JP2013137317A - Monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monitoring system which can more accurately detect objects existing in a monitoring area, and can more accurately comprehend the concrete content in each object having radio communication mediums.SOLUTION: A monitoring system 1 includes a laser sensor 100 and a radio tag reader 10. The laser sensor 100 includes: laser beam scanning means; light-receiving means for receiving reflected light obtained when a laser beam is reflected on an object; and detecting means for detecting the direction of the object based on a light-receiving result by the light-receiving means. The radio tag reader 10 includes: a variable directional antenna 14; directivity control means for controlling the directivity of the variable directional antenna 14; and radio communicating means for performing radio communication with a radio communication medium with a radiowave transmitted and received through the variable directional antenna 14 as a medium. The directivity control means controls the directivity of the variable directional antenna 14 based on a detection result of the object by the laser sensor 100.

Description

  The present invention relates to a monitoring system.

  Conventionally, for example, an apparatus as disclosed in Patent Document 1 is provided as a technique for detecting the distance and direction to a detection object using a laser beam. In the apparatus of Patent Document 1, an optical isolator that transmits laser light and reflects reflected light from a detection object toward the detection means is provided on the optical axis of the laser light from the laser light generation means. Furthermore, a concave mirror that rotates about the central axis in the optical axis direction is provided on the optical axis of the laser light that passes through the optical isolator. The concave mirror reflects the laser light toward the space and reflects it from the detection object. Reflecting light toward the optical isolator enables 360 ° horizontal scanning.

Japanese Patent No. 2789741 JP 2007-74323 A

  However, the laser radar device as in Patent Document 1 can detect the distance and azimuth to an object, but has a problem that specific information about the object cannot be acquired. For example, it cannot be distinguished whether an object is a permitted object or an unauthorized object.

  On the other hand, as a technique for detecting a distance and a direction by using a wireless communication technique, a wireless tag searching device as in Patent Document 2 is provided. In the technique of Patent Document 2, the distance and direction of the wireless tag are estimated based on the received intensity of the received electromagnetic wave, the reception characteristic of the antenna, and the transmission characteristic of the wireless tag. According to this technique, since various information recorded in the wireless tag can be acquired on the search device side, it is possible not only to detect the presence / absence of an object but also to acquire specific information about the object. However, the technique of Patent Document 2 is limited to the detection of the wireless tag, and there is a problem that it is impossible to detect other than the wireless tag. For example, it cannot be detected when there is an intruder who does not have a wireless tag within the communicable range of the search device.

  The present invention has been made in order to solve the above-described problems. The object of the present invention is not limited to the presence or absence of a wireless communication medium. An object of the present invention is to provide a monitoring system capable of grasping the specific contents of each object more accurately for objects having media.

According to the first aspect of the present invention, there is provided a laser beam scanning unit that scans a laser beam, a light receiving unit that receives reflected light reflected from an object by the laser beam scanned by the laser beam scanning unit, and a light receiving unit that receives the light. Detecting means for detecting the orientation of the object based on the result, and a laser device,
A variable directivity antenna, directivity control means for controlling the directivity of the variable directivity antenna, and wireless communication means for performing wireless communication with a wireless communication medium via a radio wave transmitted and received via the variable directivity antenna A wireless reader having
One or more wireless communication media capable of wireless communication with the wireless reader;
With
The detection means is configured to detect the azimuth of the object and the distance to the object based on a light reception result of the reflected light by the light receiving means,
The directivity control means controls the directivity of the variable directivity antenna so as to emit radio waves based on the orientation of the object detected by the detection means,
The wireless communication means of the wireless reader is:
Transmitting at least the distance data detected by the detection means to the wireless communication medium via the variable directional antenna;
The wireless communication medium is
Receiving means for receiving the distance data from the wireless reader;
Response determination means for determining whether to transmit a response radio wave to the wireless reader based on at least the distance data received by the reception means;
Response radio wave transmission means for transmitting the response radio wave to the wireless reader when the response determination means determines to transmit the response radio wave;
It is characterized by having.

The monitoring system according to claim 1 , wherein the directivity control unit is configured to emit a radio wave toward the object based on an orientation of the object detected by the detection unit. It is characterized by controlling the directivity of the directional antenna.

The invention of Configuration 2 is the monitoring system according to Configuration 1, and further includes the detection object based on a reading result of the wireless communication medium by the wireless communication unit and registration data registered in advance in a predetermined registration unit. An object discriminating means for discriminating whether or not the detected object is a permitted object is provided.

The invention of Configuration 3 is the monitoring system according to any one of Claim 1, Configuration 1, and Configuration 2 , wherein the wireless communication means of the wireless reader transmits the output of the wireless reader in addition to the distance data. And the antenna gain of the variable directivity antenna is transmitted to the wireless communication medium via the variable directivity antenna.
The wireless communication medium receives the distance, the transmission output of the wireless reader, and the antenna gain data of the variable directivity antenna, respectively, by the receiving means, and further the radio field intensity of the radio wave received from the wireless reader Based on the radio wave intensity detection means for detecting the transmission output of the radio reader, the antenna gain of the variable directivity antenna, the antenna gain of the radio communication medium, and the radio wave intensity detected by the radio wave intensity detection means, Estimated distance calculating means for calculating an estimated distance to the wireless reader.
The response determining unit determines to transmit the response radio wave when the distance acquired by the receiving unit and the estimated distance calculated by the estimated distance calculating unit satisfy a predetermined allowable relationship. ing.

The invention of Configuration 4 is the monitoring system according to any one of Claims 1 and 1 to 3, wherein one or a plurality of the wireless communication media capable of wireless communication with the wireless reader are provided, The detecting means is configured to detect the azimuth of the object and the distance to the object based on the result of receiving the reflected light by the light receiving means, and the directivity control means is the object detected by the detecting means. The directivity of the variable directivity antenna is controlled so as to emit radio waves based on the azimuth.
Further, the wireless communication means of the wireless reader receives at least the distance detected by the detection means, the transmission output of the wireless reader, the antenna gain of the variable directivity antenna, and the reception sensitivity data of the wireless reader. The data is transmitted to the wireless communication medium via a variable directivity antenna.
In addition, the wireless communication medium includes receiving means for receiving data on the distance from the wireless reader, the transmission output of the wireless reader, the antenna gain of the variable directivity antenna, and the reception sensitivity of the wireless reader; Radio wave intensity detection means for detecting the radio wave intensity of the radio wave received from the wireless reader, response radio wave transmission means for transmitting a response radio wave to the radio reader, transmission output of the radio reader, antenna gain of the variable directivity antenna Calculated by the estimated distance calculating means for calculating the estimated distance to the wireless reader based on the antenna gain of the wireless communication medium and the radio wave intensity detected by the radio wave intensity detecting means. The estimated distance, the antenna gain of the radio communication medium, the antenna gain of the variable directivity antenna, and the radio And a, and an output adjusting means for adjusting the output of the response radio wave based on the reception sensitivity over da.

The invention of Configuration 5 is the monitoring system according to any one of Claims 1 and 1 to 4, wherein the directivity control means is based on the orientation of the object detected by the detection means. The directivity of the variable directivity antenna is controlled so as to emit a radio wave toward the antenna, and when the directivity is controlled by the directivity control means, the wireless communication medium reads by the wireless reader. An informing means for informing when it has not been provided is provided.

The invention of configuration 6 is the monitoring system according to any one of claims 1, 1 to 5, wherein the wireless communication medium is configured as an active tag having a built-in battery.

According to the first aspect of the present invention, there is provided a laser beam scanning unit that scans a laser beam, a light receiving unit that receives reflected light reflected from an object by the laser beam scanned by the laser beam scanning unit, and a light receiving unit that receives the light. Detecting means for detecting the orientation of the object based on the result, a variable directivity antenna, directivity control means for controlling the directivity of the variable directivity antenna, and the variable directivity antenna A wireless reader having wireless communication means for wirelessly communicating with a wireless communication medium through radio waves transmitted / received via the wireless communication medium, and the directivity control means is based on the detection result of the object by the detection means. The directivity of the variable directivity antenna is controlled.
According to this configuration, an object existing in the monitoring area can be detected with higher accuracy by the laser device regardless of the presence or absence of the wireless communication medium. Furthermore, since the directivity of the variable directivity antenna can be controlled based on the detection result of the object by the laser device, appropriate directivity according to the position (distance, orientation, etc.) of the detected object detected by the laser device. Can emit radio waves, and it becomes easier to grasp the specific contents of the detected object more accurately.
In addition, one or a plurality of wireless communication media capable of wireless communication with the wireless reader are provided, and the detection unit detects the direction of the object and the distance to the object based on the light reception result of the reflected light by the light receiving unit. None, the directivity control means controls the directivity of the variable directivity antenna so as to emit radio waves based on the direction of the object detected by the detection means. Further, the wireless communication means of the wireless reader transmits at least the distance data detected by the detection means to the wireless communication medium via the variable directivity antenna.
On the other hand, the wireless communication medium includes a receiving unit that receives distance data from the wireless reader and whether or not to transmit a response radio wave to the wireless reader based on at least the distance data received by the receiving unit. Response determining means for determining and response radio wave transmitting means for transmitting a response radio wave to the wireless reader when the response determining means determines to transmit a response radio wave are provided.
In this way, distance information about the object detected by the laser device can be given to the wireless tag, and the wireless tag side can determine whether or not to respond using this distance information as a determination factor. Accordingly, it is possible to limit the wireless tags that respond based on the distance obtained by the laser device, and it becomes easy to narrow down the wireless tags to be communicated.

In the invention of configuration 1 , the directivity control means controls the directivity of the variable directivity antenna so as to emit a radio wave toward the object based on the orientation of the object detected by the detection means. In this way, radio waves can be emitted in an appropriate direction toward the object detected by the laser device. Therefore, when the detected object has a wireless communication medium, it is easy to detect the wireless communication medium satisfactorily. Become.

In the second aspect of the invention, whether or not the object detected by the detection object based on the result of reading the wireless communication medium by the wireless communication unit and the registration data registered in advance in the predetermined registration unit is a permitted object. An object discriminating means for discriminating between is provided. In this way, when an object is detected by the laser device, it can be appropriately and satisfactorily determined whether or not the detected object is a permitted object.

In the third aspect of the invention, the wireless communication means of the wireless reader transmits the transmission output of the wireless reader and the antenna gain of the variable directional antenna to the wireless communication medium via the variable directional antenna in addition to the distance data. It has a configuration.
The wireless communication medium receives the distance, the transmission output of the wireless reader, and the antenna gain data of the variable directivity antenna, respectively, by the receiving means, and further detects the radio wave intensity of the radio wave received from the wireless reader. Calculates the estimated distance to the wireless reader based on the intensity detection means, the transmission output of the wireless reader, the antenna gain of the variable directivity antenna, the antenna gain of the wireless communication medium, and the radio wave intensity detected by the radio wave intensity detection means Estimated distance calculating means. In this way, the wireless reader side parameters can be acquired on the wireless tag side, and the distance to the wireless reader can be estimated more accurately by considering the parameters together with the wireless tag side parameters.
Further, the response determination unit determines that the response radio wave is transmitted when the distance acquired by the reception unit and the estimated distance calculated by the estimated distance calculation unit satisfy a predetermined allowable relationship. Accordingly, it is possible to limit the response from the wireless tag having a low relationship in which the distance acquired from the wireless tag reader and the estimated distance do not satisfy the allowable relationship, thereby reducing the power consumption of the wireless tag and improving the efficiency of the communication processing. Can be planned.

The invention of configuration 4 is provided with one or a plurality of wireless communication media capable of wireless communication with a wireless reader, and the detection means determines the direction of the object and the distance to the object based on the result of receiving the reflected light by the light receiving means. The directivity control means controls the directivity of the variable directivity antenna so as to emit radio waves based on the direction of the object detected by the detection means.
Further, the wireless communication means of the wireless reader transmits at least the distance detected by the detection means, the transmission output of the wireless reader, the antenna gain of the variable directional antenna, and the reception sensitivity data of the wireless reader via the variable directional antenna. To the wireless communication medium.
The wireless communication medium includes a receiving means for receiving data of a distance from the wireless reader, a transmission output of the wireless reader, an antenna gain of the variable directivity antenna, and a receiving sensitivity of the wireless reader, and a radio wave received from the wireless reader. Radio wave intensity detection means for detecting the radio wave intensity of the radio, response radio wave transmission means for transmitting a response radio wave to the wireless reader, transmission output of the radio reader, antenna gain of the variable directivity antenna, antenna gain of the radio communication medium, And an estimated distance calculating means for calculating an estimated distance to the wireless reader based on the radio field intensity detected by the radio field intensity detecting means, an estimated distance calculated by the estimated distance calculating means, and an antenna gain of the wireless communication medium An output adjustment means for adjusting the output of the response radio wave based on the antenna gain of the variable directivity antenna and the reception sensitivity of the wireless reader The has.
In this way, the wireless reader side parameters can be acquired on the wireless tag side, and the distance to the wireless reader can be estimated more accurately by considering the parameters together with the wireless tag side parameters. Furthermore, since the output of the response radio wave is adjusted based on the estimated distance, the antenna gain of the wireless communication medium, the antenna gain of the variable directivity antenna, and the reception sensitivity of the wireless reader, the response radio wave Can be set more appropriately, and wasteful power consumption can be effectively reduced.

According to the fifth aspect of the invention, the directivity control means controls the directivity of the variable directional antenna so as to emit a radio wave toward the object based on the orientation of the object detected by the detection means. Informing means for informing when the wireless communication medium is not read by the wireless reader when the directivity is controlled by the sex control means is provided.
In this way, when the object detected by the laser device does not have a wireless communication medium, it can be detected more accurately, and such an abnormal object (not having a wireless communication medium) It is possible to inform that the (object) has been detected.

In the invention of Configuration 6 , the wireless communication medium is configured as an active tag having a built-in battery. This makes it easy to secure a wide communication area for the wireless communication medium, so that the monitoring area for the laser device and the wireless reader can be set wider.

FIG. 1 is an explanatory diagram for conceptually explaining the monitoring system according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view schematically illustrating a laser sensor (laser device) used in the monitoring system of FIG. FIG. 3 is a block diagram schematically illustrating an electrical configuration of a wireless tag reader (wireless reader) used in the monitoring system of FIG. FIG. 4 is a block diagram schematically illustrating an electrical configuration of a wireless tag used in the monitoring system of FIG. FIG. 5 is a block diagram schematically illustrating an electrical configuration of a controller used in the monitoring system of FIG. FIG. 6 is a flowchart illustrating the flow of monitoring processing performed on the controller side in the monitoring system of FIG. FIG. 7 is a flowchart illustrating the flow of response processing performed on the wireless tag side in the monitoring system of FIG. FIG. 8A is an explanatory diagram for explaining detection of a person by the laser sensor, and FIG. 8B is an explanatory diagram for explaining an example of emitting radio waves toward the person detected by the laser sensor. . FIG. 9A is an explanatory diagram illustrating a command frame transmitted from the wireless tag reader to the wireless tag, and FIG. 9B is an explanatory diagram illustrating a response frame transmitted from the wireless tag to the wireless tag reader.

[First embodiment]
Hereinafter, a first embodiment in which the monitoring system of the present invention is embodied will be described with reference to the drawings.
(Overview of monitoring system)
First, an overview of the monitoring system 1 according to the first embodiment will be described. FIG. 1 is an explanatory diagram for conceptually explaining the monitoring system according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view schematically illustrating a laser sensor (laser device) used in the monitoring system of FIG. FIG. 3 is a block diagram schematically illustrating an electrical configuration of a wireless tag reader (wireless reader) used in the monitoring system of FIG. FIG. 4 is a block diagram schematically illustrating an electrical configuration of a wireless tag used in the monitoring system of FIG. FIG. 5 is a block diagram schematically illustrating an electrical configuration of a controller used in the monitoring system of FIG.

  As shown in FIG. 1, the monitoring system 1 according to the first embodiment is configured as an object detection system that detects an object (such as an intruder) entering a predetermined monitoring area, for example. A laser sensor 100 corresponding to an example of “device”, a wireless tag reader 10 corresponding to an example of “wireless reader”, a controller 80 connected thereto, and a wireless tag possessed by a person (for example, an authorized person) 50. Hereinafter, each of these devices will be described in detail.

(Laser device)
As shown in FIG. 2, the laser sensor 100 includes a laser diode 110 and a photodiode 120 that receives reflected light L2 from the detection object, and is configured as a device that detects the distance and direction to the detection object. .

  The laser diode 110 receives a pulse current from a drive circuit (not shown) under the control of a control circuit 170 configured as a microcomputer, for example, and intermittently emits a pulse laser beam (laser light L1) corresponding to the pulse current. Yes. When the laser light L1 is generated from the laser diode 110 and the laser light L1 is reflected by the detection object, the photodiode 120 receives the reflected light L2 and converts it into an electrical signal. In FIG. 2, laser light from the laser diode 110 to the detection object is conceptually indicated by a symbol L1, and reflected light from the detection object to the photodiode is conceptually indicated by a symbol L2. . In addition, as for the reflected light from the detection object, the light in a predetermined region is taken into the deflecting unit 141, and FIG. 2 shows an example in which the reflected light in the region between the two lines indicated by reference numeral L2 is taken. ing. In the present embodiment, the photodiode 120 corresponds to an example of “light receiving means”, and functions so that the laser light scanned by the laser light scanning means receives the reflected light reflected by the object.

  A lens 160 is provided on the optical axis of the laser light L1 emitted from the laser diode 110. The lens 160 is configured as a collimating lens, and converts the laser light L1 from the laser diode 110 into parallel light. A mirror 130 is provided on the optical path of the laser light L1 that has passed through the lens 160. The mirror 130 includes a reflecting surface 130 a that is inclined with respect to the optical axis of the laser beam L 1 that has passed through the lens 160, and reflects the laser beam L 1 that has passed through the lens 160 toward the rotation deflection mechanism 140. In the example of FIG. 2, the laser beam L1 in the horizontal direction that has passed through the lens 160 is reflected in the vertical direction (a direction parallel to a center axis 142a described later) by the mirror 130, and the reflected laser beam in the vertical direction. L1 is incident on the deflection unit 141 of the rotation deflection mechanism 140.

  The rotation deflection mechanism 140 includes a deflection unit 141 made of a mirror having a flat reflecting surface 141a, a support base 143 that supports the deflection part 141, a shaft part 142 connected to the support base 143, and the shaft part. And a bearing (not shown) that rotatably supports 142. The deflecting unit 141 is disposed on the optical axis of the laser beam L1 reflected by the mirror 130 and is rotatable about the central axis 142a. The deflecting unit 141 is configured to deflect (reflect) the laser light L1 from the laser diode 110 toward the space and deflect (reflect) reflected light L2 from the detection object toward the photodiode 120. . In addition, the direction of the central axis 142a, which is the rotation center of the deflection unit 141, coincides with the direction of the laser beam L1 incident on the deflection unit 141 from the mirror 130, and the incident position where the laser beam L1 enters the deflection unit 141. P1 is a position on the central axis 142a. In the example of FIG. 2, the direction of the central axis 142a is the vertical direction (Y-axis direction), and the plane direction orthogonal to the central axis 142a is the horizontal direction. Further, a predetermined direction in the horizontal direction is shown as the X-axis direction.

  As shown in FIG. 2, the reflecting surface 141a of the deflecting unit 141 is inclined at an angle of 45 ° with respect to the vertical direction (the direction of the laser light L1 incident on the reflecting surface 141a), and enters from the mirror 130 side. The laser beam L1 is reflected in the horizontal direction. Further, since the deflecting unit 141 rotates around the central axis 142a in the direction coinciding with the direction of the incident laser light L1, the incident angle of the laser light L1 is always maintained at 45 ° regardless of the rotational position of the deflecting unit 141. The direction of the laser beam L1 from the position P1 is configured to be constantly in the horizontal direction (direction orthogonal to the central axis 142a). In the present embodiment, the above-described configuration for scanning laser light, that is, the laser diode 110, the mirror 130, and the rotation deflection mechanism 140 correspond to an example of “laser light scanning means”.

  Further, a motor 150 that drives the rotation deflection mechanism 140 is provided. The motor 150 rotates and drives the deflection unit 141 connected to the shaft unit 142 by rotating the shaft unit 142. In addition, as a specific configuration of the motor 150, for example, a servo motor or the like may be used, or a pulsed laser beam is output in synchronization with a timing at which the deflecting unit 141 faces a direction in which distance measurement is desired using a motor that rotates constantly. Thus, detection of a desired direction may be possible. Further, as shown in FIG. 2, a rotation angle position sensor 152 that detects the rotation angle position of the shaft portion 142 of the motor 150 (that is, the rotation angle position of the deflection unit 141) is provided. As the rotation angle position sensor 152, various types of sensors can be used as long as they can detect the rotation angle position of the shaft portion 142, such as a rotary encoder.

  A condensing lens 162 that condenses the reflected light toward the photodiode 120 is provided on the optical path of the reflected light L2 from the rotation deflection mechanism 140 to the photodiode 120, and the condensing lens 162 and the photodiode. Between 120, a filter 164 is provided. The condensing lens 162 condenses the reflected light L2 from the deflection unit 141 and guides it to the photodiode 120. The filter 164 functions to transmit the reflected light L2 and remove light other than the reflected light L2 on the optical path of the reflected light L2 from the rotation deflection mechanism 140 to the photodiode 120. The filter 164 is constituted by a wavelength selection filter that transmits only light of a specific wavelength corresponding to the reflected light L2 (for example, light of a certain region) and blocks other light.

  In the present embodiment, the laser diode 110, the photodiode 120, the mirror 130, the lens 160, the rotation deflection mechanism 140, the motor 150, and the like are housed in the case 103, and dust protection and impact protection are achieved. Around the deflection unit 141 in the case 103, a window-shaped light guide unit 104 that allows the laser light L1 and the reflected light L2 to pass is formed so as to surround the deflection unit 141. The light guide unit 104 has an annular shape centering on the optical axis of the laser light L1 incident on the deflecting unit 141, and is configured to extend approximately 360 °. A laser light transmission plate 105 made of a material such as the like is arranged to prevent dust.

  In this laser apparatus, the relative rotation position of the deflecting unit 141 with reference to a predetermined reference position (for example, the origin position of the rotary encoder) can be detected. With reference to the “position”, each rotation position of the deflecting unit 141 at each irradiation of the pulsed laser light irradiated intermittently can be detected (that is, each rotation position at each irradiation is “ It is possible to detect how much the position is rotated with reference to the “reference position”). When the reflected light from the detection object is received by the photodiode 120 at any of the rotation positions, the angle of the deflection unit 141 at the time of the light reception is an angle rotated from the “reference position”. It is possible to identify whether there is. Therefore, the direction of the detection object can be detected using the reference direction as the irradiation direction of the laser beam L1 emitted from the deflecting unit 141 at the “reference position”. Further, when light is received by the photodiode 120 in this way, the laser light is measured by measuring the time from when the laser light L1 is output by the laser diode 110 until the reflected light L2 is detected by the photodiode 120. The distance to the detected object can be obtained in consideration of the speed of light (speed of light). In the present embodiment, such a direction and distance detection process is performed by the control circuit 170, and this control circuit corresponds to an example of a “detection unit”. Based on the light reception result by the light reception unit, the direction of the object and the object It works to detect the distance up to.

(Wireless tag reader)
Next, the wireless tag reader 10 will be described.
As shown in FIG. 3, the wireless tag reader 10 is configured as a wireless tag reader / writer, performs communication with the wireless tag 50 using electromagnetic waves, reads information recorded in the wireless tag 50, It is configured to write information. The wireless tag reader 10 is mainly configured by a control unit 11, a transmission unit 12, a reception unit 13, and a variable directivity antenna 14.

  The control unit 11 includes a CPU 31, a memory 32, a timer circuit 33, and the like, and has a configuration that governs overall control of the wireless tag reader 10.

  The transmission unit 12 includes a coding unit 21, a modulation unit 22, an amplification unit 23, and the like, and is configured to output a carrier (carrier wave) having a predetermined frequency from a carrier oscillator (not shown). The encoding unit 21 is connected to the control unit 11, encodes transmission data output from the control unit 11, and outputs the encoded transmission data to the modulation unit 22. The modulation unit 22 is a part to which the carrier (carrier wave) from the carrier oscillator and the transmission data from the encoding unit are input, and when the command (carrier wave) output from the carrier oscillator is transmitted to the communication target A modulated signal, for example, ASK (Amplitude Shift Keying) modulated by the encoded transmission code (modulated signal) output from the encoding unit 21 is generated and output to the amplifying unit 23.

  The amplifying unit 23 amplifies the input signal (the modulated signal modulated by the modulating unit) with a predetermined gain, and outputs the amplified signal to the variable directivity antenna 14 via a filter, a matching circuit, etc. (not shown). . When a transmission signal is output to the variable directivity antenna 14 in this way, the transmission signal is radiated to the outside from the variable directivity antenna 14 as an electromagnetic wave.

  The variable directivity antenna 14 is configured by a known variable directivity antenna such as an ESPAR antenna, and the directivity is controlled by the control unit 11. Specifically, for example, the emission direction of radio waves can be switched along the scanning direction (horizontal direction) of the laser sensor 100 as shown in FIG.

  The receiving unit 13 includes a demodulating unit 25, a decoding unit 26, and the like, and is configured to receive a radio wave signal received by the variable directivity antenna 14. The receiving unit 13 receives a received signal from the variable directivity antenna 14 via a matching circuit (not shown), filters it with a filter (not shown), amplifies it with an amplifier (not shown), and demodulates the amplified signal. Demodulated by the unit 25. Then, the demodulated signal waveform is binarized by a binarization processing unit (not shown), decoded by the decoding unit 26, and then the decoded signal is output to the control unit 11 as received data. The receiving unit 13 is provided with a carrier sense unit 27 that checks whether a channel for emitting radio waves is available.

(Wireless tag)
The wireless tag 50 corresponds to an example of a “wireless communication medium”, and is configured as, for example, a known RFID tag in hardware. As illustrated in FIG. 4, as illustrated in FIG. 4, the control unit 51, the antenna 54, and the reception unit 53. , A transmission unit 52, a power supply unit 59, and the like. In the example of FIG. 4, the wireless tag 50 is configured as a so-called active tag, provided with a built-in battery (for example, a lithium coin battery), and the power supply unit 59 receives power supply from the built-in battery, and the control unit Power for operation is supplied to each component including 51.

  The control unit 51 includes a CPU 55, a memory 56, a timer circuit 57, and the like. The CPU 55 performs various controls (such as response processing in FIG. 7) and arithmetic processing in the wireless tag 50. The memory 56 includes various semiconductor memories such as a ROM and an EEPROM, and includes tag identification information (tag ID) for identifying the wireless tag 50 and information handled in response processing (FIG. 7) described later. Various information is stored.

  The receiving unit 53 includes a demodulating unit 65, a decoding unit 66, a received signal strength detecting unit 67, and the like. In the receiving unit 53, the signal received by the antenna 54 is demodulated by the demodulating unit 65, and the demodulated signal is decoded by the decoding unit 66, thereby outputting the data superimposed on the received signal to the control unit 51. doing. The received signal strength detection unit 67 is a part that detects the radio wave strength of the received signal received by the antenna 54, and outputs the detection signal to the control unit 51. The receiving unit 13 is also provided with a carrier sense unit 68 that checks whether a channel for emitting radio waves is available.

  The transmission unit 52 mainly includes a coding unit 61, a modulation unit 62, and an amplification unit 63. The transmitter 52 encodes the data output from the controller 51 as transmission data by the encoder 61 and then modulates the data by the modulator 62. The modulated signal is amplified by the amplifying unit 63 and output to the antenna 54. Thus, the transmission data output to the antenna 54 is radiated from the antenna 54 as a radio wave signal.

(controller)
Next, the controller 80 will be described. The controller 80 is configured as an information processing apparatus as shown in FIG. 5, for example, and is mainly configured by a CPU 81, a storage unit 82, an input unit 83, a communication interface 84, a display unit 85, a buzzer 86, and the like.

  The CPU 81 is configured to perform various controls (for example, processing as shown in FIG. 6) in accordance with a program stored in the storage unit 82. The storage unit 82 includes a semiconductor memory such as a ROM, a RAM, and a nonvolatile memory, and has a configuration capable of storing various types of information. The communication interface 84 is an interface for communicating with the laser sensor 100 and the wireless tag reader 10. Information transmission to the laser sensor 100, information input from the laser sensor 100, or information to the wireless tag reader 10 is performed via the communication interface 84. Transmission and information input from the wireless tag reader 10 are performed. The display unit 85 is configured by a lamp such as an LED or a display such as a liquid crystal display panel, and is configured to perform various displays. The buzzer 86 is configured to sound according to the control of the CPU 81.

(Object detection by monitoring system)
Next, object detection performed in the monitoring system 1 will be described.
FIG. 6 is a flowchart illustrating the flow of monitoring processing performed on the controller 80 side in the monitoring system 1 of FIG. FIG. 7 is a flowchart illustrating the flow of response processing performed on the wireless tag 50 side in the monitoring system 1 of FIG. FIG. 8A is an explanatory diagram for explaining detection of a person by the laser sensor, and FIG. 8B is an explanatory diagram for explaining an example of emitting radio waves toward the person detected by the laser sensor. . FIG. 9A is an explanatory diagram illustrating a command frame transmitted from the wireless tag reader to the wireless tag, and FIG. 9B is an explanatory diagram illustrating a response frame transmitted from the wireless tag to the wireless tag reader.

  For example, the controller 80 performs the monitoring process according to the flowchart shown in FIG. The monitoring process in FIG. 6 is executed, for example, every predetermined short time. First, it is determined whether or not an object is detected in the monitoring area (S1). And when an object is detected, it becomes Yes by S1 and the direction and distance of the detected object are acquired.

  In the present embodiment, as shown in FIG. 8A, the above-described laser sensor 100 (FIG. 2) is within a predetermined range (for example, a range within a predetermined distance from the laser sensor 100, and the deflecting unit 41 has a predetermined first position). Object detection is performed with a monitoring range AR1 within a range scanned from one rotation position to a predetermined second rotation position so that laser scanning within the monitoring range AR1 is continuously performed. It has become. In the laser sensor 100, when an object is detected within the monitoring range AR1, the detection signal is output to the controller 80, and the direction and distance of the detected object are also output. In S1, it is determined whether or not such a detection signal is output. If the detection signal is output, the direction (azimuth) and distance of the detected object output from the laser sensor 100 is obtained in S1. It has come to be.

  After S2, the directivity of the directional antenna is set based on the direction (azimuth of the detected object) acquired in S2. In this embodiment, for example, the laser sensor 100 and the wireless tag reader 10 are disposed adjacent to each other as shown in FIG. 8A, and a predetermined direction (arrow F) is set by the laser sensor 100 as shown in FIG. When the object Ps is detected in FIG. 8B, as shown in FIG. 8B, in the same direction as the detection direction (detection direction) detected by the laser sensor 100 or in a plurality of switchable directions, The directivity of the variable directivity antenna 14 is controlled so as to emit radio waves in the direction closest to the detection direction. In FIG. 8B, an area of a radio wave radiated in the direction of the object Ps (for example, an area having a predetermined radio wave intensity or more) is conceptually indicated by B1.

  In the present embodiment, the control unit 11 corresponds to an example of “directivity control means” and functions to control the directivity of the variable directivity antenna 14. Specifically, based on the detection result of the object by the detection means. To control the directivity of the variable directional antenna 14 (more specifically, based on the orientation of the object detected by the detecting means, the directivity of the variable directional antenna 14 is controlled so as to emit a radio wave toward the object. Is functioning).

  After S3, a command frame (transmission command frame) to be transmitted to the wireless tag 50 is created (S4). This transmission command frame has a structure as shown in FIG. 9A, for example, and includes a header, command, reader ID, transmission output, antenna gain, reception sensitivity, laser sensor measurement distance, allowable range, CRC, and the like. It is.

  The “command” is, for example, a specific command that requests a response to the wireless tag 50. The wireless tag 50 receives this specific command and returns a response when a predetermined condition (allowable range, etc.) is satisfied. Control is made. “Reader ID” is a unique ID of the wireless tag reader 10. “Transmission output” is a transmission output of radio waves from the wireless tag reader 10, and is based on, for example, the setting contents of the wireless tag reader 10 (for example, the amplification value of the amplifying unit 23, etc.) at the present time (when the process of S4 is executed) It is determined. Note that “transmission output” may be a predetermined fixed value.

  “Antenna gain” is the antenna gain of the variable directivity antenna 14, which may be registered in advance in the wireless tag reader 10 as a fixed value, and is obtained by acquiring the current setting value (when executing the process of S 4). Also good. The “reception sensitivity” is the reception sensitivity (reception input) of the wireless tag reader 10 and may be registered in advance as a fixed value in the wireless tag reader 10, and the current set value (when the process of S4 is executed) is acquired. It may be a value. The “laser sensor measurement distance” is the distance to the detected object detected by the laser sensor 100 and acquired in S2. The “allowable range” is a reference value used in determination processing described later, and is a value for limiting the wireless tag 50 that returns a response. As the “allowable range”, a predetermined set value or a value arbitrarily designated by the user is used. “Header” and “CRC” are specific data indicating the beginning and end of a data frame.

  After S4, the command frame generated in S4 is transmitted to the wireless tag (S5). Specifically, when a radio wave including the command frame of S4 as data is radiated in the direction set in S3, the data is transmitted to the wireless tag 50 located in this direction.

  In the present embodiment, the control unit 11, the transmission unit 12, and the reception unit 13 correspond to an example of “wireless communication means”, and the wireless tag 50 and the wireless tag 50 are wirelessly transmitted through radio waves transmitted and received via the variable directivity antenna 14. Specifically, it functions to perform communication. Specifically, the distance detected by the detection means (laser sensor measurement distance), the transmission output of the wireless tag reader 10, the antenna gain of the variable directivity antenna 14, the reception sensitivity of the wireless tag reader 10 It functions to transmit data or the like to the wireless tag 50 via the variable directional antenna 14. Then, after the data transmission in S5, the response from the wireless tag 50 is determined (S6).

  Here, the response process in the wireless tag 50 will be described. The wireless tag 50 is executed, for example, every predetermined short time. First, it is determined whether or not the wireless tag 50 has received a radio wave from the wireless tag reader 10 (S10). When the radio wave from the wireless tag reader 10 is received, S10 is Yes and the received radio wave intensity is acquired (S11). In S11, the detection value detected by the reception signal intensity detection unit 67 is acquired as the reception radio wave intensity. The received signal intensity detection unit 67 corresponds to an example of “radio wave intensity detecting means” and functions to detect the radio wave intensity of the radio wave received from the wireless tag reader 10.

After S11, processing for acquiring various information from the command frame obtained from the wireless tag reader 10 is performed (S12). Specifically, as shown in FIG. 9A, the command, the reader ID, the transmission output of the wireless tag reader 10, the antenna gain of the variable directivity antenna 14, the reception sensitivity of the wireless tag reader 10, and the laser sensor are measured. And the allowable range set by the wireless tag reader 10 are acquired.
In the present embodiment, the control unit 51 and the reception unit 53 correspond to an example of “reception unit”, and the measurement distance at the laser sensor 100, the transmission output of the wireless tag reader 10, the antenna gain of the variable directivity antenna 14, the wireless It functions to receive data such as the reception sensitivity of the tag reader 10.

  After S12, the distance d between the wireless tag 50 and the wireless tag reader 10 is estimated based on the information acquired in S12. This distance d is obtained by solving for d based on the following equations 1 and 2, for example.

  For example, the use frequency is 2450 MHz, the transmission output of the wireless tag reader 10 is 0 dBm, the antenna gain of the variable directivity antenna 14 is 6 dBi, and the antenna gain of the antenna 54 of the wireless tag 50 is 2 dBi, which is obtained in S11. When the received radio wave intensity (reception input) is −60 dBm, when the distance d is obtained by the above formulas 1 and 2, a result of about 24.5 m is obtained.

  In the present embodiment, the control unit 51 corresponds to an example of an “estimated distance calculation unit”, and includes a transmission output of the wireless tag reader 10, an antenna gain of the variable directivity antenna 14, an antenna gain of the wireless tag 50, and a radio wave intensity detection unit. It functions to calculate the estimated distance d to the wireless tag reader 10 based on the detected radio wave intensity (reception input).

  After S13, the distance d (estimated distance) obtained in S13 is related to the distance measured by the laser sensor (the distance acquired in S12) and the allowable range (the “allowable range acquired in S12). It is judged whether or not If the difference between the estimated distance d and the laser sensor measurement distance acquired in S12 exceeds the allowable range, the process proceeds to No in S14, and the response process ends. That is, in this case, since there is a high possibility that the object carrying the wireless tag 50 is not a detected object detected by the laser sensor 100, no response radio wave is transmitted.

  It is determined that the distance d (estimated distance) obtained in S13 is within the allowable range (the “allowable range” acquired in S12) in relation to the distance measured by the laser sensor 100 (the distance acquired in S12). If YES in step S14, the transmission output is calculated (S15). This transmission output is calculated by the above formula 1 and the following formula 3.

  For example, the use frequency is 2450 MHz, the antenna gain of the variable directivity antenna 14 is 6 dBi, the reception sensitivity (reception input) of the wireless tag reader 10 is −96 dBm, and the antenna gain of the antenna 54 of the wireless tag 50 is 2 dBi. Yes, when the distance d (estimated distance) obtained in S13 is 24.5 m, when the transmission output Pt is obtained by the above equations 1 and 3, a result of about −36 dBm is obtained.

  In the present embodiment, the control unit 51 that performs the process of S15 corresponds to an example of an “output adjustment unit”, and the estimated distance d calculated by the estimated distance calculation unit, the antenna gain of the wireless tag 50, and the variable directivity. It functions to determine the output value of the response radio wave based on the antenna gain of the directional antenna 14 and the reception sensitivity of the wireless tag reader 10 and adjust the output value of the response radio wave.

  After S15, a response data frame (response frame) for the wireless tag reader 10 is created (S16). This response frame is created, for example, with a configuration as shown in FIG. 9B. In this example, a header, a command, a tag ID, a wireless tag estimated distance, a status, a CRC, and the like are included. The “tag ID” is a unique ID of the wireless tag 50. Further, the “wireless tag estimated distance” is the estimated distance d calculated in S13. After S16, a process of transmitting the response frame generated in S16 to the wireless tag reader 10 as response data is performed (S17).

  In the present embodiment, the control unit 51 that performs the process of S14 corresponds to an example of a “response determination unit”, and whether or not to transmit a response radio wave to the wireless tag reader 10 is determined based on at least the distance received by the reception unit. It functions to make a determination based on data (laser sensor measurement distance data), and more specifically, the distance acquired by the receiving means (laser sensor measurement distance) and the estimated distance calculated by the estimated distance calculating means When d satisfies a predetermined allowable relationship, it functions to determine that a response radio wave is transmitted. The control unit 51 that executes the process of S17 corresponds to an example of a “response radio wave transmission unit”, and transmits a response radio wave to the wireless tag reader 10 when the response determination unit determines to transmit the response radio wave. To work.

  As described above, when the response process is performed by the wireless tag 50 and it is determined to respond to the data transmission from the wireless tag reader 10 (S5) (Yes in S14), the response radio wave is transmitted and no response is made. Is determined (No in S14), the response radio wave is not transmitted.

  On the other hand, as shown in S6 of FIG. 6, the wireless tag reader 10 determines whether or not there is a response from the wireless tag 50 after the data transmission in S5 (specifically, after the data transmission in S5, a response is made within the required time. (S6). If there is a response, it is determined Yes in S6. If the answer is YES in S6, this response radio wave (response radio wave transmitted in S17) is received by a reception process (not shown), and the response frame (FIG. 9B) from the radio tag 50 is sent to the radio tag reader 10. Will be obtained.

  On the other hand, if it is determined in S6 that there is no response, S6 is No and a notification process is performed (S7). This notification process may be a process of displaying error information on the display unit 85, for example, and may cause the buzzer 86 to make a predetermined sound. In the present embodiment, the CPU 81, the buzzer 86, and the like that perform the processing of S7 correspond to an example of the “notification unit”, and the radio waves are radiated to the detected object by controlling the directivity by the directivity control unit. The wireless tag reader 10 functions to notify when the wireless tag 50 is not read.

If it is determined Yes in S6, as described above, a response frame (FIG. 9B) is acquired by a reception process (not shown), but the tag ID included in this response frame is registered in advance. It may be determined whether or not the registered ID (for example, a registration ID stored in advance as a database in the storage unit 82) is applicable. When the received tag ID corresponds to the registration ID, the person who owns the wireless tag 50 that responds to the tag ID may be determined as the authorized person.
In the present embodiment, such a determination can be made by the CPU 81. The CPU 81 corresponds to an example of an object discriminating unit, and an object detected by a detection object based on a result of reading the wireless tag 50 by the wireless communication unit and registration data registered in advance in a predetermined registration unit is permitted. It functions to discriminate whether or not it is an object.

(Main effects of this embodiment)
According to the monitoring system 1 according to the present embodiment, the laser sensor 100 can detect an object present in the monitoring area with higher accuracy without being limited to the presence or absence of the wireless tag 50. Furthermore, since the directivity of the directional antenna 14 can be controlled based on the detection result of the object by the laser sensor 100, it is possible to appropriately select the position (distance, azimuth, etc.) of the detected object detected by the laser sensor 100. Radio waves can be emitted with directivity, and the specific contents of the detected object can be easily grasped more accurately.

  Further, in the monitoring system 1 according to the present embodiment, the directivity of the variable directional antenna 14 is controlled so as to emit radio waves toward the object based on the orientation of the object detected by the detection means. In this way, radio waves can be emitted in an appropriate direction toward the object detected by the laser sensor 100. Therefore, when the detected object has the wireless tag 50, the wireless tag 50 is detected well. It becomes easy.

  In the monitoring system 1 according to the present embodiment, the object detected by the detected object is permitted based on the reading result of the wireless tag 50 by the wireless communication unit and the registration data registered in advance in the predetermined registration unit. Object discriminating means for discriminating whether or not the object is an object is provided. In this way, when an object is detected by the laser sensor 100, it can be appropriately and satisfactorily determined whether or not the detected object is a permitted object.

In the monitoring system 1 according to the present embodiment, the directivity of the variable directivity antenna 14 is controlled so as to emit radio waves based on the orientation of the object detected by the detection means, and the wireless tag reader 10 performs wireless communication. The means transmits at least distance data detected by the detection means to the wireless tag 50 via the variable directivity antenna 14. On the other hand, the wireless tag 50 receives at least whether the wireless tag reader 10 receives the distance data (laser sensor measurement distance data) and whether to transmit a response radio wave to the wireless tag reader 10. Response determination means for determining based on distance data (laser sensor measurement distance data) received by the means, and when the response determination means determines that a response radio wave is to be transmitted, a response radio wave is transmitted to the wireless tag reader 10 Response radio wave transmitting means is provided.
In this way, information on the distance (laser sensor measurement distance) about the object detected by the laser sensor 100 can be given to the wireless tag 50, and whether or not the wireless tag 50 side responds with this distance information as a determination element. Can be determined. Therefore, it is possible to limit the wireless tags that respond based on the distance obtained by the laser sensor 100 (the distance to the detection object), and it is easy to narrow down the wireless tags to be communicated.

Further, in the monitoring system 1 according to the present embodiment, the wireless communication means of the wireless tag reader 10 includes the transmission output of the wireless tag reader 10 and the variable directional antenna 14 in addition to the distance data (laser sensor measurement distance data). The antenna gain is transmitted to the wireless tag 50 via the variable directivity antenna 14.
The wireless tag 50 receives the distance (laser sensor measurement distance), the transmission output of the wireless tag reader 10, and the antenna gain data of the variable directivity antenna 14 by the receiving means, and further receives the data from the wireless tag reader 10. Radio wave intensity detection means for detecting the radio wave intensity of the radio wave, the transmission output of the wireless tag reader 10, the antenna gain of the variable directivity antenna 14, the antenna gain of the wireless tag 50, and the radio wave intensity detected by the radio wave intensity detection means. And an estimated distance calculating means for calculating an estimated distance to the wireless tag reader 10. In this way, the wireless tag reader 10 side parameter can be acquired on the wireless tag 50 side, and the distance from the wireless tag reader 10 can be estimated more accurately by considering it together with the wireless tag 50 side parameter. become.
Furthermore, the response determination unit determines that the response radio wave is transmitted when the distance (laser sensor measurement distance) acquired by the reception unit and the estimated distance calculated by the estimated distance calculation unit satisfy a predetermined allowable relationship. ing. Accordingly, it is possible to limit the response from the wireless tag having a low relationship in which the distance (laser sensor measurement distance) acquired from the wireless tag reader 10 and the estimated distance do not satisfy the allowable relationship, thereby achieving power saving of the wireless tag. Therefore, it is possible to improve the efficiency of communication processing.

Further, in the monitoring system 1 according to the present embodiment, the wireless communication means of the wireless tag reader 10 has at least the distance (laser sensor measurement distance) detected by the detection means, the transmission output of the wireless tag reader 10, and the variable directional antenna 14. The antenna gain and the reception sensitivity data of the wireless tag reader 10 are transmitted to the wireless tag 50 through the variable directivity antenna 14.
The wireless tag 50 receives data from the wireless tag reader 10 such as distance (laser sensor measurement distance), transmission output of the wireless tag reader 10, antenna gain of the variable directivity antenna 14, and reception sensitivity of the wireless tag reader 10. Receiving means; radio wave intensity detecting means for detecting radio wave intensity of radio waves received from the wireless tag reader 10; response radio wave transmitting means for transmitting response radio waves to the radio tag reader 10; transmission output of the radio tag reader 10; variable directivity Based on the antenna gain of the antenna 14, the antenna gain of the wireless tag 50, and the radio field intensity detected by the radio field intensity detection unit, the estimated distance calculation unit that calculates the estimated distance to the radio tag reader 10 and the estimated distance calculation unit The calculated estimated distance, the antenna gain of the wireless tag 50, and the variable directivity antenna And 4 of the antenna gain, and an output adjusting means for adjusting the output of the response radio wave based on the reception sensitivity of the wireless tag reader 10 is provided.
In this way, the wireless tag reader 10 side parameter can be acquired on the wireless tag 50 side, and the distance from the wireless tag reader 10 can be estimated more accurately by considering it together with the wireless tag 50 side parameter. become. Furthermore, since the output of the response radio wave is adjusted based on the estimated distance, the antenna gain of the wireless tag 50, the antenna gain of the variable directivity antenna 14, and the reception sensitivity of the wireless tag reader 10, The output of the response radio wave can be set more appropriately, and the waste of power consumption can be effectively reduced.

In the monitoring system 1 according to the present embodiment, the directivity control unit controls the directivity of the variable directivity antenna 14 so as to emit a radio wave toward the object based on the orientation of the object detected by the detection unit. In addition, there is provided notification means for performing notification when the wireless tag reader 10 does not read the wireless tag 50 when the directivity is controlled by the directivity control means.
In this way, when the object detected by the laser sensor 100 does not have the wireless tag 50, this can be detected more accurately, and such an abnormal object (having the wireless tag 50) can be detected. It is possible to notify that no object is detected.

  In the monitoring system 1 according to the present embodiment, the wireless tag 50 is configured as an active tag having a built-in battery. This makes it easy to secure a wide communication area for the wireless tag 50, so that the monitoring area for the laser sensor 100 and the wireless tag reader 10 can be set wider.

[Other Embodiments]
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  In the above embodiment, an example is shown in which there is only one object with the wireless tag 50 in the management area. However, even when there are a plurality of objects with the wireless tag 50, each object has a time difference. Similar detection can be performed.

DESCRIPTION OF SYMBOLS 1 ... Monitoring system 10 ... Wireless tag reader (wireless reader)
11. Control unit (directivity control means, wireless communication means)
12 ... Transmitter (wireless communication means)
13: Receiver (wireless communication means)
14 ... Variable directional antenna 50 ... Wireless tag (wireless communication medium)
51. Control unit (reception means, response determination means, response radio wave transmission means, estimated distance calculation means, output adjustment means)
52 ... Transmitter (response radio wave transmitting means)
53. Receiving part (receiving means)
67. Received signal intensity detection unit (radio wave intensity detection means)
80 ... Controller 81 ... CPU (object discrimination means, notification means)
86 ... Buzzer (notification means)
100: Laser sensor (laser device)
120... Photodiode (light receiving means)
110 ... Laser diode (laser beam scanning means)
130: Mirror (laser beam scanning means)
140... Turning deflection mechanism (laser beam scanning means)
170 ... Control circuit (detection means)

Claims (1)

A laser beam scanning unit that scans the laser beam; a light receiving unit that receives the reflected light reflected by the object by the laser beam scanned by the laser beam scanning unit; and A detecting device for detecting an orientation, and a laser device,
A variable directivity antenna, directivity control means for controlling the directivity of the variable directivity antenna, and wireless communication means for performing wireless communication with a wireless communication medium via a radio wave transmitted and received via the variable directivity antenna A wireless reader having
One or more wireless communication media capable of wireless communication with the wireless reader;
With
The detection means is configured to detect the azimuth of the object and the distance to the object based on a light reception result of the reflected light by the light receiving means,
The directivity control means controls the directivity of the variable directivity antenna so as to emit radio waves based on the orientation of the object detected by the detection means,
The wireless communication means of the wireless reader is:
Transmitting at least the distance data detected by the detection means to the wireless communication medium via the variable directional antenna;
The wireless communication medium is
Receiving means for receiving the distance data from the wireless reader;
Response determination means for determining whether to transmit a response radio wave to the wireless reader based on at least the distance data received by the reception means;
Response radio wave transmission means for transmitting the response radio wave to the wireless reader when the response determination means determines to transmit the response radio wave;
A monitoring system comprising:

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