KR20020041669A - Intruder dectection system using passive infrared detector and sensing method of the same - Google Patents

Abstract

PURPOSE: A human body sensor system and sensing method of sensor system is provided to realize a low cost sensor system by employing a micro controller(micro processor) for temperature compensation. CONSTITUTION: A human body sensor system(100) comprises an infrared sensor(114) for receiving an infrared signal from a signal source, converting the infrared signal into an electrical signal, and outputting the electrical signal; an amplifier(116) for receiving the electrical signal, amplifying the voltage and outputting the result; a filter(118) for removing noise of high frequency band from the amplified electrical signal; a temperature measuring circuit(130) for outputting an analog signal responsive to the ambient temperature of the infrared sensor; an analog-digital converter(122) for receiving analog signal from the filter and the temperature measuring circuit, converting the analog signal into a digital signal, and outputting the digital signal; and a processor(124) for receiving digital signal, sampling the data, storing the sampled data, calculating sampling variables with respect to the digital signal during a predetermined time period, and comparing the pre-stored characteristics of the signal radiated from a human body with the sampling variables, so as to thereby determine the type of signal source. The processor compensates to prevent erroneous operation of the system caused due to the environmental condition of the infrared sensor, and controls to output an alarm signal in the case the signal source is human.

Description

Human body detection system using passive infrared sensor and its detection method {INTRUDER DECTECTION SYSTEM USING PASSIVE INFRARED DETECTOR AND SENSING METHOD OF THE SAME}

The present invention relates to a sensor system, and more particularly, to a human body sensing system using a passive infrared sensor and a sensing method thereof.

In general, an unmanned human body detection system, that is, a sensor system detects a change in a signal by using an infrared sensor and determines the presence or absence of a human body. The sensor system is divided into active and passive according to the operating principle of the infrared sensor. The active sensor system installs the receiver and the transmitter in a fixed place in a certain place and in a certain direction, and receives the infrared light from the transmitter, and when an object enters between the two devices, the infrared rays are blocked to alert Occurs. The passive sensor system includes a pyroelectric infrared sensor with a wide viewing angle, and when an object (for example, a human body or an animal) approaches the viewing angle of the infrared sensor, an infrared ray emitted from the object is detected and an alarm is generated. Generate.

Accordingly, the present invention relates to a passive infrared sensor system, which is an improved patent for "Intelligent Passive Infrared Detector" of Korean Patent Application No. 10-2000-0008099 (February 21, 2000) filed by the applicant. The present invention relates to a human body detection system and a method for detecting the same, which accurately identify an animal and a human body using a microprocessor or a microcontroller and a temperature measuring circuit, and to prevent malfunction due to environmental factors.

The passive sensor system is described in detail as follows.

First, since the human body temperature is 36 to 37 ° C., humans emit far infrared rays having a peak of 9 to 10 μm. Infrared sensors for detecting them include a thermal type and a quantum type. Thermotypes operate at room temperature and have no wavelength dependence, but have low sensitivity and slow response. In addition, the quantum type has a high sensitivity and a fast response, but requires a cooling material such as liquid nitrogen, and also has a disadvantage of having a wavelength dependency. Therefore, the security system for detecting the human body is inexpensive and light and simple properties are required, and thermal sensors are widely used rather than quantum sensors. Thermal devices are typical, for example, thermistor brooms, thermopiles, pyroelectric devices, etc., and pyroelectric devices are widely used for security systems.

1 is a block diagram showing the configuration of a human body detection system according to an embodiment of the prior art.

Referring to the drawings, the human body detection system 10 includes a mirror (or lens) 12 for collecting light, an infrared sensor 14 for detecting a signal emitted from the human body, and an output signal of the infrared sensor 14. An amplifier 16 for amplifying a signal, a filter 18 for removing a high frequency signal component of an amplified signal, and an output of a comparator 20 and a comparator 20 for comparing the filtered signal with a predetermined specific reference voltage and outputting the same. When a human body is detected in response to the signal, a driving circuit 26 for generating an alarm signal with an alarm device (not shown) or the like is included. It also includes a timer circuit 24 for setting the operating time of the alarm device. Here, the sensor system according to Korean Patent Application No. 10-2000-0008099 uses a microcontroller as the driving circuit.

Since the energy emitted by the human body is very weak, the pyroelectric sensor detects within a range of about 1 m when the environment temperature is 25 ° C. Therefore, a method of collecting and detecting energy radiated from the human body by using a reflector or a plastic lens for condensing is used. For example, the lens can detect a range of about 5-15 m.

The signal output from the infrared sensor is attenuated in the 15 kHz frequency band to eliminate the influence of high frequency commercial frequency using the filter, and in the 0.2 kHz frequency band to reduce the influence of environmental temperature change. ) Is about 60 ms.

The signal output from the filter is compared with a specific reference voltage preset in the comparator, and when it is higher than the reference voltage, the driving circuit of the alarm device (for example, chime, buzzer, automatic door or alarm) is operated for a time set in the timer circuit. .

FIG. 2 is a circuit diagram of the pyroelectric infrared sensor shown in FIG. 1.

Referring to the drawings, the pyroelectric infrared sensor 14 is a thermal sensor, which is more sensitive than thermistor borometer and thermopile and is suitable for capturing the movement of the human body.

The pyroelectric infrared sensor 14 includes a pair of sensor electrodes and uses, for example, a ferroelectric ceramic of zirconate titanate-based ceramic (PZT), or the like, and has a high voltage (for example, 3 kV to several kV) between the sensor electrodes. / Mm) to polarize. By this treatment, the positive and negative charges appearing on the surface of the device are electrically neutralized in combination with floating ions having reverse charges in the air. Therefore, when the surface temperature of the device changes, the magnitude of the polarization of the device changes according to the temperature change. For this reason, the neutralization state of the charge in the stable state is broken down, and since the relaxation time of the element surface charge and the floating ion charge is different, it is electrically unbalanced, and thus there is a charge with no connection partner. The phenomenon in which charge is generated in accordance with the temperature change is called a pyroelectric effect.

Therefore, the pyroelectric infrared sensor 14 passes only the infrared rays necessary by the optical filter (not shown) of the window when infrared rays of various wavelengths are incident. Subsequently, only the necessary infrared rays are passed through the heat absorption film on the surface of the device. When the surface temperature of the device rises and the pyroelectric effect is generated, surface charge is generated. The generated surface charge is voltage amplified by the FET and converts the impedance. Therefore, when a voltage for driving the FET is supplied from the drain terminal, which is a power input terminal, the amplified signal is a resistance between the source terminal, which is an output terminal connected to the outside, and the earth terminal, which is a ground terminal. R _G and R _S ) are outputted by increasing the bias voltage.

However, since the pyroelectric element 14 is a differential element that generates a signal only in response to a temperature change, the signal is not output when the human body does not move. Therefore, when there is movement of the human body, the signal is output in proportion to the change amount, but when the human body moves slowly, the signal output amount decreases, and when the human body is stationary, the signal is not output as in the absence of the human body. In addition, it may cause a malfunction by external light such as sunlight or the like, and may also cause a malfunction due to a temperature change in the surrounding environment. In addition, various animals having a body temperature similar to the human body and the ability to distinguish the human body may be a cause of malfunction.

Therefore, the conventional human body detection system has a problem of generating a malfunction alarm even for an object (for example, an animal) emitting heat by comparing the magnitude of the instantaneous output waveform of the signal output from the infrared sensor to detect the human body. .

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and to detect a heat source according to a human body or an animal by digitizing a signal detected from an infrared sensor, and a human body detecting system and a method of detecting the same to prevent malfunction due to environmental factors. To implement

1 is a block diagram showing the configuration of a human body detection system according to an embodiment of the prior art;

FIG. 2 is a circuit diagram of the pyroelectric infrared sensor shown in FIG. 1;

3 is a block diagram showing the configuration of a human body detection system according to the present invention;

4 is a flowchart showing an operation procedure of the human body detecting system according to the present invention;

5 is a flowchart showing in detail the sampling procedure shown in FIG. 4;

6 is a flow chart showing in detail the signal analysis procedure shown in FIG. 4;

7 is a waveform diagram illustrating a difference due to a change rate of a signal according to an environmental factor and a signal output from a human according to an embodiment of the present invention;

8 is a waveform diagram illustrating a difference due to a temperature change between a signal according to environmental factors and a signal output from a human according to another embodiment of the present invention;

9 is a waveform diagram showing a difference between a signal output from a human and an animal according to an embodiment of the present invention;

10 is a waveform diagram illustrating characteristics of sampling parameters of a waveform according to an embodiment of the present invention;

11A-11B illustrate sampling data for determining an animal according to an embodiment of the present invention; And

12A to 12B are diagrams illustrating sampling data for determining a human according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: human body detection system 112: mirror

114: infrared sensor 116: amplifier

118 filter 122 analog-to-digital converter

124 processor 130 temperature measuring circuit

According to one aspect of the present invention for achieving the above object, a sensor system comprising: an infrared sensor which receives an infrared signal from a signal source and converts it into an electrical signal; An amplifier for receiving the electrical signal and amplifying and outputting a voltage; A filter for removing noise in a high frequency band of the amplified electrical signal; A temperature measuring circuit outputting an analog signal corresponding to the ambient temperature of the infrared sensor; An analog-to-digital converter that receives an analog signal from the filter and the temperature measuring circuit and converts the analog signal into a digital signal; Receives the digital signal and samples and stores a plurality of data according to signal characteristics, calculates sampling parameters for the digital signal for a predetermined time, compares and analyzes the characteristics of the signal radiated from a pre-stored human body and the sampling parameters. And a processor for determining a type of the signal source, wherein the processor compensates to prevent the system from malfunctioning from environmental factors of the infrared sensor and controls to output an alarm signal when the signal source is human. .

In a preferred embodiment of this feature, the infrared sensor is provided with a pyroelectric sensor element.

In a preferred embodiment of this feature, the temperature compensation circuit is provided with a transistor.

In a preferred embodiment of this feature, the analog-to-digital converter and the processor are provided in one integrated circuit.

According to an aspect of the present invention for achieving the above object, an infrared sensor for detecting a signal source, an amplifier, a filter, a temperature measuring circuit for measuring the ambient temperature of the infrared sensor, the filter and the A sensor system comprising: an analog-to-digital converter that receives an analog signal from a temperature measuring circuit and converts the signal into a digital signal and outputs the digital signal; and a processor having a memory device for storing data according to characteristics of the digital signal. A method comprising: initializing the system; Measuring the ambient temperature of the infrared sensor using the temperature measuring circuit; Sampling the output signal of the analog to digital converter; Compensating the sampled data to prevent malfunction due to ambient temperature of the infrared sensor; Determining a type of a signal source by comparing data on characteristics of a signal emitted from a human body previously stored in the memory device with the compensated sampled data; And if the signal source is a human body, determining that the alarm signal is output.

In a preferred embodiment of this feature, the sampling step comprises: Filtering to remove noise of an output signal of the analog to digital converter; Linearizing the filtered signal; Calculating and storing the sampling data of the linearized signal.

In this embodiment, the step of calculating and storing the sampling data calculates and stores variables of an average value, a variance value, a frequency, a maximum value, a minimum value, and an average slope of the signal for a predetermined time.

(Action)

Therefore, according to the present invention, the human body detection system can perform accurate human body detection by preventing malfunctions caused by various animals and environmental factors such as high frequency noise and abrupt ambient temperature change.

(Example)

DETAILED DESCRIPTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram showing the configuration of a human body detection system according to the present invention.

Referring to the drawings, the human body detection system 100 includes a novel processor 124, an analog to digital converter (ADC) 122, and a temperature measuring circuit 130. The human body detection system 100 includes a mirror (or lens) 112, an infrared sensor 114, an amplifier 116, and a filter 118, which are provided as one module 110.

The mirror 112 collects human infrared rays emitted from various directions and outputs the infrared rays to the infrared sensor 114. Therefore, the red-line sensor 114 can capture the signal even with a small infrared signal.

The infrared sensor 114 receives the focused infrared signal from the mirror 112, converts the infrared signal into an electrical signal, and outputs the converted electrical signal to the amplifier 116.

The amplifier 116 amplifies and outputs a voltage of an electrical signal output from the infrared sensor 114. For example, an op amp may be provided in multiple stages to obtain a sufficient voltage amplification gain.

The filter 118 removes noise of a high frequency band of the amplified electrical signal and outputs the noise to the analog-to-digital converter 122.

The temperature measuring circuit 130 is provided with, for example, a temperature measuring transistor, and measures the ambient temperature of the infrared sensor element 114 using a characteristic in which a current changes in response to a temperature. The measured signal is output to the analog to digital converter 122.

The analog-to-digital converter 122 receives an analog signal from the filter 118 and the temperature measuring circuit 130, converts the analog signal into a digital signal, and outputs the analog signal.

In addition, the processor 124 stores various data regarding the digital signal converted by the analog-to-digital converter 122 in a memory device (not shown) provided in the processor 124, and stores the data for a predetermined time. Sampling variables such as average value, variance, frequency, maximum and minimum values, instantaneous slope and average slope are calculated and stored. Then, the compensation for the ambient temperature input from the temperature measuring circuit is processed, classified and analyzed for each type to determine the type of signal source to accurately determine the presence or absence of a human body. If it is determined that the human body is present, the output signal is output to an alarm device or the like. Here, the processor 124 and the analog-to-digital converter 122 are provided as a microcontroller (or microprocessor) 120 provided in one integrated circuit.

Accordingly, the human body detection system 100 may perform accurate human body detection by preventing environmental factors such as high frequency noise and sudden changes in ambient temperature and malfunctions caused by various animals.

Specifically, the operation of the processor will be described with reference to FIGS. 4 to 6.

4 is a flowchart illustrating an operation procedure of a human body detecting system according to an exemplary embodiment of the present invention. This procedure is a program executed by the processor 124 and is stored in a memory device included in the processor 124.

Referring to the drawing, in step S200, the processor 124 performs stabilization and system initialization of the sensor. In operation S220, the ambient temperature of the infrared sensor 114 is measured. That is, the ambient temperature of the infrared sensor 114 is calculated using the data converted from the output signal of the temperature measuring circuit 130 into the digital signal through the analog-digital converter 122. In step S240, the output signal of the infrared sensor 114 is sampled. That is, the output signal of the infrared sensor 114 is received at a predetermined time unit, and the digital signal is received from the analog-to-digital converter 114 and sampled with data for determining a signal source (heat source), that is, values of sampling variables. In operation S280, temperature compensation of the sampled data is performed in order to prevent a malfunction due to the ambient temperature of the infrared sensor 114. For example, a difference between an ambient temperature of 27 ° C. and an ambient temperature of the infrared sensor 114 measured from the temperature measuring circuit is calculated, and a proper proportional constant is calculated through this. Each of the sampling data is then multiplied by a proportional constant to temperature compensate the sampling data so that the signal is independent of changes in ambient temperature.

Subsequently, in step S300, the value of the signal emitted from the human body is provided as reference data, compared with the sampled data, and then the type of the signal source (heat source) is determined. Therefore, if the heat source is a human body in step S340, the procedure goes to step S360 to transmit an output signal OUTPUT for informing the alarm signal to the alarm device. If the human body is not a heat source, the procedure proceeds to step S220 to continue processing the procedures.

FIG. 5 is a flowchart showing in detail the procedure of the sampling step shown in FIG. 4. Here, the sampling method converts the output signal of the infrared sensor 114, which is an analog signal, into a digital scene through the analog-to-digital converter 122, and then calculates data of the maximum value 255 and the minimum value 0 by calculating the necessary parameters. Stored in the memory device of the processor 124. When a signal is not detected, the reference value 93 corresponding to the bias voltage of the amplifier 116 is set.

Referring to the figure, in step S242, the processor 124 receives the digital signal from the analog-to-digital converter 122 and removes noise to prevent malfunction due to noise. For example, the error of the signal is reduced by sampling a bit less than the conversion bit of the digital signal output by the analog-to-digital converter 122 at the maximum, minimum, and intermediate values of which the change due to noise is severe. Therefore, the output is limited due to the saturation state of the amplifier 116 for amplifying the output signal of the infrared sensor 114. In general, the maximum output value of the infrared sensor 114 is 180 to 190, and these values are sampled to the reference value 183, the minimum value is usually 0 to 10, and these values are sampled to the reference value 3. The intermediate value is usually 90 to 100, and is sampled at a value corresponding to the bias voltage of the amplifier 116, that is, the reference value 93. As a result, the place where the signal change is severe is corrected to reduce the error.

Next, the signal detected in step S244 is linearized. For example, if the value of three consecutive signals is S1, S2, S3, the signal value is stored in a memory device (not shown) of the processor 124, and if S1-S3 <R, S2 = (S1 + S2 ) / 2 to handle the linearization of the signal. Here, it is assumed that there is no change in the signal when the difference S1-S3 of the two signals is smaller than R, and it is determined that S2 does not change regardless of the value of S2. And R is a change threshold value, and has a value (eg, sampling value 6) of about 2% of the maximum value of the signal according to the noise of the supply voltage.

If the signal is subsequently linearized, the peak average value of one period is calculated in step S246. In step S248, the peak average value of the changed signal in the detection interval is calculated in one period, and the maximum value of the signal and the frequency of the maximum value are calculated in one step in S250. Subsequently, in step S252, the minimum value of the signal and the frequency of the minimum value are calculated during one period. At this time, the maximum value is limited to the reference value 183 and the minimum value to the reference value 3 due to the saturation state of the amplifier 116. In general, a signal detected from the human body is represented by a maximum value of 183 and a minimum value of 3, in which case, the frequency of the maximum value and the minimum value is calculated during a sampling period of one cycle. The frequency count determines the degree of change in the signal by counting the number and calculating the ratio for the entire interval when a value other than the intermediate reference value 93 is detected during the sampling interval of one period.

In step S254, the variance of the signal is calculated using the average of the signal of one period, and in step S256, the average slope is calculated by obtaining the difference of successive signal values for one period. In step S258, the average slope is calculated by obtaining a difference with respect to continuous signal values other than the specific reference value 93 of one period. Subsequently, in step S260, the number of signal values other than the specific reference value 93 is calculated in one period, and in step S262, the infrared sensor 114 calculates the number of signals at which the alarm value, that is, the value of the alarm threshold value or more, is output. . The average slope calculates and stores the difference between two consecutive signals and then calculates the average value. Therefore, the rate of change for the whole signal can be calculated. The average slope of the gumm signal is calculated when the two consecutive signals are detected as values other than the reference value 93, the difference is calculated by storing the difference between the two signals, and then the change rate is calculated. In addition, the average of the signal calculates the average of the signal value in the sampling period of one period, and the average of the detection signal is calculated when the signal value other than the reference value 93 is detected in the sampling period of one period.

6 is a flowchart illustrating a procedure of a signal analysis step for determining the heat source illustrated in FIG. 4.

Referring to the drawing, when temperature compensation for the ambient temperature is performed on the data extracted in the sampling step in step S302, the threshold value of the signal radiated from the human body distinguished from these environmental factors is analyzed. That is, the data extracted in the sampling step, that is, the variables, are compared with reference values of signals that the human body can produce. Then, it is determined whether the signal detected in step S304 is a momentary or continuous change by a human body or an animal. If the result of the discrimination is a momentary change, the procedure goes to step S306 to analyze the signal for the momentary change within one period. If the result of the determination is a continuous change, the procedure proceeds to step S314 to analyze the signal for the continuous change for one period.

Therefore, in the case of a momentary change, the maximum and minimum values of the peaks are analyzed in step S308, and the difference between the maximum and minimum values of these peaks is analyzed in step S310. In step S312, the ratio of the peak mean value of the detection interval to the instantaneous change and the peak mean value for one period is analyzed.

In addition, when the detected signal is constantly changing, the difference between the maximum value and the minimum value of the peak is analyzed in step S316, and the peak average value of the detection interval is analyzed in step S318. The average slope of the peak is then analyzed in step S320, and the maximum value of the peak is analyzed in step S322.

Therefore, as a result of the analysis, the instantaneous change occurs three times consecutively, and if the condition occurs two or more times among the variables of the above-described steps (S306 to S312), the heat source is determined as a human. In the case of continuous change, it is determined as a human being when all four conditions of the above-described steps S314 to S322 are satisfied.

As described above, the human body detection system of the present invention not only compensates for environmental factors, that is, temperature changes, but also analyzes signals according to speeds according to temperature changes to determine the presence or absence of the human body.

7 and 8 are waveform diagrams showing the difference between a signal according to an environmental factor and a signal output from a human according to an embodiment of the present invention. FIG. 7A illustrates a detection signal for a thermal change of the environment, and FIG. 7B illustrates a detection waveform of a signal radiated from a human body. As shown in the figure, the signal waveform due to the thermal change tends to be asymmetrical in the vertical peak change. And human signals tend to be symmetrical overall. Therefore, the judgment on the thermal change of the environment can be determined by symmetry.

In addition, as shown in (a) of FIG. 8, the signal generated by the thermal change of the environment is very slow and slow. However, as shown in (b) of FIG. 8, a signal emitted by a human has a large change and relatively fast change compared to the signal of FIG. 8 (b). Therefore, the thermal change of the environment can be distinguished by the speed and width of the change of the signal.

In other words, the signal emitted from the human body has a large gradient of change and a large value of the overall variables. However, changes in the heat source due to environmental factors (eg, ambient temperature changes, wind, etc.) are considerably slower and smaller than those at which the rate of change is radiated from the human body.

9 is a waveform diagram showing a difference between signals output from a human and an animal according to an embodiment of the present invention. The waveform shown here illustrates the waveform when the heat source passes once in front of the infrared sensor for easy identification.

Referring to the drawings, FIG. 9 (a) shows a signal from an animal (for example, a dog, a cow, etc.), and FIG. 9 (b) shows a signal from a human. Comparing these figures, it can be seen that the signals generated by humans and animals have only a difference in magnitude and almost no temperature difference. Therefore, it is very difficult to distinguish the waveform difference into an analog signal. Therefore, one of the differences distinguished by the naked eye is the asymmetry of the waveform, as shown in FIG.

10 is a waveform diagram illustrating characteristics of sampled variables of a waveform according to an embodiment of the present invention in order to understand the waveform characteristics of humans and animals as digital signals.

Referring to the figure, the alarm threshold value means a voltage value at which the infrared sensor sounds an alarm. The bias voltage represents the bias voltage of the amplifier, and the detection time represents the actually detected time of the entire sampling time.

For example, in the case of sampling four times, the average value in the signals A, B, C, and D is the average value of the peak magnitude at each point, and the average slope is | AB |, | BC in the interval for each signal. It becomes the average value of |, | CD |. The peak variance is then the variance of the peak during the sampling period.

11A and 11B are diagrams showing sampling data for determining an animal according to an exemplary embodiment of the present invention. This shows the digital sampling data of the dog case and shows the sampling data for the instantaneous change and the continuous change. In this case, the instant change means that the non-sensing time 420 is 8 or more, and the continuous change 422 means that the non-sensing time 420 is 7 or less.

Referring to the drawings, the values of the variables for the instantaneous change should satisfy Table 1 below, and the values of the variables for the continuous change should satisfy Table 2 below. And the constants for these Table 1 and Table 2 conditions are experimental values. Therefore, during the 30 detection processes, the detection false positive for the continuous change three times (400, 406, 414), the detection false positive for the instant change six times (402, 404), a total of eight detection false positives.

Number of Upper Saturations> 99 Number of Lower Saturations> 99 Peak Maximum-Minimum> 113 Peak Average (R)> 19 Peak Average (R)-Average> 12

Peak Maximum> 121 Peak Maximum-Minimum> 89 Peak Average (R)> 19 Average Slope> 1

12A and 12B illustrate sampling data for determining a thermal change of a human and the environment according to an exemplary embodiment of the present invention. FIG. 12A is digital sampling data of a signal issued by a human, and FIG. 12B is digital sampling data of a signal with respect to a thermal change of an environment. Here, the instantaneous change 424 means that the non-sensing time 420 is 8 or more, and the continuous change means the non-sensing time 420 is 7 or less.

Referring to the drawings, the value of the variables for the instantaneous change is judged as "?" When three or more of the conditions in Table 1 are satisfied, and the judgment result is recognized as a human when two or more of the three consecutive are satisfied. If not, it was not recognized as a human being. The values of the variables for continuous change were recognized as human beings when all the conditions of Table 2 were satisfied. Therefore, as a result of 14 detections detected by humans through 30 detection processes, one detection of "?" 410 and one detection of "X" 408 was detected as a false detection. However, humans were identified before three detection false positives occurred.

As shown in FIG. 12B, the detection result of the thermal change of the environment has been detected 412 times in one of the 14 determination results.

As described above, the human body detection system of the present invention may implement a low-cost human body detection system by including a controller (or a microprocessor) for temperature compensation.

In addition, by digitizing and processing the detection signal of the infrared sensor, it is easy to develop a program for the detection function, it is possible to accurately detect the human body.

Claims (7)

In the sensor system: An infrared sensor which receives an infrared signal from a signal source and converts the infrared signal into an electrical signal; An amplifier for receiving the electrical signal and amplifying and outputting a voltage; A filter for removing noise in a high frequency band of the amplified electrical signal; A temperature measuring circuit outputting an analog signal corresponding to the ambient temperature of the infrared sensor; An analog-to-digital converter that receives an analog signal from the filter and the temperature measuring circuit and converts the analog signal into a digital signal; Receives the digital signal and samples and stores a plurality of data according to signal characteristics, calculates sampling parameters for the digital signal for a predetermined time, compares and analyzes the characteristics of the signal radiated from a pre-stored human body and the sampling parameters. A processor for determining the type of the signal source, And the processor compensates for preventing the system from malfunctioning from environmental factors of the infrared sensor and controls to output an alarm signal when the signal source is human. The method of claim 1, The infrared sensor is a sensor system, characterized in that provided with a pyroelectric sensor element. The method of claim 1, The temperature compensation circuit is a sensor system, characterized in that provided with a transistor. The method of claim 1, The analog-to-digital converter and the processor is a sensor system, characterized in that provided as one integrated circuit. An infrared sensor for detecting a signal source, an amplifier, a filter, a temperature measuring circuit for measuring the ambient temperature of the infrared sensor, and an analog signal from the filter and the temperature measuring circuit are converted into a digital signal and outputted. A sensor system comprising a processor having an analog-to-digital converter and a memory device for storing data in accordance with the characteristics of the digital signal, the sensing method of the sensor system comprising: Initializing the system; Measuring the ambient temperature of the infrared sensor using the temperature measuring circuit; Sampling the output signal of the analog to digital converter; Compensating the sampled data to prevent malfunction due to ambient temperature of the infrared sensor; Determining a type of a signal source by comparing data on characteristics of a signal emitted from a human body previously stored in the memory device with the compensated sampled data; And if the signal source is a human body, determining that the alarm source outputs an alarm signal. The method of claim 5, The sampling step; Filtering to remove noise of an output signal of the analog to digital converter; Linearizing the filtered signal; Calculating and storing the sampling data of the linearized signal. The method of claim 6, The calculating and storing of the sampling data may include calculating and storing variables of an average value, a variance value, a frequency, a maximum value, a minimum value, and an average slope of the signal for a predetermined time. .