JP3333646B2 - Infrared human body detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for intrusion detection devices for crime prevention, automatic control of loads such as lighting, etc., and detects infrared radiation emitted from a human body by an infrared light receiving element to detect movement of the human body. In particular, the present invention relates to an infrared type human body detection device that does not malfunction even outdoors.

[0002]

2. Description of the Related Art FIG. 10 shows an example of a conventional infrared type human body detecting device. This kind of infrared type human body detecting device includes, for example, a light collecting unit 1 composed of a Fresnel lens, an infrared light receiving element 2 composed of a pyroelectric element, an amplifier 3, a bandpass filter 4, a comparison circuit 5, a delay circuit 6, and an output circuit 7. When the infrared light emitted from the human body is collected by the light collecting unit 1, the infrared light is detected by the infrared light receiving element 2 and converted into an electric signal, and the electric signal is amplified to a predetermined level by the amplifying unit 3. After that, unnecessary frequency components are further removed by the bandpass filter 4 and input to the comparison circuit 5 where the unnecessary frequency components are compared with a predetermined reference level (threshold). A signal is output to output a control signal from the output circuit 7, and the delay circuit 6 is configured to hold the load on for a set off delay time.

However, in such a conventional infrared human body detecting device, as shown in FIGS.
Variations in sensitivity of a plurality of light receiving elements having different positive / negative polarities due to sudden light incidence or sudden light blocking (for example, variations in light receiving element itself, variations in optical sensitivity of a light receiving surface of a condenser lens, etc. ), And even if the human body does not pass through the monitoring area (hereinafter referred to as a detection beam), a malfunction such as outputting a human body detection signal and turning on the load has occurred.

When such an infrared detecting device is used outdoors, the air in the detecting beam fluctuates due to the wind, and the ambient temperature gradually changes.
In some cases, an output was generated and a malfunction occurred. On the other hand, the pyroelectric element used as the infrared light receiving element 2 has an inherent property that when it undergoes a sudden change in ambient temperature, a sudden output is generated despite the absence of infrared light (pop-con noise). This phenomenon also causes a human body detection signal to be output, causing a malfunction.

Therefore, in order to improve the malfunction described above,
When reliability is particularly required, a timer 8 and a pulse count circuit 9 are further provided after the comparison circuit 5 as shown in FIG.
The number of ON outputs that are output when the reference level is exceeded is counted by the comparison circuit 5 within a preset time, and the number is set to a preset number (3 in the example in the figure).
For the first time, it is determined that a human body is detected, a control signal for turning on the load is output from the output circuit 7, and the load is turned on for the off-delay operation time set by the delay circuit 6. It is configured to be continued. Regarding the basic operation, FIG.
See (e).

However, even though the reliability of the infrared type human body detecting device employing such a pulse counting method is improved, it takes a long time from when the human body enters the detection beam until the human body detection signal is output. And the response becomes poor. For this reason, it is often not used for load control such as lighting, and when there are few detection beams or when the number of output pulses due to movement of the human body is small, a human body detection signal is not output and a false alarm occurs. Has also occurred.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has various malfunction factors, for example, sudden light noise, especially in a place where there are many malfunction factors, such as outdoors. An object of the present invention is to provide a highly reliable infrared human body detection device that is less likely to malfunction due to thermal noise and pop-con noise.

[0008]

According to the present invention, which has been proposed to achieve the above object, the results of collecting and analyzing, as test data, changes in the waveform of a received light signal when a person passes through a detection area. It has been developed and has the following structural features. The present invention described in claim 1 is a light-collecting unit that collects infrared light emitted from a human body, a light-receiving element having a differential configuration for detecting an amount of change in the infrared light and converting the change into an electric signal, An amplifier for amplifying an output signal from the light receiving element to a predetermined level; a band filter for removing unnecessary frequency components from the amplified signal output from the amplifier; a peak of a waveform signal output from the band filter It includes a peak value detecting circuit for detecting a value, and a signal processing unit for outputting a human body detection signal based on the magnitude relation of the peak value of the detected waveform signal within a predetermined time by the peak value detecting circuit In the infrared human body detection device, the signal processing unit compares the absolute value of the first peak value with the absolute value of the second peak value, and calculates the second peak value. The absolute value is greater than the absolute value of the first peak value Wherein the first outputting the human body detection signal if heard.

According to a second aspect of the present invention, there is provided a light collecting section for collecting infrared rays radiated from a human body, and a differential configuration for detecting a change amount of the infrared rays and converting the change into an electric signal. A light-receiving element, an amplification unit that amplifies an output signal from the light-receiving element to a predetermined level, and a bandpass filter that removes unnecessary frequency components in the amplified signal output from the amplification unit,
A peak value detection circuit for detecting a peak value of a waveform signal output from the bandpass filter ; and a human body based on a magnitude relationship between a plurality of peak values of the waveform signal detected within a predetermined time by the peak value detection circuit. a infrared human body detection device and a signal processing unit for outputting a detection signal, the signal processing section, the absolute value of the first shot th peak value, the absolute value of the second shot th peak value In comparison, if the absolute value of the second peak value is smaller than the absolute value of the first peak value,
The method further comprises comparing the absolute value of the third peak value with a predetermined reference level, and outputting a human body detection signal when the absolute value of the third peak value exceeds the reference level. I do.

[0010]

[0011]

According to the present invention, the following functions are provided.
That is , in the present invention, the peak value detection circuit of the signal processing unit includes:
Each time a waveform signal is output from the bandpass filter, the waveform signal is fetched and the peak value is detected. When a plurality of peak values are detected within a predetermined time after the first peak value is detected, the comparison determination is performed. The section outputs a human body detection signal as a result of the magnitude comparison of these peak values.

[0012] Here is to identify the comparison reference in this case, in the present invention as set forth in claim 1, the signal processing unit
May compare the magnitude of the respective peak value of the waveform signal detected by the peak value detecting circuit, the absolute value of the absolute value and the second shot-th peak value of the first shot th peak value at a predetermined time unit Then, the human body detection signal is output only when the absolute value of the second peak value is greater than the absolute value of the first peak value.

[0013] While the present invention described in claim 2,
The signal processing unit compares the absolute value of the first peak value with the absolute value of the second peak value among a plurality of peak values of the waveform signal detected in a predetermined time unit, When the absolute value of the second peak value is smaller than the absolute value of the first peak value, the absolute value of the third peak value is further referred to, and the third peak value is further referred to. Only when the absolute value of the peak value exceeds a predetermined reference level (threshold), a human body detection signal is output.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an infrared type human body detecting apparatus according to an embodiment of the present invention. FIG. 1 is a block diagram showing a hardware configuration of an infrared human body detection device according to the present invention.

The infrared human body detecting device A according to the present invention comprises a human body M
A light-collecting unit 1 for collecting infrared light emitted from the light-receiving device, an infrared light-receiving element 2 having a differential configuration for detecting a change amount of the infrared light and converting it into an electric signal, and an amplifier for amplifying an output signal from the light-receiving element 2 3 and a bandpass filter 4 for removing unnecessary frequency components from the amplified signal output from the amplification unit 3
And a signal processing unit 8 that receives a waveform signal output from the bandpass filter 4 to detect a peak value and performs a discrimination process described later, and loads when a human body detection signal is output from the signal processing unit 8. And a delay circuit 6 for setting an off-delay operation time during which the load is continuously turned on.

Here, the signal processing section 8 includes a peak value detecting circuit 81 and a comparing / determining section 82. When the peak value detecting circuit 81 receives the waveform signal output from the bandpass filter 4, the peak value is detected. When a plurality of peak values are detected within a predetermined time, the comparison and determination unit 82 compares the absolute values of the peak values to determine the presence or absence of the human body M, and when a predetermined condition is satisfied. It is configured to output a human body detection signal for the first time.

In the infrared human body detecting device A, a quantitative change in infrared light caused by the movement of the human body M is transmitted through the light condensing unit 1 to a differential configuration using, for example, a dual element. The light is detected by the light receiving element 2 and converted into an electric signal. The electric signal is amplified by the amplifier 3, and unnecessary frequency components are removed by the bandpass filter 4. The peak value of the waveform signal output from the bandpass filter 4 exhibits various patterns according to the intrusion speed and the passing speed into the detection area. Deciding.

Next, the pattern of the waveform signal output from the bandpass filter will be described. FIG. 2A is an output waveform diagram when a strong light of a halogen lamp is rapidly irradiated on the infrared human body detecting device A, and FIG. 2B is a diagram showing a sudden change in temperature in the detection beam or an infrared human body. FIG. 2C is an output waveform diagram when a rapid temperature change occurs in the detection device A, and FIG.
Shows an output waveform diagram of pop-con noise of the pyroelectric element. Here, pop-con noise is noise generated by the light-receiving element itself when the ambient temperature changes rapidly.
This is considered to be a major cause of malfunction (false alarm). FIGS. 3B and 3C are waveform diagrams showing noise response waveforms of the light receiving detection element and the amplifying unit when step-like noise as shown in FIG. 3A is input. .

Here, focusing on the value of the inflection point of each output waveform, that is, the absolute value of the peak value, any of the sudden noise output waveforms, as shown in FIGS. The absolute value of the second peak value Vp2 is smaller than the absolute value of the first peak value Vp1. This is because the input to the light receiving element becomes almost step-shaped (see FIG. 3A). When such a step-shaped input is applied to the light receiving element, FIG.
As shown in (c), the pyroelectric element constituting the light receiving element produces only one output for detecting a change in the amount of infrared rays. However, when amplifying this electric signal in the amplifier, the AC component is amplified. Therefore, the second output is generated due to the transient response characteristic. Then, the second peak value Vp2 generated at this time is the first peak value Vp.
It is known that the absolute value of the second peak value Vp2 does not become larger than the absolute value of the first peak value Vp1 because it is due to the tilt of p1.

FIGS. 5A to 5C are waveform diagrams showing output waveforms when the human body M passes one detection beam B formed by the infrared detection device as shown in FIG. It is. As shown in FIG.
The output waveform when passing through varies depending on the frequency characteristics of the light receiving element, the characteristics of the bandpass filter in the amplifier, the moving speed of the human body, and the like, and the output waveform and the number of output pulses also change. That is, when the human body M passes through one detection beam B, the passing speed is low and medium (0.3 to 1).
m / s), two or more output waveforms are generated, and the absolute value m / s of the second peak value Vp2 is equal to or greater than the absolute value of the first peak value Vp1. It will be,
When passing at a high speed (1 m / s or more), the second occurrence of the output waveform is extremely small even if it occurs.
The absolute value Vp2 of the first peak value is the first peak value Vp.
It becomes smaller than the absolute value of p1. FIG. 5C shows an example in which the first peak value Vp1 is generated.

[0021] FIG. 7 (a) ~ (c) shows an output waveform when the two detection beams B which are formed by infrared human body detection device A according to the present invention, the B is the human body M passes . When a dual element is used as the light receiving element, two detection beams B (+) and B (-) having opposite positive / negative characteristics are formed by the condensing part as the optical system. Output waveforms when the human body M passes through these detection beams B (+) and B (-) are as shown in FIGS. 7A to 7C. .3 m / s to 1 m / s), the output waveform has the third peak, and the absolute value of the second peak value Vp2 is the first peak value Vp
The magnitude becomes equal to or larger than the absolute value of 1, and when passing at a high speed (1 m / s or more), one output waveform is generated when passing the first detection beam B (+),
When passing the next detection beam B (-), 1
And two output waveforms, these two detection beams B
Although (+) and B (-) have different electrical polarities, they have the same sensitivity because they use the same light receiving element and optical system.
The absolute value of the second peak value Vp2 is equal to or greater than the absolute value of the first peak value Vp1.
Therefore, the absolute value of the first peak value Vp1 and the absolute value of the second peak value Vp2 are compared by the comparison / determination unit 82, and the absolute value of the second peak value Vp2 is compared with the first peak value Vp2. If the configuration is such that the human body detection signal is output only when the absolute value of the peak value Vp1 of the eye is equal to or larger than the absolute value, depending on sudden thermal noise, optical noise, and pop-con noise specific to the pyroelectric element, No detection signal is output, and it can be accurately grasped that the human body has passed the two detection beams B (+) and B (-). (Claim 1 ) FIG. 8 is a schematic diagram showing the human body M and the arrangement of the detection beams when four detection beams are formed by the infrared human body detection device A according to the present invention. The output waveform when four detection beams B (+), B (-), B (+), and B (-) have passed is shown. When the human body M passes through one set of detection beams B (+) and B (-) shown in FIG. 8 and crosses another set of detection beams B (+) and B (-), for example, When the hand or foot of the human body M enters another detection beam, the output waveforms shown in FIGS. 7A to 7C are not obtained. In this case, FIG. The output waveform becomes as shown.

That is, the absolute value of the second peak value Vp2 becomes smaller than the absolute value of the first peak value Vp1,
In such a case, the two detection beams B (+), B
In addition to (−), another set of detection beams B (+), B
That is, the human body M is applied to (−), and three or more peak values occur within a certain continuous time.
Therefore, in the present invention, when the absolute value of the second peak value Vp2 is smaller than the absolute value of the first peak value Vp1, the presence / absence of the third peak value is determined. When the absolute value exceeds a predetermined reference level VTH, the comparison / determination section 82 outputs a human body detection signal, thereby ensuring the detection of the human body M for the first time in the above case. I have. (Claim 2 )
As described above, the embodiment and the principle of the present invention have been described.
The present invention is not limited to the above-described embodiments, and design changes can be made without departing from the scope of the present invention.

[0023]

According to the present invention, the human body and noise, for example, sudden optical noise, thermal noise, pop-con noise, etc. are identified from the change pattern of the peak value of the received waveform signal. It can be used in places where malfunctions are strong, such as outdoors. Further, regardless of the rate of passage of the sensing beam of the human body, because the noise can be reliably removed, it is possible to prevent a malfunction with high reliability.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a hardware configuration of an infrared human body detection device according to the present invention.

FIGS. 2A to 2C are waveform diagrams showing waveform signals generated when noise is input.

FIGS. 3A to 3C are waveform diagrams showing response waveforms to noise.

FIG. 4 is a schematic diagram showing an arrangement of detection beams when a human body passes through one detection beam.

FIGS. 5A to 5C are diagrams showing output waveforms corresponding to the passing speed when a human body passes through one detection beam.

FIG. 6 shows an infrared type human body detecting device according to the present invention;
It is a schematic diagram which shows the arrangement | positioning of the detection beam when a human body passes when one detection beam is formed.

FIGS. 7A to 7C are diagrams illustrating output waveforms corresponding to passing speeds when a human body passes through two detection beams.

FIG. 8 is a schematic diagram showing an arrangement of detection beams when a human body passes through a plurality of detection beams.

FIG. 9 shows an infrared human body detection device according to the present invention.
FIG. 7 is a diagram illustrating an output waveform when a human body passes through a plurality of detection beams.

FIG. 10 is a block diagram showing a conventional example of a conventional infrared human body detection device.

FIGS. 11A to 11C are time charts for explaining output waveforms of various parts of a conventional infrared human body detection device.

FIG. 12 is a block diagram of an infrared human body detection device employing a pulse counting method.

13 (a) to 13 (e) are time charts for explaining output waveforms of various parts of the pulse counting type infrared human body detecting device.

[Explanation of symbols]

 A Infrared human body detection device of the present invention 1 Condensing unit 2 Infrared detecting element (light receiving element) 3 Amplifying unit 4 Bandpass filter 5 Comparison circuit 6 Delay circuit 7 Output circuit 8 Signal processing unit 81 Peak value detection circuit 82 Comparison judgment unit M human body

Claims (2)

(57) [Claims] 1. A condenser for collecting infrared rays emitted from a human body.
Part and its infraredThe amount of changeDetect and convert to electrical signal
Element with differential configuration for output and output from the light receiving element
An amplifier for amplifying a signal to a predetermined level, and an output from the amplifier.
A band that removes unnecessary frequency components from the amplified signal
Band filter and waveform signal output from the band filter
Value detection circuit that detects the peak value ofAnd thePeak value
The duplication of the waveform signal detected within a predetermined time by the detection circuit
Generates a human body detection signal based on the
Powerful signal processing unitAn infrared human body detection device with
What  The signal processing unit calculates the absolute value of the first peak value,
The absolute value of the second peak is compared with the second peak.
The absolute value of the peak value is larger than the absolute value of the first peak value
Output a human body detection signal for the first time
Infrared human body detection device. 2. A condenser for collecting infrared rays emitted from a human body.
Part and its infraredThe amount of changeDetect and convert to electrical signal
Element with differential configuration for output and output from the light receiving element
An amplifier for amplifying a signal to a predetermined level, and an output from the amplifier.
A band that removes unnecessary frequency components from the amplified signal
Band filter and waveform signal output from the band filter
Value detection circuit that detects the peak value ofAnd thePeak value
The duplication of the waveform signal detected within a predetermined time by the detection circuit
Generates a human body detection signal based on the
Powerful signal processing unitAn infrared human body detection device with
What  The signal processing unit calculates the absolute value of the first peak value,
The absolute value of the second peak is compared with the second peak.
The absolute value of the peak value is smaller than the absolute value of the first peak value
In this case, the absolute value of the third peak value is
The absolute value of the third peak value is compared with the reference level.
Outputs a human body detection signal when the reference level is exceeded.
An infrared human body detection device, characterized in that: