Detector

Abstract

To provide a detector excellent in alarm accuracy while suppressing increase in manufacturing cost.SOLUTION: A detector includes an infrared sensor for outputting a detection signal according to infrared emission in a predetermined detection area; and an alarm output part for outputting an alarm detection signal showing that an object to be detected is detected on the basis of the detection signal. When the frequency of the detection signal is equal to or less than a predetermined first frequency, the alarm output part outputs the alarm signal; when the frequency of the detection signal is higher than the first frequency, the alarm output part does not output the alarm signal; and the first frequency is a predetermined frequency on the basis of an upper limit movement speed being the upper limit movement speed of an assumed object to be detected.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a detection device.

Background Art

[0002] As a detection device, for example, the one described in Patent Document 1 is already known. This detection device (referred to as an "infrared sensor" in Patent Document 1) includes an infrared sensor (referred to as a "heat ray sensor" in Patent Document 1). Then, based on the detection signal of the infrared sensor, an alarm is issued.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the detection device as described above, it is conceivable to improve the accuracy of alarm by improving the signal-to-noise ratio (SN ratio) of the detection signal of the infrared sensor. Here, for example, in order to improve the SN ratio, it is conceivable to perform fast Fourier transform processing.

[0005] However, when performing fast Fourier transform processing, since the computational load is high, it is necessary to mount a relatively expensive processing device. Furthermore, in fast Fourier transform processing, in principle, a delay occurs in the calculation of the result.

[0006] An object of the present invention is to provide a detection device with good alarm accuracy while suppressing an increase in manufacturing cost.

Means for Solving the Problems

[0007] The features of the present invention include an infrared sensor that outputs a detection signal in response to infrared radiation within a predetermined detection area, and a reporting output unit that outputs a reporting signal indicating that a detection target has been detected based on the detection signal. When the frequency of the detection signal is equal to or lower than a predetermined first frequency, the reporting output unit outputs the reporting signal. When the frequency of the detection signal is higher than the first frequency, the reporting output unit does not output the reporting signal. The first frequency is a frequency determined in advance based on the upper limit moving speed, which is the upper limit value of the assumed moving speed of the detection target.

[0008] Generally, when a detection target passes through a detection area, the higher the moving speed of the detection target, the higher the frequency of the output detection signal. According to this configuration, the first frequency is determined in advance based on the upper limit moving speed. Therefore, when the frequency of the detection signal is higher than the first frequency, it is considered that the detection signal (peak) is noise rather than being output due to the detection target passing through the detection area.

[0009] According to this configuration, when the frequency of the detection signal is equal to or lower than the first frequency, a reporting signal is output. When the frequency of the detection signal is higher than the first frequency, a reporting signal is not output. Therefore, a configuration can be realized in which a reporting signal is output when the detection signal is not noise, and a reporting signal is not output when the detection signal is noise.

[0010] Moreover, according to this configuration, it is not necessary to perform fast Fourier transform processing, and it is possible to determine whether the detection signal (peak) is noise only by comparing the frequency of the detection signal with the first frequency. As a result, since the computational load is relatively low, it is not necessary to install a relatively expensive processing device.

[0011] From the above, according to this configuration, it is possible to realize a detection device with good reporting accuracy while suppressing an increase in manufacturing cost.

[0012] Furthermore, in the present invention, it is preferable that the first frequency is a frequency determined in advance based on the frequency of the detection signal when the object to be detected moves at the upper limit moving speed at a position at a predetermined distance from the device.

[0013] Generally, the closer the passing position of the object to be detected is to the detection device, the higher the frequency of the output detection signal. And according to this configuration, the first frequency is determined in advance based on the frequency of the detection signal when the object to be detected moves at the upper limit moving speed at a position at a predetermined distance from the detection device. Therefore, for example, by appropriately determining the predetermined distance, the first frequency can be determined based on the frequency of the detection signal when the distance of the passing position of the object to be detected from the detection device is the shortest among the assumed cases. Thereby, the first frequency becomes an appropriate value.

[0014] Furthermore, in the present invention, when the frequency of the detection signal is higher than the first frequency, if the amplitude level value, which is a value corresponding to the amplitude of the detection signal, is smaller than a predetermined first threshold value, the reporting output unit does not output the reporting signal. When the frequency of the detection signal is higher than the first frequency and the amplitude level value is equal to or greater than the first threshold value, it is preferable that the reporting output unit outputs the reporting signal.

[0015] Even when the frequency of the detection signal is higher than the first frequency, if the amplitude of the detection signal (or the amplitude of the detection signal after a predetermined filtering process, etc.) is relatively large, the detection signal may not be noise but may be output when the object to be detected passes through the detection area. Here, according to this configuration, when the frequency of the detection signal is higher than the first frequency and the amplitude level value is equal to or greater than the first threshold value, the reporting output unit outputs the reporting signal. Thereby, false non - reporting can be prevented.

[0016] Furthermore, in the present invention, when the frequency of the detection signal is higher than the first frequency and the amplitude level value is smaller than the first threshold value, if the amplitude level value is smaller than a predetermined second threshold value that is smaller than the first threshold value, the alarm output unit does not output the alarm signal. When the frequency of the detection signal is higher than the first frequency, the amplitude level value is smaller than the first threshold value, and the amplitude level value is equal to or greater than the second threshold value, and when a predetermined condition is satisfied, the alarm output unit does not output the alarm signal. When the frequency of the detection signal is higher than the first frequency, the amplitude level value is smaller than the first threshold value, and the amplitude level value is equal to or greater than the second threshold value, and when the predetermined condition is not satisfied, the alarm output unit outputs the alarm signal. It is preferable that a noise determination unit is provided to determine whether a peak whose amplitude level value is smaller than the first threshold value and equal to or greater than the second threshold value is noise, and the predetermined condition is that the noise determination unit determines that the peak is noise.

[0017] According to this configuration, when the frequency of the detection signal is higher than the first frequency, the amplitude level value is smaller than the first threshold value, and the amplitude level value is equal to or greater than the second threshold value, and when it is determined that the detected peak is not noise, the alarm signal is output. Thereby, false alarms can be prevented.

[0018] Furthermore, in the present invention, when the frequency of the detection signal is higher than a predetermined second frequency that is higher than the first frequency, it is preferable that the alarm output unit does not output the alarm signal regardless of the amplitude level value.

[0019] According to this configuration, the first frequency is determined in advance based on the upper limit moving speed, and the second frequency is higher than the first frequency. Therefore, when the frequency of the detection signal is higher than the second frequency, it is considered that the detection signal (peak) is not output by the detection target passing through the detection area, but is noise.

[0020] According to this configuration, when the frequency of the detection signal is higher than the second frequency, the alarm signal is not output regardless of the amplitude level value, thereby preventing false alarms.

[0021] Furthermore, in the present invention, it is preferable that the object to be detected is a human body.

[0022] This configuration makes it possible to realize a detection device that outputs an alarm signal when an intruder enters or passes through a detection area. As a result, by appropriately installing the detection device, it is possible to realize a configuration in which an alarm is issued when an intruder enters a predetermined area (for example, a restricted access area, a protected area, a building, etc.).

[0023] Furthermore, in the present invention, it is preferable that the infrared sensor is a pyroelectric infrared sensor.

[0024] According to this configuration, an infrared sensor that outputs a detection signal in response to infrared radiation within a detection area can be provided reliably and at a relatively low cost.

[0025] Furthermore, in the present invention, it is preferable that a signal processing unit is provided that receives the detection signal and processes the detection signal, the alarm output unit is configured to output the alarm signal based on a processing result by the signal processing unit, and the first frequency is a cutoff frequency of a digital low-pass filter set in the signal processing unit.

[0026] This configuration allows the number of components to be reduced compared to when the low-pass filter is configured using an analog filter, thereby suppressing increases in manufacturing costs.

[0027] Furthermore, in the present invention, it is preferable to include a memory unit that stores a candidate frequency group, which is a plurality of frequencies predetermined based on the upper limit movement speed, and a setting unit that sets one frequency selected from the candidate frequency group as the first frequency.

[0028] According to this configuration, the frequency to be set as the first frequency can be selected from a plurality of frequencies, which makes it possible to set an appropriate frequency as the first frequency depending on the load status of the signal processing unit and the environment around the detection device.

[0029] Furthermore, in the present invention, when the frequency of the detection signal is equal to or lower than the first frequency, if an amplitude level value, which is a value corresponding to the amplitude of the detection signal, is equal to or higher than a predetermined third threshold value, the alarm output unit outputs the alarm signal, and when the frequency of the detection signal is equal to or lower than the first frequency, if the amplitude level value is smaller than the third threshold value, the alarm output unit preferably does not output the alarm signal.

[0030] Even if the frequency of the detection signal is equal to or lower than the first frequency, if the amplitude of the detection signal (or the amplitude of the detection signal after a predetermined filter process, etc.) is relatively small, the detection signal (peak) is considered to be noise and not output due to the object to be detected passing through the detection area.

[0031] According to this configuration, when the frequency of the detection signal is equal to or lower than the first frequency, and the amplitude level value is smaller than the third threshold, the alarm signal is not output, thereby preventing false alarms. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 2 is a plan view showing the configuration of the detection device. [Diagram 2] FIG. 2 is a front view showing the configuration of the detection device. [Figure 3] FIG. 2 is a block diagram showing the configuration of a detection device. [Figure 4] 10 is a flowchart of an alarm control flow. [Figure 5] 10A and 10B are diagrams illustrating examples of waveforms before and after digital low-pass filter processing. [Figure 6] FIG. 10 is a diagram showing an example of a case where a peak is determined not to be noise. [Figure 7]This is a diagram showing an example case where a peak is determined to be noise. [Figure 8] This is a flowchart of the transmission control flow in the first alternative embodiment.

Embodiments for Carrying Out the Invention

[0033] The embodiments for carrying out the present invention will be described with reference to the drawings. In the following description, unless otherwise specified, the direction of arrow F in the drawings is defined as "front", the direction of arrow B is defined as "rear", the direction of arrow L is defined as "left", and the direction of arrow R is defined as "right". Also, the direction of arrow U in the drawings is defined as "up" and the direction of arrow D is defined as "down".

[0034] 〔Configuration of Detection Device〕 As shown in FIGS. 1 and 2, the detection device 1 has a columnar shape extending in the vertical direction. However, the present invention is not limited to this, and the detection device 1 can have any shape.

[0035] In this embodiment, the detection device 1 is fixed to the outer wall (not shown) of a building or the like. Also, the detection device 1 is installed at a position away from the ground. However, the present invention is not limited to this, and the detection device 1 can be fixed to any object and installed at any position.

[0036] As shown in FIG. 3, the detection device 1 includes an infrared sensor 3. Although not particularly limited, in this embodiment, the infrared sensor 3 is a pyroelectric infrared sensor.

[0037] More specifically, the infrared sensor 3 is a dual-type pyroelectric infrared sensor having a pair of pyroelectric elements. The pair of pyroelectric elements are connected in a state where the polarities of the surface charges are opposite to each other. Note that the present invention is not limited to this. For example, the infrared sensor 3 may be a quad-type pyroelectric infrared sensor having four pyroelectric elements. Since the structures of dual-type and quad-type pyroelectric infrared sensors are well-known, the description thereof is omitted.

[0038] Figures 1 and 2 show the detection area 2 of the detection device 1. The detection area 2 is composed of a left detection area 2L and a right detection area 2R. The left detection area 2L and the right detection area 2R respectively correspond to the pair of pyroelectric elements described above. Note that the present invention is not limited to this. The detection area 2 may be divided into three or more areas. Also, the detection area 2 may be divided into a plurality of areas by optical components such as lenses.

[0039] In a plan view, the left detection area 2L spreads fan-shaped from the detection device 1 to the left front side. Also, in a plan view, the right detection area 2R spreads fan-shaped from the detection device 1 to the right front side.

[0040] The infrared sensor 3 outputs a detection signal according to a change in infrared radiation within the detection area 2. For example, when a detection target object E that emits infrared rays passes through the left detection area 2L, a positive detection signal (positive voltage) is output from the infrared sensor 3, and when the detection target object E passes through the right detection area 2R, a negative detection signal (negative voltage) may be output from the infrared sensor 3. Thus, the detection device 1 includes an infrared sensor 3 that outputs a detection signal according to infrared radiation within a predetermined detection area 2.

[0041] In the present embodiment, the detection target object E of the detection device 1 is a human body. However, the present invention is not limited to this. The detection target object E may be, for example, a vehicle or the like.

[0042] 〔Outline of Alarm Transmission〕 As shown in FIG. 3, the detection device 1 includes a signal processing unit 4 and an alarm transmission output unit 5. The detection signal output by the infrared sensor 3 is sent to the signal processing unit 4. The signal processing unit 4 processes the detection signal. That is, the detection device 1 includes a signal processing unit 4 that receives the detection signal and processes the detection signal.

[0043] The alarm transmission output unit 5 is configured to output an alarm transmission signal based on the processing result by the signal processing unit 4. The alarm transmission signal is a signal indicating that the detection target object E has been detected.

[0044] The transmission output unit 5 outputs a transmission signal to a transmission device (not shown). When receiving the transmission signal, the transmission device notifies that the detection target object E has been detected by sound, light, or the like. The transmission device may or may not be included in the detection device 1.

[0045] Here, the processing result by the signal processing unit 4 is based on the detection signal output by the infrared sensor 3. That is, the transmission output unit 5 outputs a transmission signal based on the detection signal output by the infrared sensor 3.

[0046] As described above, the detection device 1 includes a transmission output unit 5 that outputs a transmission signal indicating that the detection target object E has been detected based on the detection signal. Further, the transmission output unit 5 is configured to output a transmission signal based on the processing result by the signal processing unit 4.

[0047] As shown in FIG. 3, the signal processing unit 4 includes an AD conversion unit 41, an amplitude determination unit 42, a frequency determination unit 43, a noise determination unit 44, and a filter processing unit 45.

[0048] The AD conversion unit 41 performs AD conversion on the detection signal sent from the infrared sensor 3 to the signal processing unit 4. The amplitude determination unit 42 determines the amplitude of the detection signal sent from the infrared sensor 3 to the signal processing unit 4. The frequency determination unit 43 determines the frequency of the detection signal sent from the infrared sensor 3 to the signal processing unit 4. The noise determination unit 44 performs noise determination as described later. The filter processing unit 45 performs digital low-pass filter processing on the detection signal output by the infrared sensor 3.

[0049] 〔Transmission control flow〕 The detection device 1 is configured to perform processing related to the output of the transmission signal according to the transmission control flow shown in FIG. 4. Hereinafter, this transmission control flow will be described.

[0050] When the transmission control flow is started, first, the process of step S01 is executed. In step S01, AD conversion is performed on the detection signal sent from the infrared sensor 3 to the signal processing unit 4 by the AD conversion unit 41. As a result, a waveform indicating the transition of the detection signal (voltage) is generated. An example of the generated waveform is shown at the upper part of FIG. 5. Thereafter, the process proceeds to step S02.

[0051] In step S02, it is determined by the amplitude determination unit 42 whether there is a peak (a mountain-shaped part including a maximum value) having an amplitude equal to or greater than a reference amplitude value AB (corresponding to the "third threshold value" according to the present invention) (see FIG. 5) in the waveform generated in step S01.

[0052] If there is a peak having an amplitude equal to or greater than the reference amplitude value AB ( "Yes" in step S02), the process proceeds to step S03. If there is no peak having an amplitude equal to or greater than the reference amplitude value AB ( "No" in step S02), the process proceeds to step S09.

[0053] For example, at the upper part of FIG. 5, a first peak P1 and a second peak P2 are shown. The amplitudes of both are the first amplitude A1. Assume that the first amplitude A1 is equal to or greater than the reference amplitude value AB. In this case, at the time when the first peak P1 and the second peak P2 are detected, in step S02, it is determined that there is a peak having an amplitude equal to or greater than the reference amplitude value AB. Note that the determination in step S02 may be made at the time when at least one of the first peak P1 and the second peak P2 is detected (for example, at the time when the first peak P1 is detected).

[0054] In step S03, it is determined by the frequency determination unit 43 whether the frequency of the detection signal output by the infrared sensor 3 is equal to or less than a predetermined first frequency. More specifically, it is determined by the frequency determination unit 43 whether the frequency of the peak determined to exist in step S02 is equal to or less than the first frequency.

[0055] Here, the first frequency is a frequency determined in advance based on an upper limit moving speed. The upper limit moving speed is the upper limit of the expected moving speed of the detection object E. In other words, the first frequency is a frequency determined in advance based on the upper limit moving speed, which is the upper limit of the expected moving speed of the detection object E.

[0056] More specifically, the first frequency is a frequency determined in advance based on the frequency of the detection signal when the object to be detected E moves at the upper limit of the moving speed at a position a predetermined distance from the device (detection device 1). The first frequency may be, for example, the frequency of the detection signal when the object to be detected E moves at the upper limit of the moving speed at a position a predetermined distance from the device (detection device 1).

[0057] The predetermined distance may be any distance and may be set appropriately. For example, the predetermined distance may be the lower limit of the distance between the anticipated detection target object E and the detection device 1. The predetermined distance may also be the distance in a planar view.

[0058] If the frequency of the detection signal (peak) is higher than the first frequency ("No" in step S03), the process proceeds to step S04. If the frequency of the detection signal (peak) is equal to or lower than the first frequency ("Yes" in step S03), the process proceeds to step S09.

[0059] In step S04, the frequency determination unit 43 determines whether the frequency of the detection signal output by the infrared sensor 3 is higher than a predetermined second frequency. More specifically, the frequency determination unit 43 determines whether the frequency of the peak determined to exist in step S02 is higher than the second frequency. The second frequency is higher than the first frequency.

[0060] If the frequency of the detection signal (peak) is equal to or lower than the second frequency ("No" in step S04), the process proceeds to step S05. If the frequency of the detection signal (peak) is higher than the second frequency ("Yes" in step S04), the alarm control flow ends.

[0061] In step S05, it is determined by the amplitude determination unit 42 whether the amplitude level value is equal to or greater than a predetermined first threshold value. Note that the amplitude level value is a value corresponding to the amplitude of the detection signal (peak) output by the infrared sensor 3. Specifically, the amplitude level value may be the amplitude of the detection signal itself output by the infrared sensor 3, or may be the amplitude of the detection signal after a predetermined filtering process (for example, digital low-pass filtering).

[0062] The amplitude level value in step S05 is the amplitude of the detection signal itself output by the infrared sensor 3. When the amplitude level value is smaller than the first threshold value ("No" in step S05), the process proceeds to step S06. When the amplitude level value is equal to or greater than the first threshold value ("Yes" in step S05), the process proceeds to step S08.

[0063] In step S06, it is determined by the amplitude determination unit 42 whether the amplitude level value is equal to or greater than a predetermined second threshold value. Note that the second threshold value is smaller than the first threshold value. Also, although not particularly limited, the above-mentioned reference amplitude value AB may be greater than the first threshold value, may be the same as the first threshold value, or may be smaller than the first threshold value. Also, the above-mentioned reference amplitude value AB may be greater than the second threshold value, may be the same as the second threshold value, or may be smaller than the second threshold value.

[0064] The amplitude level value in step S06 is the amplitude of the detection signal itself output by the infrared sensor 3. When the amplitude level value is equal to or greater than the second threshold value ("Yes" in step S06), the process proceeds to step S07. When the amplitude level value is smaller than the second threshold value ("No" in step S06), the process proceeds to step S09.

[0065] In step S07, it is determined whether a predetermined condition is satisfied. More specifically, the noise determination unit 44 determines whether a peak whose amplitude level value is less than the first threshold and equal to or greater than the second threshold (in other words, the peak determined as "No" in step S05 and determined as "Yes" in step S06) is noise. That is, the predetermined condition in the present embodiment is that the noise determination unit 44 determines that the peak is noise.

[0066] As described above, the detection device 1 includes a noise determination unit 44 that determines whether a peak whose amplitude level value is less than the first threshold and equal to or greater than the second threshold is noise.

[0067] If the predetermined condition is not satisfied (specifically, if it is determined that the peak is not noise) (in step S07, "No"), the process proceeds to step S08. If the predetermined condition is satisfied (specifically, if it is determined that the peak is noise) (in step S07, "Yes"), the process proceeds to step S09.

[0068] In step S08, a predetermined signal is sent from the signal processing unit 4 to the alarm output unit 5. The signal is a signal instructing the output of an alarm signal. As is clear from the above description, the signal is sent based on the processing result by the signal processing unit 4. The alarm output unit 5 outputs an alarm signal in response to the signal. Then, the process proceeds to step S09.

[0069] As described above, when the frequency of the detection signal is higher than the first frequency, and the amplitude level value is less than the first threshold, and the amplitude level value is equal to or greater than the second threshold, if the predetermined condition is not satisfied, the alarm output unit 5 outputs an alarm signal.

[0070] Also, when the frequency of the detection signal is higher than the first frequency and the amplitude level value is equal to or greater than the first threshold, the alarm output unit 5 outputs an alarm signal.

[0071] In step S09, the filter processing unit 45 performs digital low-pass filter processing on the detection signal (the waveform generated in step S01) output by the infrared sensor 3. The cut-off frequency at this time is the first frequency, which is set in the filter processing unit 45. That is, the first frequency is the cut-off frequency of the digital low-pass filter set in the signal processing unit 4.

[0072] For example, assume that the frequencies of the first peak P1 and the second peak P2 shown at the upper part of FIG. 5 are higher than the first frequency. Also, assume that the frequencies of the third peak P3 and the fourth peak P4 shown at the upper part of FIG. 5 are lower than the first frequency. Further, the amplitudes of the third peak P3 and the fourth peak P4 shown at the upper part of FIG. 5 are both the second amplitude A2.

[0073] At this time, when the digital low-pass filter processing by the filter processing unit 45 is executed, as shown in the lower part of FIG. 5, the amplitudes of the first peak P1 and the second peak P2 change to the third amplitude A3. The third amplitude A3 is significantly smaller than the first amplitude A1. Also, at this time, the amplitudes of the third peak P3 and the fourth peak P4 do not change and remain the second amplitude A2.

[0074] Note that the first amplitude A1, the second amplitude A2, and the third amplitude A3 are all values corresponding to the amplitude of the detection signal output by the infrared sensor 3. That is, the first amplitude A1, the second amplitude A2, and the third amplitude A3 are all amplitude level values.

[0075] As shown in FIG. 4, after step S09, the process proceeds to step S10. In step S10, the amplitude determination unit 42 determines whether there is a peak having an amplitude equal to or greater than the reference amplitude value AB in the waveform after the digital low-pass filter processing.

[0076] If a peak having an amplitude equal to or greater than the reference amplitude value AB exists (Yes in step S10), the process proceeds to step S11. If no peak having an amplitude equal to or greater than the reference amplitude value AB exists (No in step S10), this reporting control flow ends temporarily.

[0077] Although not particularly limited, in the present embodiment, the digital low-pass filter process executed in step S09 is configured such that when a peak having a frequency higher than the first frequency exists and the amplitude of the peak before the process is smaller than the first threshold value, the amplitude of the peak after the process becomes smaller than the reference amplitude value AB.

[0078] In step S11, a predetermined signal is sent from the signal processing unit 4 to the reporting output unit 5. The signal is a signal instructing the output of the reporting signal. As is clear from the above description, the signal is sent based on the processing result by the signal processing unit 4. The reporting output unit 5 outputs a reporting signal in response to the signal. Then, this reporting control flow ends temporarily.

[0079] For example, it is assumed that the third amplitude A3 shown at the bottom of FIG. 5 is smaller than the reference amplitude value AB. In this case, at the time when the first peak P1 and the second peak P2 are detected, in step S10, it is determined that no peak having an amplitude equal to or greater than the reference amplitude value AB exists. Therefore, in this case, the process of step S11 is not executed. That is, in this case, after step S10, the reporting signal is not output. The determination in step S10 may be made at the time when at least one of the first peak P1 and the second peak P2 is detected (for example, the time when the first peak P1 is detected).

[0080] Also, the second amplitude A2 shown at the lower part of FIG. 5 shall be greater than the reference amplitude value AB. In this case, when the third peak P3 and the fourth peak P4 are detected, in step S10, it is determined that there is a peak having an amplitude equal to or greater than the reference amplitude value AB. Therefore, in this case, the process of step S11 is executed. That is, in this case, after step S10, an alarm signal is output. Note that the determination in step S10 may be made at the time when at least one of the third peak P3 and the fourth peak P4 is detected (for example, at the time when the third peak P3 is detected).

[0081] As described above, when the frequency of the detection signal is equal to or lower than the first frequency and the amplitude level value, which is a value corresponding to the amplitude of the detection signal, is equal to or greater than the predetermined reference amplitude value AB, the alarm output unit 5 outputs an alarm signal.

[0082] Note that, if the second amplitude A2 shown at the lower part of FIG. 5 is smaller than the reference amplitude value AB, when the third peak P3 and the fourth peak P4 are detected, in step S10, it is determined that there is no peak having an amplitude equal to or greater than the reference amplitude value AB. Therefore, in this case, the process of step S11 is not executed. That is, in this case, after step S10, no alarm signal is output.

[0083] As described above, when the frequency of the detection signal is equal to or lower than the first frequency and the amplitude level value is smaller than the reference amplitude value AB, the alarm output unit 5 does not output an alarm signal.

[0084] Note that, after the process of step S08 is executed, if in step S10 it is determined that there is a peak having an amplitude equal to or greater than the reference amplitude value AB, since the alarm signal has already been output, the process of step S11 may be skipped (omitted).

[0085] As is clear from the above description, when the frequency of the peak in the detection signal is higher than the first frequency (「No」 in step S03 of FIG. 4), and the amplitude level value of the peak is smaller than the first threshold value (「No」 in step S05), and when the amplitude level value of the peak is smaller than the second threshold value (「No」 in step S06), the process of step S08 is not executed. Also, in this case, by the digital low-pass filter process executed in step S09, the amplitude of the peak after the process becomes smaller than the reference amplitude value AB. Therefore, the process of step S11 is not executed either.

[0086] That is, when the frequency of the detection signal is higher than the first frequency and the amplitude level value is smaller than the first threshold value, and when the amplitude level value is smaller than a predetermined second threshold value that is smaller than the first threshold value, the alarm output unit 5 does not output an alarm signal.

[0087] Also, as is clear from the above description, when the frequency of the peak in the detection signal is higher than the first frequency (「No」 in step S03), and the amplitude level value of the peak is smaller than the first threshold value (「No」 in step S05), and when the amplitude level value of the peak is equal to or greater than the second threshold value (「Yes」 in step S06), and when a predetermined condition is satisfied (「Yes」 in step S07), the process of step S08 is not executed. Also, in this case, by the digital low-pass filter process executed in step S09, the amplitude of the peak after the process becomes smaller than the reference amplitude value AB. Therefore, the process of step S11 is not executed either.

[0088] That is, when the frequency of the detection signal is higher than the first frequency, and the amplitude level value is smaller than the first threshold value, and the amplitude level value is equal to or greater than the second threshold value, and when a predetermined condition is satisfied, the alarm output unit 5 does not output an alarm signal.

[0089] Also, as is clear from the above description, when the frequency of the peak in the detection signal is higher than the first frequency ( "No" in step S03), and when the amplitude level value of the peak is smaller than the first threshold value ( "No" in step S05), except for a predetermined case (specifically, when "Yes" in step S06 and "No" in step S07), the process of step S08 is not executed. Also, in this case, by the digital low-pass filter process executed in step S09, the amplitude of the peak after the process becomes smaller than the reference amplitude value AB. Therefore, the process of step S11 is not executed either.

[0090] That is, when the frequency of the detection signal is higher than the first frequency, and the amplitude level value, which is a value corresponding to the amplitude of the detection signal, is smaller than a predetermined first threshold value, the alarm output unit 5 does not output an alarm signal.

[0091] Also, as is clear from the above description, when the frequency of the peak in the detection signal is higher than the second frequency ( "Yes" in step S04), regardless of the amplitude level value of the peak, the processes of step S08 and step S11 are not executed. Therefore, in this case, even if the amplitude level value of the peak is greater than or equal to the first threshold value, the alarm signal is not output.

[0092] That is, when the frequency of the detection signal is higher than a predetermined second frequency that is higher than the first frequency, regardless of the amplitude level value, the alarm output unit 5 does not output an alarm signal.

[0093] Also, as is clear from the above description, when the frequency of the peak in the detection signal is higher than the first frequency ( "No" in step S03), except for a predetermined case (specifically, when "No" in step S04 and "Yes" in step S05, and when "No" in step S04, "No" in step S05, "Yes" in step S06, and "No" in step S07), the process of step S08 is not executed. Also, in this case, except for a predetermined case (specifically, when "No" in step S04 and "Yes" in step S05), the amplitude of the peak after the process becomes smaller than the reference amplitude value AB by the digital low-pass filter process executed in step S09. Therefore, the process of step S11 is not executed either.

[0094] That is, when the frequency of the detection signal is higher than the first frequency, the alarm output unit 5 does not output an alarm signal.

[0095] Also, as is clear from the above description, when the frequency of the peak in the detection signal is equal to or lower than the first frequency ( "Yes" in step S03), except for a predetermined case (specifically, when "No" in step S10), the process of step S11 is executed.

[0096] That is, when the frequency of the detection signal is equal to or lower than a predetermined first frequency, the alarm output unit 5 outputs an alarm signal.

[0097] 〔Noise determination〕 As described above, the noise determination unit 44 shown in FIG. 3 determines whether a peak whose amplitude level value is smaller than the first threshold and equal to or greater than the second threshold is noise. At this time, when the detection signal (value before AD conversion) corresponding to the peak is continuously equal to or greater than the second threshold for a predetermined number of times (or a predetermined time), the noise determination unit 44 determines that the peak is not noise. Otherwise, the noise determination unit 44 determines that the peak is noise. Although not particularly limited, in the present embodiment, the predetermined number of times is 3 times.

[0098] For example, as shown in FIG. 6, a first detection value Q1, a second detection value Q2, a third detection value Q3, a fourth detection value Q4, and a fifth detection value Q5 are shown. These are detection signals output by the infrared sensor 3, and it is assumed that they correspond to peaks whose amplitude level values are smaller than the first threshold value and equal to or greater than the second threshold value. As shown in FIG. 6, the infrared sensor 3 in the present embodiment outputs a detection signal every predetermined period t1.

[0099] As shown in FIG. 6, the second detection value Q2, the third detection value Q3, and the fourth detection value Q4 are continuous detection signals, and all of them are equal to or greater than the second threshold value. Therefore, in this case, the noise determination unit 44 determines that this peak is not noise.

[0100] Further, for example, as shown in FIG. 7, a sixth detection value Q6, a seventh detection value Q7, an eighth detection value Q8, a ninth detection value Q9, and a tenth detection value Q10 are shown. These are detection signals output by the infrared sensor 3, and it is assumed that they correspond to peaks whose amplitude level values are smaller than the first threshold value and equal to or greater than the second threshold value.

[0101] As shown in FIG. 7, the seventh detection value Q7, the eighth detection value Q8, and the ninth detection value Q9 are continuous detection signals. Also, the seventh detection value Q7 and the ninth detection value Q9 are equal to or greater than the second threshold value. However, the eighth detection value Q8 is smaller than the second threshold value. Also, the sixth detection value Q6 and the tenth detection value Q10 are also smaller than the second threshold value. Therefore, in this case, the noise determination unit 44 determines that this peak is noise.

[0102] Note that the present invention is not limited to this. The determination by the noise determination unit 44 may be performed based on the value after AD conversion (in other words, the above-described waveform). Also, the determination by the noise determination unit 44 may be performed based on the waveform before a predetermined filter process (for example, digital low-pass filter process), or may be performed based on the waveform after a predetermined filter process (for example, digital low-pass filter process).

[0103] [Storage unit and setting unit] 3, the detection device 1 includes a storage unit 6 and a setting unit 7. The storage unit 6 stores a group of candidate frequencies. The group of candidate frequencies is a plurality of frequencies that are determined in advance based on an upper limit moving speed.

[0104] In this way, the detection device 1 includes a storage unit 6 that stores a candidate frequency group, which is a plurality of frequencies that are determined in advance based on the upper limit moving speed.

[0105] The setting unit 7 acquires one frequency selected from the group of candidate frequencies from the storage unit 6. Then, the setting unit 7 sends the selected frequency to the filter processing unit 45. As a result, the filter processing unit 45 sets the selected frequency as the first frequency.

[0106] In this way, the detection device 1 includes a setting unit 7 that sets one frequency selected from the group of candidate frequencies as the first frequency.

[0107] Although not particularly limited, the setting unit 7 may be configured to accept a manual operation to select one frequency from the group of candidate frequencies, and in this case, the setting unit 7 may set the frequency selected by the manual operation as the first frequency.

[0108] The signal processing unit 4, AD conversion unit 41, amplitude determination unit 42, frequency determination unit 43, noise determination unit 44, filter processing unit 45, alarm output unit 5, memory unit 6, and setting unit 7 may be physical devices such as a microcomputer, or may be functional units in software.

[0109] Generally, when the detection target E passes through the detection area 2, the higher the moving speed of the detection target E, the higher the frequency of the output detection signal. According to the configuration described above, the first frequency is determined in advance based on the upper limit moving speed. Therefore, if the frequency of the detection signal is higher than the first frequency, the detection signal (peak) is considered to be noise, not a signal output due to the detection target E passing through the detection area 2.

[0110] According to the configuration described above, an alarm signal is output when the frequency of the detection signal is equal to or lower than the first frequency. Furthermore, when the frequency of the detection signal is higher than the first frequency, no alarm signal is output. Therefore, a configuration can be realized in which an alarm signal is output when the detection signal is not noise, and no alarm signal is output when the detection signal is noise.

[0111] Moreover, with the configuration described above, there is no need to perform fast Fourier transform processing, and it is possible to determine whether the detection signal (peak) is noise or not simply by comparing the frequency of the detection signal with the first frequency. This reduces the calculation load, eliminating the need to install a relatively expensive processing device.

[0112] As described above, this configuration makes it possible to realize a detection device 1 that issues an alarm with good accuracy while suppressing increases in manufacturing costs.

[0113] [First Alternative Embodiment] In the above embodiment, the detection device 1 is configured to perform processing related to the output of an alarm signal in accordance with the alarm control flow shown in FIG.

[0114] However, the present invention is not limited to this. Below, a first alternative embodiment of the present invention will be described, focusing on the differences from the above embodiment. The configuration other than the parts described below is the same as the above embodiment. Furthermore, the same reference numerals are used to designate the same configuration as the above embodiment.

[0115] FIG. 8 shows the reporting control flow in the first alternative embodiment according to the present invention. When this reporting control flow is started, first, the process of step S21 is executed. Since the process of step S21 is the same as the process of step S01 (see FIG. 4) in the reporting control flow in the above embodiment, the description thereof is omitted.

[0116] After step S21, the process proceeds to step S22. Since the process of step S22 is the same as the process of step S09 (see FIG. 4) in the reporting control flow in the above embodiment, the description thereof is omitted.

[0117] After step S22, the process proceeds to step S23. In step S23, it is determined by the frequency determination unit 43 whether the frequency of the waveform after the digital low-pass filter process is performed in step S22 is equal to or less than the first frequency.

[0118] When the frequency of the waveform is equal to or less than the first frequency (``Yes'' in step S23), the process proceeds to step S24. When the frequency of the waveform is higher than the first frequency (``No'' in step S23), the process proceeds to step S26.

[0119] In step S24, it is determined by the amplitude determination unit 42 whether the amplitude level value is equal to or greater than the first threshold value. The amplitude level value in step S24 is the amplitude of the waveform after the digital low-pass filter process is performed in step S22. When the amplitude level value is equal to or greater than the first threshold value (``Yes'' in step S24), the process proceeds to step S25. When the amplitude level value is less than the first threshold value (``No'' in step S24), this reporting control flow ends once. Note that the present invention is not limited thereto. In step S24, a configuration may be adopted in which the amplitude determination unit 42 determines whether the amplitude level value is equal to or greater than the reference amplitude value AB.

[0120] The process of step S25 is the same as the processes of steps S08 and S11 (see FIG. 4) in the reporting control flow in the above embodiment, so the description thereof is omitted. After step S25, this reporting control flow ends once.

[0121] In step S26, the filter processing unit 45 executes digital low-pass filter processing on the detection signal (the waveform generated in step S21) output by the infrared sensor 3. Note that the cut-off frequency at this time is the second frequency and is set in the filter processing unit 45. That is, in this first alternative embodiment, the second frequency is the cut-off frequency of the digital low-pass filter set in the signal processing unit 4.

[0122] After step S26, the process proceeds to step S27. In step S27, the frequency determination unit 43 determines whether the frequency of the waveform after the digital low-pass filter processing in step S26 is equal to or lower than the second frequency.

[0123] If the frequency of the waveform is equal to or lower than the second frequency (Yes in step S27), the process proceeds to step S28. If the frequency of the waveform is higher than the second frequency (No in step S27), this reporting control flow ends once.

[0124] In step S28, the amplitude determination unit 42 determines whether the amplitude level value is equal to or higher than the first threshold value. The amplitude level value in step S28 is the amplitude of the waveform after the digital low-pass filter processing in step S26. If the amplitude level value is equal to or higher than the first threshold value (Yes in step S28), the process proceeds to step S25. If the amplitude level value is smaller than the first threshold value (No in step S28), the process proceeds to step S29.

[0125] In step S29, it is determined by the amplitude determination unit 42 whether the amplitude level value is greater than or equal to the second threshold value. The amplitude level value in step S29 is the amplitude of the waveform after the digital low-pass filter processing is performed in step S26. If the amplitude level value is greater than or equal to the second threshold value (Yes in step S29), the process proceeds to step S30. If the amplitude level value is less than the second threshold value (No in step S29), this reporting control flow ends once.

[0126] In step S30, it is determined whether a predetermined condition is satisfied, similar to step S07 (see FIG. 4) of the reporting control flow in the above embodiment. The predetermined condition in this first alternative embodiment is the same as that in the above embodiment.

[0127] If the predetermined condition is not satisfied (No in step S30), the process proceeds to step S25. If the predetermined condition is satisfied (Yes in step S30), this reporting control flow ends once.

[0128] In this first alternative embodiment, the frequency of the waveform does not change before and after the digital low-pass filter processing performed in steps S22 and S26. In other words, the frequency of the waveform after the digital low-pass filter processing is equal to the frequency of the detection signal output by the infrared sensor 3. That is, the frequency of the waveform after the digital low-pass filter processing corresponds to the "frequency of the detection signal" according to the present invention.

[0129] 〔Other Embodiments〕 (1) The first frequency does not have to be a frequency determined in advance based on the frequency of the detection signal when the detection object E moves at the upper limit moving speed at a position at a predetermined distance from the device (detection device 1).

[0130] (2) When the frequency of the detection signal is higher than the first frequency, the reporting output unit 5 may be configured not to output a reporting signal regardless of the amplitude level value.

[0131] (3) When the frequency of the detection signal is higher than the first frequency and the amplitude level value is smaller than the first threshold value, the alarm output unit 5 may be configured not to output an alarm signal regardless of whether the amplitude level value is equal to or greater than the second threshold value.

[0132] (4) The filter processing unit 45 may be an analog low-pass filter.

[0133] (5) The cut-off frequency of the digital low-pass filter set in the filter processing unit 45 may be higher or lower than the first frequency.

[0134] (6) The storage unit 6 may not be provided.

[0135] (7) The setting unit 7 may not be provided.

[0136] (8) When the frequency of the detection signal is equal to or lower than the first frequency, the alarm output unit 5 may be configured to output an alarm signal regardless of the amplitude level value.

[0137] In addition, the configurations disclosed in the above-described embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as no contradiction occurs. Further, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope not departing from the object of the present invention.

Industrial Applicability

[0138] The present invention can be used for a detection device.

Explanation of Signs

[0139] 1: Detection device 2: Detection area 3: Infrared sensor 4: Signal processing unit 5: Alarm output unit 6: Storage unit 7: Setting unit 44: Noise determination unit AB: Reference amplitude value (third threshold value) E: Object to be detected

Claims

1. an infrared sensor that outputs a detection signal in response to infrared radiation within a predetermined detection area; an alarm output unit that outputs an alarm signal indicating that the object to be detected has been detected based on the detection signal, When the frequency of the detection signal is equal to or lower than a predetermined first frequency, the alarm output unit outputs the alarm signal; When the frequency of the detection signal is higher than the first frequency, the alarm output unit does not output the alarm signal, A detection device in which the first frequency is a frequency that is determined in advance based on an upper limit movement speed that is an upper limit value of an expected movement speed of the object to be detected.

2. The detection device according to claim 1 , wherein the first frequency is a frequency determined in advance based on a frequency of the detection signal when the object to be detected moves at the upper limit moving speed at a position a predetermined distance from the device.

3. When the frequency of the detection signal is higher than the first frequency, and an amplitude level value that is a value corresponding to the amplitude of the detection signal is smaller than a predetermined first threshold value, the alarm output unit does not output the alarm signal, The detection device according to claim 1 , wherein the alarm output unit outputs the alarm signal when the amplitude level value is equal to or greater than the first threshold value when the frequency of the detection signal is higher than the first frequency.

4. When the frequency of the detection signal is higher than the first frequency and the amplitude level value is smaller than the first threshold value, if the amplitude level value is smaller than a predetermined second threshold value that is smaller than the first threshold value, the alarm output unit does not output the alarm signal, When a frequency of the detection signal is higher than the first frequency, and the amplitude level value is smaller than the first threshold value, and the amplitude level value is equal to or greater than the second threshold value, if a predetermined condition is satisfied, the alarm output unit does not output the alarm signal, When the frequency of the detection signal is higher than the first frequency, and the amplitude level value is smaller than the first threshold value, and the amplitude level value is equal to or greater than the second threshold value, if the predetermined condition is not satisfied, the alarm output unit outputs the alarm signal, a noise determination unit that determines whether or not a peak whose amplitude level value is smaller than the first threshold value and equal to or greater than the second threshold value is noise; The detection device according to claim 3 , wherein the predetermined condition is that the peak is determined to be noise by the noise determination unit.

5. The detection device according to claim 3 , wherein when the frequency of the detection signal is higher than a predetermined second frequency that is higher than the first frequency, the alarm output unit does not output the alarm signal regardless of the amplitude level value.

6. 3. The detection device according to claim 1, wherein the object to be detected is a human body.

7. 3. The detection device according to claim 1, wherein the infrared sensor is a pyroelectric infrared sensor.

8. a signal processing unit that receives the detection signal and processes the detection signal; the alarm output unit is configured to output the alarm signal based on a processing result by the signal processing unit, The detection device according to claim 1 or 2, wherein the first frequency is a cutoff frequency of a digital low-pass filter set in the signal processing unit.

9. a storage unit that stores a candidate frequency group that is a plurality of frequencies that are predetermined based on the upper limit moving speed; The detection device according to claim 8 , further comprising: a setting unit that sets one frequency selected from the group of candidate frequencies as the first frequency.

10. When the frequency of the detection signal is equal to or lower than the first frequency, and an amplitude level value corresponding to the amplitude of the detection signal is equal to or higher than a predetermined third threshold, the alarm output unit outputs the alarm signal; The detection device according to claim 1 , wherein when the frequency of the detection signal is equal to or lower than the first frequency and the amplitude level value is smaller than the third threshold value, the alarm output unit does not output the alarm signal.

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