JP5942166B2 - Lighting device - Google Patents

Description

  The present invention includes a sensor that transmits a radio wave having a predetermined frequency and receives a reflected wave reflected from an object by the transmitted radio wave, and the presence of a moving body based on a frequency difference between the transmitted and received waves And an illumination device that turns on the illumination light source.

  2. Description of the Related Art Conventionally, there has been provided an illumination device that detects the presence or absence of a human body in a detection area by a sensor and turns on or off an illumination light source according to the detection result (see, for example, Patent Document 1). An active type sensor is known as such a sensor. An active sensor detects the presence or absence of a moving body in a detection area by transmitting a detection wave such as an electromagnetic wave by itself and receiving a detection wave reflected by an object.

  By the way, it is assumed that there is a noise source such as a light source that periodically generates noise of a specific frequency around an active sensor. In this case, there is a problem that the S / N ratio of the active sensor is lowered due to the noise generated from the noise source, the detection wave reflected by the human body is buried in the noise, and the detection sensitivity is lowered. It was. Further, the periodic noise may vary depending on the positional relationship (direction, angle, etc.) between the illumination light source and the active sensor.

  Therefore, in the illumination device of Patent Document 1, for each frequency component N times the frequency of noise, a filter is set in a frequency band (for example, 10 to 20 Hz) including the N times frequency component. By such filter setting, a frequency component N times the frequency of noise can be cut, and the detection wave reflected by the human body and the noise can be distinguished.

JP 2009-129775 A

  However, when the filter is set as in the lighting device of Patent Document 1, the filter is set to a frequency component that is not necessary in some cases, and as a result, there is a possibility that the detection sensitivity may be lowered. .

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an illuminating device capable of reducing the influence of noise and improving detection sensitivity.

In order to solve the above-described problem, an illumination device according to the present invention includes a sensor that transmits a radio wave having a predetermined frequency and receives a reflected wave reflected from an object by the transmitted radio wave. In a lighting device that detects the presence of a moving body based on the difference in frequency of transmission / reception waves as a detection result by, and turns on the illumination light source, the detection result by the sensor is subjected to fast Fourier transform processing, and the signal intensity for each frequency is A fast Fourier transform processing unit to analyze, a threshold setting unit for setting a threshold used to determine the presence or absence of the moving object based on the signal intensity analyzed by the fast Fourier transform processing unit, and the fast Fourier transform processing unit and in comparing the analyzed the signal strength and the threshold value, it said that the signal strength to determine whether more than said threshold value, determination unit the presence or absence of the movable body, If the signal strength by serial determination unit is determined to exceed the threshold value, and a control unit for lighting the illumination light source, the threshold setting unit, the amount of change based on the time course of each frequency of the signal strength The threshold value is set periodically with reference to FIG.

In the above SL configuration, the determination unit, it is preferable to perform a comparison between the signal intensity and the threshold for each frequency.

  ADVANTAGE OF THE INVENTION According to this invention, the influence of noise can be reduced and the illuminating device which can aim at the improvement of detection sensitivity can be provided.

It is a block diagram for demonstrating schematic structure of the illuminating device in 1st Embodiment. It is a flowchart for demonstrating the example of control for setting a threshold value in the illuminating device same as the above. It is a flowchart for demonstrating the example of control for performing lighting control in the illuminating device same as the above. It is a table for demonstrating the relationship between the signal strength for every frequency, and a threshold value in the illuminating device same as the above. It is a table for demonstrating the relationship between the signal strength for every frequency, and a threshold value in the illuminating device same as the above. FIG. 6 is a frequency characteristic diagram for explaining a transition of a threshold value that changes for each frequency in the illumination device of the above. In the illuminating device in 2nd Embodiment, it is a table for demonstrating the relationship between the signal strength for every frequency, and a threshold value. In the illuminating device in 2nd Embodiment, it is a frequency characteristic figure for demonstrating transition of the signal strength for every frequency.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The illuminating device of this embodiment is an instrument provided with an active radio wave sensor.

  As shown in FIG. 1, the illumination device 1 according to the present embodiment includes a sensor 2, a control unit 10 mainly composed of a microcomputer, an illumination light source 3, and a light source control unit 4 that controls lighting of the illumination light source 3. Has been. Moreover, the sensor 2, the control part 10, the illumination light source 3, and the light source control part 4 are electrically connected.

First, the sensor 2 will be described.
The sensor 2 is an active sensor that detects the presence or absence of a moving body in the detection area by transmitting a detection wave such as an electromagnetic wave to the detection area and receiving the detection wave reflected by the object. Further, the sensor 2 outputs a detection signal indicating a difference between the frequency of the transmitted electromagnetic wave and the frequency of the electromagnetic wave reflected by the object to the control unit 10. In this embodiment, a Doppler sensor is used as the sensor 2. A Doppler sensor transmits electromagnetic waves (millimeter waves) toward a detection area, and when an object that reflects the electromagnetic waves is moving, the frequency of the reflected waves is shifted by the Doppler effect. It is a sensor that detects the presence or absence of a moving body from the difference in frequency. The sensor 2 of the present embodiment uses, for example, 24 GHz electromagnetic waves.

Next, the control unit 10 will be described.
As shown in FIG. 1, the control unit 10 determines whether or not there is a fast Fourier transform processing unit 11 that performs a fast Fourier transform (FFT) process, a threshold setting unit 12 that sets a threshold, and a moving object in the detection area. The determination unit 13 is configured. In the following description, the fast Fourier transform processing unit 11 is referred to as an FFT processing unit 11. The FFT processing unit 11, the threshold setting unit 12, and the determination unit 13 are electrically connected.

  The FFT processing unit 11 performs FFT processing on the detection signal and analyzes the signal spectrum intensity for each frequency. The FFT processing unit 11 performs the FFT processing in units of time t1 (in the embodiment, 0.5 seconds). In the present embodiment, the moving body to be detected is a human body. Then, the FFT processing unit 11 sets a specific frequency band of the detection signal necessary for detecting the human body, analyzes the signal spectrum intensity by 1 Hz in this frequency band, and outputs the analysis value to the determination unit 13. Yes. In this embodiment, the specific frequency band is set to 20 to 400 Hz. In the following description, the signal spectrum intensity of the detection signal may be simply indicated as “signal intensity”.

  The threshold value setting unit 12 is connected to a memory 12a capable of writing and reading necessary data. Further, the threshold setting unit 12 sets a threshold for comparison with the analysis value analyzed by the FFT processing unit 11 in order to determine whether or not a human body exists in the detection area.

  The determination unit 13 is connected to a memory 13a that can write and read necessary data. The determination unit 13 A / D converts the value output from the FFT processing unit 11 into a digital value. Then, the determination unit 13 compares the threshold set by the threshold setting unit 12 with the signal strength subjected to the FFT process for every 1 Hz in the specific frequency band, and determines the presence or absence of a human body from the comparison result. Moreover, the light source control part 4 makes the illumination light source 3 light, when it determines with the determination part 13 having a human body in a detection area. In addition, the illumination light source 3 in this embodiment is a discharge lamp.

Hereinafter, details of control for turning on the illumination light source 3 will be described.
The threshold setting unit 12 sets a setting mode for setting a threshold and a normal mode for lighting the illumination light source 3. The setting mode is set only once immediately after the AC power is supplied to the lighting device 1. Also, the setting mode ends when a threshold value is set. Then, after the setting mode ends, the normal mode is set. Further, in the normal mode, it is determined whether or not a human body exists using the threshold set in the setting mode, but the threshold is not set.

First, the contents of control during the setting mode will be described.
The threshold value setting unit 12 reads the analysis value of the signal intensity analyzed by the FFT processing unit 11 at every specified period (for example, 3 seconds). Then, the threshold setting unit 12 causes the memory 12a to store analysis values for 10 specified periods. That is, when the specified period is 3 seconds, the threshold setting unit 12 stores the analysis value of the signal intensity for 30 seconds in the memory 12a.

  For example, in FIG. 4, “−80 dB” is detected in the first and second cycles and “−78 dB” is detected in the past 3 to 5 cycles as the signal intensity at 20 Hz. In addition, “−79 dB” is detected in the past 6th to 8th cycles, and “−77 dB” is detected in the past 9th and 10th cycles. In this case, the threshold setting unit 12 stores the detected values for 10 cycles in the memory 12a for each cycle. Hereinafter, similarly, the threshold setting unit 12 also stores the signal intensities detected at other frequencies in the memory 12a for each period.

  After the analysis value of the signal intensity for 30 seconds is stored in the memory 12a, the threshold setting unit 12 detects the maximum value and the minimum value of the signal intensity for the past 10 cycles from the memory 12a for each frequency. More specifically, using the signal intensity at 20 Hz, as described with reference to FIG. 4, “−77 dB” is detected in the past 9th and 10th cycles. Therefore, “−77 dB” is the maximum value of the signal intensity at 20 Hz. On the other hand, “−80 Hz” is detected in the first and second cycles. Therefore, “−80 dB” is the minimum value of the signal intensity at 20 Hz.

And the threshold value setting part 12 determines whether the present state is a steady state for every frequency. The "steady state" in this embodiment refers to a condition change width of the signal strength of each frequency is within a predetermined range over a certain time. The threshold setting unit 12 determines that the state is “steady state” when the difference between the maximum value and the minimum value of the signal intensity is equal to or less than a predetermined value. In this embodiment, the predetermined value is “5 dB”.

  The value “5 dB” is a value that takes into account variations in detection accuracy. That is, as long as the illumination light source 3 is lit stably, the values detected at the same frequency for the past 10 cycles do not vary greatly.

In the present embodiment, the difference between the maximum value and the minimum value of the signal intensity for each frequency corresponds to the first analysis value.
As shown in FIG. 2, the threshold setting unit 12 determines whether or not the difference between the maximum value and the minimum value of the signal strength is “5 dB” or less in order to determine whether or not the current state is a steady state. Is determined for each frequency (step S10). To explain with a specific example, as described above, the maximum value of the signal strength at 20 Hz is “−77 dB”, while the minimum value of the signal strength is “−80 dB”. Therefore, at 20 Hz, the difference between the maximum value and the minimum value of the signal intensity is “3 dB”, and the threshold setting unit 12 makes an affirmative determination in step S10.

  When the difference between the maximum value and the minimum value of each signal intensity for each frequency is “5 dB” or less (step S10: YES), the threshold setting unit 12 is in a steady state at the frequency when step S10 is executed. Is determined. Then, the threshold setting unit 12 sets, as a threshold, a value obtained by adding the specified value to the maximum value of the signal strength detected at the frequency when the determination in step S10 is affirmative (step S11).

  The “specified value” added to the maximum value of the signal strength is detected when the value after addition is larger than the signal strength of noise and the human body is detected when added to the maximum value of the signal strength. The value is smaller than the signal intensity. In the present embodiment, the specified value is “10 dB”.

  To explain with a specific example, since the difference “3 dB” between the maximum value and the minimum value of the signal intensity at 20 Hz is smaller than “5 dB”, “−77 + 10 = −67 Hz” is set as the threshold value at 20 Hz. .

  In the present embodiment, unlike the human body that is the detection target, the signal intensity detected when there is an object that is not the detection target is “noise”. For example, if there is a noise source such as a light source that periodically generates noise around the sensor 2, the sensor 2 transmits and receives radio waves to and from the noise source. However, when noise is periodically generated, the signal strength of the noise is detected at a specific frequency. And even if it is the frequency component of noise, if the signal intensity is within a certain range at the same frequency for the past 10 cycles, a value obtained by adding the specified value to the maximum value of the signal intensity is set as the threshold value. Therefore, the signal strength of noise does not exceed the threshold value. That is, even when there is no moving object in the detection area, the illumination light source 3 is not erroneously turned on due to noise interference.

  On the other hand, when the difference between the maximum value and the minimum value of each signal intensity for each frequency exceeds “5 dB” (step S10: NO), the threshold setting unit 12 is in a steady state at the frequency when step S10 is executed. It is determined that it is not.

  As an example in which the difference between the maximum value and the minimum value exceeds “5 dB”, the signal intensity is increased during the period corresponding to the past 10 cycles because the moving body (human body, curtain, etc.) keeps moving in the detection area. This is not stable. When the difference between the maximum value and the minimum value is large, since the lighting state of the illumination light source 3 is not stable, the maximum value calculated during the past 10 cycles is not appropriate as the threshold value. That is, if a value obtained by adding a specified value to the maximum value detected during the past 10 cycles is set as a threshold, the signal strength detected when a human body exists in the detection area may not exceed the threshold. This is because the human body in the detection area cannot be detected.

  For this reason, the threshold value setting unit 12 sets a predetermined threshold value (step S12). The predetermined threshold value is a value that is larger than the maximum value of the detected signal intensity and smaller than the signal intensity detected when the human body is detected regardless of the frequency in the specific frequency band (for example, −50 Hz).

Then, the threshold setting unit 12 sets the normal mode after setting the threshold for each frequency in the specific frequency band.
Next, the contents of control during the normal mode will be described.

  As shown in FIG. 3, the determination unit 13 reads the analysis value of the signal intensity analyzed by the FFT processing unit 11 after the normal mode is started for each frequency. Then, the determination unit 13 compares the read signal strength with a threshold value at a frequency when the signal strength is detected, and determines whether the signal strength exceeds the threshold value (step S20). In the present embodiment, the signal intensity analyzed by the FFT processing unit 11 after the normal mode is started corresponds to the second analysis value for moving body determination.

  When the signal strength does not exceed the threshold value (step S20: NO), the determination unit 13 sets a value “0” indicating that the signal strength does not exceed the threshold value to the determination flag set for each frequency in the memory 13a. Set (step S21). Thereafter, the determination unit 13 proceeds to step S23.

  On the other hand, when the signal strength exceeds the threshold (step S20: YES), the determination unit 13 sets a value “1” indicating that the signal strength exceeds the threshold to the determination flag set for each frequency. (Step S22). Thereafter, the determination unit 13 proceeds to step S23.

  In step S23, the determination unit 13 determines whether or not the frequency that is the determination target in step S20 is 400 Hz. That is, the determination unit 13 determines whether or not the comparison determination between the signal intensity and the threshold value for each frequency in the specific frequency band is completed. When the frequency to be determined in step S20 is not 400 Hz (step S23: NO), the comparison determination between the signal intensity and the threshold value for each frequency in the specific frequency band is not completed. Therefore, the determination unit 13 returns to step S20 and executes a comparison determination between the signal intensity and the threshold value at the next frequency.

  On the other hand, when the frequency to be determined in step S20 is 400 Hz (step S23: YES), the comparison determination between the signal intensity and the threshold value for each frequency in the specific frequency band is completed. Therefore, the determination unit 13 determines whether or not the number of times the signal intensity exceeds the threshold is “5 times” or more (step S24). In step S <b> 24, the determination unit 13 determines whether or not the number of determination flags in which a value “1” indicating that the signal intensity exceeds the threshold is set in the specific frequency band is 5 or more.

  When the number of times the signal intensity exceeds the threshold is “5 times” or more (step S24: YES), the determination unit 13 determines that a human body exists in the detection area. And the determination part 13 outputs the instruction | indication signal which instruct | indicates that a human body exists to the light source control part 4 (step S25).

On the other hand, when the number of times the signal intensity exceeds the threshold is less than “5” (step S24: NO), the determination unit 13 does not output the instruction signal.
When the instruction signal is input from the determination unit 13, the light source control unit 4 transmits a control signal for turning on the illumination light source 3 to the illumination light source 3 to turn on the illumination light source 3. The light source controller 4 starts counting a predetermined lighting holding time (for example, 10 seconds) every time a control signal is output. When the lighting holding time is counted, the light source control unit 4 transmits a control signal for turning off the illumination light source 3 to the illumination light source 3 to turn off the illumination light source 3.

Hereinafter, an operation example (action) until the illumination light source 3 is turned on will be described.
In the specific frequency band, when the difference between the maximum value and the minimum value of the signal strength for each frequency for the past 10 cycles is “5 dB” or less, the threshold for each frequency adds 10 dB to the maximum value of the signal strength. It becomes the value.

  As shown in FIG. 4, since “−77 dB” is detected as the maximum value of the signal intensity at 20 Hz, the threshold setting unit 12 sets “−77 + 10 = −67 dB” as the threshold at 20 Hz. Further, since “−70 dB” is detected as the maximum value of the signal intensity at 80 Hz, the threshold setting unit 12 sets “−70 + 10 = −60 dB” as the threshold at 80 Hz.

On the other hand, at 398 Hz, since the difference between the maximum value and the minimum value of the signal intensity exceeds “5 dB”, a predetermined “−50 dB” is set as the threshold value at 398 Hz.
If the detection result as shown in FIG. 5 is obtained during the normal mode setting, the frequency characteristic as shown in FIG. 6 is obtained accordingly. In FIG. 6, the horizontal axis is frequency (Hz), and the vertical axis is signal intensity (dB).

  As shown in FIG. 5, “−80 dB” is detected as the signal intensity at 20 Hz during the normal mode setting. Since “−80 dB” does not exceed the threshold “−67 dB” at 20 Hz, “0” is set in the determination flag.

  On the other hand, “−45 dB” is detected as the signal intensity P1 at 80 Hz. Since “−45 dB” exceeds the threshold value “−60 dB” at 80 Hz, “1” is set in the determination flag. Similarly, it is assumed that the signal strength P2 at 81 Hz, the signal strength P3 at 82 Hz, the signal strength P4 at 83 Hz, and the signal strength P5 at 84 Hz exceed the signal strength set for each threshold. In this case, the determination unit 13 sets “1” to the determination flag corresponding to each frequency.

  And the determination part 13 determines that a human body exists in a detection area by the number of the determination flags in which "1" is set in the specific frequency band being five. Then, the determination unit 13 outputs an instruction signal to the light source control unit 4. Thereafter, the light source control unit 4 performs control so that the illumination light source 3 is turned on.

  When it is determined that the current state is a steady state, a value that is 10 dB larger than the maximum value of the signal intensity detected in the steady state is set as a threshold for determining the presence or absence of a human body. This threshold value is larger than the signal intensity of noise at a specific frequency detected when an object different from the human body is detected, and smaller than the signal intensity detected when the human body is detected. Therefore, the noise does not exceed the threshold value, and only the signal intensity detected when the human body exists exceeds the threshold value. As a result, the signal intensity indicating the presence of the human body is not buried in noise, and the detection sensitivity does not decrease.

Next, characteristic effects of the present embodiment will be described.
(1) The threshold value setting unit 12 is a signal that is greater than the signal strength of noise at a specific frequency that is detected when an object that is not a detection target is detected, and that is detected when a moving body that is a detection target exists. A value smaller than the intensity is set as a threshold value at a specific frequency. By setting the threshold value in this way, a value obtained by performing FFT processing on a detection signal based on an object that is not a detection target does not exceed the threshold value. On the other hand, the value obtained by performing the FFT process on the detection signal detected when there is a moving object to be detected exceeds the threshold. Therefore, it is possible to easily distinguish between a moving body that is a detection target and an object that is not a detection target depending on whether or not the threshold is exceeded, and to easily determine the presence or absence of the moving body that is a detection target. Therefore, it is possible to improve the detection sensitivity by reducing the influence of noise at a specific frequency.

  (2) The determination unit 13 compares the signal strength for each frequency analyzed by the FFT processing unit 11 with the threshold value for each frequency when the normal mode is set. According to this, as compared with a method of distinguishing a moving body that is a detection target and an object that is not a detection target by not setting a frequency band (for example, 20 to 30 Hz) including a specific frequency exceeding the threshold as a determination target. Thus, the presence or absence of the moving object can be determined more accurately. For example, even if the signal intensity is detected at 25 Hz due to the presence of the moving object, “25 Hz” is included in the frequency band, so that it is determined that the moving object does not exist, and the detection sensitivity decreases. . On the other hand, according to the method of comparing the analysis value for each frequency and the threshold value for each frequency, the presence or absence of the moving object can be determined more accurately.

  (3) The threshold value is calculated by adding a specified value to the maximum value of signal intensity for each frequency. The specified value is greater than the signal strength of noise at a specific frequency detected when an object different from the human body is detected when added to the maximum value of the signal strength to be added, and The value is smaller than the signal intensity detected by detecting the human body. Therefore, if a value obtained by adding a specified value to the maximum value of signal intensity recognized as noise is set as a threshold value, the noise will not exceed the threshold value. In addition, regardless of the noise value, it is possible to set a threshold value suitable for each noise characteristic.

  (4) The threshold setting unit 12 sets a value obtained by adding a specified value to the maximum value of the signal intensity for each frequency as a threshold for each frequency. According to this, when the threshold value is uniformly set regardless of the frequency, even if the signal strength does not exceed the threshold value, the signal strength may exceed the threshold value when the threshold value is set for each frequency. . Therefore, the detection sensitivity can be further improved.

(5) A threshold value suitable for the state can be set depending on whether or not the intensity of each frequency of the detection signal falls within a certain range (5 dB).
(6) By using a Doppler sensor as a sensor, it is possible to detect the presence or absence of a moving body that moves within the detection area, and an object that is stationary at a fixed position can be excluded from the detection target.

  (7) The change width of the signal intensity for each frequency does not fall within a certain range (5 dB) for a certain period of time, because the lighting state of the illumination light source 3 is not stable, and is calculated during the past 10 cycles. This means that the maximum value is not suitable as a threshold value. In this way, even in a state where the change width of the signal intensity for each frequency does not fall within a certain range, it is possible to easily distinguish a human body from an object that is not a detection target by setting a predetermined threshold value. In addition, the presence or absence of a human body in the detection area can be easily determined.

(8) By setting the mode, it is possible to automatically set a threshold value after power-on, and to determine the presence or absence of the moving object using the set threshold value.
(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. In the following description, the same reference numerals are given to the same configurations and the same control contents as those of the already described embodiments, and the overlapping description is omitted or simplified.

In the present embodiment, the threshold setting unit 12 periodically sets a threshold during lighting control of the illumination light source 3.
More specifically, the threshold value setting unit 12 reads the analysis value analyzed by the FFT processing unit 11 every specified period (for example, 5 seconds). Then, the threshold value setting unit 12 stores the analysis values in a plurality of cycles (6 cycles in this example) in the memory 12a so that the period in which the analysis values are stored is longer than the lighting holding time (for example, 10 seconds). Let That is, when the specified period is 5 seconds, the threshold setting unit 12 stores the analysis value of the signal intensity for 30 seconds in the memory 12a. When the threshold setting unit 12 stores the signal intensity at the start of a new specified period, the threshold setting unit 12 erases the signal intensity of the earliest stored period (in this case, the previous six times) to obtain a new signal intensity. Can be stored.

  Thereafter, the threshold setting unit 12 detects the maximum value and the minimum value of the signal intensity for the past six cycles from the memory 12a for each frequency. Then, the threshold setting unit 12 determines, for each frequency, whether the difference between the maximum value and the minimum value of the signal intensity is “5 dB” or less. When the detected difference is “5 dB” or less, the threshold setting unit 12 sets a value obtained by adding 10 dB to the maximum value of the signal intensity at the frequency as a new threshold.

On the other hand, when the difference between the maximum value and the minimum value of the signal intensity exceeds “5 dB”, the threshold setting unit 12 does not change the set threshold.
Thereafter, the threshold setting unit 12 determines a predetermined period (5 seconds in this example) according to the amount of change in signal intensity for each frequency based on the time transition for six periods, that is, the difference between the maximum value and the minimum value of the signal intensity. ) A threshold value is set periodically every time.

  In the present embodiment, in the current specified cycle, the signal strength for each frequency used in the determination with the threshold value is stored as the signal strength in the past first cycle at the start of the next specified cycle. . In this case, in the present embodiment, the difference between the maximum value and the minimum value of the signal strength for each frequency in the first to sixth cycles corresponds to the first analysis value. On the other hand, the signal intensity for each frequency in the current specified period corresponds to the second analysis value. That is, the second analysis value can be used as the first analysis value when the current specified period ends.

Hereinafter, an operation example (action) until the threshold is set will be described.
As shown in FIG. 7, the signal intensity for the past six cycles is stored for each frequency. Then, the threshold setting unit 12 detects the maximum value and the minimum value for each frequency from the signal intensity for the past six cycles. For example, it is assumed that “−80 dB” is detected in the past 1st and 2nd cycles and “−78 dB” is detected in the past 3rd and 4th cycles as the signal intensity at 20 Hz. Further, it is assumed that “−77 dB” is detected as the signal intensity at 20 Hz in the past fifth and sixth cycles. In this case, the maximum value of the signal intensity at 20 Hz is “−77 Hz”. On the other hand, the minimum value of the signal intensity at 20 Hz is “−80 Hz”. Therefore, the difference between the maximum value and the minimum value of the signal intensity at 20 Hz is “3 dB”. Here, since the calculated “3 dB” is smaller than “5 dB”, “−77 + 10 = −67 Hz” is set as the threshold value.

  Further, it is assumed that “−80 dB” is detected in the past first cycle and “−72 dB” is detected in the past second cycle as the signal intensity at 398 Hz. Further, it is assumed that “−78 dB” is detected in the past 3rd and 4th cycles and “−70 dB” is detected in the past 5th and 6th cycles as the signal intensity at 398 Hz. In this case, the maximum value of the signal intensity at 398 Hz is “−70 Hz”. On the other hand, the minimum value of the signal intensity at 398 Hz is “−80 Hz”. Therefore, the difference between the maximum value and the minimum value of the signal intensity at 398 Hz is “10 dB”. Here, since the calculated “10 dB” is larger than “5 dB”, it is maintained without setting a new threshold (here, −50 dB).

  In this way, by setting the threshold periodically based on the time transition, even if the signal strength of the noise changes, it is possible to perform detection suitable for the state change without being affected by the noise after the change. it can. That is, since a value obtained by adding a specified value to the maximum value of the signal strength at a specific frequency is set as the threshold value, the threshold value is not exceeded regardless of the value of the noise signal strength. As a result, the signal intensity indicating the presence of the human body is not buried in noise, and the detection sensitivity does not decrease.

Next, according to the second embodiment, in addition to the effects (1) to (6) of the first embodiment, the following effects are obtained.
(9) The threshold setting unit 12 periodically sets a threshold. That is, since the threshold value is reset according to the change in the surrounding environment, it is possible to detect the presence or absence of the moving object with the optimum sensitivity according to the change in the surrounding environment.

  (10) When the threshold value is set uniformly regardless of the frequency, the signal intensity that does not exceed the threshold value at a certain time may exceed the threshold value due to a change in noise with time. Therefore, by periodically setting a threshold value, it is possible to detect the presence or absence of a moving object with an optimum sensitivity in accordance with changes in the surrounding environment.

  (11) The threshold setting unit 12 periodically sets a threshold with reference to the amount of change in signal strength for each frequency based on time transition. According to this, it is possible to set a threshold value that matches a change in signal strength based on a time transition. Therefore, the influence of noise at a specific frequency can be reduced and the detection sensitivity can be improved, so that a situation in which the detection signal is buried in noise and cannot be detected can be avoided.

In addition, you may change each said embodiment of this invention as follows.
-In 2nd Embodiment, you may make it reset a threshold value every time the period (for this example, 6 cycles) which memorize | stored signal strength passes.

  In the first embodiment, the setting mode may be set so that the setting mode is continuously set until the difference between the maximum value and the minimum value of the signal intensity is 5 dB or less without setting a time limit in the setting mode. . The situation where the difference between the maximum value and the minimum value of the signal intensity is 5 dB or less is a state in which the illumination light source 3 is stably lit and variation in detection accuracy is suppressed.

  In the first embodiment, the threshold value setting unit 12 may be instructed to the threshold value setting unit 12 and may be operated by the user, and the threshold value may be set by the user's switch operation. At this time, if the difference between the maximum value and the minimum value of the signal intensity does not become 5 dB or less even after the elapse of a predetermined set time, an object other than the human body (curtain etc.) is caused by voice or lamp flashing. May notify the user that the vehicle is not in a steady state. In addition, as an alerting | reporting content, the aspect in which the concrete content which should be performed in order to set it as a steady state, such as "Please close a window" and "Get out of a room." Is preferable. Accordingly, the user receives the notification and suppresses the movement of the moving body other than the human body or operates the switch for setting the threshold value so that the steady state is obtained.

  In the second embodiment, a predetermined value may be set as a threshold immediately after the illumination light source 3 is turned on after the power is turned on. The specification may be such that the signal strength is stored when a predetermined time has elapsed since a predetermined value is set as the threshold, and the threshold is periodically set according to the stored signal strength.

  In each of the above embodiments, the value added to the maximum value of the signal strength for setting the threshold value may not be 10 dB. That is, any value may be added as long as it is a value that can distinguish a mobile object that is a detection target from an object that is not a detection target.

  In the above embodiments, the lighting holding time may be any time. However, since the number of times of output of the control signal to the illumination light source 3 increases as the lighting holding time is shorter, for example, 10 seconds or more is preferable.

  In each of the above embodiments, the light source control unit 4 may be provided on the power supply line to the illumination light source 3, and in this case, the power supply to the illumination light source 3 is turned on / off instead of outputting a control signal. Thus, the illumination light source 3 can be turned on / off.

  -In above-mentioned embodiment, the sensor 2 should just be an active type sensor, and is not restricted to the millimeter wave sensor using a millimeter wave. For example, a microwave sensor using a microwave or a distance measuring sensor that detects a distance to an object in a detection area using an ultrasonic wave as a detection wave may be used.

  In each of the above embodiments, when the signal intensity exceeding the threshold is 1 to 4, or 6 or more, it may be determined that a human body exists in the detection area. However, considering the accuracy of detection sensitivity, it is preferable to determine that a human body exists in the detection area when there are a plurality of signal intensities exceeding the threshold.

  -In each said embodiment, the frequency band of the detection signal required in order to detect a human body may not be a frequency band of 20-400 Hz. That is, the speed is changed as appropriate based on the moving speed of the human body, the frequency of the radio wave transmitted by the sensor 2, the speed of light, and the angle of the moving direction of the moving body with respect to the straight line connecting the upper end of the object and the sensor. May be.

-In each said embodiment, as long as it becomes more than lighting holding time, the number of periods of the signal strength memorize | stored may be what value.
Next, a technical idea that can be grasped from the above embodiment and another example will be added below.

(A) In the illumination device according to claim 1 or 2 , the lighting device includes a counting unit that counts the number of times the signal intensity exceeds the threshold, and the determination unit is configured such that the number of times counted by the counting unit is An illuminating device characterized in that the presence of the moving object is determined when a prescribed number of times equal to or greater than two has been reached.

  (B) In the illuminating device according to the technical idea (a), the threshold value setting unit is configured to output the threshold value when a change width of the intensity for each frequency of the detection result is not within a certain range for a certain time. Is not updated or a predetermined threshold value is set.

  (C) In the lighting device according to claim 1, when a power source is turned on to the lighting device, a setting mode for setting the threshold value to the threshold value setting unit is set, and then the set threshold value is used. An illumination apparatus comprising: a mode setting unit that sets a normal mode for determining whether or not the moving object is present and performing lighting control of the illumination light source.

  (D) In the illumination device described in the technical idea (c), the threshold setting unit includes a change range of the intensity for each frequency of the detection result within a certain range over a certain time in the setting mode. Sometimes, a value larger than the noise intensity at the specific frequency detected by detecting an object different from the moving body and smaller than the intensity of the moving body is set as a threshold value at the specific frequency. The lighting device is characterized in that a predetermined threshold value is set when the change width of the intensity for each frequency of the detection result does not fall within a certain range for a certain time.

  DESCRIPTION OF SYMBOLS 1 ... Illuminating device, 2 ... Sensor, 3 ... Illumination light source, 4 ... Light source control part (control part), 11 ... Fast Fourier transform process part (FFT process part), 12 ... Threshold setting part, 13 ... Determination part.

Claims (2)

Provided with a sensor for transmitting a radio wave of a predetermined frequency and receiving a reflected wave reflected from the object by the transmitted radio wave, and moving based on the difference in frequency of the transmitted and received waves as a detection result by the sensor In the lighting device that detects the presence of the body and turns on the illumination light source,
Fast Fourier transform processing the detection result by the sensor, and analyze the signal intensity for each frequency ;
A threshold setting unit that sets a threshold used to determine the presence or absence of the moving object based on the signal intensity analyzed by the fast Fourier transform processing unit;
A determination unit that compares the signal intensity analyzed by the fast Fourier transform processing unit with the threshold value, and determines whether the signal intensity exceeds the threshold value, thereby determining whether or not the moving object is present;
A control unit that turns on the illumination light source when the determination unit determines that the signal intensity exceeds the threshold; and
The said threshold value setting part refers to the variation | change_quantity based on the time transition for every frequency of the said signal strength, and sets a threshold regularly . The lighting device according to claim 1.
The said determination part performs the comparison with the said signal strength and the said threshold value for every frequency, The illuminating device characterized by the above-mentioned.