JPH0886883A - Human body detector - Google Patents

Abstract

PURPOSE: To provide a human body detector which accurately detects a person even if the ambient temperature changes and surely identifies and detects the person even from a material body. CONSTITUTION: A plurality of thermal array sensors 3 output signals λ1 , λ2 , λ3 corresponding to radiant intensities which indicate a peak wave length band and its shorter and longer wave length bands different in accordance with change of the ambient temperature. A computing circuit 5 and a discrimination circuit 7 identify radiant intensity patterns of Vλ1 , Vλ2 , Vλ3 from these thermal array sensors 3 and judge whether it is a person.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a human body detecting device for detecting the presence of a person by detecting infrared rays emitted from the human body, and in particular, it is possible to accurately detect the intensity of the infrared ray which changes according to the ambient temperature. It is about technology.

[0002]

2. Description of the Related Art As a conventional human body detecting device, for example, there is a human body detecting device shown in FIG. 6, in which an infrared ray radiated from a human body is condensed by an optical system 101 to generate a thermal sensor 102.
The scanning means 103 sequentially takes out the output for each of the plural kinds of wavelength bands obtained by the above, and the discrimination means 104 discriminates whether or not it is a human body from the difference between the intensity of the infrared radiation and the peak wavelength of the radiation intensity. The alarming means 105 issues an appropriate alarm to take appropriate action when a person is detected.

In general, the infrared radiation emitted from an object also varies in radiation intensity depending on the temperature of the object, and the higher the temperature, the greater the radiation intensity. The surface temperature of a person's face is around 32 ° C, and a radiant intensity by wavelength shows a peak near 9.5 μm. The thermal sensor detects infrared rays emitted from the human body as heat,
Since the voltage is output according to the radiation intensity, the temperature of the object can be estimated by the voltage.

[0004]

However, in the above-mentioned human body detecting device, a narrow wavelength band centered on the peak wavelength of the human face (hereinafter referred to as a peak wavelength band) and a plurality of different bandwidths. Since the wavelength band having the above is fixedly detected by providing the infrared sensor with the interference filter, the peak wavelength is also deviated when the surface temperature of the human face changes with the change of the ambient temperature such as the ambient temperature. There is a problem in that the accuracy becomes poor and it becomes extremely difficult to detect particularly at low temperatures.

The same applies to an object other than a human, and even if the object is originally different from a human, the peak wavelength of the object comes to be included in the peak wavelength band of the human body due to a change in ambient temperature. There was also the problem of misidentifying a person. The present invention has been made in view of the above problems, and provides a human body detection device capable of accurately detecting a person even when the ambient temperature changes, and reliably recognizing and detecting a person from an object. The purpose is to provide.

[0006]

Therefore, the present invention solves the above-mentioned conventional problems, and the present invention determines the presence of a human body by detecting the radiation intensity of infrared rays emitted from the human body. In the human body detection device, a prism that disperses the infrared light into a plurality of wavelength bands including peak wavelengths of radiation intensity of a human body that differ according to changes in ambient temperature, and a prism provided corresponding to each wavelength band disperse by the prism An infrared detection sensor that detects the radiation intensity of each wavelength band of the infrared rays, and a temperature detection unit that detects the ambient temperature;
Radiation intensity information storage means for storing beforehand the magnitude and pattern information of the radiation intensity of the human body corresponding to each ambient temperature, and the magnitude and pattern information of the radiation intensity according to the ambient temperature measured by the temperature detection means. And a determination unit that determines a human body based on the detection result of the infrared detection sensor.

Here, the discrimination means compares the radiation intensity pattern information read from the radiation intensity information storage means with the ambient temperature and the radiation intensity pattern information based on the detection result of the infrared detection sensor. First to make a decision
Of the radiation intensity information read out from the radiation intensity information storage means according to the ambient temperature and the radiation intensity magnitude information based on the detection result of the infrared detection sensor. The second comparison determination means may be included.

The first comparison / determination means compares and determines whether or not the detection result of the infrared detection sensor matches the magnitude relation of the radiation intensity of each wavelength band stored in advance,
The second comparison and determination means may be configured to make a determination by comparing whether the total sum of the detection results is equal to a predetermined value stored in advance. Further, the infrared detection sensor may be a thermal array sensor.

[0009]

Therefore, according to the human body detecting apparatus of the present invention, the infrared ray detecting sensor radiates infrared rays which are separated into a plurality of wavelength bands including peak wavelengths of different radiation intensities of the human body according to the ambient temperature. A signal corresponding to the intensity is output, and the determining unit determines whether or not the person is a person based on the magnitude of the radiation intensity according to the ambient temperature and the pattern information and each detected radiation intensity. Therefore, even if the ambient temperature changes, it is possible to detect a person with high accuracy, and moreover, it is possible to reliably recognize and detect a person from an object, and by using a prism, it is not necessary to switch the wavelength selection filter, The structure of the entire device can be simplified.

Here, after comparing the patterns (for example, magnitude relationship) of the detection result of the infrared detection sensor, it is compared whether or not the magnitude of the radiant intensity of the detection result (for example, the total value) is equal to a predetermined value. Since the distribution state of the entire radiation intensity including the peak wavelength of the input signal is known, it is possible to easily distinguish the human body from other objects. Furthermore, in the case where the infrared detection sensor is a thermal array sensor,
The sensor part has a simple structure and is easy to install, and the thermal sensors can be formed in an array to obtain a large output.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A human body detecting device will be described below with reference to the drawings. FIG. 1 is a schematic block diagram of a human body detecting apparatus showing an embodiment of the present invention. Infrared rays radiated from a human body or an object are collected by the optical system 1, dispersed by the lens array / prism array 2, and then the thermal type array sensor 3
Is incident on. Usually, the optical system 1 is composed of a concave reflecting mirror having no chromatic aberration.

FIG. 2 shows an enlarged detailed view of the lens array / prism array 2, and FIG. 3 shows the optical path of the collected infrared rays. The infrared light collected by the optical system 1 forms an image at point A in front of the lens array 2a and then becomes parallel light, and each prism of the prism array 2b splits this into three wavelength bands. Since the thermal sensor array 3 has three elements corresponding to each prism, three types of spectroscopic light are incident on the thermal sensor array 3 at a time, which is proportional to the energy intensity of each wavelength band. The voltage is output as the sum total according to the number of prisms. As described above, since the light is dispersed using the prism, conventionally, it is not necessary to switch the filter with a chopper or the like according to the wavelength band, and the configuration is simple and the mounting is easy. Moreover, since a plurality of thermal sensors are formed in an array, a large output can be obtained, and an amplifier circuit can be reduced or omitted, which is economical. The prism array 2b used here is a two-dimensional array of pixels required for detecting a human body.

Here, assuming that the three types of wavelength bands are continuous and narrow wavelength bands, and λ ₁ , λ ₂ , and λ ₃ are from the shorter wavelength side, λ ₁ is 8 to 9 μm, λ ₂ is 9 to 10 μm, λ ₃
Is set to 10 to 11 μm. Although only three types of wavelength bands are used in this embodiment, as the number of types of wavelength bands increases, the resolution with respect to temperature is improved and the accuracy of human body discrimination is improved. Further, regarding the definition of the thermal sensor used in the present embodiment, it is a kind of infrared sensor that catches infrared rays as heat and outputs a voltage according to its intensity, and a plurality of sensors are integrated on an array. The thermal array sensor is arranged in the above area, and includes a two-dimensional sensor composed of a thermopile or the like.

Next, the discrimination of the human body will be described in detail. The output voltage from the thermal sensor array 3 is sequentially scanned by the scanning circuit 4 for each wavelength band, taken out, and output to the arithmetic circuit 5. An air temperature measuring unit 6 is connected to the arithmetic circuit 5, and the ambient temperature information measured by the air temperature measuring unit 6 including a thermistor or the like is input and reference temperature information previously written in a storage circuit (not shown). Compared with, the target of comparison discrimination is changed.

That is, the surface temperature of a human face is usually 32 °
Although it is near C, it becomes gradually lower as the ambient temperature becomes lower and reaches about 20 ° C. Therefore, by setting the above reference temperature to 20 ° C and comparing it with the ambient temperature,
Since the peak wavelength band of the person due to the difference in ambient temperature can be specified, the human body can be accurately discriminated. FIG.
FIG. 4 is a diagram showing a radiation intensity curve of each object.

In the figure, the peak wavelength band of the curve of 32 ° C showing the radiation intensity of a normal human body is λ ₂ , whereas the curve of 20 ° C showing the radiation intensity of a human body at low temperature shows the peak wavelength. The band shifts to the longer wavelength side and becomes λ ₃ . Therefore, the output voltages Vλ ₁ , V at λ ₁ , λ ₂ , λ ₃
By comparing the magnitude relationship between λ ₂ and Vλ ₃ , it can be predicted whether or not the infrared rays are from the human body even if there is a difference in ambient temperature.

Further, conventionally, regarding an object having a high emissivity at a high temperature, the total amount of radiation in the wavelength band of 8 to 13 μm was substantially the same, and it was difficult to discriminate, but the radiation intensity of the face of a person having a surface temperature of 32 ° C. There is a peak in the vicinity of 9.5 μm, and an object having a low emissivity at high temperature has a peak in a portion included in approximately λ ₁ . Therefore, by comparing the magnitude relationships of the output voltages Vλ ₁ , Vλ ₂ , and Vλ _{3 in} the same manner as described above, it is possible to determine whether the infrared rays are from the human body or an object having a low emissivity at high temperature.

However, in a rare case, the peak wavelength of the object may be included in the peak wavelength band of the person due to the change in ambient temperature even if the object is different from the person. For example, when a high-temperature object is cooled by the ambient temperature and reaches a surface temperature of 32 ° C, the peak wavelength is included in λ ₂ , and in such a case, it may be erroneously recognized in a simple size comparison. There is a nature.

Therefore, in the arithmetic circuit 5, the output voltages Vλ ₁ , V which are written in advance in the storage circuit (not shown).
Reference pattern information for λ ₂ and V λ ₃ and thermal sensor array 3
Further, the discrimination circuit 7 outputs the output voltage V to the human body predicted by comparing the output values of
The sum of λ ₁ , Vλ ₂ , and Vλ ₃ is calculated and compared with the reference sum information previously written in the storage circuit (not shown).
Since the radiant intensity curve has different distributions (slopes and shapes) depending on the object, objects having the same peak wavelength band have a unique sum value. Therefore, if the reference sum is the sum of the radiant intensities of the human face in the wavelength band λ _{1 to} λ ₃ , the infrared rays from the human body whose surface temperature has changed can be discriminated while eliminating the above-mentioned misrecognition and the infrared rays from the human body. Or from an object whose surface temperature has changed.

In this embodiment, the arithmetic circuit 5 and the discrimination circuit 7 having the function as the discrimination means read the reference temperature information, the reference pattern information and the reference summation information from the respective storage circuits to make the first discrimination. However, the above-mentioned various reference information may be read from the same memory circuit with the arithmetic circuit 5 and the discrimination circuit 7 as one discrimination circuit.

The processing flow of the apparatus will be described with reference to the flowchart of FIG. First, when the apparatus is activated, in S1, the scanning circuit 4 scans the thermal array sensor and outputs the output voltages Vλ ₁ , Vλ ₂ , Vλ of the respective wavelength bands λ ₁ , λ ₂ , λ _{3.
Get three} . Further, in S2, the arithmetic circuit 5 inputs the ambient temperature T ₀ measured by the air temperature measuring unit 6 as ambient temperature information, and S3
In step S3, the magnitude relation is compared with the reference temperature information indicating the reference temperature T _a input from the storage circuit. The reference temperature is set to 20 ° C. When the ambient temperature T ₀ is higher than the reference temperature T _a , the process proceeds to S4, and when the ambient temperature T ₀ is lower than T _a , the process proceeds to S5.

If the temperature is high, in S4, Vλ ₂
The patterns of> Vλ ₃ and Vλ ₂ > Vλ ₁ , that is, the magnitude relationship, are compared. If you are a person, the surface temperature is 32 ° C
Since it is in the vicinity, the output voltage has the highest Vλ ₂ and the above condition is satisfied, and it is determined that there is a possibility of being a person, and the process proceeds to S6.
If it is an object, the values other than V λ ₂ will be high, so return to S1 and continue measurement.

In S6, the discriminating circuit 7 obtains the magnitude of the output voltage, that is, the sum Vλ ₁ + Vλ ₂ + Vλ ₃ , and compares it with the reference sum information Va input from the memory circuit. Since the reference summation information Va is set in advance to the summation value of the radiation intensity of the human face at 32 ° C., in the case of a person, the summation of the output voltage becomes the same value as the reference summation information Va, and the discrimination circuit 7 is determined to be a person, and the process proceeds to S7.

When Vλ ₁ + Vλ ₂ + Vλ ₃ = Va is not satisfied, it means that the object is not a person but a temperature lower or higher than that of a person, or an object having a different radiation intensity distribution.
In this case, the process returns to S1 to continue the measurement. In S7, a corresponding process is performed when a person such as issuing an alarm from the alarm unit 8 is detected.

Similarly, when the ambient temperature T ₀ is lower than the reference temperature T _a , the magnitude relationship of Vλ ₃ > Vλ ₂ > Vλ ₁ is compared in S5. If you are a person, the surface temperature is 2
Since the output voltage is around 0 ° C, Vλ ₃ is the highest and Vλ is the highest.
₂ and Vλ ₁ are successively lowered and the above conditions are satisfied, and there is a possibility of being a person, so the process proceeds to S8. In S8, the discrimination circuit 7 compares and discriminates the total sum of the output voltages and the reference total sum information Vb in the same manner as described above. The reference total information Vb is the total value of the radiation intensity of the human face at 20 ° C. If the person is a person, the total output voltage is the same value as the reference total information Vb, and the discrimination circuit 7 is a person. It is determined that there is, and the process proceeds to S7. When it is determined that the person is not a person, the process returns to S1 to continue the measurement.

It should be noted that the reference summation information Vb indicates that a person's face is 20 °.
Since it is used when it is about C, it has a value smaller than Va. In this embodiment, the arithmetic circuit 5
After the first determination in step 1), the second determination in the determination circuit 7 is performed to recognize the radiation intensity pattern.
The human body can be accurately discriminated even when the surface temperature of the face is different, and the human body and other objects can be easily discriminated.

[0027]

As described above, according to the present invention, the infrared ray detection sensor radiates the infrared ray radiated intensity into a plurality of wavelength bands including the peak wavelengths of the radiant intensity different from the human body according to the ambient temperature. It outputs a signal according to the above, and the determination means is configured to determine whether or not a person is based on the magnitude of the radiant intensity according to the ambient temperature and each radiant intensity detected with the pattern information. Can be accurately detected, and a person can be surely recognized and detected from an object, and the structure of the entire apparatus can be simplified.

Here, after comparing the patterns (for example, magnitude relationship) of the detection result of the infrared detection sensor, it is compared whether or not the magnitude of the radiant intensity of the detection result (for example, the total value) is equal to a predetermined value. With this, the human body and other objects can be easily distinguished. Furthermore, in the case where the infrared detection sensor is a thermal array sensor, the structure of the sensor portion is simple and easy to install, and
This has the effect that a large output can be obtained by forming the thermal sensors in an array.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a human body detection apparatus according to this embodiment.

FIG. 2 is an enlarged detailed view of a lens array / prism array in the present embodiment.

FIG. 3 is a diagram showing an optical path of condensed infrared rays in the present embodiment.

FIG. 4 is a diagram showing a radiation intensity curve of each object in the present embodiment.

FIG. 5 is a flowchart illustrating a processing flow of the apparatus according to the present exemplary embodiment.

FIG. 6 is a schematic block diagram of a conventional human body detection device in a conventional example.

[Explanation of symbols]

 1 Optical System 2 Lens Array / Prism Array 3 Thermal Array Sensor 5 Arithmetic Circuit 6 Air Temperature Measuring Section 7 Discrimination Circuit 8 Alarm Section

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Claims (4)

[Claims] 1. A human body detection device for determining the presence of a human body by detecting the radiation intensity of infrared rays emitted from the human body, wherein the infrared ray includes a peak wavelength of the radiation intensity of the human body which varies depending on a change in ambient temperature. A prism that splits into a plurality of wavelength bands, an infrared detection sensor that is provided corresponding to each wavelength band split by the prism and that detects the radiation intensity of each wavelength band of the infrared radiation, and a temperature that detects the ambient temperature A detection unit, a radiation intensity information storage unit that stores in advance the magnitude and pattern information of the radiation intensity of the human body corresponding to each ambient temperature, and the magnitude of the radiation intensity according to the ambient temperature measured by the temperature detection unit. And a determination unit that determines a human body based on pattern information and a detection result of the infrared detection sensor. 2. The determination means compares and determines the radiation intensity pattern information read from the radiation intensity information storage means in accordance with the ambient temperature and the radiation intensity pattern information based on the detection result of the infrared detection sensor. The first comparison / determination means for performing the above, the magnitude information of the radiation intensity read from the radiation intensity information storage means according to the ambient temperature, and the magnitude information of the radiation intensity based on the detection result of the infrared detection sensor. The human body detection device according to claim 1, further comprising a second comparison / determination means for performing comparison / determination. 3. The first comparison / determination means makes a comparison by determining whether or not the detection result of the infrared detection sensor matches a magnitude relationship of radiation intensity of each wavelength band stored in advance, and the second comparison / determination means. 3. The human body detection device according to claim 2, wherein the comparison and determination means compares and determines whether the total sum of the detection results is equal to a predetermined value stored in advance. 4. The human body detection device according to claim 1, wherein the infrared detection sensor is a thermal array sensor.