.

  In addition to the motion detection device of the present invention, a position measurement device that measures the position of the moving object in the motion detection region in a non-contact manner is configured to constitute a position motion detection device that detects both the position and motion of the moving object in a non-contact manner May be. The position measuring device includes an exciter for propagating an electromagnetic field on the surface of a moving body, a first electrode and a second electrode that are spaced apart from the moving body and spaced apart from each other to include a motion detection region. And an electromagnetic field fluctuation detector for measuring the position of the moving body from the phase difference of the electromagnetic field reaching the electrode and the second electrode.

  By providing such a position measuring device, it is possible to detect the position of the moving object, to detect only the position of the moving object excited by the exciter, and not to detect other moving objects. it can. That is, the position can be detected by distinguishing a specific moving body from other moving bodies.

  The exciter is only required to be attached to a position where electromagnetic waves can be propagated to the surface of the moving body, and may be directly attached to the moving body, or may be attached to another object that contacts the moving body. The oscillation frequency of the exciter is, for example, 1 to 100 MHz in a frequency band where an electromagnetic field can propagate on the human body surface.

The electromagnetic field fluctuation detector can be configured as follows, for example.
The electromagnetic field variation detector receives the third phase shifter connected to the first electrode, the fourth phase shifter connected to the second electrode and having the same phase shift amount as the third phase shifter, and the first electrode. A third multiplier that multiplies the signal and a signal received by the second electrode and phase-shifted by the fourth phase shifter, and a signal received by the first electrode and phase-shifted by the third phase shifter. A fourth multiplier that multiplies the received signal by the signal received by the second electrode and outputs the result, a second subtractor that takes a difference between the output of the third multiplier and the output of the fourth multiplier, A second low-pass filter that cuts out and outputs a high-frequency component of the output of one subtractor.
If comprised in this way, offset will be stabilized and the measurement accuracy of a position can be improved.

  In the configuration of the electromagnetic field fluctuation detector, the amount of phase shift of the third phase shifter and the fourth phase shifter is preferably 90 °. This is because the position detection accuracy is improved because the output of the electromagnetic field fluctuation detector is maximized and the offset is stabilized.

  In the present invention, the moving body for detecting the movement is a part of a human body such as a human hand, and can be used for detecting the movement of an animal other than a human. It can also be used to detect the movement of a robot or the like.

  According to the present invention, a change in multipath due to the motion of a moving object can be detected as a phase difference between signals, so that the motion of the moving object can be detected without contact. In particular, since microwave radiation is used, the operation can be detected with high resolution. For example, a fine movement such as a finger movement of a hand can be detected without contact. According to the ninth aspect of the invention, it is possible to distinguish a specific moving object from other moving objects and detect the position of the specific moving object. For example, since both hand movement (hand position) and finger movement can be detected in a non-contact manner, it is possible to detect a hand gesture and operate a device in accordance with the gesture.

The figure which showed the structure of the operation | movement detection apparatus 1 of Example 1. FIG. The figure which showed the structure of the other phase difference detector. The figure which showed the structure of the position operation | movement detection apparatus of Example 2. FIG. The figure which showed the structure of the position measuring apparatus 3. FIG. The graph which showed the result of having detected the motion of a human hand using the position motion detection apparatus of Example 2. FIG. FIG. 5 is a diagram illustrating a configuration of an operation detection device according to a third embodiment.

  Hereinafter, specific examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the examples.

  FIG. 1 is a diagram illustrating the configuration of the motion detection apparatus 1 according to the first embodiment. The operation detection apparatus 1 according to the first embodiment includes a radiator 7 and a phase difference detector 2.

[Configuration of radiator 7]
As shown in FIG. 1, the radiator 7 includes an oscillator 10 and a transmission antenna 13 connected to the oscillator 10 via a band pass filter 11 and an amplifier 12. The band pass filter 11 transmits only the frequency band of the electric signal oscillated by the oscillator 10, and the amplifier 12 amplifies the electric signal in the transmission band. These bandpass filter 11 and amplifier 12 are not necessarily required, but it is desirable to provide them in order to remove noise and the like to increase the output and improve the operation sensitivity of the operation detection apparatus 1 of the first embodiment. . The electric signal amplified by the amplifier 12 is radiated from the transmitting antenna 13 to the space as an electromagnetic wave.

  The radiator 7 is installed in the vicinity of a place where it is desired to detect the movement of a human fingertip. The oscillator 10 only needs to oscillate microwaves, and has an oscillation frequency of 300 MHz to 3 THz, for example. With a microwave, motion detection can be performed with high resolution. That is, it is possible to detect the movement of a small part such as the movement of the fingertip of the hand. From the point of availability of the oscillator 10 capable of oscillating at a high frequency, 2.0 to 6.0 GHz is desirable.

[Configuration of Phase Difference Detector 2]
As shown in FIG. 1, the phase difference detector 2 is provided with two receiving antennas 20A and 20B which are located at a predetermined distance from the transmitting antenna 13 of the radiator 7 and are provided apart from each other. doing. In addition, the transmission antenna 13 and the reception antennas 20A and B are arranged so that an area where the transmission antenna 13 and the reception antennas 20A and B are connected overlaps an area (motion detection area) where it is desired to detect finger movement. With such an arrangement, the distance between the transmitting antenna 13 and the receiving antennas 20A and 20B and the distance between the receiving antennas 20A and 20B are arbitrary. The electric signals from the antenna 13 are received by the two antennas 20A and 20B. The antennas 20A and 20B are connected to the input sides of the multipliers 23A and 23B through band pass filters 21A and 21B and amplifiers 22A and 22B, respectively. The bandpass filters 21A and B transmit only the oscillation frequency band of the oscillator 10, and the amplifiers 22A and 22A amplify electric signals from the bandpass filters 21A and B, respectively.

  A PLL (Phase-locked loop) circuit 24 is commonly connected to the other input side of the multipliers 23A and 23B. The PLL circuit 24 generates a signal whose frequency is close to the oscillation frequency of the oscillator 10. In the multipliers 23A and 23B, the phase of the electrical signal received by the antenna 20A is compared with the phase of the electrical signal received by the antenna 20B by multiplying the electrical signal from the antennas 20A and 20B by the signal from the PLL circuit 24. Down-converted to easy intermediate frequency electrical signal.

  Note that down-conversion using the multipliers 23A and 23B and the PLL circuit 24 is not always necessary. In the case where the oscillator 10 having a low oscillation frequency is used, the multipliers 23A, B and the PLL circuit 24 may be omitted.

  The output sides of the multipliers 23A and B are connected to the two input sides of the multiplier 28 via bandpass filters 25A and 25 and amplifiers 27A and 27B, respectively. The bandpass filters 25A and 25B transmit only signals in the intermediate frequency band. The amplifiers 27A and B amplify the electric signals from the PLL circuits 26A and B. The multiplier 28 multiplies the electric signals from the amplifiers 27A and 27B and outputs the result. Then, after being amplified by the amplifier 26, the difference signal is extracted by the low-pass filter 29 out of the sum signal and the difference signal generated by the multiplication by the multiplier 28, and is extracted as the output of the phase difference detector 2. The electrical signal output from the phase difference detector 2 is a DC value corresponding to the phase difference between the electrical signal received by the antenna 20A and the electrical signal received by the antenna 20B.

[Modification of phase difference detector]
The phase difference detector 2 can use another configuration as long as it can detect the phase difference of the electrical signals received by the receiving antennas 20A and 20B. For example, the configuration shown in FIG. 2 can be adopted. The phase difference detector of the modification shown in FIG. 2 is obtained by replacing the configuration of the section from the bandpass filters 25A and 25B to the amplifier 26 in the phase difference detector 2 of the first embodiment as follows. The output of the band pass filter 25A is divided into two, one being connected to the multiplier 129A via the amplifier 127, and the other being connected to the multiplier 129B via the phase shifter 128B and the amplifier 127. The output of the bandpass filter 25B is also divided into two parts, one being connected to the multiplier 129B via the amplifier 127, and the other being connected to the phase shifter 128A having the same phase shift amount as the phase shifter 128B, and the amplifier 127. It is connected to the multiplier 129A. The output sides of the multipliers 129 </ b> A and B are connected to the subtractor 120, and the output side of the subtractor is connected to the amplifier 26.

  In the phase difference detector of this modification, as in the phase difference detector 2 of the first embodiment, a DC value reflecting the phase difference between the electrical signal received by the antenna 20A and the electrical signal received by the antenna 20B is output. As obtained. Since the output is larger than that of the phase difference detector 2 of the first embodiment, it is possible to detect operation with higher sensitivity. In particular, if 90 ° is selected as the phase amount of the phase shifters 128A and B in the phase difference detector of the modified example, the output is twice as large as that of the phase difference detector 2 of the first embodiment, and the sensitivity is higher. Motion detection is possible. Further, since the output is a sine wave and the output is 0 when the phase difference is 0, it is easier to detect the variation in the phase difference and the operation detection accuracy is improved.

[Operation of Operation Detection Device 1 of First Embodiment]
Next, the operation of the motion detection device 1 according to the first embodiment will be described. Here, it is assumed that the palm is positioned between the transmitting antenna 13 and the receiving antennas 20A and B, and the movement of the finger of the hand is detected. At this time, since the multipath from the transmitting antenna 13 to the receiving antennas 20A and 20B changes according to the movement of the finger of the hand, the phase between the signal received by the receiving antenna 20A and the signal received by the receiving antenna 20B A difference is made. Thus, since there is a correspondence between the movement of the finger of the hand and the phase difference between the signals, the movement of the finger of the hand can be detected in a non-contact manner by detecting the phase difference by the phase difference detector 2. The reason why the motion detection apparatus 1 of the first embodiment has a high resolution is that even if a minute multipath change due to a fine motion is used, the phase difference is large because a microwave is used, and the phase difference is detected. Because it can. In addition, since the motion detection device 1 according to the first embodiment detects a motion in a non-contact manner using a microwave, the motion detection device 1 can be hidden by a material such as cloth or plastic, and the surrounding design is not impaired. It is possible to detect the operation.

  The operation detection device 1 according to the first embodiment is based on the operation principle of detecting a change in multipath as a phase difference as described above. The multipath may be either a transmission type or a reflection type. It doesn't matter. The transmission type is a case where a moving object is positioned between the transmitting antenna 13 and the receiving antennas 20A and 20B, and a multipath that bypasses and transmits the moving object from the transmitting antenna 13 to reach the receiving antennas 20A and 20B. This is the case. The reflection type is based on the same principle as that of radar, and includes two moving antennas, and two receiving antennas 20A and 20B are arranged on the same plane side as the transmitting antenna 13 with respect to a plane perpendicular to a straight line connecting the transmitting antenna 13 and the moving object. This is a case where a path is formed that is reflected from the transmitting antenna 13 by a moving object and reaches the receiving antennas 20A and 20B.

  As described above, in the motion detection device 1 according to the first embodiment, microwaves are radiated from the transmission antenna 13 and received by the two reception antennas 20A and 20B, and the human being between the transmission antenna 13 and the reception antennas 20A and 20B is received. By detecting the change in the phase difference of the received signal due to the change in the fingertip movement, the movement of the human fingertip can be detected in a non-contact manner. The motion detection device 1 according to the first embodiment can detect a fine motion such as a gesture by hand and operate an electronic device or the like.

  FIG. 3 is a diagram illustrating the configuration of the position motion detection apparatus according to the second embodiment. The position motion detection device according to the second embodiment is obtained by adding a position measurement device 3 to the motion detection device 1 according to the first embodiment.

  As shown in FIG. 4, the position measuring device 3 includes an exciter 4 attached to a moving body and two electromagnetic field fluctuation detectors 5 that are arranged apart from the exciter 4. However, in FIG. 4, only one of the two electromagnetic field fluctuation detectors 5 is illustrated.

[Configuration of Exciter 4]
The exciter 4 includes an oscillator 40 and an electrode 42 connected to the oscillator 40 via a band pass filter 41 and an amplifier 43. The oscillation frequency of the oscillator 40 is a frequency at which an electromagnetic field can propagate on the surface of a moving body, and is 1 to 100 MHz for a human body. The band pass filter 41 transmits only the frequency band of the electric signal oscillated by the oscillator 40, and the amplifier 43 amplifies the electric signal transmitted through the band pass filter 41. Further, the electrode 42 excites an electromagnetic field by an electric signal from the amplifier 43 and propagates the electromagnetic field to the moving body surface. The band-pass filter 41 and the amplifier 43 are not necessarily required, but it is desirable to provide them in order to remove noise and improve the position measurement accuracy.

  The electrode 42 may have a disk shape, a square shape, or the like, for example. If the size of the electrode 42 is reduced to about 1/100 or less of the wavelength of the electromagnetic field, there is no radiation mode from the electrode 42 and a near field by an evanescent set wave is formed around the electrode 42. For example, in the case of 100 MHz, the electrode 42 may be 3 cm or less (the longest part of the electrode 42, the diameter if it is a disc, the diagonal if it is a square).

  The exciter 4 is attached to a human body that is a motion detection target. In this embodiment, the moving body is a hand. The exciter 4 may be directly attached to the moving body as in the second embodiment, but may be attached to a place other than the moving body to excite an electromagnetic field and propagate to the moving body.

[Configuration of electromagnetic field fluctuation detector 5]
The electromagnetic field fluctuation detector 5 includes two electrodes 50A and B (corresponding to the first electrode and the second electrode of the present invention) provided apart from each other. The electrodes 50 </ b> A and B receive an electromagnetic field propagating on the human body surface as an electric signal by the exciter 4. A band pass filter 51A and an amplifier 52A are connected to the electrode 50A, and a band pass filter 51B and an amplifier 52B are connected to the electrode 50B, respectively. The bandpass filters 51A and 51B transmit only the oscillation frequency band of the oscillator 40, and the amplifiers 52A and 52A amplify electric signals from the bandpass filters 51A and 51B, respectively.

  The electromagnetic field fluctuation detector 5 has multipliers 53A and 53B, respectively. The multiplier 53A is connected to the amplifier 52A via the amplifier 54, and is connected to the amplifier 52B via the phase shifter 55A and the amplifier 54. On the other hand, the multiplier 53B is connected to the amplifier 52A via the phase shifter 55B and the amplifier 54, and is connected to the amplifier 52B via the amplifier 54. The phase shifter 55A outputs the phase of the electrical signal from the electrode 50B, and the phase shifter 55B outputs the phase of the electrical signal from the electrode 50B, and the phase shift amount is set equal. The multiplier 53A multiplies the electrical signal from the electrode 50A and the electrical signal from the electrode 50B phase-shifted by the phase shifter 55A and outputs the result. The multiplier 53B multiplies the electrical signal from the electrode 50B and the electrical signal from the electrode 50A phase-shifted by the phase shifter 55B and outputs the result.

  The output side of the multipliers 53A, B is connected to a subtractor 56, which takes the difference between the output electrical signals and outputs the difference. On the output side of the subtractor 56, an amplifier 57 and a low-pass filter 58 are connected in order. The amplifier 57 amplifies the electric signal output from the subtractor 56, and the low-pass filter 58 cuts and outputs a high frequency component (other than an electric signal close to a direct current component).

  Hereinafter, the electrodes of the other electromagnetic field fluctuation detector 5 corresponding to the electrodes 50A and 50B of one electromagnetic field fluctuation detector 5 are denoted by 50C and D, respectively. The electrodes 50A to 50D are disposed on a rectangular frame-shaped plastic frame 6, and a straight line connecting the electrodes 50A and 50B (a straight line parallel to the x-axis direction) and between the electrodes 50C and D of the electromagnetic field fluctuation detector 5 are disposed. Are arranged so as to be orthogonal to each other (a straight line parallel to the y-axis direction). Further, the transmission antenna 13 of the radiator 7 is disposed in the vicinity of the electrode 50D, and the reception antennas 20A and 20B of the phase difference detector 2 are disposed in the vicinity of the electrode 50C. An area surrounded by the plastic frame 6 is an operation detection area. The straight line connecting the electrodes 50A and 50B and the straight line connecting the electrodes 50C and D are arranged so as to be orthogonal to each other. However, it is not always necessary, and the two straight lines may be arranged at an angle. However, in order to improve the accuracy of position measurement, it is desirable to make them orthogonal. In addition, the positional relationship between the transmitting antenna 13, the receiving antennas 20A and 20B, and the electrodes A to D is not necessarily as described above, and the motion detection region by the radiator 7 and the phase difference detector 2 and the position measurement are not necessarily required. What is necessary is just to arrange | position the transmitting antenna 13, receiving antenna 20A, B, and electrode 50A-D so that the moving body detection area by the apparatus 3 may overlap.

[Operation of Position Measuring Device 3]
In the position measuring device 3, when the moving body excited by the exciter 4 is brought close to the plastic frame 6, the position of the moving body in the x-axis direction and the y-axis are calculated from the respective voltage values output from the two electromagnetic field fluctuation detectors 5. The position of the moving body (the position of the hand) in the axial direction can be measured. That is, the two-dimensional position of the moving object can be measured in a non-contact manner. Hereinafter, the operation of moving object position measurement in the x-axis direction of the position measuring device 3 will be described.

  First, an electromagnetic field is propagated to the surface of the moving body by the exciter 4 attached to the moving body. That is, an electric signal is oscillated by the oscillator 40, noise components and the like are removed through the bandpass filter 41 and the electric signal is amplified by the amplifier 43, and then the electromagnetic field is excited from the electrode 42 to propagate the electromagnetic field to the surface of the moving body. If the moving body is a human body, the oscillator 40 oscillates a frequency of 1 to 100 MHz band. If the frequency is in the range of 1 to 100 MHz, the excited electromagnetic field can be propagated to the human body surface. Since the human body has a high relative dielectric constant, it is assumed that the wavelength is greatly shortened and propagates. For example, at 10.7 MHz, the relative dielectric constant of the human body is about 160, which is a very high value.

  The two electrodes 50A and B of the electromagnetic field fluctuation detector 5 are arranged at a position close to the moving body without being in contact with the moving body, and the electromagnetic field propagating on the surface of the moving body by the two electrodes 50A and B is used as an electric signal. Receive. The phases of the electric signals received by the electrodes 50A and 50B differ depending on the relative distance between the moving body position and the electrodes 50A and 50B.

  The electrical signal received at the electrode 50A of the electromagnetic field fluctuation detector 5 is cos (ωt + θA), the electrical signal received at the electrode 50B is cos (ωt + θB), where ω is 2πf, and f is the oscillation frequency of the oscillator 40. The multiplier 53A receives the electric signal cos (ωt + θA) and the electric signal cos (ωt + θB−φ) whose phase is delayed by φ by the phase shifter 55A. The multiplier 53B receives the electric signal cos (ωt + θB) and the electric signal cos (ωt + θA−φ) whose phase shift is delayed by φ by the phase shifter 55B. Therefore, the output of the multiplier 53A is cos (ωt + θA) · cos (ωt + θB−φ), and is (½) · cos (ψ + φ) except for the high-frequency component cut by the low-pass filter 28 at the subsequent stage. . Here, θA−θB, that is, the phase difference is set as ψ. Similarly, the output of the multiplier 53B is (1/2) · cos (ψ−φ).

  The electrical signals (1/2) · cos (ψ + φ) and (1/2) · cos (ψ−φ) output from the multipliers 53 A and B are input to the subtractor 56. The output from the subtractor 56 is (1/2) · cos (ψ−φ) − (1/2) · cos (ψ + φ) = sinψ · sinφ. Thereafter, after the signal is amplified by the amplifier 57, the high frequency component which has already been omitted in the calculation is cut by the low-pass filter 58, and sinφ · sinφ is output.

  The voltage value of sinψ · sinφ is a value corresponding to the phase difference ψ (= θA−θB) of the electrical signal received by the electrodes 50A, B, and the phase difference ψ is in the vicinity of the electrodes 50A, B. It is a value corresponding to the position of the moving body in the x-axis direction. Therefore, the position of the moving body in the vicinity of the electrodes 50A, B in the x-axis direction can be measured from the voltage value of the electrical signal sinψ · sinφ. As shown in this result, when φ is 90 °, the output becomes maximum from sin φ = 1, so that the phase shift amount φ of the phase shifters 55A and 55B is desirably set to 90 °. This is because the sensitivity of position measurement can be improved.

  Similarly, the position of the moving body in the y-axis direction can be measured by the other electromagnetic field fluctuation detector 5. Therefore, according to the position measuring device 3, the two-dimensional position of the moving body can be measured without contact.

  As described above, the electromagnetic field fluctuation detector 5 divides the received two electric signals into two, delays one of the two, and multiplies them to obtain the difference. This is because the offset is not stabilized simply by multiplying the received electrical signal to cut the high frequency component, and the position measurement accuracy deteriorates. However, when high position accuracy is not required, the phase shifters 55A and B, the multiplier 53B, and the subtractor 56 may be deleted from the electromagnetic field fluctuation detector 5.

[Operation of Position Motion Detection Device of Embodiment 2]
The position motion detection apparatus according to the second embodiment can detect the two-dimensional position of the moving body (hand) by the position measurement apparatus 3 as described above. However, only the position measuring device 3 cannot detect a fine movement of the moving body. Thus, the radiator 7 and the phase difference detector 2 detect the fine movement of the moving object in the same manner as in the first embodiment. That is, according to the position motion detection apparatus of the second embodiment, it is possible to distinguish and detect two-dimensional large moving body motion and fine motion. Further, it is possible to selectively detect only the motion of a specific moving body excited by the position measuring device 3, and it is possible to prevent detection of the motion of another moving body that is not excited. Thereby, it can be specified that the fine motion of the moving object detected by the radiator 7 and the phase difference detector 2 is the operation of the specific moving object excited by the exciter 4 of the position measuring device 3.

  The position motion detection apparatus according to the second embodiment can detect a gesture of a specific person's hand, for example, by matching the movement of the entire hand as a two-dimensional large moving body movement and the movement of a fingertip as a fine movement. It is possible to operate an electronic device or the like with a hand gesture. As an example, a gesture of a driver's hand holding the steering wheel is provided by setting the position motion detection device of the second embodiment so that the vehicle steering is set as the motion detection region and the exciter 4 is provided in the driver's seat to excite the driver. Can be detected in the vicinity of the steering wheel to operate the power window and the like, so that it cannot be operated with the gesture of the hand of the passenger in the passenger seat who does not hold the steering wheel.

  Note that the frequency after down-conversion in the phase difference detector 2 of the position motion detection apparatus according to the second embodiment is preferably equal to the frequency excited by the exciter 4 of the position measurement apparatus 3. This facilitates the comparison of the phase difference.

[Experimental example]
FIG. 5 is a graph showing the result of detecting the motion of a human hand using the position motion detection device of the second embodiment. The exciter 4 of the position measuring device 3 was attached to the hand, and the position measuring device 3 was operated. The movement of the hand was repeated such as waving hand between A and B, stopping, repeating the action of making the hand goo and par, stopping and waving hand between A and B. The excitation frequency by the exciter 4 of the position measuring device 3 is 10.7 MHz, the frequency of the microwave radiated by the radiator 7 is 5.8 GHz, and the phase difference detector 2 downconverts 5.8 GHz to 10.7 MHz. Thus, the excitation frequency by the exciter 4 was made equal. In FIG. 5, the horizontal axis represents the elapsed time, and the vertical axis represents the outputs of the phase difference detector 2 and the electromagnetic field fluctuation detector 5 (of the two electromagnetic field fluctuation detectors 5 that measure the position in the x-axis direction). Yes. In FIG. 5, the sign P is the output of the electromagnetic field fluctuation detector 5, and the sign Q is the output of the phase difference detector 2.

  It can be seen that the output value P of the electromagnetic field fluctuation detector 5 greatly increases or decreases periodically in the section where the hand-waving operation is performed. That is, it can be seen that the motion of waving can be detected. On the other hand, in the section where the operation of repeating the stop and the goo and par is performed, the output value is almost constant, and it can be seen that the operation of repeating the goo and par cannot be detected. This indicates that the electromagnetic field fluctuation detector 5 cannot detect a fine movement such as a finger movement of the hand because the operation resolution is low.

  Further, it can be seen that the output Q of the phase difference detector 2 periodically increases and decreases in the same manner as in the case of the electromagnetic field fluctuation detector 5 in the section where the hand-waving operation is performed. That is, the motion of waving can be detected. On the other hand, in the section where the operation of repeating goo and par is performed, the output value periodically increases or decreases although the fluctuation range is smaller than the section where the operation of waving is performed. That is, it is possible to detect the fingertip movement of repeating goo and par. Further, in the section where the operation is stopped, the output value is almost constant, and it can be seen that the operation of shaking hands and the operation of repeating goo and par can be distinguished. This indicates that the motion detection using the radiator 7 and the phase difference detector 2 has a high resolution.

  From the above experiment, using the position motion detection apparatus of the second embodiment, it is possible to distinguish and detect both a large motion of shaking hands and a fine motion of repeating goo and par, and further excited by the exciter 4. It has been shown that it is possible to detect only the movement of a specific person's hand.

  FIG. 6 is a diagram illustrating the configuration of the motion detection apparatus according to the third embodiment. The motion detection apparatus according to the third embodiment includes a radiator 100 and a phase difference extractor 200.

[Configuration of radiator 100]
As shown in FIG. 6, the radiator 100 has the same configuration as that of the radiator 7 of the first embodiment up to the oscillator 10, the bandpass filter 11, and the amplifier 12. The difference is that the output from the amplifier 12 is divided into two and input to the transmitting antennas 130A and 130B. The transmission antennas 130A and B are the same as the transmission antenna 13.

[Configuration of Phase Difference Extractor 200]
The phase difference extractor 200 has one receiving antenna 220 as shown in FIG. The arrangement of the transmission antennas 130A and 130B and the reception antenna 220 is just the opposite of that of the transmission antenna 13 and the reception antennas 20A and B of the first embodiment. The reception antenna 220 receives electrical signals from the transmission antennas 130A and 130B. The receiving antenna 220 is connected to the input side of the multiplier 223 via the band pass filter 221 and the amplifier 222. A PLL circuit 224 is connected to the other input side of the multiplier 223. The output side of the multiplier 223 is connected to the input side of the nonlinear element 230 via a band pass filter 225 and an amplifier 227. Here, each component from the receiving antenna 220 to the amplifier 227 and the PLL circuit 224 are the same as the receiving antenna 20A to the amplifier 27A and the PLL circuit 24 of the first embodiment.

  The nonlinear element 230 is used to generate a square component of an input signal. Of the output from the non-linear element 230, only the DC component is extracted by the low-pass filter 240 and extracted as the output of the phase difference extractor 200. The electric signal output from the phase difference extractor 200 has a DC value corresponding to the phase difference between the microwave from the transmission antenna 130A to the reception antenna 220 and the microwave from the transmission antenna 130B to the reception antenna 220. is there.

[Operation of Operation Detection Device of Example 3]
Next, the operation of the motion detection apparatus according to the third embodiment will be described. Here, as in the case of the first embodiment, it is assumed that the palm is positioned between the transmitting antennas 130A and 130B and the receiving antenna 220, and the movement of the finger of the hand is detected. At this time, a phase difference occurs between the microwave from the transmitting antenna 130A to the receiving antenna 220 and the microwave from the transmitting antenna 130B to the receiving antenna 220 according to the movement of the finger of the hand. Since the signal reflecting this phase difference is received by the receiving antenna 220 and the DC value reflecting the phase difference can be extracted by the phase difference extractor 200, the movement of the finger of the hand can be detected without contact. .

The extraction of the phase difference by the phase difference extractor 200 will be described in more detail. The electrical signal output from the transmission antennas 130A and 130B is cos (ωt), the phase changes by θA in the path from the transmission antenna 130A to the reception antenna 220, and the phase changes by θB in the path from the transmission antenna 130B to the reception antenna 220 Then, the electrical signal received by the receiving antenna 220 is cos (ωt + θA) + cos (ωt + θB). This electric signal is input to the nonlinear element 230, and a square component is generated. That is, a component of {cos (ωt + θA) + cos (ωt + θB)} ² is generated. Of this square component, the DC component is 1 + cos (ψ). Of the output of the non-linear element 230, other than this DC component is cut by the low-pass filter 240. After all, the output of the phase difference extractor 200 becomes 1 + cos (ψ), and the phase difference ψ can be extracted from this DC value.

  As described above, in the motion detection device according to the third embodiment, a signal reflecting the phase difference of the microwave generated by the change in the movement of the person's finger is received by the receiving antenna 220, and the phase difference is extracted. The movement of the fingertip can be detected without contact. If the position measuring device 3 is combined with the motion detecting device of the third embodiment, the same effect as the position motion detecting device of the second embodiment can be obtained.

  From Example 1 and Example 3, if at least one of the transmitting antenna and the receiving antenna is plural (except when both are one), the movement of the human fingertip is similarly detected in a non-contact manner. I can guess what I can do. Further, the configuration for extracting the phase difference from the signal received by the receiving antenna 220 is not limited to the phase difference detector 200 shown in the third embodiment.

  In the first and second embodiments, the motion detection device of the present invention is used to detect the motion of a human hand, but of course, it can also be used to detect the motion of an excitable moving body other than a human. Can do.

  According to the present invention, since it is possible to detect a fine movement such as a fingertip movement, the present invention can be applied to operating a device with a hand gesture.

1: Motion detector 2: Phase difference detector 3: Position measurement device 4: Exciter 5: Electromagnetic field fluctuation detector 7: Radiator 10, 40: Oscillator 11, 21A, B, 25A, B: Band pass filter 12, 22A, B, 27A, B: Amplifier 13, 130A, B: Transmitting antenna 20A, B, 220: Receiving antenna 23A, B, 28, 53A, B, 129A, B: Multiplier 24: PLL circuit 29, 58, 240 : Low-pass filter 42, 50A, B: Electrode 55A, B, 128A, B: Phase shifter 56, 120: Subtractor 230: Non-linear element

Claims (12)

In a motion detection device that detects the motion of a moving body without contact,
A transmitting antenna that radiates microwaves;
Two receiving antennas that receive microwaves from the transmitting antenna, spaced apart from each other and spaced from the transmitting antenna;
A detector for receiving microwaves respectively by the two receiving antennas and detecting a phase difference between the two received signals;
Have
From the phase difference detected by the detector, detect the motion of the moving object in the motion detection region between the transmitting antenna and the receiving antenna.
An operation detection device characterized by the above. In a motion detection device that detects the motion of a moving body without contact,
Two transmitting antennas spaced apart from each other that radiate microwaves;
A receiving antenna for receiving microwaves from the transmitting antenna, spaced apart from the transmitting antenna;
Have
The reception antenna receives a signal reflecting the phase difference between the microwave from one of the transmission antennas and the microwave from the other transmission antenna, and from the phase difference, between the transmission antenna and the reception antenna Detecting the motion of the moving object in the motion detection area of
An operation detection device characterized by the above. The detector is
A multiplier that multiplies and outputs the two received signals;
A first low-pass filter that outputs a high frequency component out of the output of the multiplier;
The motion detection device according to claim 1, comprising: The detector is
A first phase shifter to which a signal from one of the receiving antennas is input;
A second phase shifter that receives a signal from the other of the receiving antennas and has a phase shift amount equal to that of the first phase shifter;
A first multiplier that multiplies and outputs a signal received by one of the receiving antennas and a signal received by the other of the receiving antennas and phase-shifted by the second phase shifter;
A second multiplier that multiplies and outputs a signal received by one of the receiving antennas and phase-shifted by the first phase shifter and a signal received by the other of the receiving antenna;
A first subtractor that takes a difference between an output of the first multiplier and an output of the second multiplier;
A first low-pass filter that cuts out and outputs a high-frequency component of the output of the first subtractor;
The motion detection device according to claim 1, comprising:   The motion detection device according to claim 4, wherein a phase shift amount of the first phase shifter and the second phase shifter is 90 °. A nonlinear element that squares and outputs a signal from the receiving antenna;
A first low-pass filter that cuts and outputs a high-frequency component of the output of the nonlinear element;
The motion detection device according to claim 2, further comprising:   The motion detection apparatus according to claim 1, wherein the microwave is 300 MHz to 10 GHz.   The motion detection apparatus according to claim 1, wherein the moving body is a hand. A position motion detection device comprising: the motion detection device according to any one of claims 1 to 7; and a position measurement device that measures the position of the moving body in the motion detection region in a non-contact manner. And
The position measuring device includes:
An exciter that propagates an electromagnetic field to the surface of the moving body;
A first electrode and a second electrode that are spaced apart from the moving body and spaced apart from each other to include the motion detection region; and from a phase difference of an electromagnetic field that reaches the first electrode and the second electrode. An electromagnetic field fluctuation detector for measuring the position of the moving body;
Having
A position motion detection apparatus characterized by the above. The electromagnetic field fluctuation detector is
A third phase shifter to which a signal from the first electrode is input;
A fourth phase shifter that receives a signal from the second electrode and has a phase shift amount equal to that of the third phase shifter;
A third multiplier that multiplies a signal received by the first electrode and a signal received by the second electrode and phase-shifted by the fourth phase shifter;
A fourth multiplier that multiplies and outputs the signal received by the first electrode and phase-shifted by the third phase shifter and the signal received by the second electrode;
A second subtractor that takes a difference between the output of the third multiplier and the output of the fourth multiplier;
Of the output of the first subtractor, a second low-pass filter that cuts and outputs a high-frequency component;
Having
The position motion detection device according to claim 9.   The position motion detection device according to claim 10, wherein a phase shift amount of the third phase shifter and the fourth phase shifter is 90 °.   The position motion detection device according to claim 11, wherein an oscillation frequency of the exciter is 1 to 100 MHz.