Patent Application
20140347230
The present invention relates to an electromagnetic wave visualizing system.
Various electronic devices supporting social infrastructures have been operated with higher speeds in response to improved functionality. Thus, such electronic devices need to be designed such that electromagnetic noise from the devices does not cause electromagnetic interference on an increasing number of radio sets. In the event of electromagnetic interference, a survey needs to be quickly conducted on the spot. Hence, systems for visualizing the emission sources of electromagnetic noise in real time have been demanded.
Patent Literature 1 discloses, as a technique for visualizing electromagnetic waves, a system that scans a sensor for detecting an electromagnetic field strength, detects the position of the sensor from a camera image, and then superimposes the electromagnetic field strength and the sensor position on a display.
Patent Literatures 2 and 3 disclose techniques for performing arrival-direction estimating signal processing such as MUSIC (Multiple Signal Classification) and ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques) on the signals of multiple antennas and depicting an electromagnetic field distribution on a display based on the information.
In Patent Literature 4, an anemometer is achieved by a lens and an antenna.
PLT 1: WO2009/028186
PLT 2: Japanese Patent Application Laid-Open No. 2005-207847
PLT 3: Japanese Patent Application Laid-Open No. 2011-53055
PLT 4: Japanese Patent Application Laid-Open No. 2008-122416
In the technique of Patent Literature 1, a sensor scans a surface of a device and thus easily recognizes a part where electromagnetic noise is emitted. However, electromagnetic noise cannot be recognized in real time because of scanning, leading to difficulty in recognizing electromagnetic noise emitted like a burst. The technique described in Patent Literature 2 is likely to be affected by multipath. A reduction in the influence of multipath requires the stages of estimation in the arrival direction as in the technique of Patent Literature 3. This may reduce immediacy. In the technique described in Patent Literature 4, antennas are used for a receiving sensor. The antennas need to be mechanically operated in order to avoid interference between the antennas and increase a resolution. Thus, this system also reduces immediacy.
As described above, in the techniques of Patent Literatures 1 to 4, it is difficult to visualize the source of electromagnetic noise in real time. An object of the present invention is to provide an electromagnetic wave visualizing system that can visualize the emission source of electromagnetic noise in real time.
This application includes multiple solutions to the problem. The present invention has a representative configuration:
An electromagnetic wave visualizing system includes:
an emission direction separation unit that changes the emission direction of an electromagnetic wave according to the incoming direction of the electromagnetic wave;
a plurality of sensors, each detecting the energy of an electromagnetic wave emitted from the emission direction separation unit and outputting a sensing signal having strength corresponding to the detected energy;
a processing unit capable of receiving the sensing signal from each of the sensors, the processing unit outputting a display signal when receiving the sensing signal from the sensor, the display signal including information on the arrival direction of an electromagnetic wave according to the sensor having transmitted the sensing signal; and
a display unit capable of displaying the arrival directions of electromagnetic waves, the display unit displaying the arrival direction of an electromagnetic wave when receiving the display signal.
According to the present invention, the emission source of electromagnetic waves can be visualized in real time.
Referring to
As shown in
The emission direction separation unit 11 includes, for example, an electromagnetic wave lens that focuses electromagnetic waves entering the lens and then changes the emission directions and positions of electromagnetic waves emitted from the lens, according to the arrival directions of incoming electromagnetic waves. Electromagnetic waves in multiple arrival directions are caused to converge at different positions, that is, the electromagnetic waves are focused at different positions. The lens will be specifically discussed later. The sensor unit 12 includes the sensors 12(1), 12(2), 12(3), . . . that detect the energy of electromagnetic waves emitted from the emission direction separation unit 11 and output sensing signals having strength corresponding to the detected energy. Thus, the sensor located at the focal position (focus) of electromagnetic waves entering the lens outputs the sensing signal. In other words, the sensors selectively output the sensing signals according to the focal position of electromagnetic waves entering the lens.
The processing unit 13 can receive the sensing signals from the respective sensors of the sensor unit 12 and has a table in which the sensor positions are associated with the arrival angles of electromagnetic waves, that is, arrival direction information on electromagnetic waves. When receiving the sensing signal from one of the sensors of the sensor unit 12, the processing unit 13 obtains, from position information on the sensor having transmitted the sensing signal, arrival direction information on electromagnetic waves according to a sensor position with reference to the table, and then the processing unit 13 outputs a display signal including the arrival direction information on the electromagnetic waves and strength information on the received sensing signal. Furthermore, the processing unit 13 receives an image signal for an image captured by the camera unit 14, generates a display signal by superimposing, on the image signal, the signal including the electromagnetic wave arrival direction information and the strength information on the sensing signal, and then outputs the display signal to the display unit 15.
The display unit 15 can display multiple noise positions. When receiving the display signal from the processing unit 13, the display unit 15 displays the position of an electromagnetic wave on a measuring object and the strength of the sensing signal, that is, the strength of the electromagnetic wave on, for example, an LCD (Liquid Crystal Display) based on the electromagnetic wave arrival direction information and the strength information on the sensing signal that are included in the display signal. Moreover, the display unit 15 displays the display signal received from the processing unit 13, thereby simultaneously displaying an image captured by the camera unit 14. As described above, the display unit 15 displays the information including the electromagnetic wave arrival direction information and the strength information on the sensing signal such that the information is superimposed on the image of the measuring object captured by the camera unit 14.
As illustrated in the example of
In the example of
When receiving the sensing signal from one of the sensors of the sensor unit 12, the processing unit 13 may be configured to output, if the received sensing signal is so strong as to reach at least a predetermined value, a display signal that includes only arrival direction information on electromagnetic waves according to the sensor having transmitted the sensing signal but does not include strength information on the received sensing signal. In this case, the display unit 15 displays the position of the sensor regardless of the strength of the sensing signal. For example, in the example of
Referring to
For example, as shown in
The ideal value of the relative dielectric constant ∈r at a distance r from the center of the Luneburg lens 11a is expressed by the following formula: where 2R is the diameter of the lens.
The relative dielectric constant ∈r desirably changes on the Luneburg lens 11a in a continuous manner. Actually, as shown in
Moreover, the relative dielectric constant ∈r changes an effective dielectric constant with a hole formed on a certain material, thereby achieving the Luneburg lens 11a.
In the present example, the spherical Luneburg lens is used but the lens used as the emission direction separation unit 11 is not limited to a Luneburg lens. The lens may have any shapes as long as an emission direction separating function is provided according to the arrival directions of electromagnetic waves. For example, an aspheric lens is usable.
Referring to
Referring to
As shown in
The metal patches 21 are sufficiently small relative to a wavelength λ of an electromagnetic wave to be measured. The length of one side of the metal patch 21 is ( 1/10)λ or less. For example, if the frequency of measured electromagnetic wave is 2.4 GHz, one side of the metal patch 21 is 12.5 mm in length. In the present example, the metal patch 21 is a square metal plate but is not limited to a square shape.
As shown in
As shown in
The voltage sensor 27 detects a voltage induced across the resistor 25, through the voltage sensor vias 26. Specifically, for example, the voltage sensor 27(1) detects a voltage induced across the resistor 25(1), the voltage sensor 27(2) detects a voltage induced across the resistor 25 (2), and the voltage sensor 27(3) detects a voltage induced across the resistor 25(3). The voltage sensor 27 includes, for example, an amplifier, an AD converter, and a voltage measuring device.
When electromagnetic waves are emitted to one of the metal patches 21 constituting the low-reflective electromagnetic field sheet, a voltage is induced only across the resistor 25 connected to the irradiated metal patch 21. Thus, the arrival direction of electromagnetic waves can be identified by the position of the voltage sensor 27 connected to the resistor 25.
At this point, if the resistor 25 has a resistance of 377Ω like a wave impedance, the impedance of a space is matched to that of the sensor unit 12, allowing the sensor unit 12 to absorb the energy of electromagnetic waves without reflecting the electromagnetic waves.
Referring to
A camera for capturing an image of the measuring object 16 is preferably disposed at the center of the lens (center position). However, the camera disposed at the center of the lens may interfere with a measurement of electromagnetic waves. Actually, the camera is disposed with a camera position difference 83 from the center of the lens like a camera 82. An actual image 82b captured by the camera 82 is deviated by the camera position difference 83 from an image 81b captured by the camera located at the center of the lens. Thus, a center position correction is performed by the camera position difference 83.
Moreover, the camera has a known maximum viewing angle of θ. As described above, arrival angle information on electromagnetic waves measured by the sensor unit 12 is obtained with reference to the table in which the positions of the sensor unit are associated with the arrival angle information on the electromagnetic waves.
The viewing angle of the camera 82 is joined to the viewing angles of electromagnetic field measurement results obtained by the lens unit 11 and the sensor unit 12. An image of the measuring object 16 is captured by the camera 82 with the joined viewing angles; meanwhile, electromagnetic waves are measured by the lens unit 11 and the sensor unit 12. Moreover, the processing unit 13 performs a center position correction by the camera position difference 83, and then both images are superimposed and displayed on the display unit 15, achieving visual analyses of electromagnetic waves.
The dielectric 20 is thin and is made of materials such as polyimide. The dielectric 20 can be bent with flexibility and thus allows the low-reflective electromagnetic field sheet to be easily attached along the spherical surface of the Luneburg lens 11a. Alternatively, a plate-like sensor may be divided along a lens.
In the present example, the voltage sensor 27 measures a voltage for detecting electromagnetic waves. Other devices such as a power measuring element may be used as long as the energy of electromagnetic waves can be detected.
Moreover, in the present example, the low-reflective electromagnetic field sensor includes the square metal patches 21 acting as electromagnetic wave absorbing devices. Nonreflective devices in any other shapes may be used as long as electromagnetic waves are absorbed and energy is generated between the devices. The sensor unit 12 and the processing unit 13, which are separated units, may be combined into a single unit.
In the configuration of the present example, the positions of generated electromagnetic waves are displayed while the energy level of electromagnetic waves is displayed. The energy level of electromagnetic waves may not be displayed, specifically, only the positions of generated electromagnetic waves with energy having a predetermined value or more may be displayed in this configuration.
The first example can achieve the following effects:
(1) The arrival direction of electromagnetic waves can be detected and displayed in real time.
(2) The energy level of electromagnetic waves can be detected and displayed in real time.
(3) Since the Luneburg lens is used as the emission direction separation unit, incoming electromagnetic waves can be easily focused.
(4) The flexible low-reflective electromagnetic field sheet is used as the sensor unit and thus can be easily attached to the Luneburg lens.
(5) The low-reflective electromagnetic field sensor including the metal patches and resistors allows efficient absorption of incoming electromagnetic waves. Additionally, if the resistance is 377Ω like a wave impedance, the energy of incoming electromagnetic waves can be more efficiently absorbed.
Referring to
As shown in
In the example of
Thus, the emission direction separation unit 11 of the second example is effective for providing lenses with larger diameters so as to detect electromagnetic waves with higher sensitivity. Since the energy of electromagnetic waves at a focal position is determined by the effective opening area of the lens, a larger lens can collect larger energy. The provision of multiple lenses can efficiently collect energy.
Referring to
The function of separating and amplifying electromagnetic waves can be achieved not only by lenses but also by antennas such as parabolic antennas. As shown in
In the example of
The sensors 12(1), 12(2), 12(3), and 12(4) are disposed at the focal positions of the parabolic antennas so as to detect only electromagnetic waves in a specific direction and estimate the arrival direction of the electromagnetic waves.
Referring to
As shown in
The metal patches 51 are sufficiently small relative to a wavelength λ of an electromagnetic wave to be measured, like the metal patch 21 of the first example. The length of one side of the metal patch 51 is ( 1/10)λ or less.
The dielectric 50 is thin and is made of materials such as polyimide. The dielectric 50 can be bent with flexibility.
As in the first example, a ground 54 that is a conductor serving as a second layer parallel to the first layer is provided with the dielectric 50 interposed between the ground 54 and the metal patch 51. The ground 54 is substantially identical in size to the dielectric 50.
The ground 54 is connected to the metal patch 51 via a conductor via 52 with the dielectric 50 interposed between the ground 54 and the metal patch 51. Specifically, the metal patch 51(1) is connected to the ground 54 via a via 52(1), the metal patch 51(2) is connected to the ground 54 via a via 52(2), and the metal patch 51(3) is connected to the ground 54 via a via 52(3).
Furthermore, row voltage sensor wires 57 in
The row voltage sensor 58 is connected to the row voltage sensor wire 57 via a row voltage sensor via 56. The column voltage sensor 68 is directly connected to the column voltage sensor wire 67.
A conductor voltage sensor via 53 is provided on each end of the resistor 55. The voltage sensor via 53 penetrates the dielectric 50 and the ground 54 and is connected to the row voltage sensor 58 and the column voltage sensor 68 via the row voltage sensor wire 57 and the column voltage sensor wire 67. The ground 54 has a hole where the voltage sensor via 53 is inserted. This electrically disconnects the ground 54 and the voltage sensor via 53.
Specifically, for example, voltage sensor vias 53(1) and 53(2) are provided on the respective ends of the resistor 55(1) in the first row and the first column. The voltage sensor via 53(1) is connected to the row voltage sensor wire 57(1) and the column voltage sensor wire 67(1) while the voltage sensor via 53(2) is connected to a row voltage sensor wire 57(2) and a column voltage sensor wire 67(2). A row voltage sensor 58(1) is connected to the row voltage sensor wire 57(1) and 57(2) while a column voltage sensor 68(1) is connected to the column voltage sensor wire 67(1) and 67(2). Thus, both ends of the resistor 55(1) are respectively connected to the row voltage sensor 58(1) and the column voltage sensor 68(1).
Similarly, both ends of a resistor 55(2) in the first row and the second column are respectively connected to the row voltage sensor 58(1) and the column voltage sensor 68(2) while both ends of a resistor 55(3) are respectively connected to the row voltage sensor 58(1) and a column voltage sensor 68(3). Both ends of the resistor 55(21) in the second row and the first row are respectively connected to a row voltage sensor 58(2) and the column voltage sensor 68(1) while both ends of a resistor 55(31) in the third row and the first column are respectively connected to a row voltage sensor 58(3) and the column voltage sensor 68(1).
The row voltage sensor 58 detects a voltage induced to the resistor 55 in the same row, through the voltage sensor via 53. The column voltage sensor 68 detects a voltage induced to the resistor 55 in the same column, through the voltage sensor via 53. Specifically, for example, the row voltage sensor 58(1) detects a voltage induced to the resistors 55(1), 55(2), 55(3) . . . in the first row while the column voltage sensor 68(1) detects a voltage induced to the resistors 55(1), 55(21), 55(31) . . . in the first row. Thus, the row voltage sensor 58 and the column voltage sensor 68 identify the resistor 55 having received an induced voltage. In other words, the arrival direction of electromagnetic waves is identified.
Thus, in the fourth example, the row voltage sensor 58 detects the row that receives an induced voltage; meanwhile, the column voltage sensor 68 detects the column that receives an induced voltage, thereby detecting the position of the element having an induced voltage. In the fourth example, the number of voltage sensors can be smaller than that of the first example.
In the fourth example, any sensors capable of detecting the energy of elements may be used instead of the voltage detecting sensor as in the first embodiment.
In this explanation, the resistors extending in the horizontal direction of
Referring to
In the fifth example, unlike in the first example, a lens unit 11 includes a plurality of lenses that directly receive electromagnetic waves from noise sources. In the example of
As shown in
The distance d is expressed by the following formula: where α1 is the angle of an electromagnetic wave detected in the lens 11f from the noise source 17, and α2 is the angle of an electromagnetic wave detected in the lens 11g.
Equation 3 is solved for a and is substituted into Equation 2 to obtain the following equation: where d is a distance to the noise source 17.
If a spherical Luneburg lens is used, information on an elevation angle and an azimuth angle is provided as detected angles. Thus, the position of the noise source 17 can be three-dimensionally detected by the two lenses 11f and 11g, the two sensor units 12f and 12g, and a processing unit 13. In the case of a two-dimensional display unit, for example, the two-dimensional position (the arrival direction of noise) of the noise source 17 is displayed as well as a numerical value (e.g., 15 m) representing a distance to the noise source 17.
In the present example, the two lenses and the two sensor units are used. At least three lenses and at least three sensor units may be used instead.
The fifth example makes it possible to detect the arrival direction of an electromagnetic wave, that is, the two-dimensional position of the emission source of electromagnetic waves and a distance to the emission source of electromagnetic waves, thereby easily specifying the three-dimensional position of the emission source of electromagnetic waves.
The present invention is not limited to the foregoing embodiment. It is needless to say that various changes can be made within the scope of the invention.
In the embodiment, the emission position of electromagnetic waves and the level of energy are displayed on a background captured by a camera. Alternatively, the relative emission position of electromagnetic waves and the level of energy can be displayed without using a background captured by a camera.
Moreover, the level of energy of electromagnetic waves may not be displayed. In other words, only the emission position of electromagnetic waves with energy having a predetermined value or more may be displayed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-279895 | Dec 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/077588 | 10/25/2012 | WO | 00 | 6/19/2014 |
