JP6267531B2 - Radio wave sensor and detection method - Google Patents

Description

  The present invention relates to a radio wave sensor and a detection method, and more particularly to a radio wave sensor and a detection method for detecting an object using radio waves.

  Japanese Patent Laying-Open No. 2012-247215 (Patent Document 1) discloses an object identification device that is mounted on a vehicle and identifies the type of an object that exists around the vehicle. The object identification device is an object including information on a reflection intensity and a distance to an object around the vehicle obtained by irradiating the vehicle with a sound wave or an electromagnetic wave and detecting the sound wave or a reflected wave of the electromagnetic wave. Information and information on the height of the object obtained by image processing are acquired. The object identification device corrects the reflection intensity according to the height of the object and the distance to the object. Then, the object identification device identifies the type of the object according to the corrected reflection intensity.

Koji Yoichi, and two others, “Application of expanding millimeter-wave technology”, [online], [searched on January 24, 2014], Internet <URL: http: // www. spc. co. jp / spc / pdf / giho21_09. pdf> Takayuki Inaba, Tetsuro Kirimoto, “Automotive Millimeter Wave Radar”, Automotive Technology, February 2010, Vol. 64, No. 2, p. 74-79

JP 2012-247215 A

  However, in the object identification device described in Patent Document 1, since the type of an object is identified by using sound wave or electromagnetic wave irradiation processing and detection processing, and image processing, the configuration of the device becomes complicated and expensive. There is a problem.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a radio wave sensor and a detection method capable of accurately detecting an object on a pedestrian crossing with a simple and low-cost configuration. It is to be.

  (1) In order to solve the above-described problem, a radio wave sensor according to an aspect of the present invention is an irradiation range in a first area which is an area of a start portion of a pedestrian crossing and does not include the entire pedestrian crossing. A transmission unit capable of transmitting radio waves from the first antenna, a reception unit receiving radio waves from the first area, and an object in the first area based on the radio waves received by the reception unit. A detection unit for detecting.

  (13) A radio wave sensor according to another aspect of the present invention includes a transmission unit that transmits radio waves to a target area that is an area including a part or all of a pedestrian crossing, and reception that receives radio waves from the target area. Section, a difference signal having a frequency component of a difference between a frequency component of a predetermined radio wave and a frequency component of a received radio wave received by the receiver, or a frequency distribution that is information on a frequency distribution of the received radio wave An analysis unit that creates information, and a detection unit that detects an object in the target area based on the frequency distribution information created by the analysis unit.

  (14) In order to solve the above-described problem, a detection method according to an aspect of the present invention is a detection method in a radio wave sensor, which is an area at the start of a pedestrian crossing, and does not include the entire pedestrian crossing. A step of transmitting a radio wave from a first antenna while limiting an irradiation range to a first area, which is an area, a step of receiving a radio wave from the first area, and an object in the first area based on the received radio wave Detecting.

  (15) Further, a detection method according to another aspect of the present invention is a detection method in a radio wave sensor, the step of transmitting radio waves to a target area which is an area including a part or all of a pedestrian crossing, and the target This is information regarding the frequency distribution of the difference signal having the frequency component of the difference between the frequency component of the predetermined radio wave and the frequency component of the received radio wave that is the received radio wave, or the received radio wave. Creating frequency distribution information; and detecting an object in the target area based on the created frequency distribution information.

  The present invention can be realized not only as a radio wave sensor having such a characteristic processing unit, but also as a program for causing a computer to execute such characteristic processing steps. Further, it can be realized as a semiconductor integrated circuit that realizes part or all of the radio wave sensor, or as a system including the radio wave sensor.

  According to the present invention, it is possible to accurately detect an object on a pedestrian crossing with a simple and low-cost configuration.

FIG. 1 is a diagram showing a configuration of a signal control system according to the first embodiment of the present invention. FIG. 2 is a diagram showing a configuration of the radio wave sensor in the signal control system according to the first embodiment of the present invention. FIG. 3 is a diagram showing a configuration of a radio wave processing unit in the radio wave sensor according to the first embodiment of the present invention. FIG. 4 is a diagram illustrating a configuration of a differential signal generation unit in the reception wave processing unit according to the first embodiment of the present invention. FIG. 5 is a diagram illustrating an example of the arrangement of the transmission antenna, the reception antenna, and the object according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating an example of a pedestrian Doppler spectrum generated by the FFT processing unit in the radio wave sensor according to the first embodiment of the present invention. FIG. 7 is a diagram schematically illustrating an example of a Doppler spectrum generated by the FFT processing unit in the radio wave sensor according to the first embodiment of the invention. FIG. 8 is a diagram illustrating an example of a Doppler spectrum of an automobile generated by the FFT processing unit in the radio wave sensor according to the first embodiment of the invention. FIG. 9 is a diagram illustrating an example of a change in the detection target speed of the automobile with respect to the radio wave sensor according to the first embodiment of the invention. FIG. 10 is a diagram illustrating a configuration of a detection unit in the signal processing unit according to the first embodiment of the present invention. FIG. 11 is a diagram showing a configuration of a modification of the detection unit in the signal processing unit according to the first embodiment of the present invention. FIG. 12 is a flowchart defining an operation procedure when the radio wave sensor according to the first embodiment of the present invention detects an object in the target area. FIG. 13 is a flowchart defining an operation procedure when the detection unit in the radio wave sensor according to the first embodiment of the present invention detects an object in the target area. FIG. 14 is a diagram illustrating an example of a Doppler spectrum generated by the FFT processing unit in the radio wave sensor according to the first embodiment of the present invention when pedestrians and automobiles are mixed. FIG. 15 is a diagram showing a configuration of a signal control system according to the second embodiment of the present invention. FIG. 16 is a diagram illustrating a state in which the signal control system illustrated in FIG. 15 is viewed from the road toward the intersection. FIG. 17 is a diagram showing a configuration of a radio wave sensor according to the second embodiment of the present invention. FIG. 18 is a diagram illustrating a configuration of a radio wave processing unit in the radio wave sensor according to the second embodiment of the present invention. FIG. 19 is a diagram illustrating a configuration of the nearest area detection unit in the signal processing unit according to the second embodiment of the present invention. FIG. 20 is a diagram illustrating a configuration of a modified example of the nearest area detection unit in the signal processing unit according to the second embodiment of the present invention. FIG. 21 is a flowchart defining an operation procedure when the radio wave sensor according to the second embodiment of the present invention detects an object in the nearest target area. FIG. 22 is a flowchart defining an operation procedure when the radio wave sensor according to the second embodiment of the present invention detects an object in a distant object area. FIG. 23 is a diagram showing a configuration of a radio wave sensor according to the second embodiment of the present invention.

  First, the contents of the embodiment of the present invention will be listed and described.

  (1) The radio wave sensor according to the embodiment of the present invention limits the irradiation range to a first area which is an area of a start portion of a pedestrian crossing and does not include the entire pedestrian crossing, A transmission unit capable of transmitting from one antenna; a reception unit that receives radio waves from the first area; and a detection unit that detects an object in the first area based on the radio waves received by the reception unit. .

  As described above, for example, the radio wave received from the vehicle is included in the radio wave received by the receiving unit by limiting the irradiation range to the first area where the vehicle is unlikely to be located and transmitting the radio wave from the first antenna. Since the possibility can be reduced, it is possible to avoid a situation in which it is difficult to accurately detect an object by simultaneously receiving a radio wave from a vehicle and a radio wave from a human. Accordingly, it is possible to accurately detect, for example, a human being as an object on the pedestrian crossing.

  Further, for example, since a person who wants to cross a pedestrian crossing in the first area can be detected as an object, after the person moves out of the first area and can no longer detect the person In addition, it can be estimated that the person after movement is located in a different area from the starting part of the pedestrian crossing.

  In addition, since the object can be detected without performing image processing, the radio wave sensor can be configured at low cost and with a simple configuration.

  (2) Preferably, the transmission unit further restricts an irradiation range to a second area including a portion of the pedestrian crossing farther from the radio wave sensor than the first area, and transmits radio waves from the second antenna. The receiving unit further receives radio waves from the second area, and the detection unit further receives the second radio wave based on the radio waves from the second area received by the receiving unit. Detect objects in the area.

  As described above, the configuration in which the irradiation range is limited to the second area in addition to the first area, the radio wave is transmitted from the second antenna, and the object in the second area is detected, for example, a vehicle and a human can be located. It is possible to further grasp the vehicle and human presence status in the second area which is a pedestrian crossing.

  Further, for example, when humans and vehicles are mixed in the second area, even when it is difficult to accurately detect the object in the second area, the second area is based on the detection result of the object in the first area. The detection accuracy of the object in the two areas can be increased.

  (3) More preferably, the transmission unit temporally switches between transmission of radio waves from the first antenna and transmission of radio waves from the second antenna.

  In this way, the radio wave transmitted from the first antenna and the second antenna are transmitted by the configuration in which the period during which the radio wave is transmitted from the first antenna and the period during which the radio wave is transmitted from the second antenna are separated. Since interference between radio waves can be prevented, deterioration of reception characteristics due to interference can be avoided with simple processing.

  (4) Preferably, the radio wave sensor further includes a differential signal having a frequency component that is a difference between a frequency component of a predetermined radio wave and a frequency component of a received radio wave received by the receiving unit, or the received radio wave. And an analysis unit that creates frequency distribution information, which is information relating to the frequency distribution, and the detection unit detects the object based on the frequency distribution information created by the analysis unit.

  Thus, frequency distribution information that is information about the distribution of the detection target velocity that is a component along the direction of approaching or moving away from the radio wave sensor among the components of the relative velocity of each surface portion of the target object with respect to the radio wave sensor. Since the content of the frequency distribution information varies depending on the object at the pedestrian crossing, the object at the pedestrian crossing can be detected with high accuracy.

  (5) More preferably, the detection unit detects a person as the object based on a relationship between a reference range defined by a frequency and intensity and the frequency distribution in the frequency distribution information.

  As described above, with the configuration in which the person in the pedestrian crossing is detected using the reference range, the person in the pedestrian crossing can be easily and accurately detected based on the relationship between the reference range and the frequency distribution.

  (6) More preferably, the detection unit acquires a target waveform that is a part or all of the frequency distribution based on a magnitude relationship between the intensity of each frequency component in the frequency distribution and a predetermined threshold value. When the acquired target waveform is continuously included in the reference range, a human is detected as the target.

  The target waveform due to the reflected wave from a human at a pedestrian crossing is often included in the reference range. For this reason, it is possible to detect a person at the pedestrian crossing more accurately.

  (7) More preferably, when the target waveform is included in the reference range and the variation in the frequency axis direction of the peak of the target waveform is continuously less than a predetermined value, the detection unit is When the fluctuation in the intensity axis direction of the peak continues to be less than a predetermined value within the reference range, or the target waveform is included in the reference range, and the fluctuation in the frequency axis direction of the peak continues. The human is detected as the object in any one of the cases where the fluctuation is less than the predetermined value and the fluctuation of the peak in the intensity axis direction is continuously lower than the predetermined value.

  In many cases, at least one of the fluctuation in the frequency axis direction and the fluctuation in the intensity axis direction of the peak of the target waveform due to the reflected wave from the human at the pedestrian crossing is small. For this reason, it is possible to detect a person at the pedestrian crossing more accurately.

  (8) More preferably, the detection unit detects the vehicle as the object based on a relationship between a reference range defined by frequency and intensity and the frequency distribution in the frequency distribution information.

  As described above, with the configuration in which the vehicle in the pedestrian crossing is detected using the reference range, the vehicle in the pedestrian crossing can be easily and accurately detected based on the relationship between the reference range and the frequency distribution.

  (9) More preferably, the detection unit acquires a target waveform that is a part or all of the frequency distribution based on a magnitude relationship between the intensity of each frequency component in the frequency distribution and a predetermined threshold value. When at least a part of the acquired target waveform is not continuously included in the reference range, a vehicle is detected as the target object.

  In many cases, at least a part of the target waveform due to the reflected wave from the vehicle at the pedestrian crossing is not included in the reference range. For this reason, the vehicle in a pedestrian crossing can be detected more accurately.

  (10) More preferably, when the target waveform is included in the reference range and the fluctuation in the frequency axis direction of the peak of the target waveform is continuously greater than or equal to a predetermined value, the detection unit is When the fluctuation in the intensity axis direction of the peak is continuously greater than or equal to a predetermined value or included in the reference range, or the target waveform is included in the reference range, and the fluctuation in the frequency axis direction of the peak continues. The vehicle is detected as the object in any one of the cases where the fluctuation is greater than or equal to a predetermined value and the fluctuation of the peak in the intensity axis direction is continuously greater than or equal to the predetermined value.

  In many cases, at least one of the fluctuation in the frequency axis direction and the fluctuation in the intensity axis direction of the peak of the target waveform due to the reflected wave from the vehicle at the pedestrian crossing is large. For this reason, the vehicle in a pedestrian crossing can be detected still more accurately.

  (11) More preferably, the detection unit acquires a target waveform that is a part or all of the frequency distribution based on a magnitude relationship between the intensity of each frequency component in the frequency distribution and a predetermined threshold value. The target is detected based on the number of peaks included in the acquired target waveform.

  In many cases, the number of peaks included in the target waveform due to the reflected wave from the vehicle at the pedestrian crossing is large, and the number of peaks included in the target waveform due to the reflected wave from the human at the pedestrian crossing is often small. For this reason, an object can be detected more accurately based on the number of peaks included in the object waveform.

  (12) Preferably, the direction of directivity of the first antenna is along the crossing direction of the pedestrian crossing.

  With such a configuration, the detection target speed suitable for the target detection process can be acquired for each type of the target, so that the target can be detected more accurately.

  (13) The radio wave sensor according to the embodiment of the present invention includes a transmission unit that transmits radio waves to a target area that is an area including a part or all of a pedestrian crossing, and a reception unit that receives radio waves from the target area. A difference signal having a frequency component that is a difference between a frequency component of a predetermined radio wave and a frequency component of a received radio wave that is a radio wave received by the receiving unit, or frequency distribution information that is information on a frequency distribution of the received radio wave. An analysis unit to be created and a detection unit to detect an object in the target area based on the frequency distribution information created by the analysis unit.

  As described above, the frequency distribution information, which is information about the distribution of the detection target speed on each surface portion of the target object, differs depending on the target object in the pedestrian crossing. The object can be detected with high accuracy.

  In addition, since the object can be detected without performing image processing, the radio wave sensor can be configured at low cost and with a simple configuration.

  (14) A detection method according to an embodiment of the present invention is a detection method in a radio wave sensor, and is a first area that is an area of a start portion of a pedestrian crossing and does not include the entire pedestrian crossing. Transmitting a radio wave from the first antenna while limiting an irradiation range; receiving a radio wave from the first area; and detecting an object in the first area based on the received radio wave. .

  As described above, for example, the radio wave received from the vehicle is included in the radio wave received by the receiving unit by limiting the irradiation range to the first area where the vehicle is unlikely to be located and transmitting the radio wave from the first antenna. Since the possibility can be reduced, it is possible to avoid a situation in which it is difficult to accurately detect an object by simultaneously receiving a radio wave from a vehicle and a radio wave from a human. Accordingly, it is possible to accurately detect, for example, a human being as an object on the pedestrian crossing.

  Further, for example, since a person who wants to cross a pedestrian crossing in the first area can be detected as an object, after the person moves out of the first area and can no longer detect the person In addition, it can be estimated that the person after movement is located in a different area from the starting part of the pedestrian crossing.

  In addition, since the object can be detected without performing image processing, the radio wave sensor can be configured at low cost and with a simple configuration.

  (15) A detection method according to an embodiment of the present invention is a detection method in a radio wave sensor, the step of transmitting radio waves to a target area that is an area including a part or all of a pedestrian crossing, and from the target area A frequency distribution that is a difference signal having a frequency component that is a difference between a frequency component of a predetermined radio wave and a frequency component of a received radio wave that is a received radio wave, or information on a frequency distribution of the received radio wave A step of creating information, and a step of detecting an object in the target area based on the created frequency distribution information.

  As described above, the frequency distribution information, which is information about the distribution of the detection target speed on each surface portion of the target object, differs depending on the target object in the pedestrian crossing. The object can be detected with high accuracy.

  In addition, since the object can be detected without performing image processing, the radio wave sensor can be configured at low cost and with a simple configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated. Moreover, you may combine arbitrarily at least one part of embodiment described below.

<First Embodiment>
[Configuration and basic operation]
FIG. 1 is a diagram showing a configuration of a signal control system according to the first embodiment of the present invention.

  With reference to FIG. 1, the signal control system 201 includes a radio wave sensor 101, a signal control device 151, and a pedestrian signal lamp 161. The signal control device 151 and the pedestrian signal lamp 161 in the signal control system 201 constitute a traffic signal device, for example, installed in the vicinity of the intersection CS1.

  The radio wave sensor 101 functions as a moving object detection sensor that detects a target object Tgt that moves in the target area A1. Here, the target area A1 is an area set by a sensor installer who is an installer of the radio wave sensor 101, for example.

  Specifically, as shown in FIG. 1, the sensor installer targets, for example, a pedestrian Tgt2 and a car Tgt1 moving on a pedestrian crossing PC1 located between the sidewalks Pv1 and Pv2 installed across the road Rd1. In the case of the object Tgt, an area including the entire pedestrian crossing PC1 is set as the target area A1. For example, the sensor installer may set an area including a part of the pedestrian crossing PC1 as the target area A1. In addition, for example, when the radio wave sensor 101 is attached to an automobile, the sensor installer can target a predetermined range in front of the automobile when the pedestrian Tgt2 and the automobile Tgt1 positioned in front of the automobile are the target Tgt. Set as area A1.

  The radio wave sensor 101 is installed, for example, in the vicinity of the road Rd1 extending to the intersection CS1. Specifically, the radio wave sensor 101 is fixed to, for example, a support column P1 installed near the road Rd1.

  The pedestrian signal lamp 161 and the signal control device 151 are fixed to, for example, the support P1. The radio wave sensor 101 and the signal control device 151 are connected by a signal line (not shown), for example. The signal control device 151 and the pedestrian signal lamp 161 are connected by a signal line (not shown), for example. The radio wave sensor 101 may be installed on the road Rd1 or may be mounted on a car.

  The radio wave sensor 101 detects the target object Tgt in the target area A1, and determines the type of the detected target object Tgt. More specifically, the radio wave sensor 101 transmits a radio wave to the target area A1 including the pedestrian crossing PC1 under the control of the signal control device 151, for example. Specifically, the target object Tgt is an automobile Tgt1, a pedestrian Tgt2, or the like. The target object Tgt is moving, for example, in the target area A1, and reflects the radio wave transmitted from the radio wave sensor 101.

  For example, the radio wave sensor 101 detects the target Tgt in the target area A1 based on the radio wave reflected by the target Tgt, and determines the type of the detected target Tgt. More specifically, the radio wave sensor 101 determines a vehicle and a human as the type of the target Tgt, for example. The radio wave sensor 101 transmits the determination result to the signal control device 151.

  Under the control of the signal control device 151, the pedestrian signal lamp 161 illuminates and displays “recommend” or “to rare” for the pedestrian Tgt2 crossing the pedestrian crossing PC1, for example.

  When the signal control device 151 receives the determination result from the radio wave sensor 101, the signal control device 151 controls the pedestrian signal lamp 161 based on the received determination result.

  For example, the signal control device 151 performs a process according to the type of the target Tgt when the remaining time for lighting “recommend” in the pedestrian signal lamp 161 is small. Specifically, for example, when the determination result received from the radio wave sensor 101 indicates that the type of the target Tgt is human, the signal control device 151 extends the remaining time. Note that the signal control device 151 may notify the pedestrian Tgt2 by voice that, for example, there is little remaining time to light “Recommend”. For example, when the determination result indicates that the type of the target object Tgt is a vehicle, the signal control device 151 does not extend the remaining time.

  In addition, the signal control device 151 indicates that it is dangerous when the determination result indicates that the type of the object Tgt is human, for example, when the signal light device 161 for the pedestrian is turned on “Tarely”. A warning is given to the pedestrian Tgt2 by voice.

  Note that the signal control device 151 may provide a service to the automobile Tgt1 based on the determination result received from the radio wave sensor 101. Specifically, when the determination result indicates that the type of the object Tgt is human, the signal control device 151 gives a warning to the car Tgt1 that attention should be paid to the pedestrian Tgt2 in the pedestrian crossing PC1, for example.

[Configuration of radio wave sensor]
FIG. 2 is a diagram showing a configuration of the radio wave sensor in the signal control system according to the first embodiment of the present invention.

  With reference to FIG. 2, the radio wave sensor 101 includes a transmission antenna 1, a reception antenna 6, a radio wave processing unit 11, a signal processing unit 14, and an initial value setting unit 17. The signal processing unit 14 includes a detection unit 41 and an FFT (Fast Fourier Transform) processing unit (analysis unit) 43. Note that the transmission antenna 1 and the reception antenna 6 may be provided outside the radio wave sensor 101.

  FIG. 3 is a diagram showing a configuration of a radio wave processing unit in the radio wave sensor according to the first embodiment of the present invention.

  Referring to FIG. 3, radio wave processing unit 11 includes a transmission wave processing unit (transmission unit) 21 and a reception wave processing unit (reception unit) 22. The transmission wave processing unit 21 includes a millimeter wave generation unit 23, a directional coupler 24, and a power amplifier 25. The millimeter wave generator 23 includes a voltage generator 26 and a voltage controlled oscillator 27. The reception wave processing unit 22 includes a low noise amplifier 28, a differential signal generation unit 29, and an A / D converter (ADC) 30.

  FIG. 4 is a diagram illustrating a configuration of a differential signal generation unit in the reception wave processing unit according to the first embodiment of the present invention.

  Referring to FIG. 4, difference signal generation unit 29 includes a mixer 31, an IF (Intermediate Frequency) amplifier 32, and a low-pass filter 33.

  2 to 4, initial value setting unit 17 holds an upper limit value and a lower limit value in the reflection intensity axis direction and an upper limit value and a lower limit value in the frequency axis direction of pedestrian range Rgp. Details of the pedestrian range Rgp will be described later.

  The transmission wave processing unit 21 transmits a radio wave to the target area A1 via the transmission antenna 1. Specifically, the millimeter wave generation unit 23 in the transmission wave processing unit 21 generates a radio wave having a frequency of, for example, 24 GHz, that is, a millimeter wave, and outputs the generated millimeter wave to the directional coupler 24. The millimeter wave generation unit 23 may generate a radio wave having a frequency of, for example, 60 GHz band, 76 GHz band, or 79 GHz band. In addition, the millimeter wave generation unit 23 may generate, for example, a radio wave having a frequency in the microwave band lower than that in the millimeter wave band, or a radio wave having a frequency in the terahertz band higher than that in the millimeter wave band. It may be generated.

  More specifically, the voltage generator 26 in the millimeter wave generator 23 generates a constant voltage, for example, and outputs the generated constant voltage to the voltage controlled oscillator 27. Specifically, the voltage controlled oscillator 27 is a VCO (Voltage-controlled oscillator), generates a transmission wave in the millimeter wave band having a frequency corresponding to a constant voltage received from the voltage generation unit 26, and directs the generated transmission wave in a direction. To the sex coupler 24.

  The directional coupler 24 distributes the transmission wave received from the millimeter wave generation unit 23 to the power amplifier 25 and the reception wave processing unit 22. The power amplifier 25 amplifies the transmission wave received from the directional coupler 24 and outputs it to the transmission antenna 1.

  The transmission antenna 1 transmits the transmission wave received from the power amplifier 25 to the target area A1. As shown in FIG. 1, the transmission antenna 1 is installed such that the direction Dir of the transmission wave is along the transverse direction of the pedestrian crossing PC1, for example. Here, the directivity direction Dir of the transmission wave is, for example, a direction from the radio wave sensor 101 to the center Ctr of the target area A1.

  Preferably, for example, the transmitting antenna 1 has a direction in which the direction Dir of the transmission wave is projected onto the plane of the pedestrian crossing PC1 in the normal direction of the plane, and the pedestrian Tgt2 sets the pedestrian crossing PC1 in the target area A1 The moving direction vm, that is, the direction vm2 is set to be parallel or antiparallel.

  FIG. 5 is a diagram illustrating an example of the arrangement of the transmission antenna, the reception antenna, and the object according to the first embodiment of the present invention.

  Referring to FIG. 5, received wave processing unit 22 receives a radio wave from target area A <b> 1 via receiving antenna 6. Specifically, the reception wave processing unit 22 receives a millimeter wave from the target area A 1, that is, a reflected wave, via the reception antenna 6. Here, the receiving antenna 6 can receive, for example, the reflected wave R1 (t) generated by reflecting the transmission wave T1 (t) transmitted from the transmission antenna 1 by the object Tgt in the target area A1. If it is.

  Specifically, the reception antenna 6 may be the same antenna as the transmission antenna 1 or may be a different antenna. In the case where the transmission antenna 1 and the reception antenna 6 are separate antennas, the reception antenna 6 may be arranged at a position away from the transmission antenna 1, but the transmission antenna 1 is simplified in order to simplify the configuration of the radio wave sensor 101. It is preferable to arrange in the vicinity of 1.

  More specifically, the reflected wave received by the receiving antenna 6 reflects, for example, the transmitted wave transmitted by the transmitting antenna 1 from the surface portion Pi that is a part of the surface of the target Tgt located in the target area A1. The partially reflected wave generated by doing is included.

  Here, the moving speed of the surface portion Pi along the direction approaching or moving away from the radio wave sensor 101 is defined as a detection target speed vdi. In other words, the component of the relative velocity of the surface portion Pi with respect to the receiving antenna 6 along the direction approaching or moving away from the radio wave sensor 101 is the detection target velocity vdi.

  For example, if the relative velocity of the surface portion Pi with respect to the receiving antenna 6 is defined as a partial velocity vpi, the detection target velocity vdi is represented by the inner product of the unit vector ndi in the direction from the surface portion Pi to the receiving antenna 6 and the partial velocity vpi. The Note that the radio wave sensor 101 may be fixed to, for example, a support that does not move with respect to the ground, such as the column P1, or may be fixed to a thing that moves with respect to the ground. For example, when the radio wave sensor 101 is fixed to the column P1, the reception antenna 6 and the target area A1 are fixed with respect to the ground, so the partial speed vpi is also a relative speed of the surface portion Pi with respect to the ground.

  The target object Tgt may be a rigid body that maintains its shape, or may be a non-rigid body that changes its shape. Specifically, when the target object Tgt is the automobile Tgt1, the target object Tgt is a rigid body, and when the target object Tgt is the pedestrian Tgt2, the target object Tgt is a non-rigid body.

  The frequency f1ri of the partially reflected wave from the surface portion Pi in the object Tgt received by the receiving antenna 6 is shifted according to the detection target velocity vdi corresponding to the surface portion Pi with respect to the frequency f1 of the transmitted wave. The amplitude of the partially reflected wave is an amplitude corresponding to the reflection cross-sectional area σi of the surface portion Pi.

More specifically, in the case where the transmission wave T1 (t) is represented by the following expression (1), for example, when the reception antenna 6 is arranged in the vicinity of the transmission antenna 1, the partially reflected wave R1i (t) is Koji Yoichi, and two others, “Application of Expanding Millimeter-Wave Technology”, [online], [searched on January 24, 2014], Internet <URL: http: // www. spc. co. jp / spc / pdf / giho21_09. pdf> (Non-patent Document 1), or Takayuki Inaba, Tetsuro Kirimoto, “Millimeter-wave Radar for Vehicle Use”, Automotive Technology, February 2010, Vol. 64, No. 2, As shown in 74-79 (Non-Patent Document 2), it is represented by the following equation (2).

  Here, φ1 is an initial phase. A is the amplitude of the transmitted wave. Li is the distance between the receiving antenna 6 and the surface portion Pi. c is the speed of light. ai is a value determined by, for example, the amplitude A, the antenna gain of the transmission antenna 1 and the reception antenna 6, the wavelength of the transmission wave, the distance Li, the reflection cross section σi, and the like.

  The frequency f1ri of the partially reflected wave R1i (t) is a frequency obtained by adding f1 × (2 × vdi / c) to the frequency f1 of the transmission wave T1 (t) as shown in the equation (2). Specifically, when the surface portion Pi moves in the direction approaching the receiving antenna 6, vdi becomes positive, so the frequency f1ri is higher than the frequency f1, and the surface portion Pi moves in a direction away from the receiving antenna 6. Since vdi is negative, the frequency f1ri is lower than the frequency f1.

The Doppler reflected wave R1d (t) from all objects, specifically, the automobile Tgt1 and the pedestrian Tgt2 is represented by the following expression (3).

Here, J is the number of surface portions Pi in all objects. The reflected wave R1 (t) received by the receiving antenna 6 generally includes a Doppler reflected wave R1d (t) and a non-Doppler reflected wave R1nd (t) from a portion other than the object Tgt. Therefore, the reflected wave R1 (t) is a superposition of the Doppler reflected wave R1d (t) and the non-Doppler reflected wave R1nd (t), and is expressed by the following equation (4).

  Here, a situation is assumed in which the detection target speed of the part other than the object Tgt is zero, that is, a situation where the frequency of the non-Doppler reflected wave R1nd (t) is the same as the frequency f1 of the transmission wave T1 (t).

  2 to 4 again, the low noise amplifier 28 in the reception wave processing unit 22 amplifies the reflected wave R1 (t) received by the reception antenna 6 and outputs the amplified signal to the difference signal generation unit 29.

  The difference signal generation unit 29 multiplies a predetermined radio wave, specifically, the transmission wave T1 (t) received from the directional coupler 24 and the reflected wave R1 (t) received from the low noise amplifier 28, and calculates the difference signal and the sum. Generate a frequency signal. The difference signal generation unit 29 outputs the difference signal among the generated difference signal and sum frequency signal to the A / D converter 30.

  More specifically, the mixer 31 in the differential signal generation unit 29 multiplies the transmission wave T1 (t) by the reflected wave R1 (t), and the frequency component of the transmission wave T1 (t) and the reflected wave R1 (t). A difference signal having a frequency component that is a difference from the frequency component and a sum frequency signal having a frequency component that is the sum of both frequency components are generated.

In the mixer 31, the partial difference signal B1i (t) generated from the transmission wave T1 (t) and the partial reflection wave R1i (t) included in the reflection wave R1 (t) is expressed by the following equation (5). The

Here, K1i is the amplitude of the partial difference signal. −4π × f1 × Li / c is the delay phase θ1i. 2 × f1 × vdi / c is the Doppler frequency f1di. Further, the Doppler difference signal B1d (t) based on the Doppler reflected wave R1d (t) is expressed by the following equation (6).

Here, J is the number of surface portions Pi in all the objects as in the case of Expression (3). Further, the difference signal based on the non-Doppler reflected wave R1nd (t) becomes the DC component DC1 because the frequency of the non-Doppler reflected wave R1nd (t) is the same as the frequency f1 of the transmitted wave T1 (t). Therefore, the differential signal B1 (t) based on the reflected wave R1 (t) is expressed by the following equation (7).

  The IF amplifier 32 is an amplifier having a large amplification factor from, for example, a low frequency band to an intermediate frequency band, and greatly amplifies the difference signal B1 (t) among the difference signal B1 (t) and the sum frequency signal generated in the mixer 31. The signal is amplified at a rate, and the amplified differential signal B1 (t) is output to the low-pass filter 33.

  The low-pass filter 33 attenuates a component having a predetermined frequency or higher, for example, a component having a frequency of 1 kHz or higher, among the frequency components of the differential signal B1 (t) amplified by the IF amplifier 32.

  The A / D converter 30 performs a sampling process of the difference signal B1 (t) using, for example, a predetermined sampling frequency. More specifically, the A / D converter 30 converts the differential signal B1 (t) received from the differential signal generation unit 29 into a digital signal of m bits (m is a natural number of 2 or more) using a predetermined sampling frequency, for example. Then, the converted digital signal is output to the signal processing unit 14.

  The signal processing unit 14 processes the digital signal received from the reception wave processing unit 22. More specifically, the FFT processing unit 43 in the signal processing unit 14 creates frequency distribution information that is information related to the frequency distribution of the difference signal B1 (t) based on the digital signal received from the A / D converter 30.

  Specifically, the FFT processing unit 43 accumulates, for example, a digital signal received from the A / D converter 30 for a predetermined observation time Tobs, specifically 100 milliseconds. The accumulated digital signal indicates the amplitude of the difference signal B1 (ts) at each sampling timing ts included in the observation time Tobs, that is, the time spectrum.

  The FFT processing unit 43 performs fast Fourier transform on the time spectrum, and creates information on the frequency spectrum of the difference signal B1 (t) at the observation time Tobs as frequency distribution information. Hereinafter, the frequency spectrum is also referred to as Doppler spectrum DS1. Specifically, the Doppler spectrum DS1 indicates the amplitude of each frequency component included in the difference signal B1 (t) at the observation time Tobs. Further, the frequency distribution information is, for example, coordinate data indicating each point of the Doppler spectrum DS1.

  More specifically, the horizontal axis of the Doppler spectrum DS1 is, for example, the Doppler frequency f1d. Here, it is possible to calculate the detection target speed vd as c × f1d / 2 / f1 from the Doppler frequency f1d based on the equation (5). In the Doppler spectrum DS1, since the Doppler frequency f1d has a positive value, the detection target speed vd has a positive value. In other words, the magnitude of the detection target speed vd can be calculated from the Doppler frequency f1d. Therefore, it is possible to convert the horizontal axis of the Doppler spectrum DS1 into the magnitude of the detection target speed vd.

  The vertical axis of the Doppler spectrum DS1 is, for example, the intensity of the reflected wave that the reception wave processing unit 22 receives from the target area A1 via the reception antenna 6, that is, the reflection intensity Ir.

  Further, the Doppler spectrum DS1 shows the distribution of the detection target velocity vdi of each surface portion of the target Tgt. In other words, in the Doppler spectrum DS1, for example, the reflection intensity Irk at the Doppler frequency f1dk is the intensity when the reflected waves from the respective surface portions having the detection target speed corresponding to the Doppler frequency f1dk are superimposed.

  Since the time spectrum targeted by the FFT processing unit 43 for the fast Fourier transform process is discrete data, the Doppler spectrum DS1 is composed of discrete data. Hereinafter, discrete data constituting the Doppler spectrum DS1 is also referred to as a DS signal Sf [n]. Note that the FFT processing unit 43 may use a continuous time spectrum as an object of the fast Fourier transform process, for example.

  The DS signal Sf [n] is an array having an index n, for example. The index n is an integer from zero to (nmax−1), for example. nmax is, for example, the length of the DS signal Sf [n]. The data interval df of the DS signal Sf [n], that is, the resolution of the Doppler spectrum is, for example, about the reciprocal of the observation time Tobs. The frequency corresponding to the index n is, for example, df × n. Therefore, the DS signal Sf [n] indicates, for example, the reflection intensity Ir at the frequency (df × n).

  The FFT processing unit 43 outputs information about the created Doppler spectrum DS1, that is, frequency distribution information, to the detection unit 41.

(Characteristics of pedestrian Doppler spectrum)
FIG. 6 is a diagram illustrating an example of a pedestrian Doppler spectrum generated by the FFT processing unit in the radio wave sensor according to the first embodiment of the present invention.

  In FIG. 6, for example, a pedestrian Tgt2, which is the object Tgt in the target area A1, specifically, one or a plurality of walking humans and one or a plurality of traveling bicycles are shown as a crosswalk PC1 shown in FIG. The Doppler spectrum DS1m when moving along the transverse direction is shown. The horizontal axis represents the Doppler frequency f1d, that is, the magnitude of the detection target velocity vd, and the vertical axis represents the reflection intensity Ir.

  For example, the pedestrian Tgt2 moves at a substantially constant speed along the crossing direction of the pedestrian crossing PC1, that is, the direction Dir of the transmission wave directivity. Therefore, the magnitude of the detection target speed vd of the pedestrian Tgt2, ie , Continuously included in a certain range. Here, | vd | represents the absolute value of the detection target speed vd.

  Specifically, | vd | of the pedestrian Tgt2, that is, the Doppler frequency f1d, is continuously included in the frequency axis direction in the Doppler spectrum DS1m, specifically, in the range of 50 Hz or more and 700 Hz or less in the Doppler frequency f1d axis direction. It is. Here, the Doppler frequencies f1d of 50 Hz and 700 Hz correspond to, for example, | vd | at 1.1 kilometers per hour and 15 kilometers per hour, respectively.

  Further, for example, since the cross sectional area of reflection of the pedestrian Tgt2 is smaller than that of the automobile Tgt1, the reflection intensity Ir of the pedestrian Tgt2 is often below a certain level. Specifically, the reflection intensity Ir of the pedestrian Tgt2 is continuously included in a range of −90 dBm or more and −60 dBm or less, for example.

  Hereinafter, as shown in FIG. 6, a range in which the Doppler frequency f1d satisfies 50 Hz to 700 Hz and the reflection intensity Ir satisfies −90 dBm to −60 dBm is defined as a reference range, that is, a pedestrian range Rgp.

  Note that the pedestrian range Rgp is not limited to the above range. For example, the lower limit value and the upper limit value in the frequency axis direction of the pedestrian range Rgp may be appropriately set according to the frequency of the transmission wave T1 (t) used by the radio wave sensor 101. Further, for example, depending on the position and orientation of the radio wave sensor 101 and the transmission characteristics and reception characteristics of the radio wave sensor 101, the lower limit value of the pedestrian range Rgp, specifically the reflection intensity Ir axis direction, and You may set an upper limit suitably.

[Definition of target waveform]
FIG. 7 is a diagram schematically illustrating an example of a Doppler spectrum generated by the FFT processing unit in the radio wave sensor according to the first embodiment of the invention.

  Referring to FIG. 7, in DS signal Sf [n] constituting the Doppler spectrum, reflection of −90 dBm or more, which is a predetermined threshold Tha, specifically, a lower limit value in the direction of the reflection intensity axis of pedestrian range Rgp. A continuous DS signal Sf [n] having an intensity Ir is defined as a target waveform W.

  Of the Doppler frequencies f1d at the two intersections NL and NU between the threshold value Tha and the target waveform W, the Doppler frequency f1d at the intersection NL on the low frequency side is defined as the lower limit frequency fL. Further, the Doppler frequency f1d at the intersection NU on the high frequency side is defined as the upper limit frequency fU.

  In other words, the DS signal Sf [n] in the frequency range not lower than the lower limit frequency fL and not higher than the upper limit frequency fU is the target waveform W.

  For example, the target waveform W shown in FIG. 7 includes two peaks. Note that the target waveform W may include one peak, or may include three or more peaks.

  Of the peaks included in the target waveform W, a peak having the maximum reflection intensity Ir is defined as a main peak Mp. Further, of the peaks included in the target waveform W, peaks other than the main peak Mp are defined as sub-peaks Sp. Further, the reflection intensity Ir of the main peak Mp is defined as the target waveform intensity. Hereinafter, the lower limit frequency fL, the upper limit frequency fU, and the target waveform intensity are also referred to as waveform characteristics of the target waveform W.

  When the waveform characteristic of the target waveform W satisfies the following predetermined condition, that is, the waveform inclusion condition, it is defined that the target waveform W is included in the pedestrian range Rgp.

  That is, the lower limit frequency fL is equal to or higher than the lower limit value in the frequency axis direction of the pedestrian range Rgp, the upper limit frequency fU is equal to or lower than the upper limit value in the frequency axis direction of the pedestrian range Rgp, and the target waveform strength is the pedestrian range Rgp. When it is below the upper limit in the reflection intensity axis direction, the waveform characteristics of the target waveform W satisfy the waveform inclusion condition, and the target waveform W is included in the pedestrian range Rgp as shown in FIG.

  Referring to FIG. 6 again, Doppler spectrum DS1m includes three target waveforms Wm1, Wm2, and Wm3 at Doppler frequencies of 60 to 70 Hz, 100 to 130 Hz, and 410 to 475 Hz, respectively.

  Since the waveform characteristics of the target waveforms Wm1 to Wm3 satisfy the waveform inclusion condition, the target waveforms Wm1 to Wm3 are included in the pedestrian range Rgp. Each of the target waveforms Wm1 and Wm3 includes one main peak Mp. Further, the target waveform Wm2 includes one main peak Mp and one sub peak Sp1.

  As described above, for example, since the pedestrian Tgt2 moves at a substantially constant speed along the crossing direction of the pedestrian crossing PC1, the waveform characteristic of the target waveform W by the pedestrian Tgt2 is determined as a waveform inclusion condition at a certain time. In many cases. That is, the target waveform W by the pedestrian Tgt2 is often continuously included in the pedestrian range Rgp.

(Characteristics of automobile Doppler spectrum)
FIG. 8 is a diagram illustrating an example of a Doppler spectrum of an automobile generated by the FFT processing unit in the radio wave sensor according to the first embodiment of the invention.

  FIG. 8 shows, for example, the Doppler spectrum DS1c when the automobile Tgt1, which is the object Tgt, is moving in the target area A1. The horizontal axis represents the Doppler frequency f1d, that is, | vd |, and the vertical axis represents the reflection intensity Ir. Note that the horizontal and vertical scales shown in FIG. 8 are the same as the horizontal and vertical scales shown in FIG. 6, respectively.

  In the Doppler spectrum DS1c, when the Doppler frequencies are 10 to 60 Hz, 110 to 520 Hz, and 590 to 620 Hz, three target waveforms of Wc1, Wc2, and Wc3 are included, respectively. Each of the target waveforms Wc1 and Wc3 includes one main peak Mp. The target waveform Wc2 includes one main peak Mp and nine sub-peaks Sp1 to Sp9.

  Further, since the waveform characteristics of the target waveforms Wc1 and Wc2 do not satisfy the waveform inclusion condition, at least a part of the target waveforms Wc1 and Wc2 is not included in the pedestrian range Rgp. Moreover, since the waveform characteristic of the target waveform Wc3 satisfies the waveform inclusion condition, the target waveform Wc3 is included in the pedestrian range Rgp.

  FIG. 9 is a diagram illustrating an example of a change in the detection target speed of the automobile with respect to the radio wave sensor according to the first embodiment of the invention.

  Referring to FIG. 9, for example, when automobile Tgt1 crosses pedestrian crossing PC1 at a right angle at a constant speed vc2, the detection target speed vd of automobile Tgt1 with respect to radio wave sensor 101 changes according to the position of automobile Tgt1. Specifically, when the position is changed to Posc1, Posc2, and Posc3 by moving the automobile Tgt1, the detection target speed vd changes to vcd1, zero, and vcd3, respectively.

  Therefore, when the automobile Tgt1 changes its position from Posc1 to Posc2, the target waveform by the automobile Tgt1 moves from the high frequency side to the low frequency side. Thereafter, when the position of the automobile Tgt1 changes from Posc2 to Posc3, the target waveform of the automobile Tgt1 moves from the low frequency side to the high frequency side.

  That is, the target waveform of the automobile Tgt1 in the Doppler spectrum DC1 moves from the high frequency side to the low frequency side with time, and then moves from the low frequency side to the high frequency side. When observing the Doppler spectrum DC1 by the automobile Tgt1, only the target waveform moving from the high frequency side to the low frequency side with time is observed, or only the target waveform moving from the low frequency side to the high frequency side with time is observed. Sometimes.

  More specifically, for example, when the automobile Tgt1 moves in the vicinity of Posc2 positioned ahead of the direction Dir of the transmission wave of the radio wave sensor 101, | vd | of the automobile Tgt1 with respect to the radio wave sensor 101 is almost zero. Therefore, the lower limit frequency fL is observed on the lower frequency side than the lower limit value in the frequency axis direction of the pedestrian range Rgp as in the target waveform Wc1 shown in FIG.

  Further, since the reflection sectional area of the automobile Tgt1 is larger than the reflection sectional area of the pedestrian Tgt2, the target waveform intensity is larger than the upper limit value in the reflection intensity axis direction of the pedestrian range Rgp as in the target waveform Wc2 shown in FIG. There are many.

  Further, for example, in a long-length automobile Tgt1 such as a truck, when the front surface portion Pf of the automobile Tgt1 is located at Posc2, the rear surface portion Pr of the automobile Tgt1 may be located at Posc1. At this time, | vd | corresponding to the surface portion Pf is zero, whereas | vd | corresponding to the surface portion Pr becomes | vd1 |, so that zero to 2 in the frequency axis direction in the Doppler spectrum DC1. A wide target waveform over xf1 × | vd1 | / c is observed. Specifically, it is a wide target waveform such as a target waveform Wc2 shown in FIG. Further, in the automobile Tgt1, the reflection cross-sectional areas of the respective surface portions are often greatly different. For this reason, for example, like the target waveform Wc2 shown in FIG. 8, the number of peaks included in the target waveform by the automobile Tgt1 often increases.

  Further, unlike the case where the automobile Tgt1 crosses the pedestrian crossing PC1 at a right angle at a constant speed vc2 as shown in FIG. 9, for example, the automobile Tgt1 crosses the pedestrian crossing PC1 diagonally by making a right turn or a left turn at the intersection CS1. In this case, | vd | of the automobile Tgt1 with respect to the radio wave sensor 101 becomes large. For this reason, the upper limit frequency fU of the target waveform of the automobile may be observed on the higher frequency side than the upper limit value in the frequency axis direction of the pedestrian range Rgp.

  In summary, the waveform characteristics of the target waveform by the automobile Tgt1 often do not satisfy the waveform inclusion condition instantaneously or continuously. In other words, at least a part of the target waveform by the automobile Tgt1 is often not included in the pedestrian range Rgp instantaneously or continuously. In addition, the target waveform of the automobile Tgt1 often includes more peaks than the target waveform of the pedestrian Tgt2.

  Further, in the Doppler spectrum DC1, the variation in the frequency axis direction of the peak of the target waveform due to the automobile Tgt1 is often larger than the variation in the frequency axis direction of the target waveform due to the pedestrian Tgt2.

  Specifically, for example, when the magnitude of the Doppler frequency fMp of the main peak Mp of the target waveform by the automobile Tgt1 is larger than the magnitude of the Doppler frequency fMp of the main peak Mp of the target waveform by the pedestrian Tgt2. There are many.

  Further, in the Doppler spectrum DC1, the fluctuation in the reflection intensity axis direction of the peak of the target waveform due to the automobile Tgt1 is often larger than the fluctuation in the reflection intensity axis direction of the peak of the target waveform due to the pedestrian Tgt2.

  Specifically, for example, the increment of the target waveform intensity of the target waveform by the automobile Tgt1 is often larger than the increment of the target waveform intensity of the peak of the target waveform by the pedestrian Tgt2.

  More specifically, in the target waveform by the automobile Tgt1, even when the target waveform is included in the pedestrian range Rgp, the fluctuation in the frequency axis direction of the peak of the target waveform is greater than or equal to a predetermined frequency change allowable value Qf, and In many cases, the fluctuation in the peak reflection intensity axis direction satisfies at least one of a predetermined intensity change allowable value Qi or more.

  On the other hand, in the target waveform by the pedestrian Tgt2, the target waveform is included in the pedestrian range Rgp, the fluctuation in the frequency axis direction of the peak of the target waveform is continuously less than the frequency change allowable value Qf, and the peak In many cases, the variation in the reflection intensity axis direction is continuously less than the intensity change allowable value Qi.

  This is because the pedestrian Tgt2 moves at a substantially constant speed along the crossing direction of the pedestrian crossing PC1, whereas the automobile Tgt1 crosses the pedestrian crossing PC1 while greatly changing | vd |.

[Object detection processing based on pedestrian range Rgp]
FIG. 10 is a diagram illustrating a configuration of a detection unit in the signal processing unit according to the first embodiment of the present invention.

  Referring to FIG. 10, detection unit 41 includes a spectrum analysis unit 51, a buffer 52, a counter 53, and a type determination unit 54. The spectrum analysis unit 51 includes a target waveform acquisition unit 55, a waveform inclusion condition determination unit 56, and a peak fluctuation acquisition unit 57. The counter 53 outputs a count value Cnt as a count result.

  The detection unit 41 detects the object Tgt based on, for example, information on the Doppler spectrum DS1 created by the FFT processing unit 43. Specifically, the detection unit 41 detects a person or a vehicle as the object Tgt based on the relationship between the pedestrian range Rgp and the Doppler spectrum DS1 defined by the Doppler frequency f1d and the reflection intensity Ir. In other words, the object It is determined whether there is a human or a vehicle as the object Tgt in the area A1.

  More specifically, the buffer 52 in the detection unit 41 holds information regarding the Doppler spectrum DS1. The content of the Doppler spectrum DS1 held in the buffer 52 is updated to the content of the Doppler spectrum DS1 received from the FFT processing unit 43 every 100 milliseconds, for example.

  For example, whenever the content of the Doppler spectrum DS1 held in the buffer 52 is updated, the spectrum analysis unit 51 analyzes the updated Doppler spectrum DS1.

  More specifically, the target waveform acquisition unit 55 in the spectrum analysis unit 51 sets, for example, a lower limit value in the reflection intensity axis direction of the pedestrian range Rgp held by the initial value setting unit 17, specifically, −90 dBm as a threshold value Tha. Set as.

  Then, the target waveform acquisition unit 55 acquires a target waveform W that is a part or all of the Doppler spectrum DS1 based on the magnitude relationship between the reflection intensity Ir of each frequency component in the Doppler spectrum DS1 and the threshold value Tha.

  Specifically, the target waveform acquisition unit 55 has a continuous DS signal having a reflection intensity Ir equal to or higher than the threshold value Tha in the DS signal Sf [n] constituting the Doppler spectrum DS1 held in the buffer 52. Sf [n] is acquired as the target waveform W. Note that the target waveform acquisition unit 55 may acquire one target waveform W or a plurality of target waveforms W, for example.

  The target waveform acquisition unit 55 outputs the acquired target waveform W to the waveform inclusion condition determination unit 56 and the peak fluctuation acquisition unit 57.

  For example, in the Doppler spectrum DS1, when the target waveform W cannot be acquired because there is no DS signal Sf [n] having a reflection intensity Ir equal to or higher than the threshold value Tha in the Doppler spectrum DS1, the target waveform acquisition unit 55 changes the peak of the reset notification. While outputting to the acquisition part 57, the count value Cnt of the counter 53 is reset to zero.

  When the waveform inclusion condition determination unit 56 receives the target waveform W from the target waveform acquisition unit 55, the received target waveform W is an upper limit value and a lower limit in the reflection intensity axis direction of the pedestrian range Rgp held by the initial value setting unit 17. It is determined whether it is included in the pedestrian range Rgp determined by the value and the upper limit value and lower limit value in the frequency axis direction.

  For example, when receiving a plurality of target waveforms W from the target waveform acquisition unit 55, the waveform inclusion condition determination unit 56 determines whether or not all of the received target waveforms W are included in the pedestrian range Rgp. .

  Specifically, the waveform inclusion condition determination unit 56 acquires, for example, the lower limit frequency fL, the upper limit frequency fU and the target waveform intensity, that is, the waveform characteristics, of the target waveform W, and the acquired waveform characteristics are based on the pedestrian range Rgp. It is determined whether or not the waveform inclusion condition is satisfied.

  For example, when the waveform inclusion condition determination unit 56 determines that the waveform characteristic of the target waveform W satisfies the waveform inclusion condition, the waveform inclusion condition determination unit 56 displays a condition conformity notification indicating that the waveform characteristic of the target waveform W satisfies the waveform inclusion condition. To 57.

  On the other hand, for example, when the waveform inclusion condition determination unit 56 determines that the waveform characteristics of the target waveform W do not satisfy the waveform inclusion condition, that is, when at least a part of the acquired target waveform W is not included in the pedestrian range Rgp. The count value Cnt of the counter 53 is decremented.

  When receiving the target waveform W from the target waveform acquisition unit 55, the peak fluctuation acquisition unit 57 acquires the peak fluctuation Vf in the frequency axis direction of the received target waveform W and the peak reflection fluctuation axis Vi.

  Specifically, for example, the peak fluctuation acquisition unit 57 identifies the main peak Mp included in the target waveform W, and determines the reflection intensity Ir of the identified main peak Mp, that is, the target waveform intensity, and the Doppler frequency fMp of the main peak Mp. get. The peak fluctuation acquisition unit 57 stores, for example, the acquired target waveform intensity and Doppler frequency fMp.

  For example, when the condition conformance notification received from the waveform inclusion condition determining unit 56 is the first condition conformance notification after receiving the reset notification from the target waveform acquiring unit 55, the peak variation acquiring unit 57 sets zero to the variation Vf and Acquired as Vi.

  For example, when the condition conformance notification received from the waveform inclusion condition determining unit 56 is the second or subsequent condition conformance notification after receiving the reset notification from the target waveform acquiring unit 55, the peak fluctuation obtaining unit 57 performs the following processing. I do.

  That is, for example, the peak fluctuation acquisition unit 57 acquires, as the fluctuation Vf, the absolute value of the difference between the Doppler frequency fMp stored when the previous condition conformance notification is received and the Doppler frequency fMp acquired this time. Similarly, the peak fluctuation obtaining unit 57 obtains, for example, the absolute value of the difference between the target waveform intensity saved when the previous condition conformity notification was received and the current target waveform intensity, that is, the magnitude of the increment, as the fluctuation Vi. .

  For example, the peak fluctuation acquisition unit 57 increments the count value Cnt of the counter 53 when the acquired fluctuation Vf is less than the frequency change allowable value Qf and the fluctuation Vi is less than the intensity change allowable value Qi.

  On the other hand, the peak fluctuation acquisition unit 57 decrements the count value Cnt of the counter 53 when, for example, the acquired fluctuation Vf is equal to or greater than the frequency change allowable value Qf or the fluctuation Vi is equal to or greater than the intensity change allowable value Qi.

  The type determining unit 54 monitors the count value Cnt of the counter 53 and determines the type of the object Tgt based on the count value Cnt.

  Specifically, for example, the state in which the target waveform W is included in the pedestrian range Rgp, the variation Vf is less than the frequency change allowable value Qf, and the variation Vi is less than the intensity change allowable value Qi continues. The count value Cnt of the counter 53 becomes larger than a predetermined threshold value Thm having a positive value, for example. In this case, the type determining unit 54 determines the type of the object Tgt as human and transmits the determination result to the signal control device 151.

  Further, for example, at least a part of the target waveform W is not continuously included in the pedestrian range Rgp, so that the count value Cnt of the counter 53 becomes smaller than a predetermined threshold value Thc having a negative value, for example. Alternatively, the state in which the target waveform W is included in the pedestrian range Rgp, the variation Vf is equal to or greater than the frequency change allowable value Qf, and the variation Vi is equal to or greater than the intensity change allowable value Qi continues. Cnt becomes smaller than a predetermined threshold value Thc having a negative value, for example. In these cases, the type determination unit 54 determines the type of the object Tgt as a vehicle, and transmits the determination result to the signal control device 151.

  The type determining unit 54 is configured to determine the type of the object Tgt as a vehicle when at least a part of the target waveform W is not continuously included in the pedestrian range Rgp, but is limited to this. Not what you want. For example, the type determining unit 54 may be configured to determine the type of the object Tgt as a vehicle at a timing when at least a part of the target waveform W is not included in the pedestrian range Rgp. Specifically, the type determining unit 54 may determine the type of the object Tgt as a vehicle at the timing when the count value Cnt of the counter 53 is decremented, for example.

  Further, although the peak fluctuation acquisition unit 57 is configured to increment or decrement the count value Cnt of the counter 53 based on the fluctuation of the main peak Mp, the present invention is not limited to this. For example, the peak fluctuation acquisition unit 57 comprehensively determines the fluctuation of the main peak Mp and the fluctuation of the sub peak Sp of the target waveform W, and increments or decrements the count value Cnt of the counter 53 based on the comprehensive judgment result. The structure which performs this may be sufficient.

  Further, the peak fluctuation acquisition unit 57 is configured to acquire the magnitude of the peak frequency increment of the target waveform W as the fluctuation in the frequency axis direction of the peak of the target waveform W in the continuously created Doppler spectrum. However, the present invention is not limited to this. For example, the peak fluctuation acquisition unit 57 may be configured to acquire an increase rate of the peak frequency of the target waveform W as a fluctuation in the frequency axis direction of the peak of the target waveform W in a continuously created Doppler spectrum.

  In addition, the peak fluctuation acquisition unit 57 is configured to acquire the magnitude of the increase in the reflection intensity Ir of the target waveform W as the fluctuation in the reflection intensity axis direction of the peak of the target waveform W in the continuously created Doppler spectrum. However, the present invention is not limited to this. For example, the peak fluctuation acquisition unit 57 may be configured to acquire an increase rate of the reflection intensity Ir of the target waveform W as a fluctuation in the peak reflection intensity axis direction of the target waveform W in a continuously created Doppler spectrum. Good.

  In addition, the detection unit 41 according to the first embodiment of the present invention includes the target waveform W included in the pedestrian range Rgp, and the variation in the frequency axis direction of the peak of the target waveform W continues, so that the frequency change allowable value Qf If the variation in the reflection intensity axis direction of the peak is continuously less than the intensity change allowable value Qi, the human body is detected as the object Tgt. However, the present invention is not limited to this. . For example, when the target waveform W is included in the pedestrian range Rgp and the fluctuation of the peak of the target waveform W in the frequency axis direction is continuously less than a predetermined value, or the target waveform W is less than the predetermined value, A configuration may be adopted in which a human is detected as the object Tgt in any one of cases where the fluctuation in the reflection intensity axis direction of the peak of the target waveform W is included in Rgp and is continuously less than a predetermined value.

  In addition, the detection unit 41 according to the first embodiment of the present invention includes the target waveform W included in the pedestrian range Rgp, and the variation in the frequency axis direction of the peak of the target waveform W continues, so that the frequency change allowable value Qf In the case where the peak is reflected and the fluctuation in the reflection intensity axis direction is continuously greater than or equal to the intensity change allowable value Qi, the vehicle is detected as the object Tgt. However, the present invention is not limited to this. . For example, when the target waveform W is included in the pedestrian range Rgp and the fluctuation of the peak of the target waveform W in the frequency axis direction is continuously greater than or equal to a predetermined value, or the target waveform W is the pedestrian range The vehicle may be detected as the target object Tgt in any one of cases where the fluctuation in the reflection intensity axis direction of the peak of the target waveform W is included in Rgp and continuously exceeds a predetermined value.

  Further, the detection unit 41 according to the first embodiment of the present invention is configured to detect a person and a vehicle as the object Tgt based on the relationship between the pedestrian range Rgp and the Doppler spectrum DS1, It is not limited to. For example, the detection unit 41 may be configured to detect either a human or a vehicle as the object Tgt based on the relationship between the pedestrian range Rgp and the Doppler spectrum DS1.

[Object detection processing based on the number of peaks]
FIG. 11 is a diagram showing a configuration of a modification of the detection unit in the signal processing unit according to the first embodiment of the present invention.

  Referring to FIG. 11, detection unit 44, which is a modification of detection unit 41, includes peak number counting unit 46, comparison unit 47, type determination unit 48, buffer 52, and target waveform acquisition unit 55. . The operations of the buffer 52 and the target waveform acquisition unit 55 are the same as those of the buffer 52 and the target waveform acquisition unit 55 shown in FIG.

  The detection unit 44 detects the target Tgt, specifically a vehicle or a pedestrian, based on the number of peaks included in the target waveform W. In other words, either the human or the vehicle is the target Tgt in the target area A1. Determine if it exists.

  More specifically, the buffer 52 in the detection unit 44 holds the Doppler spectrum DS1. The target waveform acquisition unit 55 sets, for example, the lower limit value in the reflection intensity axis direction of the pedestrian range Rgp held by the initial value setting unit 17, specifically, −90 dBm as the threshold value Tha.

  Then, the target waveform acquisition unit 55 has a continuous DS signal Sf [n] having a reflection intensity Ir equal to or higher than the threshold value Tha in the DS signal Sf [n] constituting the Doppler spectrum DS1 held in the buffer 52. ] As the target waveform W, and the acquired target waveform W is output to the peak number counting unit 46.

  When receiving the target waveform W from the target waveform acquisition unit 55, the peak number counting unit 46 calculates the number of peaks included in the received target waveform W. Specifically, when the peak number counting unit 46 receives, for example, the target waveforms Wm1, Wm2, and Wm3 in the Doppler spectrum DS1m shown in FIG. 6 from the target waveform acquisition unit 55, each of the received target waveforms Wm1, Wm2, and Wm3. 1, 2, and 1 peak are included.

  For example, when receiving the target waveforms Wc1, Wc2, Wc3 in the Doppler spectrum DS1c shown in FIG. 8 from the target waveform acquisition unit 55, the peak number counting unit 46 is one for each of the received target waveforms Wc1, Wc2, Wc3. , 10 and 1 peak are determined to be included. The peak number counting unit 46 outputs the calculated number of peaks to the comparison unit 47.

  When the comparison unit 47 receives the number of peaks from the peak number counting unit 46, the comparison unit 47 compares the number of received peaks with a predetermined threshold value Thp. More specifically, for example, when the number of peaks received from peak number counting unit 46 is smaller than threshold value Thp, comparing unit 47 outputs a peak number shortage notification to type determining unit 48. For example, when the number of peaks received from peak number counting unit 46 is equal to or greater than threshold value Thp, comparing unit 47 outputs a peak number satisfaction notification to type determining unit 48.

  For example, since the number of peaks included in the target waveforms Wm1, Wm2, and Wm3 by the pedestrian Tgt2 shown in FIG. 6 is as small as 1, 2, and 1, respectively, the number of each peak becomes smaller than the threshold Thp. The comparison unit 47 outputs a peak number shortage notification to the type determination unit 48. In addition, among the target waveforms Wc1, Wc2, and Wc3 by the automobile Tgt1 shown in FIG. 8, the number of peaks included in the target waveform Wc2 is as large as ten, so the number of peaks included in the target waveform Wc2 is equal to or greater than the threshold Thp. Thus, the comparison unit 47 outputs a peak number satisfaction notification to the type determination unit 48.

  The type determination unit 48 determines the type of the target Tgt based on the comparison result between the number of peaks in the comparison unit 47 and the threshold value Thp. Specifically, for example, when the type determination unit 48 receives a peak number shortage notification indicating that the number of peaks included in the target waveform W is smaller than the threshold value Thp from the comparison unit 47, the type determination unit 48 determines the type of the target Tgt. The person is confirmed, and the result of confirmation is transmitted to the signal control device 151. For example, when the type determination unit 48 receives a peak number satisfaction notification indicating that the number of peaks included in the target waveform W is greater than or equal to the threshold Thp from the comparison unit 47, the type determination unit 48 sets the type of the target Tgt as a vehicle. The confirmation result is transmitted to the signal control device 151.

  The comparison unit 47 is configured to compare the number of peaks received from the peak number counting unit 46 with one type of threshold value Thp, but is not limited thereto. For example, the comparison unit 47 may be configured to compare the number of peaks received from the peak number counting unit 46 with two or more types of threshold values. Specifically, for example, when the number of peaks is equal to or greater than a predetermined threshold value Thpc, the comparison unit 47 outputs a peak number satisfaction notification to the type determination unit 48, and the number of peaks is equal to the threshold value Thpc. If it is equal to or smaller than a smaller predetermined threshold value Thpm, a notification of insufficient peak number may be output to the type determining unit 48.

  In addition, although the peak number counting unit 46 is configured to calculate the number of peaks included in the target waveform W, it is not limited to this. The peak number counting unit 46 may be configured to calculate the number of sub-peaks included in the target waveform W, for example.

[Operation]
FIG. 12 is a flowchart defining an operation procedure when the radio wave sensor according to the first embodiment of the present invention detects an object in the target area. The radio wave sensor 101 in the signal control system 201 includes a computer, and an arithmetic processing unit such as a CPU in the computer reads and executes a program including a part or all of each step of the following flowchart from a memory (not shown). The program of this apparatus can be installed from the outside. The program of this device is distributed in a state stored in a recording medium.

  Referring to FIG. 12, first, radio wave sensor 101 transmits transmission wave T1 (t) to target area A1 that is an area including a part or all of pedestrian crossing PC1 (step S2).

  Next, the radio wave sensor 101 receives the reflected wave R1 (t) from the target area A1 (step S4).

  Next, the radio wave sensor 101 generates a differential signal B1 (t) between the reflected wave R1 (t) and the transmitted wave T1 (t), which is the received radio wave, and fast Fourier transforms the generated differential signal B1 (t). By processing, information on the Doppler spectrum DS1, which is the frequency distribution of the difference signal B1 (t), that is, frequency distribution information is created (step S6).

  Next, the radio wave sensor 101 detects the target Tgt in the target area A1 based on the created information on the Doppler spectrum DS1 (step S8).

  FIG. 13 is a flowchart defining an operation procedure when the detection unit in the radio wave sensor according to the first embodiment of the present invention detects an object in the target area.

  FIG. 13 shows details of the operation of detecting the object Tgt in the target area A1 by the detection unit 41 in step S8 of FIG.

  In the radio wave sensor 101, for example, the observation time Tobs is one observation cycle, and the Doppler spectrum DS1 is created based on the reflected wave R1 (t) with respect to the transmission wave T1 (t) transmitted during one observation cycle. . For example, every time the Doppler spectrum DS1 is created, the detection unit 41 in the radio wave sensor 101 analyzes the created Doppler spectrum DS1, and detects the object Tgt based on the analysis result.

  First, the target waveform acquisition unit 55 in the detection unit 41 has, for example, when the content of the Doppler spectrum DS1 in the buffer 52 is updated, the updated Doppler spectrum DS1 has a reflection intensity Ir that is equal to or greater than the threshold value Tha. A continuous DS signal Sf [n] is acquired as the target waveform W (step S102).

  Next, for example, when the target waveform W cannot be acquired (NO in step S102), the target waveform acquisition unit 55 resets the count value Cnt of the counter 53 to zero and waits until the contents of the buffer 52 are updated ( Step S104).

  On the other hand, when the target waveform W is acquired by the target waveform acquisition unit 55 (YES in step S102), the waveform inclusion condition determination unit 56 determines whether or not the target waveform W is included in the pedestrian range Rgp ( Step S106).

  Next, when the waveform inclusion condition determination unit 56 determines that the target waveform W is included in the pedestrian range Rgp (YES in step S106), the peak fluctuation acquisition unit 57 determines the peak of the target waveform W in the frequency axis direction. The fluctuation Vf and the fluctuation Vi in the reflection intensity axis direction of the peak are acquired (step S108).

  Next, when the obtained variation Vf is less than the frequency change allowable value Qf and the variation Vi is less than the intensity change allowable value Qi (YES in step S112), the peak variation acquisition unit 57 counts the count value Cnt of the counter 53. Is incremented (step S114).

  On the other hand, when the obtained variation Vf is equal to or greater than the frequency change allowable value Qf or the variation Vi is equal to or greater than the intensity change allowable value Qi (NO in step S112), the peak variation acquisition unit 57 counts the count value Cnt of the counter 53. Is decremented (step S116).

  Further, the peak fluctuation acquisition unit 57, when the waveform inclusion condition determination unit 56 determines that at least a part of the target waveform W is not included in the pedestrian range Rgp (NO in step S106), the count value Cnt of the counter 53 Is decremented (step S116).

  Next, when the count value Cnt of the counter 53 is larger than the threshold value Thm (YES in step S118), the type determining unit 54 determines the type of the object as a human (step S120).

  If the count value Cnt of the counter 53 is smaller than the threshold value Thc (NO in step S118 and YES in step S122), the type determining unit 54 determines the type of the target Tgt as a vehicle (step S124).

  If the count value of counter 53 is equal to or less than threshold value Thm and equal to or greater than threshold value Thc (NO in step S118 and NO in step S122), type determination unit 54 suspends the determination process of the type of object Tgt. (Step S126).

  In the radio wave sensor according to the first embodiment of the present invention, the Doppler spectrum is created based on the difference signal generated from the transmitted wave and the reflected wave. However, the present invention is not limited to this. . The radio wave sensor generates, for example, a differential signal having a frequency component that is a difference between a frequency component of a predetermined radio wave different from the transmission wave and a frequency component of the reflected wave, and a frequency spectrum IFFS in an intermediate frequency band based on the generated differential signal. It may be configured to create. Further, the radio wave sensor may be configured to directly create a millimeter-wave band frequency spectrum MWFS from reflected waves, for example.

  In the frequency spectrum IFFS or MWFS, since the differential signal based on the non-Doppler reflected wave does not become a DC component, the amplitude of the Doppler reflected wave from the object Tgt approaching the radio wave sensor is located in a higher frequency region than the frequency fnd of the differential signal, Further, the amplitude of the Doppler reflected wave from the object Tgt moving away from the radio wave sensor is located in a lower frequency region than the frequency fnd.

  Therefore, the radio wave sensor detects the object Tgt in the target area A1 in the frequency spectrum IFFS or MWFS, for example, based on the pedestrian range Rgp and the target waveform in the high frequency region and the low frequency region with respect to the frequency fnd.

  By the way, in the object identification device described in Patent Document 1, the type of the object is identified using the irradiation processing and detection processing of sound waves or electromagnetic waves and the image processing, so that the configuration of the device is complicated and expensive. There is a problem.

  On the other hand, in the radio wave sensor according to the first embodiment of the present invention, the transmission wave processing unit 21 transmits radio waves to the target area A1 that is an area including a part or all of the pedestrian crossing PC1. The reception wave processing unit 22 receives radio waves from the target area A1. The FFT processing unit 43 is a frequency distribution of the difference signal B1 (t) having a frequency component that is a difference between the frequency component of the transmission wave and the frequency component of the reception radio wave received by the reception wave processing unit 22, that is, the Doppler spectrum DS1. Frequency distribution information, which is information on Then, the detection unit 41 detects the object Tgt in the target area A1 based on the frequency distribution information created by the FFT processing unit 43.

  As described above, the frequency distribution information varies depending on the object Tgt in the pedestrian crossing PC1 due to the configuration using the frequency distribution information that is information about the distribution of the detection target speed of each surface portion in the object Tgt. The object Tgt in the pedestrian crossing PC1 can be detected with high accuracy.

  In addition, since the object Tgt can be detected without performing image processing, the radio wave sensor 101 can be reduced in cost and simple.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the detection unit 41 includes the reference range defined by the Doppler frequency f1d and the reflection intensity Ir, that is, the pedestrian range Rgp and the Doppler spectrum DS1 in the frequency distribution information. A person is detected as the object Tgt based on the relationship.

  As described above, with the configuration in which the human in the pedestrian crossing PC1 is detected using the pedestrian range Rgp, the human in the pedestrian crossing PC1 can be detected easily and accurately based on the relationship between the pedestrian range Rgp and the Doppler spectrum DS1. it can.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the detection unit 41 performs the Doppler spectrum based on the magnitude relationship between the reflection intensity Ir of each frequency component in the Doppler spectrum DS1 and the predetermined threshold value Tha. A target waveform W that is a part or all of DS1 is acquired. Then, when the acquired target waveform W is continuously included in the pedestrian range Rgp, the detection unit 41 detects a person as the target object Tgt.

  In many cases, the target waveform W due to the reflected wave from the human at the pedestrian crossing PC1 is included in the pedestrian range Rgp. For this reason, the person in the pedestrian crossing PC1 can be detected more accurately.

  In the radio wave sensor according to the first embodiment of the present invention, the detection unit 41 includes the target waveform W included in the pedestrian range Rgp, and the fluctuation of the peak of the target waveform W in the frequency axis direction continues. When it is less than the predetermined value, the target waveform W is included in the pedestrian range Rgp and the fluctuation in the reflection intensity axis direction of the peak is continuously less than the predetermined value, or the target waveform W is within the pedestrian range Rgp. Any of the cases where the fluctuation in the frequency axis direction of the peak is continuously less than the frequency change allowable value Qf and the fluctuation in the reflection intensity axis direction of the peak is continuously less than the allowable intensity change value Qi. In one, a human is detected as the object Tgt.

  In many cases, at least one of the fluctuation in the frequency axis direction and the fluctuation in the reflection intensity axis direction of the peak of the target waveform W due to the reflected wave from the human at the pedestrian crossing PC1 is small. For this reason, the person in the pedestrian crossing PC1 can be detected with higher accuracy.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the detection unit 41 includes the reference range defined by the Doppler frequency f1d and the reflection intensity Ir, that is, the pedestrian range Rgp and the Doppler spectrum DS1 in the frequency distribution information. Based on the relationship, the vehicle is detected as the object Tgt.

  In this way, by detecting the vehicle in the pedestrian crossing PC1 using the pedestrian range Rgp, the vehicle in the pedestrian crossing PC1 can be detected easily and accurately based on the relationship between the pedestrian range Rgp and the Doppler spectrum DS1. it can.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the detection unit 41 performs the Doppler spectrum based on the magnitude relationship between the reflection intensity Ir of each frequency component in the Doppler spectrum DS1 and the predetermined threshold value Tha. A target waveform W that is a part or all of DS1 is acquired. And the detection part 41 detects a vehicle as the target object Tgt, when at least one part of the acquired target waveform W is not continuously included in the pedestrian range Rgp.

  In many cases, at least a part of the target waveform W due to the reflected wave from the vehicle at the pedestrian crossing PC1 is not included in the pedestrian range Rgp. For this reason, the vehicle in the pedestrian crossing PC1 can be detected more accurately.

  In the radio wave sensor according to the first embodiment of the present invention, the detection unit 41 includes the target waveform W included in the pedestrian range Rgp, and the fluctuation of the peak of the target waveform W in the frequency axis direction continues. When the target waveform W is included in the pedestrian range Rgp and the fluctuation in the reflection intensity axis direction of the peak is continuously equal to or higher than the predetermined value, or when the target waveform W is within the pedestrian range Rgp. Any of the cases where the fluctuation in the frequency axis direction of the peak is continuously greater than or equal to the allowable frequency change value Qf and the fluctuation in the reflection intensity axis direction of the peak is continuously greater than or equal to the allowable intensity change value Qi. In one, a vehicle is detected as the object Tgt.

  In many cases, at least one of the fluctuation in the frequency axis direction and the fluctuation in the intensity axis direction of the peak of the target waveform W due to the reflected wave from the vehicle at the pedestrian crossing PC1 is large. For this reason, the vehicle in the pedestrian crossing PC1 can be detected with higher accuracy.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the detection unit 41 performs the Doppler spectrum based on the magnitude relationship between the reflection intensity Ir of each frequency component in the Doppler spectrum DS1 and the predetermined threshold value Tha. A target waveform W that is a part or all of DS1 is acquired. Then, the detection unit 41 detects the target Tgt based on the number of peaks included in the acquired target waveform W.

  The number of peaks included in the target waveform W due to the reflected wave from the vehicle at the pedestrian crossing PC1 is often large, and the number of peaks included in the target waveform W due to the reflected wave from the human at the pedestrian crossing PC1 is small. Many. For this reason, an object can be detected more accurately based on the number of peaks included in the object waveform W.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Second Embodiment>
The present embodiment relates to a radio wave sensor including an antenna that restricts an irradiation range of radio waves to a specific part of a pedestrian crossing as compared with the radio wave sensor according to the first embodiment. The contents other than those described below are the same as those of the radio wave sensor according to the first embodiment.

[Task]
(Doppler spectrum when pedestrians and cars are mixed)
FIG. 14 is a diagram illustrating an example of a Doppler spectrum generated by the FFT processing unit in the radio wave sensor according to the first embodiment of the present invention when pedestrians and automobiles are mixed.

  FIG. 14 shows, for example, a Doppler spectrum DS1h in the case where an automobile Tgt1 and a pedestrian Tgt2 are mixed as the target object Tgt in the target area A1, as shown in FIG. The horizontal axis represents the Doppler frequency f1d, that is, | vd |, and the vertical axis represents the reflection intensity Ir.

  For example, as shown in FIGS. 6 and 8, the target waveform W by the pedestrian Tgt2 often has a smaller target waveform intensity and a narrower target waveform W than the target waveform W by the automobile Tgt1. Therefore, when the target waveform W by the pedestrian Tgt2 and the target waveform W by the car Tgt1 overlap because the automobile Tgt1 and the pedestrian Tgt2 coexist in the target area A1 as in the Doppler spectrum DS1h shown in FIG. It may be difficult to detect the pedestrian Tgt2.

  Therefore, the radio wave sensor according to the second embodiment of the present invention solves such a problem by the following configuration and operation.

[Signal control system configuration]
FIG. 15 is a diagram showing a configuration of a signal control system according to the second embodiment of the present invention. FIG. 15 is a top view of the vicinity of the intersection CS1 where the radio wave sensor 102 is installed.

  FIG. 16 is a diagram illustrating a state in which the signal control system illustrated in FIG. 15 is viewed from the road toward the intersection.

  Referring to FIGS. 15 and 16, signal control system 202 includes radio wave sensor 102, signal control device 151, and pedestrian signal lamp 161. The radio wave sensor 102 includes a main body 111, a remote transmission antenna 2, a far reception antenna 7, a nearest transmission antenna 3, and a nearest reception antenna 8. The main body 111, the nearest transmitting antenna 3 and the nearest receiving antenna 8 are connected by a signal line (not shown), for example. Further, the remote transmission antenna 2 and the remote reception antenna 7 are directly attached to the main body 111, for example.

  The operations of the signal control device 151 and the pedestrian signal lamp 161 are the same as those of the signal control device 151 and the pedestrian signal lamp 161 according to the first embodiment of the present invention.

  The radio wave sensor 102 functions as a moving object detection sensor that detects a target object Tgt that moves in at least one of the nearest target area An1 and the far target area Af1. Here, the nearest target area An1 and the far target area Af1 are areas set by the sensor installer of the radio wave sensor 102, for example.

  For example, when the sensor installer sets the pedestrian Tgt2 who has crossed the pedestrian crossing PC1 and the pedestrian Tgt2 who has crossed the pedestrian crossing PC1 as the target object Tgt, An area not including the entire PC1 is set as the nearest target area An1. The nearest target area An1 is also a standby zone where a pedestrian Tgt2 who wants to cross the pedestrian crossing PC1 is located, for example.

  Specifically, as shown in FIG. 15, for example, the sensor installer sets a part of the sidewalk Pv1 on the radio wave sensor 102 side and the sidewalk Pv1 of the pedestrian crossing PC1 as the area of the start portion of the pedestrian crossing PC1. An area including a part on the side is set as the nearest target area An1.

  In addition, for example, when the pedestrian Tgt2 and the automobile Tgt1 moving in an area other than the nearest target area An1 in the pedestrian crossing PC1 are used as the target object Tgt, the sensor installer is selected from the nearest target area An1 in the pedestrian crossing PC1. Also, an area including a part away from the radio wave sensor 102 is set as a far target area Af1.

  Specifically, as shown in FIG. 15, for example, the sensor installer sets an area including a portion on the opposite side of the sidewalk Pv1 with respect to the nearest target area An1 as the far target area Af1 in the pedestrian crossing PC1.

  For example, the sensor installer may set the far target area Af1 so as to overlap a part of the nearest target area An1, or may set the far target area Af1 so as to include the nearest target area An1. .

[Configuration of radio wave sensor]
FIG. 17 is a diagram showing a configuration of a radio wave sensor according to the second embodiment of the present invention.

  Referring to FIG. 17, radio wave sensor 102 is a remote transmission instead of transmission antenna 1, reception antenna 6, and signal processing unit 14 as compared with radio wave sensor 101 according to the first embodiment shown in FIG. 2. The antenna 2, the nearest transmitting antenna 3, the far receiving antenna 7, the nearest receiving antenna 8 and the signal processing unit 15 are provided, and the radio wave processing unit 12 is further provided. Compared with the signal processing unit 14, the signal processing unit 15 further includes a nearest area detection unit 42. It should be noted that the far-field transmitting antenna 2, the nearest transmitting antenna 3, the far-side receiving antenna 7 and the nearest receiving antenna 8 may be provided outside the radio wave sensor 102. Further, the signal processing unit 15 may include a detection unit 44 instead of the detection unit 41.

  The operation of the radio wave processing unit 11 is the same as that of the radio wave processing unit 11 shown in FIG. The operations of the detection unit 41 and the FFT processing unit 43 in the signal processing unit 15 are the same as those of the detection unit 41 and the FFT processing unit 43 in the signal processing unit 14 shown in FIG.

  FIG. 18 is a diagram illustrating a configuration of a radio wave processing unit in the radio wave sensor according to the second embodiment of the present invention.

  Referring to FIG. 18, radio wave processing unit 12 includes a transmission wave processing unit (transmission unit) 81 and a reception wave processing unit (reception unit) 34. The transmission wave processing unit 81 includes a millimeter wave generation unit 83, a directional coupler 84, and a power amplifier 85. The millimeter wave generator 83 includes a voltage generator 86 and a voltage controlled oscillator 87. The reception wave processing unit 34 includes a phase shifter 35, A / D converters 36 and 90, difference signal generation units 37 and 89, and a low noise amplifier 88.

  The operations of the millimeter wave generator 83, the directional coupler 84, and the power amplifier 85 in the transmission wave processor 81 are the same as those of the millimeter wave generator 23, the directional coupler 24, and the power amplifier 25 in the transmission wave processor 21 shown in FIG. And the same for each. The operations of the voltage generator 86 and the voltage controlled oscillator 87 in the millimeter wave generator 83 are the same as those of the voltage generator 26 and the voltage controlled oscillator 27 in the millimeter wave generator 23 shown in FIG.

  The operations of the low noise amplifier 88, the difference signal generation units 37 and 89, and the A / D converters 36 and 90 in the reception wave processing unit 34 are the same as those of the low noise amplifier 28, the difference signal generation unit 29, and the A in the reception wave processing unit 22 shown in FIG. This is the same as the / D converter 30.

  Referring to FIGS. 15 to 19, the nearest transmitting antenna 3 and the nearest receiving antenna 8 are shown in, for example, FIGS. 15 and 16 in order to obtain the moving direction of the pedestrian Tgt2 moving in the nearest target area An1. Thus, it is installed on the opposite side of the pedestrian crossing PC1 with respect to the nearest target area An1, that is, on the opposite side of the sidewalk Pv2 with respect to the nearest target area An1.

  As a result, in the immediate target area An1, the pedestrian Tgt2 who wants to cross the pedestrian crossing PC1 and the pedestrian Tgt2 who has crossed the pedestrian crossing PC1 are set to the direction of the detection target speed vd of the pedestrian Tgt2, that is, the sign of the detection target speed vd. Can be identified based on.

  More specifically, for example, when the pedestrian Tgt2 moves from the pedestrian crossing PC1 toward the sidewalk Pv1, the detection target speed vd of the pedestrian Tgt2 for the nearest transmitting antenna 3 and the nearest receiving antenna 8 has a positive value. . In this case, the frequency of the reflected wave from the pedestrian Tgt2 received by the latest receiving antenna 8 is higher than the frequency of the transmitted wave transmitted by the latest transmitting antenna 3.

  On the other hand, for example, when the pedestrian Tgt2 moves from the sidewalk Pv1 toward the pedestrian crossing PC1, the detection target speed vd for the nearest transmitting antenna 3 and the nearest receiving antenna 8 of the pedestrian Tgt2 has a negative value. In this case, the frequency of the reflected wave from the pedestrian Tgt2 received by the nearest receiving antenna 8 is lower than the frequency of the transmitted wave transmitted by the nearest transmitting antenna 3.

  That is, the direction in which the pedestrian Tgt2 moves can be recognized based on the frequency of the reflected wave with respect to the frequency of the transmitted wave.

  The transmission wave processing unit 81 in the radio wave processing unit 12 can transmit a radio wave from the nearest transmission antenna 3 by limiting the irradiation range to the nearest target area An1. Specifically, for example, by setting the transmission power of the radio wave output from the transmission wave processing unit 81 and the transmission characteristics such as the directivity of the nearest transmission antenna 3, the radio wave transmitted from the nearest transmission antenna 3 is set. The irradiation range is limited to the nearest target area An1. The transmission wave processing unit 81 and the nearest transmission antenna 3 transmit, for example, a millimeter wave band radio wave having a frequency of 24 GHz band to the nearest target area An1.

  As shown in FIG. 15, the nearest transmitting antenna 3 is installed such that the direction Dirn of the transmission wave is along the transverse direction of the pedestrian crossing PC1. Here, the directivity direction Dirn of the transmission wave transmitted from the nearest transmission antenna 3 is, for example, the direction from the nearest transmission antenna 3 to the center Ctrn of the nearest target area An1.

  Preferably, the nearest transmitting antenna 3 is, for example, a direction in which the direction Dirn of the transmission wave is projected onto the plane of the pedestrian crossing PC1 in the normal direction of the plane, and the pedestrian Tgt2 is a pedestrian crossing in the target area A1. It is installed so that the direction vm3 in which the PC 1 moves is parallel or antiparallel. Here, the direction vm3 corresponds to the direction vm in which the pedestrian Tgt2 shown in FIG. 1 moves on the pedestrian crossing PC1 in the target area A1, for example.

  The received wave processing unit 34 in the radio wave processing unit 12 receives a radio wave from the nearest target area An <b> 1 via the latest receiving antenna 8. For example, the reception wave processing unit 34 orthogonally demodulates the received radio wave using the radio wave generated by the transmission wave processing unit 81.

  More specifically, the low noise amplifier 88 in the reception wave processing unit 34 amplifies the reflected wave received by the latest reception antenna 8 and outputs the amplified signal to the difference signal generation units 89 and 37.

  The difference signal generation unit 89 is a difference signal of an I (In-phase) component having a frequency component that is a difference between the frequency component of the transmission wave generated by the transmission wave processing unit 81 and the frequency component of the reflected wave received from the low noise amplifier 88. Bi1 (t) is generated, and the generated difference signal Bi1 (t) is output to the A / D converter 90.

  The A / D converter 90 generates, for example, a digital signal by performing sampling processing of the difference signal Bi1 (t) output from the difference signal generation unit 89, and outputs the generated digital signal to the signal processing unit 15.

  For example, the phase shifter 35 shifts the phase of the transmission wave generated by the transmission wave processing unit 81 by π / 2, and outputs the transmission wave with the phase shifted to the differential signal generation unit 37.

  The difference signal generation unit 37 includes a difference signal Bq1 (t) of a Q (Quadrature) component having a frequency component that is a difference between the frequency component of the transmission wave whose phase is shifted by π / 2 and the frequency component of the reflected wave received from the low noise amplifier 88. And the generated difference signal Bq1 (t) is output to the A / D converter 36.

  As with the A / D converter 90, the A / D converter 36 generates a digital signal by, for example, sampling the differential signal Bq1 (t) output from the differential signal generation unit 37, and the generated digital signal is converted into the digital signal. Output to the signal processing unit 15.

  Referring to FIGS. 3 and 17 again, the transmission wave processing unit 21 in the radio wave processing unit 11 can transmit radio waves from the remote transmission antenna 2 while limiting the irradiation range to the far target area Af1. Specifically, for example, by setting the transmission power of the radio wave output from the transmission wave processing unit 21 and the transmission characteristics such as the directivity of the far-end transmission antenna 2, the radio wave transmitted from the far-end transmission antenna 2 is set. The irradiation range is limited to the far target area Af1. The transmission wave processing unit 21 and the far transmission antenna 2 transmit, for example, a millimeter wave radio wave having the same frequency as the radio wave transmitted from the nearest transmission antenna 3, that is, a frequency in the 24 GHz band, to the far target area Af 1. Note that the transmission wave processing unit 21 and the remote transmission antenna 2 may transmit, for example, a radio wave having a frequency different from the radio wave transmitted from the nearest transmission antenna 3 to the far target area Af1.

  As shown in FIG. 15, the far-field transmission antenna 2 is installed such that the direction Dirf of the transmission wave is along the transverse direction of the pedestrian crossing PC1. Here, the directivity direction Dirf of the transmission wave transmitted from the far transmission antenna 2 is, for example, the direction from the far transmission antenna 2 to the center Ctrf of the far target area Af1.

  Preferably, the distant transmitting antenna 2 is, for example, a direction in which the direction Dirf of the transmission wave is projected onto the surface of the pedestrian crossing PC1 in the normal direction of the surface, and the pedestrian Tgt2 is a pedestrian crossing in the target area A1. It is installed so that the direction vm4 in which the PC 1 moves is parallel or antiparallel. Here, the direction vm4 corresponds to the direction vm in which the pedestrian Tgt2 shown in FIG. 1 moves on the pedestrian crossing PC1 in the target area A1, for example.

  The received wave processing unit 22 in the radio wave processing unit 11 receives a radio wave from the far target area Af 1 via the far receiving antenna 7. The reception wave processing unit 22 generates a differential signal B1 (t) having a frequency component that is a difference between the frequency component of the radio wave transmitted by the transmission wave processing unit 21 and the frequency component of the received radio wave. Then, the reception wave processing unit 22 generates a digital signal by performing sampling processing on the generated difference signal B <b> 1 (t), and outputs the generated digital signal to the signal processing unit 15.

  The signal processing unit 15 processes digital signals received from the radio wave processing unit 11 and the radio wave processing unit 12. More specifically, the FFT processing unit 43 in the signal processing unit 15 accumulates, for example, a digital signal received from the radio wave processing unit 11 for a predetermined observation time Tobs, specifically 100 milliseconds.

  Then, the FFT processing unit 43 creates frequency distribution information, which is information about the Doppler spectrum DS1, which is the frequency distribution of the difference signal B1 (t), based on the accumulated digital signal, for example, every 100 milliseconds. Distribution information is output to the detection unit 41.

  The detection unit 41 detects the target Tgt in the far target area Af1 based on the radio waves from the far target area Af1 received by the radio wave processing unit 11 and the far receiving antenna 7, for example. More specifically, the detection unit 41 detects the object Tgt based on the frequency distribution information created by the FFT processing unit 43.

  Specifically, the detection unit 41 determines the type of the object Tgt as a vehicle or a human based on the relationship between the pedestrian range Rgp defined by the Doppler frequency f1d and the reflection intensity Ir and the Doppler spectrum DS1, and the determination result Is transmitted to the signal control device 151.

  The FFT processing unit 43 accumulates the digital signal received from the radio wave processing unit 12 for a predetermined observation time Tobs, specifically 100 milliseconds. Then, based on the accumulated digital signal, the FFT processing unit 43 obtains information on the Doppler spectra DS1i and DS1q, which are the frequency distributions of the difference signals Bi1 (t) and Bq1 (t), that is, frequency distribution information, for example, 100 milliseconds. Create each. The FFT processing unit 43 outputs the created frequency distribution information to the nearest area detection unit 42.

[Object detection processing in the nearest target area based on the pedestrian range Rgp]
FIG. 19 is a diagram illustrating a configuration of the nearest area detection unit in the signal processing unit according to the second embodiment of the present invention.

  Referring to FIG. 19, the nearest area detection unit 42 includes a spectrum analysis unit 61, an I component buffer 62, a counter 63, a type determination unit 64, a Q component buffer 68, a moving direction determination unit 69, And a determination unit 70. The spectrum analysis unit 61 includes a target waveform acquisition unit 65, a waveform inclusion condition determination unit 66, and a peak fluctuation acquisition unit 67.

  The operations of the spectrum analysis unit 61, the counter 63, and the type determination unit 64 are the same as those of the spectrum analysis unit 51, the counter 53, and the type determination unit 54 in the detection unit 41 shown in FIG. The operations of the target waveform acquisition unit 65, the waveform inclusion condition determination unit 66, and the peak variation acquisition unit 67 in the spectrum analysis unit 61 are the same as those of the target waveform acquisition unit 55, the waveform inclusion condition determination unit 56, and the peak variation acquisition unit 57 in the spectrum analysis unit 51. And the same for each.

  The nearest area detection unit 42 detects the object Tgt in the nearest target area An1 based on the radio wave from the nearest target area An1 received by the radio wave processing part 12 and the nearest receiving antenna 8, for example. More specifically, the nearest area detection unit 42 detects the object Tgt based on the frequency distribution information created by the FFT processing unit 43. Specifically, the nearest area detection unit 42 determines whether a human or a vehicle exists as the target Tgt based on the relationship between the pedestrian range Rgp defined by the Doppler frequency f1d and the reflection intensity Ir and the Doppler spectrum DS1. Judging.

  Specifically, the nearest area detection unit 42 detects a person as the object Tgt based on the relationship between the pedestrian range Rgp and the Doppler spectrum DS1i or DS1q, and also detects the object Tgt based on the Doppler spectra DS1i and DS1q. The moving direction of the pedestrian Tgt2 is detected. The nearest area detection unit 42 comprehensively determines whether or not the pedestrian Tgt who is about to cross the pedestrian crossing PC1 is located in the nearest target area An1 based on the detection result.

  More specifically, the I component buffer 62 in the nearest area detection unit 42 holds information on the Doppler spectrum DS1i created based on the difference signal Bi1 (t). The content of the Doppler spectrum DS1i held in the I component buffer 62 is updated to the content of the Doppler spectrum DS1i received from the FFT processing unit 43, for example, every 100 milliseconds.

  Similarly to the I component buffer 62, the Q component buffer 68 holds information on the Doppler spectrum DS1q created based on the difference signal Bq1 (t). The content of the Doppler spectrum DS1q held in the Q component buffer 68 is updated to the content of the Doppler spectrum DS1q received from the FFT processing unit 43, for example, every 100 milliseconds.

  For example, every time the content of the Doppler spectrum DS1i held in the I component buffer 62 is updated, the spectrum analysis unit 61 analyzes the updated Doppler spectrum DS1i, and based on the analysis result, the count value of the counter 63 Cnt is reset, incremented or decremented.

  For example, the spectrum analysis unit 61 may analyze the Doppler spectrum DS1q instead of the Doppler spectrum DS1i, and reset, increment, or decrement the count value Cnt of the counter 63 based on the analysis result.

  The type determination unit 64 monitors the count value Cnt of the counter 63, and when the count value Cnt becomes larger than the threshold value Thm, for example, determines the type of the object Tgt as human and outputs the determination result to the comprehensive judgment unit 70. For example, when the count value Cnt becomes smaller than the threshold value Thc, the type determining unit 64 determines the type of the target object Tgt as a vehicle and outputs the determination result to the comprehensive determination unit 70.

  The movement direction determination unit 69 detects, that is, determines the movement direction of the object Tgt, that is, the pedestrian Tgt2 located in the nearest target area An1, based on the Doppler spectra DS1i and DS1q. More specifically, the moving direction determination unit 69 determines the moving direction of the corresponding target Tgt for each target waveform W acquired by the target waveform acquisition unit 65, for example.

  Specifically, the movement direction determination unit 69 acquires the target waveform W based on the Doppler spectrum DS1i from the target waveform acquisition unit 65, for example. Then, the movement direction determination unit 69 acquires, for example, the target waveform intensity of the acquired target waveform W, that is, the I component intensity, and the Doppler frequency fMp of the main peak Mp.

  Then, the moving direction determination unit 69 refers to, for example, the Doppler spectrum DS1q held in the Q component buffer 68, and based on the acquired Doppler frequency fMp, the reflection intensity Ir of the Doppler frequency fMp in the Doppler spectrum DS1q, that is, the Q component intensity. To get.

  For example, the moving direction determination unit 69 determines the moving direction of the target Tgt corresponding to the target waveform W based on the relationship between the sign of the I component intensity and the sign of the Q component intensity. The movement direction determination unit 69 outputs the determination result to the comprehensive determination unit 70.

  Based on the determination result of the type of the target Tgt received from the type determination unit 64 and the determination result of the movement direction of the target Tgt received from the movement direction determination unit 69, the comprehensive determination unit 70 walks to cross the pedestrian crossing PC1. It is comprehensively determined whether or not the person Tgt is located in the nearest target area An1.

  Specifically, the overall determination unit 70 receives, for example, a determination result indicating that the type of the target Tgt is human from the type determination unit 64, and the target Tgt, that is, the pedestrian Tgt2 from the movement direction determination unit 69. When the determination result indicating that the moving direction is the direction from the sidewalk Pv1 to the crosswalk PC1 shown in FIG. 15 is received, the following determination is made. That is, the comprehensive judgment unit 70 judges that the pedestrian Tgt who is going to cross the pedestrian crossing PC1 is located in the nearest target area An1.

  For example, the general determination unit 70 receives a confirmation result indicating that the type of the target Tgt is human from the type determination unit 64, and the movement direction determination unit 69 determines the movement direction of the target Tgt, that is, the pedestrian Tgt2. When the determination result indicating that the direction is from the pedestrian crossing PC1 to the sidewalk Pv1 shown in FIG. 15 is received, the following determination is made. That is, the comprehensive judgment unit 70 judges that the pedestrian Tgt2 who has finished crossing the pedestrian crossing PC1 is located in the nearest target area An1. The comprehensive judgment unit 70 transmits the judgment result to the signal control device 151.

[Object detection processing in the nearest target area based on the number of peaks]
FIG. 20 is a diagram illustrating a configuration of a modified example of the nearest area detection unit in the signal processing unit according to the second embodiment of the present invention.

  Referring to FIG. 20, a nearest area detection unit 45, which is a modification of the nearest area detection unit 42, includes an I component buffer 62, a target waveform acquisition unit 65, a Q component buffer 68, a movement direction determination unit 69, A comprehensive judgment unit 70, a peak number counting unit 71, a comparison unit 72, and a type determining unit 73 are included.

  The operations of the I component buffer 62, the target waveform acquisition unit 65, the Q component buffer 68, the moving direction determination unit 69, and the comprehensive determination unit 70 are the I component buffer 62 and the target waveform acquisition unit 65 in the nearest area detection unit 42 shown in FIG. , Q component buffer 68, moving direction determination unit 69, and overall determination unit 70 are the same. The operations of the peak number counting unit 71, the comparing unit 72, and the type determining unit 73 are the same as those of the peak number counting unit 46, the comparing unit 47, and the type determining unit 48 in the detecting unit 44 shown in FIG.

  The nearest area detection unit 45 detects the target Tgt in the nearest target area An1, specifically a vehicle or a pedestrian, based on the number of peaks included in the target waveform W. In other words, the nearest area detection unit 45 determines whether a person or a vehicle exists as the target object Tgt in the nearest target area An1 based on the number of peaks included in the target waveform W.

  More specifically, the target waveform acquisition unit 65 in the nearest area detection unit 45 sets, for example, a lower limit value in the reflection intensity axis direction of the pedestrian range Rgp held by the initial value setting unit 17, specifically, −90 dBm as a threshold value. Set as Tha.

  Then, the target waveform acquisition unit 65 acquires the target waveform W from the Doppler spectrum DS1i held in the I component buffer 62 by using the set threshold value Tha, and the acquired target waveform W to the peak number counting unit 71. Output.

  When receiving the target waveform W from the target waveform acquisition unit 65, the peak number counting unit 71 calculates the number of peaks included in the received target waveform W, and outputs the calculated number of peaks to the comparison unit 72.

  When the comparison unit 72 receives the number of peaks from the peak number counting unit 71, for example, when the number of received peaks is smaller than the threshold value Thp, the comparison unit 72 outputs a peak number shortage notification to the type determination unit 73. For example, when the number of the peaks is equal to or greater than the threshold Thp, the comparison unit 72 outputs a peak number satisfaction notification to the type determination unit 73.

  For example, when the type determining unit 73 receives a peak number shortage notification indicating that the number of peaks included in the target waveform W is smaller than the threshold Thp from the comparing unit 72, the type determining unit 73 determines the type of the target Tgt as human. The confirmation result is output to the comprehensive judgment unit 70. For example, when the type determination unit 73 receives a peak number satisfaction notification indicating that the number of peaks included in the target waveform W is equal to or greater than the threshold Thp from the comparison unit 72, the type determination unit 73 sets the type of the target Tgt as a vehicle. The final result is determined, and the final result is output to the comprehensive judgment unit 70.

  The movement direction determination unit 69 determines the movement direction of the object Tgt, that is, the pedestrian Tgt2 located in the nearest target area An1, based on the Doppler spectra DS1i and DS1q, and outputs the determination result to the comprehensive determination unit 70.

  Based on the determination result of the type of the target Tgt received from the type determination unit 73 and the determination result of the movement direction of the target Tgt received from the movement direction determination unit 69, the comprehensive determination unit 70 walks to cross the pedestrian crossing PC1. Whether or not the person Tgt is located in the nearest target area An1 is comprehensively determined, and the determination result is transmitted to the signal control device 151.

[Operation]
FIG. 21 is a flowchart defining an operation procedure when the radio wave sensor according to the second embodiment of the present invention detects an object in the nearest target area.

  Referring to FIG. 21, first, the radio wave sensor 102 limits the irradiation range to the nearest target area An1 that is the start portion of the pedestrian crossing PC1 and does not include the entire pedestrian crossing PC1, and transmits the transmission wave T1 ( t) is transmitted from the latest transmitting antenna 3 (step S202).

  Next, the radio wave sensor 102 receives the reflected wave R1 (t) from the nearest target area An1 via the nearest receiving antenna 8 (step S204).

  Next, the radio wave sensor 102 generates and generates differential signals Bi1 (t) and Bq1 (t) between the transmission wave T1 (t) and the transmission wave whose phase is shifted by π / 2 and the reflected wave R1 (t), respectively. The difference signals Bi1 (t) and Bq1 (t) are subjected to a fast Fourier transform process, whereby information on the Doppler spectra DS1i and DS1q, which are the respective frequency distributions of the difference signals Bi1 (t) and Bq1 (t), that is, frequency distribution information. Is created (step S206).

  Next, the radio wave sensor 102 detects the target Tgt in the nearest target area An1 based on, for example, information on the created Doppler spectra DS1i and DS1q (step S208).

  FIG. 22 is a flowchart defining an operation procedure when the radio wave sensor according to the second embodiment of the present invention detects an object in a distant object area.

  Referring to FIG. 22, first, the radio wave sensor 102 limits the irradiation range to a far target area Af1 including a portion farther from the radio wave sensor 102 than the nearest target area An1 in the pedestrian crossing PC1, and transmits a transmission wave T1 ( t) is transmitted from the distant transmitting antenna 2 (step S302).

  Next, the radio wave sensor 102 receives the reflected wave R1 (t) from the far target area Af1 via the far receiving antenna 7 (step S304).

  Next, the radio wave sensor 102 generates a difference signal B1 (t) between the transmission wave T1 (t) and the reflected wave R1 (t), and performs a fast Fourier transform process on the generated difference signal B1 (t). Information regarding the Doppler spectrum DS1, which is the frequency distribution of the difference signal B1 (t), that is, frequency distribution information is created (step S306).

  Next, the radio wave sensor 102 detects the target object Tgt in the far target area Af1 based on, for example, the information on the created Doppler spectrum DS1 (step S308).

[Modification of Radio Wave Sensor 102]
The radio wave sensor 102 simultaneously transmits radio waves to the nearest target area An1 and the far target area Af1, and simultaneously receives radio waves from the nearest target area An1 and the far target area Af1.

  For this reason, the radio wave transmitted by the radio wave processing unit 11 and the remote transmission antenna 2 may affect the reception processing in the nearest receiving antenna 8 and the radio wave processing unit 12 as noise. In addition, radio waves transmitted by the radio wave processing unit 12 and the nearest transmission antenna 3 may affect reception processing in the far reception antenna 7 and the radio wave processing unit 11 as noise.

  Therefore, the radio wave processing unit 11, the far transmitting antenna 2 and the far receiving antenna 7 and the radio wave processing unit 12, the nearest transmitting antenna 3 and the nearest receiving antenna 8 are sufficiently shielded so as not to leak radio waves. Therefore, design cost, production cost, etc. will increase. Therefore, in the modification of the radio wave sensor 102, such a problem is solved by the following configuration.

  FIG. 23 is a diagram showing a configuration of a radio wave sensor according to the second embodiment of the present invention.

  Referring to FIG. 23, radio wave sensor 103 which is a modification of radio wave sensor 102 shown in FIG. 17 includes signal processing unit 16 instead of radio wave processing unit 11 and signal processing unit 15, as compared with radio wave sensor 102. Furthermore, an antenna switching unit (transmission unit) 20 and a switch switching unit 38 are provided. The signal processing unit 16 includes a detection unit 41, a nearest area detection unit 42, and an FFT processing unit 43. The far-field transmitting antenna 2, the nearest transmitting antenna 3, the far receiving antenna 7 and the nearest receiving antenna 8 may be provided outside the radio wave sensor 103. Further, the signal processing unit 16 may include a detection unit 44 instead of the detection unit 41. In addition, the signal processing unit 16 may include a nearest area detection unit 45 instead of the nearest area detection unit 42.

  The operations of the far-field transmitting antenna 2, the nearest transmitting antenna 3, the far-side receiving antenna 7, the nearest receiving antenna 8, the radio wave processing unit 12, the detecting unit 41, and the nearest area detecting unit 42 are performed in the radio wave sensor 102 shown in FIG. 17. This is the same as the far-field transmitting antenna 2, the nearest transmitting antenna 3, the far receiving antenna 7, the nearest receiving antenna 8, the radio wave processing unit 12, the detecting unit 41, and the nearest area detecting unit 42.

  The switch switching unit 38 in the radio wave sensor 103 outputs a switch switching signal, specifically, high level and low level signals to the antenna switching unit 20 and the signal processing unit 16 every predetermined time, for example, 100 milliseconds.

  The antenna switching unit 20 temporally switches between transmission of radio waves from the nearest transmission antenna 3 and transmission of radio waves from the far-field transmission antenna 2. Specifically, based on the switch switching signal received from the switch switching unit 38, the antenna switching unit 20 transmits the radio wave from the nearest transmission antenna 3 and the radio wave from the remote transmission antenna 2 every 100 milliseconds, for example. Switch between transmission and transmission.

  More specifically, for example, the antenna switching unit 20 is closest to the transmission wave processing unit 81 in the radio wave processing unit 12 during a period of receiving a low-level switch switching signal from the switch switching unit 38 (hereinafter also referred to as the latest period). The transmission antenna 3 is electrically connected, and the reception wave processing unit 34 in the radio wave processing unit 12 and the nearest reception antenna 8 are electrically connected.

  Further, the antenna switching unit 20 is, for example, a period during which a high-level switch switching signal is received from the switch switching unit 38 (hereinafter also referred to as a remote period), and the transmission wave processing unit 81 and the remote transmission antenna in the radio wave processing unit 12. 2 and the received wave processing unit 34 in the radio wave processing unit 12 and the far receiving antenna 7 are electrically connected.

  That is, the transmission wave processing unit 81 in the radio wave processing unit 12 transmits a radio wave from the nearest transmitting antenna 3 while limiting the irradiation range to the nearest target area An1 in the latest period. The received wave processing unit 34 in the radio wave processing unit 12 receives the radio wave from the nearest target area An1 via the latest receiving antenna 8 in the latest period.

  The reception wave processing unit 34 orthogonally demodulates the received radio wave using the radio wave generated by the transmission wave processing unit 81 in the latest period, and generates difference signals Bi1 (t) and Bq1 (t). The reception wave processing unit 34 generates a digital signal by performing sampling processing on the generated difference signals Bi1 (t) and Bq1 (t), and outputs the generated digital signal to the signal processing unit 16.

  In addition, the transmission wave processing unit 81 in the radio wave processing unit 12 transmits a radio wave from the far-end transmission antenna 2 while limiting the irradiation range to the far target area Af1 in the far period. The received wave processing unit 34 in the radio wave processing unit 12 receives the radio wave from the far target area Af1 via the far receiving antenna 7 in the far period.

  The reception wave processing unit 34 generates a difference signal B1 (t) having a frequency component that is a difference between the frequency component of the radio wave generated by the transmission wave processing unit 81 and the frequency component of the received radio wave in the far period. Then, the received wave processing unit 34 generates a digital signal by performing sampling processing on the generated difference signal B <b> 1 (t), and outputs the generated digital signal to the signal processing unit 16.

  The signal processing unit 16 temporally switches between processing of radio waves from the nearest target area An1 received by the nearest receiving antenna 8 and processing of radio waves from the far target area Af1 received by the far receiving antenna 7. .

  Specifically, the signal processing unit 16 recognizes the latest period and the far period based on the switch switching signal received from the switch switching unit 38, for example. For example, the FFT processing unit 43 in the signal processing unit 16 accumulates a digital signal received from the radio wave processing unit 12 for a predetermined observation time Tobs, specifically, 100 milliseconds in the most recent period. Then, the FFT processing unit 43 creates information on the Doppler spectra DS1i and DS1q based on the accumulated digital signal.

  Further, the FFT processing unit 43 accumulates, for example, a digital signal received from the radio wave processing unit 12 in a remote period, for example, for a predetermined observation time Tobs, specifically 100 milliseconds, and a Doppler spectrum based on the accumulated digital signal. Create information about DS1.

  That is, the FFT processing unit 43 alternately creates information on the Doppler spectra DS1i and DS1q and information on the Doppler spectrum DS1 every 100 milliseconds, for example. For example, the FFT processing unit 43 outputs information on the created Doppler spectra DS1i and DS1q to the nearest area detection unit 42 every 200 milliseconds. Further, the FFT processing unit 43 outputs, for example, information on the created Doppler spectrum DS1 to the detection unit 41, for example, every 200 milliseconds.

  The nearest area detection unit 42 detects the object Tgt based on information on the Doppler spectra DS1i and DS1q received from the FFT processing unit 43 every 200 milliseconds, for example. Moreover, the detection part 41 detects the target object Tgt based on the information regarding the Doppler spectrum DS1 received from the FFT process part 43 every 200 milliseconds, for example.

  In the signal control system according to the second embodiment of the present invention, the nearest transmitting antenna 3 and the nearest receiving antenna 8 are placed on the opposite side of the pedestrian crossing PC1 with respect to the nearest target area An1, that is, on the nearest target area An1. On the other hand, although it was set as the structure installed in the other side of the sidewalk Pv2, it is not limited to this. In the signal control system 202, for example, the nearest transmitting antenna 3 and the nearest receiving antenna 8 are installed on the sidewalk PC1 side with respect to the nearest target area An1, that is, on the sidewalk Pv2 side with respect to the nearest target area An1. Also good. Even in such a configuration, the direction in which the pedestrian Tgt2 moves in the nearest target area An1 can be recognized based on the level of the frequency of the reflected wave with respect to the frequency of the transmitted wave.

  Further, the signal control system 202 may have a configuration in which, for example, the nearest transmitting antenna 3 and the nearest receiving antenna 8 are installed above the nearest target area An1. In such a configuration, it may be difficult to recognize the direction in which the pedestrian Tgt2 moves in the nearest target area An1, but the pedestrian Tgt2 moving in the nearest target area An1 can be detected.

  As described above, in the radio wave sensor according to the second embodiment of the present invention, the transmission wave processing unit 81 in the radio wave processing unit 12 is an area at the start of the pedestrian crossing PC1, and the entire pedestrian crossing PC1 is covered. The radio wave can be transmitted from the nearest transmitting antenna 3 by limiting the irradiation range to the nearest target area An1 that is not included. The received wave processing unit 34 in the radio wave processing unit 12 receives a radio wave from the nearest target area An1. Then, the nearest area detection unit 42 detects the object Tgt in the nearest target area An1 based on the radio wave received by the received wave processing unit 34 in the radio wave processing unit 12.

  As described above, for example, the configuration is such that the radio wave is transmitted from the nearest transmission antenna 3 by limiting the irradiation range to the nearest target area An1 where the possibility that the vehicle is located is low. Therefore, it is possible to reduce the possibility that the target Tgt can be accurately detected by receiving the radio wave from the vehicle and the radio wave from the human at the same time. be able to. Accordingly, it is possible to accurately detect, for example, a human being as the object Tgt in the pedestrian crossing PC1.

  Further, for example, since a person who wants to cross the pedestrian crossing PC1 in the nearest target area An1 can be detected as the target object Tgt, the person can move outside the nearest target area An1 and can detect the person. Even after it disappears, it can be estimated that the person after the movement is located in an area different from the start portion of the pedestrian crossing PC1 in the pedestrian crossing PC1.

  In addition, since the object Tgt can be detected without performing image processing, the radio wave sensors 102 and 103 can be reduced in cost and simple.

  Further, in the radio wave sensor according to the second embodiment of the present invention, the transmission wave processing unit 21 in the radio wave processing unit 11 includes a portion of the pedestrian crossing PC1 that is farther from the radio wave sensor 102 than the nearest target area An1. A radio wave can be transmitted from the far-field transmitting antenna 2 by restricting the irradiation range to the far target area Af1. The received wave processing unit 22 in the radio wave processing unit 11 receives a radio wave from the far target area Af1. Then, the detection unit 41 detects the object Tgt in the far target area Af1 based on the radio wave from the far target area Af1 received by the received wave processing unit 22 in the radio wave processing unit 11.

  Thus, in addition to the nearest target area An1, the irradiation range is limited to the far target area Af1, the radio wave is transmitted from the far transmitting antenna 2, and the target Tgt in the far target area Af1 is detected. In addition, it is possible to further grasp the presence state of the vehicle and the person in the far target area Af1, which is the pedestrian crossing PC1 where the person can be located.

  Further, for example, when humans and vehicles are mixed in the far target area Af1, even when it is difficult to accurately detect the target object Tgt in the far target area Af1, the detection of the target object Tgt in the nearest target area An1 is performed. Based on the result, the detection accuracy of the target Tgt in the far target area Af1 can be increased.

  Specifically, for example, when the vehicle in the far target area Af1 becomes an obstacle to radio waves from a human in the far target area Af1, or when the radio wave from the vehicle and the radio wave from the human are simultaneously received, Even when the person in Af1 cannot be detected temporarily, the person is located in the far target area Af1 based on the detection result indicating that the person who is going to cross the pedestrian crossing PC1 is located in the nearest target area An1. Can be estimated.

  Further, in the radio wave sensor according to the second embodiment of the present invention, the antenna switching unit 20 temporally switches between radio wave transmission from the nearest transmission antenna 3 and radio wave transmission from the remote transmission antenna 2. .

  In this way, by separating the period during which radio waves are transmitted from the nearest transmitting antenna 3 and the period during which radio waves are transmitted from the far transmitting antenna 2, the radio waves transmitted from the nearest transmitting antenna 3 and the far field are transmitted. Since interference between radio waves transmitted from the transmission antenna 2 can be prevented, deterioration of reception characteristics due to interference can be avoided with simple processing.

  Further, in the radio wave sensor according to the second embodiment of the present invention, the FFT processing unit 43 receives the frequency component of the transmission wave and the received radio wave that is the radio wave received by the reception wave processing unit 22 and the reception wave processing unit 34. Frequency distribution information, which is information about the respective frequency distributions of the difference signals B1 (t) and Bi1 (t) and Bq1 (t) having a frequency component different from the frequency components, that is, Doppler spectra DS1 and DS1i and DS1q, is created. Then, the detection unit 41 detects the object Tgt based on information regarding the Doppler spectrum DS1 created by the FFT processing unit 43. Further, the nearest area detection unit 42 detects the object Tgt based on information on the Doppler spectra DS1i and DS1q created by the FFT processing unit 43.

  As described above, the frequency distribution information varies depending on the object Tgt in the pedestrian crossing PC1 due to the configuration using the frequency distribution information that is information about the distribution of the detection target speed of each surface portion in the object Tgt. The object Tgt in the pedestrian crossing PC1 can be detected with high accuracy.

  In the radio wave sensor according to the second embodiment of the present invention, the directivity direction Dirn of the nearest transmitting antenna 3 is along the crossing direction of the pedestrian crossing PC1.

  With such a configuration, the detection target speed suitable for the detection process of the target Tgt can be acquired for each type of the target Tgt, specifically, the automobile Tgt1 and the pedestrian Tgt2. It can be detected accurately.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The above description includes the following features.

[Appendix 1]
A radio wave sensor,
A transmission unit capable of transmitting radio waves from a first antenna by limiting an irradiation range to a first area which is an area of a start part of a pedestrian crossing and does not include the whole of the pedestrian crossing;
A receiver for receiving radio waves from the first area;
A detection unit that detects an object in the first area based on radio waves received by the reception unit;
The first area is an area including a part of a sidewalk on the radio wave sensor side and a part on the sidewalk side of the pedestrian crossing with respect to a road,
The detection unit detects a human as the object in the first area,
The transmitting unit can further transmit a radio wave from a second antenna by limiting an irradiation range to a second area including a portion farther from the radio wave sensor than the first area in the pedestrian crossing,
The receiver further receives radio waves from the second area,
The detection unit further detects an object in the second area based on a radio wave from the second area received by the reception unit,
The second area is an area including a portion of the pedestrian crossing opposite to the sidewalk with respect to the first area,
The detection unit is a radio wave sensor that detects at least one of a human and a vehicle as the object in the second area.

[Appendix 2]
A transmitter that transmits radio waves to the target area, which is an area that includes part or all of the pedestrian crossing,
A receiving unit for receiving radio waves from the target area;
Creates a difference signal having a frequency component that is a difference between a frequency component of a predetermined radio wave and a frequency component of a received radio wave that is a radio wave received by the receiving unit, or frequency distribution information that is information on a frequency distribution of the received radio wave. An analysis unit to
A detection unit that detects an object based on the frequency distribution information created by the analysis unit;
The analysis unit generates the difference signal having a frequency component that is a difference between the frequency component of the radio wave transmitted by the transmission unit and the frequency component of the radio wave received by the reception unit, and the frequency of the generated difference signal Information relating to a spectrum is created as the frequency distribution information, and the detection unit is a human and a vehicle as the object based on a relationship between a pedestrian range defined by frequency and intensity and the frequency spectrum created by the analysis unit. A radio wave sensor that detects at least one of the above.

DESCRIPTION OF SYMBOLS 1 Transmitting antenna 2 Far transmitting antenna 3 Nearest transmitting antenna 6 Receiving antenna 7 Far receiving antenna 8 Nearest receiving antenna 11, 12 Radio wave processing unit 14, 15, 16 Signal processing unit 17 Initial value setting unit 20 Antenna switching unit ( Transmitter)
21, 81 Transmission wave processing unit (transmission unit)
22, 34 Received wave processor (receiver)
23,83 Millimeter wave generator 24,84 Directional coupler 25,85 Power amplifier 26,86 Voltage generator 27,87 Voltage controlled oscillator 28,88 Low noise amplifier 29,37,89 Difference signal generator 30,36,90 A / D converter 31 Mixer 32 IF amplifier 33 Low pass filter 35 Phase shifter 38 Switch switching unit 41, 44 Detection unit 42, 45 Nearest area detection unit 43 FFT processing unit (analysis unit)
46, 71 Peak number counting unit 47, 72 Comparison unit 48, 73 Type determination unit 51, 61 Spectrum analysis unit 52 Buffer 53, 63 Counter 54, 64 Type determination unit 55, 65 Target waveform acquisition unit 56, 66 Waveform inclusion condition determination Unit 57, 67 Peak fluctuation acquisition unit 62 I component buffer 68 Q component buffer 69 Movement direction determination unit 70 General determination unit 101, 102, 103 Radio wave sensor 151 Signal control device 161 Pedestrian signal lamp 201, 202 Signal control system

Claims (19)

A transmission unit capable of transmitting radio waves from a first antenna by limiting an irradiation range to a first area which is an area of a start part of a pedestrian crossing and does not include the whole of the pedestrian crossing;
A receiver for receiving radio waves from the first area;
Bei example and a detection unit for detecting an object in the first area based on radio waves received by the receiving unit,
The transmitter may further transmit radio waves from a second antenna by limiting an irradiation range to a second area including a part or all of the pedestrian crossing,
The first area is an area where the vehicle is less likely to be located than the second area,
The receiver further receives radio waves from the second area,
The detection unit is a radio wave sensor further detecting an object in the second area based on radio waves from the second area received by the reception unit . The transmitting unit is further among the crosswalk, Ru der able to transmit radio waves from the second antenna to limit the irradiation range in the second area including the portion distant from the radio wave sensor than the first area , radio wave sensor according to claim 1. The radio wave sensor according to claim 1 or 2, wherein the transmission unit temporally switches between radio wave transmission from the first antenna and radio wave transmission from the second antenna. The radio wave sensor further includes:
Creates a difference signal having a frequency component that is a difference between a frequency component of a predetermined radio wave and a frequency component of a received radio wave that is a radio wave received by the receiving unit, or frequency distribution information that is information on a frequency distribution of the received radio wave. With an analysis unit
The radio wave sensor according to any one of claims 1 to 3, wherein the detection unit detects the object based on the frequency distribution information created by the analysis unit.   The radio wave sensor according to claim 4, wherein the detection unit detects a human as the object based on a relationship between a reference range defined by a frequency and intensity and the frequency distribution in the frequency distribution information.   The detection unit acquires a target waveform that is a part or all of the frequency distribution based on a magnitude relationship between the intensity of each frequency component in the frequency distribution and a predetermined threshold, and the acquired target waveform is The radio wave sensor according to claim 5, wherein a human being is detected as the object when continuously included in the reference range.   When the target waveform is included in the reference range, and the fluctuation in the frequency axis direction of the peak of the target waveform is continuously less than a predetermined value, the detection unit includes the target waveform in the reference range, And when the fluctuation in the intensity axis direction of the peak is continuously less than a predetermined value, or the target waveform is included in the reference range, the fluctuation in the frequency axis direction of the peak is continuously less than a predetermined value, The radio wave sensor according to claim 6, wherein a human is detected as the object in any one of cases where the fluctuation in the intensity axis direction of the peak is continuously less than a predetermined value.   The said detection part detects a vehicle as said target object based on the relationship between the reference range prescribed | regulated by the frequency and intensity | strength, and the said frequency distribution in the said frequency distribution information, The any one of Claims 4-7 The radio wave sensor described in 1.   The detection unit acquires a target waveform that is a part or all of the frequency distribution based on a magnitude relationship between the intensity of each frequency component in the frequency distribution and a predetermined threshold, and the acquired target waveform The radio wave sensor according to claim 8, wherein a vehicle is detected as the object when at least a part is not continuously included in the reference range. When the target waveform that is a part or all of the frequency distribution is included in the reference range, and the fluctuation in the frequency axis direction of the peak of the target waveform is continuously greater than or equal to a predetermined value, the detection unit When the waveform is included in the reference range and the fluctuation in the intensity axis direction of the peak is continuously greater than or equal to a predetermined value, or the target waveform is included in the reference range and the fluctuation in the frequency axis direction of the peak is 9. The vehicle according to claim 8, wherein a vehicle is detected as the object in any one of cases where the peak value is continuously greater than or equal to a predetermined value and fluctuations in the intensity axis direction of the peak are continuously greater than or equal to a predetermined value. Radio wave sensor.   The detection unit acquires a target waveform that is a part or all of the frequency distribution based on the magnitude relationship between the intensity of each frequency component in the frequency distribution and a predetermined threshold, and adds the acquired target waveform to the acquired target waveform. The radio wave sensor according to any one of claims 4 to 10, wherein the object is detected based on the number of included peaks.   The radio wave sensor according to any one of claims 1 to 11, wherein a direction of directivity of the first antenna is along a crossing direction of the pedestrian crossing. A transmission unit that transmits radio waves from the antenna to the target area, which is an area that includes part or all of the pedestrian crossing,
A receiving unit for receiving radio waves from the target area;
Creates a difference signal having a frequency component that is a difference between a frequency component of a predetermined radio wave and a frequency component of a received radio wave that is a radio wave received by the receiving unit, or frequency distribution information that is information on a frequency distribution of the received radio wave. An analysis unit to
Based on the frequency distribution information created by the analysis unit, Bei example and a detection unit for detecting an object in said target area,
The directionality of the antenna is along the crossing direction of the pedestrian crossing,
The detection unit detects a human as the object based on a relationship between a reference range defined by frequency and intensity and the frequency distribution in the frequency distribution information,
The detection unit acquires a target waveform that is a part or all of the frequency distribution based on a magnitude relationship between the intensity of each frequency component in the frequency distribution and a predetermined threshold, and the acquired target waveform is A radio wave sensor that detects a person as the object when continuously included in the reference range . A transmission unit that transmits radio waves from the antenna to the target area, which is an area that includes part or all of the pedestrian crossing,
A receiving unit for receiving radio waves from the target area;
Creates a difference signal having a frequency component that is a difference between a frequency component of a predetermined radio wave and a frequency component of a received radio wave that is a radio wave received by the receiving unit, or frequency distribution information that is information on a frequency distribution of the received radio wave. An analysis unit to
Based on the frequency distribution information created by the analysis unit, Bei example and a detection unit for detecting an object in said target area,
The directionality of the antenna is along the crossing direction of the pedestrian crossing,
The detection unit detects a vehicle as the object based on a relationship between a reference range defined by frequency and intensity and the frequency distribution in the frequency distribution information,
The detection unit acquires a target waveform that is a part or all of the frequency distribution based on a magnitude relationship between the intensity of each frequency component in the frequency distribution and a predetermined threshold, and the acquired target waveform A radio wave sensor that detects a vehicle as the object when at least a portion is not continuously included in the reference range . A transmission unit that transmits radio waves from the antenna to the target area, which is an area that includes part or all of the pedestrian crossing,
A receiving unit for receiving radio waves from the target area;
Creates a difference signal having a frequency component that is a difference between a frequency component of a predetermined radio wave and a frequency component of a received radio wave that is a radio wave received by the receiving unit, or frequency distribution information that is information on a frequency distribution of the received radio wave. An analysis unit to
Based on the frequency distribution information created by the analysis unit, Bei example and a detection unit for detecting an object in said target area,
The directionality of the antenna is along the crossing direction of the pedestrian crossing,
The detection unit detects a vehicle as the object based on a relationship between a reference range defined by frequency and intensity and the frequency distribution in the frequency distribution information,
When the target waveform that is a part or all of the frequency distribution is included in the reference range, and the fluctuation in the frequency axis direction of the peak of the target waveform is continuously greater than or equal to a predetermined value, the detection unit When the waveform is included in the reference range and the fluctuation in the intensity axis direction of the peak is continuously greater than or equal to a predetermined value, or the target waveform is included in the reference range and the fluctuation in the frequency axis direction of the peak is A radio wave sensor for detecting a vehicle as the target object in any one of cases where the peak value is continuously greater than or equal to a predetermined value and fluctuations in the intensity axis direction of the peak are continuously greater than or equal to a predetermined value . A detection method in a radio wave sensor,
A radio wave is transmitted from the first antenna by limiting an irradiation range to a first area which is an area of a start portion of a pedestrian crossing and does not include the entire pedestrian crossing;
Receiving radio waves from the first area;
Detecting an object in the first area based on a received radio wave ;
Limiting the irradiation range to a second area including part or all of the pedestrian crossing and transmitting radio waves from the second antenna,
The first area is an area where the vehicle is less likely to be located than the second area,
The detection method further includes:
Receiving radio waves from the second area;
Detecting an object in the second area based on the received radio wave from the second area . A detection method in a radio wave sensor,
Transmitting radio waves from the antenna to the target area, which is an area that includes part or all of the pedestrian crossing,
Receiving radio waves from the target area;
Creating a difference signal having a frequency component that is a difference between a frequency component of a predetermined radio wave and a received radio wave that is a received radio wave, or frequency distribution information that is information on a frequency distribution of the received radio wave;
Based on the frequency distribution information created, viewed including the steps of detecting an object in said target area,
The directionality of the antenna is along the crossing direction of the pedestrian crossing,
In the step of detecting the object, a person is detected as the object based on a relationship between a reference range defined by frequency and intensity and the frequency distribution in the frequency distribution information,
In the step of detecting the object, an object waveform that is a part or all of the frequency distribution is acquired based on a magnitude relationship between the intensity of each frequency component in the frequency distribution and a predetermined threshold value, and acquired. A detection method of detecting a human as the target object when the target waveform is continuously included in the reference range . A detection method in a radio wave sensor,
Transmitting radio waves from the antenna to the target area, which is an area that includes part or all of the pedestrian crossing,
Receiving radio waves from the target area;
Creating a difference signal having a frequency component that is a difference between a frequency component of a predetermined radio wave and a received radio wave that is a received radio wave, or frequency distribution information that is information on a frequency distribution of the received radio wave;
Based on the frequency distribution information created, viewed including the steps of detecting an object in said target area,
The directionality of the antenna is along the crossing direction of the pedestrian crossing,
In the step of detecting the object, a vehicle is detected as the object based on a relationship between a reference range defined by frequency and intensity and the frequency distribution in the frequency distribution information,
In the step of detecting the object, an object waveform that is a part or all of the frequency distribution is acquired based on a magnitude relationship between the intensity of each frequency component in the frequency distribution and a predetermined threshold value, and acquired. A detection method for detecting a vehicle as the object when at least a part of the target waveform is not continuously included in the reference range . A detection method in a radio wave sensor,
Transmitting radio waves from the antenna to the target area, which is an area that includes part or all of the pedestrian crossing,
Receiving radio waves from the target area;
Creating a difference signal having a frequency component that is a difference between a frequency component of a predetermined radio wave and a received radio wave that is a received radio wave, or frequency distribution information that is information on a frequency distribution of the received radio wave;
Based on the frequency distribution information created, viewed including the steps of detecting an object in said target area,
The directionality of the antenna is along the crossing direction of the pedestrian crossing,
In the step of detecting the object, a vehicle is detected as the object based on a relationship between a reference range defined by frequency and intensity and the frequency distribution in the frequency distribution information,
In the step of detecting the object, a target waveform that is a part or all of the frequency distribution is included in the reference range, and a fluctuation in the frequency axis direction of a peak of the target waveform is continuously greater than or equal to a predetermined value. In some cases, the target waveform is included in the reference range, and the fluctuation of the peak in the intensity axis direction is continuously greater than or equal to a predetermined value, or the target waveform is included in the reference range and the frequency of the peak Detection in which the vehicle is detected as the object in any one of cases where the axial variation is continuously greater than or equal to a predetermined value and the peak intensity variation in the axial direction is continuously greater than or equal to a predetermined value. Method.

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