KR20200089890A - Intrusion Detection Laser Sensor based on a Reflector with Autoimmunity on Fog and method thereof - Google Patents

Abstract

The present invention provides a reflector-based laser sensor having resistance to fog which comprises a laser sensor unit which transmits a laser and a retroreflective plate which does not require power supply by reflecting the laser sensor. The laser sensor unit includes an intrusion detection sensor portion detecting an intruder in a monitoring area and a fog transmission loss measuring portion measuring the transmission loss due to fog and transmitting loss information to the MCU.

Description

Intrusion detection laser sensor based on a reflector with autoimmunity on fog and method thereof

The present invention relates to a laser sensor that minimizes the false positive rate of fog as compensation for power loss generated when fog is transmitted due to fog generation. The laser sensor for accurate detection even in the presence of fog is security for outdoor intrusion detection. It can be widely used as a sensor.

The prior art related to the present invention is disclosed in Korean Patent Registration No. 10-1185602 (announced on September 24, 2012). 1 is a configuration diagram of a fog generating warning display device using the conventional laser beam. In FIG. 1, the fog generating warning display device using the conventional laser beam generates the laser beam generated by the laser beam generator through the laser beam hole 180 and is reflected by the surrounding reflector 120, and the reflector is the top plate, the left and right side plates, and It can be installed on the inner surface of the middle plate so that the laser beam can be zigzag. When connecting multiple devices, a single power source can be used through the power connector 170, thereby reducing cost. In addition, the entire power is supplied from the power supply unit 150, and the power connection unit 170 serves to supply power to adjacent devices when connecting multiple devices. When the fog occurs, the laser beam is generated by supplying power to the laser beam generator 110 from the control unit 160 according to the detection of the light amount of the optical sensor 130, and the generated laser beam is reflected by the reflector 120 in a zigzag form When a guideline is formed and small droplets of particles are present in the guideline, it is reflected and the guideline can be displayed to the driver. In addition, as a background technology of the present invention, a laser sensor used for outdoor use has a disadvantage that is very vulnerable to fog due to the original characteristics of the laser, and because the laser is a wave energy having a very short wavelength of several hundred nm, it is like fog. When passing fine water droplet particles made of polar molecules, a large transmission loss is inevitably caused by scattering and absorption. Therefore, when a laser sensor is used in an area and a place where fog is frequently generated, a lot of misinformation occurs, and additional human and material costs are required due to unnecessary inspection. In addition, in terms of performance, it is impossible to secure the performance of the laser sensor according to the fog concentration, making it impossible to operate the security and industrial safety system safely. In order to solve this fatal problem, the present invention proposes a reflector-based laser sensor in which the laser output power and the received signal amplification rate are automatically varied according to the fog concentration. The sensor performance is optimized by accurately calculating the fog transmission loss of the laser inside the sensor in the event of fog, and then feeding the loss to the output power variable circuit (transmitter) and the received signal amplification circuit (receiver) at the same time. By varying, the laser sensor performance in a fog situation can be secured uniformly and stably. At this time, the variable range of the output power of the laser sensor may be determined within an allowable safety level required by the corresponding device. In the absence of fog, there is no atmospheric loss of laser energy, so the output power of the laser sensor and the amplification rate of the received signal are returned to the initial values. The laser sensor according to the present invention can acquire and maintain a high signal-to-noise ratio (SNR) according to the change in fog concentration, thereby maintaining stable sensor performance even in a fog-prone region and operating the entire system because it is a sensor that uses a reflector that does not require power. It can greatly improve efficiency.

The fog generating warning display device using the conventional laser beam configured as described above may warn that fog has occurred using a laser beam, but when fog occurs, there is a problem in that an intruder can be detected without false information when an intruder invades. will be. In addition, the prior art has a problem that does not reduce the error rate for whether or not fog occurs. Accordingly, an object of the present invention is to stably detect an intruder in various fog concentration situations. In addition, another object of the present invention is to minimize the false positive rate for the fog by compensating for the amount of loss of the laser sensor due to the fog.

Reflector-based laser sensor having immunity to fog of the present invention with the above object and a method for detecting an intruder using the same are characterized by comprising a laser sensor unit for transmitting a laser and a retroreflector that does not require power supply to reflect the laser. The laser sensor unit is composed of an intrusion detection sensor unit that detects an intruder in the surveillance area and a fog transmission loss measurement unit that measures the amount of transmission loss due to fog and transmits the loss amount information to the MCU.

The present invention configured as described above, the reflector-based laser sensor having immunity to fog, and the intruder detection method using the same are effective in having a stable and low fog misinformation rate by automatically compensating the amount of loss of fog of the laser even in various fog concentration situations. . In addition, the present invention has an effect that can improve the vulnerability to fog by interlocking the transmission and reception end amplification rate of the intrusion detection sensor unit by embedding a high-precision fog transmission loss measurement unit inside the laser sensor. In addition, the present invention always has a uniform and stable performance even in a variety of outdoor environments in which the atmosphere is rapidly changing, and because it uses a retroreflective plate that does not require power, it not only reduces construction cost but also facilitates installation.

1 is a block diagram of a conventional fog generating warning display device using a laser beam,
2 is a configuration of a reflector-based laser sensor having a resistance to fog of the present invention,
3 is a block diagram illustrating the operation of a reflector-based laser sensor having immunity to the present invention,
4 is a control flow diagram for a method for detecting an intruder of a reflector-based laser sensor having resistance to fog of the present invention,
5 is a diagram for calculating the amount of laser fog transmission loss for a fog transmission loss measurement unit having a linear characteristic as an embodiment applied to the present invention.

The present invention for the purpose of the above-described reflector-based laser sensor having resistance to fog and an intruder detection method using the same will be described with reference to FIGS. 2 to 5 as follows.

2 is a configuration diagram of a laser sensor based on a reflector having resistance to fog of the present invention. In FIG. 2, the reflector-based laser sensor having immunity to fog of the present invention transmits a laser signal in the direction of a retroreflector, receives the fog transmission loss amount from the fog transmission loss measurement unit 300, and controls the amount of laser signal transmission based on this. The intrusion detection sensor unit 200, the retroreflective plate 101 for reflecting the laser signal transmitted from the intrusion detection sensor unit, and receives the laser signal reflected from the retroreflective plate, measures the amount of fog transmission loss and transmits it to the intrusion detection sensor unit It characterized in that it consists of a fog transmission loss measuring unit 300. In the above, the intrusion detection sensor unit 200 controls the output power variable circuit 202 based on the received light amount difference value input from the comparator 303 and the received signal amplification rate received from the received signal amplification variable circuit 205. MCU 201 that adjusts the output and transmits the difference between the current and past laser received signal light amount to the received signal amplification variable circuit, and output power is changed by the control signal of the MCU to be input to the pulse laser transmission driver 203 The output power variable circuit 202, a pulse laser transmission driver 203 that receives an output power signal from the output power variable circuit and causes a pulse laser transmitter to transmit a laser, and receives a signal from a pulse laser transmission driver to perform laser processing. The pulse laser transmitting unit 204 for transmitting the output, and the pulse laser receiving unit 206 and the output of the pulse laser receiving unit for transmitting a received signal input as being reflected by the laser signal from the retroreflector to the received signal amplification variable circuit 205 Receiving a signal by varying the amplification factor for the laser reception signal based on the difference between the current and past laser reception signal input from the comparator 303 of the fog transmission loss measurement unit 300 to the MCU 201 It is characterized by consisting of a received signal amplification variable circuit (205) for transmitting the signal amplification rate to the MCU. In addition, the fog transmission loss measurement unit 300 for optimally changing the transmission output amplification rate and the reception signal amplification rate of the intrusion detection sensor unit 200 is for measuring the amount of laser loss caused by fog, and is continuously waved by the control signal of the MCU. A continuous wave laser transmission driver 301 that allows the laser transmission unit 302 to continuously transmit a laser, a continuous wave laser transmission unit 302 that continuously transmits a laser according to the signals of the continuous wave laser transmission driver, and a continuous wave laser transmission unit The received signal light quantity difference value comparing the current received amount received from the continuous wave laser receiving unit 304 and the past received amount received from the MCU by the continuous wave laser receiving unit 304 where the received laser signal is reflected and input from the retroreflector is MCU It characterized in that it consists of a comparator 303 to transmit to. Further, the pulse laser transmitter 204 is composed of a laser diode and an optical lens, and the pulse laser receiver 206 is composed of a photo diode and an optical lens. In addition, the fog transmission loss measurement unit 300 compares the laser reception amount of the continuous wave laser receiver of the continuous wave laser receiver in the absence of fog and the laser reception amount of the continuous wave laser receiver in the presence of fog in the comparator 303 and compares the corresponding information with the MCU 201, and the MCU adjusts the transmission output power variable circuit 202 of the laser sensor unit and the reception signal amplification variable circuit 205 of the receiver in real time based on the corresponding information, thereby realizing the fog-optimized laser transmission output and reception signal. The amplification rate may be determined. More precisely, the amount of continuous wave laser reception in the current standby (air) state is compared with the amount of laser reception in the past standby state, which is the entire time, thereby resulting in a high signal-to-noise ratio. (SNR) and stable performance in various fog situations.

Figure 3 is a block diagram for explaining the operation of the present invention based on the reflector-resistant laser sensor fog. In FIG. 3, when the first MCU is driven and the continuous wave laser transmission driver 301 of the fog transmission loss measurement unit 300 operates in the reflector-based laser sensor having immunity to the present invention, the continuous wave laser beam transmits the continuous wave laser transmitter 302. ), the laser beam transmitted through the lens is transmitted through the atmosphere and then reflected on the retroreflective plate 101, and again passes through the atmosphere to enter the continuous wave laser receiver 304. For example, when there is no fog, the reception amount of the continuous wave laser in the current standby state is stored in the memory in the MCU 201, and at this time, the MCU recognizes that there is no laser loss due to fog, thus compensating for power loss and receiving end In order to improve the signal-to-noise ratio, the amplification factor of the amplification factor variable circuits 202 and 205 of the transmitting and receiving unit is not varied. However, when fog occurs in the air, the lost laser signal due to fog is received by the continuous wave laser receiving unit 304. The received amount and the received amount (if there is no fog) stored in the memory of the MCU are different by the comparator 303. The value will be generated. Based on the difference value, the MCU increases the amplification factor of the output power variable circuit 202 at the transmitting end of the intrusion detection sensor unit 200. The pulse laser transmission driver 203 is operated based on the changed amplification rate, and the pulse laser beam having the increased output power is transmitted from the pulse laser transmitter 204 to the retroreflector.

4 is a control flow diagram for a method for detecting an intruder of a reflector-based laser sensor having resistance to fog of the present invention. In FIG. 4, the intruder detection method of the reflector-based laser sensor having immunity to fog of the present invention includes: a step in which the MCU of the intrusion detection sensor unit drives the continuous wave laser transmission driver to transmit the continuous wave laser to the retroreflector (S11) Reflecting the continuous wave laser (S12), the continuous wave laser receiving unit receives the continuous wave laser reflected from the retroreflector and transmits the continuous wave laser reception amount to the MCU (S13), and the MCU periodically receives the continuous wave laser reception amount Storing and comparing the received amount of continuous wave laser received and the received amount of continuous wave laser received immediately before the past to calculate the amount of loss, which is the difference in received light amount by fog in the current state (S14), and the MCU detects the intrusion based on the amount of loss Increasing the amplification factor of the output power variable circuit at the negative transmitting end (S15), and transmitting a pulse laser signal to the retroreflector based on the increased amplification factor of the output power variable circuit (S16) And a pulse laser receiving unit receiving the pulsed laser signal reflected from the retroreflective plate and transmitting the received pulsed laser signal to the received signal amplifying variable circuit (S17), and the receiving signal amplifying variable circuit whose amplification factor is adjusted by the MCU is It characterized in that it comprises a step (S18) of transmitting the received laser signal to the MCU, and determining whether or not chip particles invade in a fog situation based on the received laser signal (S19). In step S16, when the output power is increased by driving the pulse laser transmission driver based on the amplification factor, the increased pulse laser beam is transmitted to the retroreflector through the pulse laser transmitter. In addition, the laser beam reflected from the retroreflective plate is incident on the photodiode of the pulse laser receiver, where the intrusion detection area is formed between the laser sensor and the retroreflective plate. In addition, the received pulse laser signal is input to the MCU after passing through the receive amplification variable circuit 205 whose amplification rate is adjusted by the MCU, and the MCU determines whether intrusion is detected in a fog situation based on the received signal. will be. The laser sensor configured as described above controls the amplification rate of the transmitting and receiving end in consideration of the laser loss for the current standby state while continuously rotating the entire method in real time, so that the laser-based intrusion detection sensor generates a lot of false information due to fog loss. It will be able to improve the performance of.

은 하기 식(1)과 같고,In addition, the amount of loss of the pulse laser that is transmitted and reflected from the above to the retroreflective plate, that is, reciprocating the fog.

Is equal to the following formula (1),

... 식(1)

... Expression (1)

However, σ is the attenuation coefficient due to fog, R is the distance between the laser sensor and the retroreflector, and σ is obtained by the following equation (2).

...식(2)

... Expression (2)

However, V ₀ is the continuous wave laser received signal voltage level when there is no fog, and Vm is the received voltage level of the continuous wave laser when there is fog. In addition, λnm is the wavelength of the continuous wave laser used, q is the size distribution (size distribntion) of the fog particles, and Visibility is the visible distance concentration. Here, q is as in Equation (3) below.

... 식(3)

... Expression (3)

5 is a diagram for calculating the amount of laser fog transmission loss for a fog transmission loss measurement unit having a linear characteristic as an embodiment applied to the present invention. In FIG. 5, the transmission loss amount is the same as the laser output power amplification factor to be compensated by the output power variable circuit, wherein the amplification factor of the received signal amplification variable circuit is controlled by the MCU based on the signal-to-noise ratio (SNR). In the example of FIG. 5, the wavelength λnm of the continuous wave laser used is 650nm, the distance R between the sensor and the retroreflector is set to 5m, and the fog situation is assumed to vary from 10m to 100m based on the visible distance and the fog is When there is no, the received voltage level measured by the continuous wave laser receiving unit 304 of the fog transmission loss measuring unit 300 is set to 4.15V. Referring to FIG. 5, as the visible distance concentration of the fog gradually decreases from 10 m to 100 m, the reciprocating loss of the continuous wave laser gradually decreases, so that the reception voltage at the continuous wave laser receiver increases from 0.09 V to 2.86 V. In this case, when the reciprocating loss amount of the laser is obtained using Equations (1) to (3), it is 16.63 dB to 1.62 dB. At this time, the corresponding loss amount is linked to the compensation amplification factor of the output power variable circuit 202 in the intrusion detection sensor unit 200. For example, in the above Figure 5, when the visible distance concentration is 50m, when calculating the amount of laser reciprocation loss due to fog, the laser reception voltage is V ₀ =4.15V when there is no fog, and the received laser reception voltage in a fog situation with a visible distance concentration of 50m Is 1.95V, so that the fog attenuation factor σ is calculated by Eq. (2) above as in Eq. (4) below.

... 식(4)

... Expression (4)

Substituting Equation (4) into Equation (1) to calculate the amount of laser reciprocating loss is as shown in Equation (5) below, and the corresponding value is equal to the amplification factor to be compensated by the output power variable circuit 202.

... 식(5)

... Expression (5)

As described above, the present invention can guarantee a very low misinformation rate and ensure uniform and stable performance at the same time because the transmission and reception end amplification rate of the sensor is interlocked in various fog concentration situations by the fog transmission loss measurement unit in the laser sensor. It is possible.

100: laser sensor, 200: intrusion detection sensor unit,
201: MCU, 202: output power variable circuit,
203: pulse laser transmission driver, 204: pulse laser transmission unit,
205: receiving signal amplification variable circuit, 206: pulse laser receiver,
300: fog transmission loss measurement unit, 301: continuous wave ray transmission driver,
302: continuous wave laser transmitter, 303: comparator,
304: continuous wave laser receiver

Claims (14)

Reflector-based laser sensor having a resistance to fog for easy and stable detection of intruders in the fog,
The reflector-based laser sensor having resistance to fog,
An intrusion detection sensor unit 200 that transmits a laser signal in a direction of a retroreflector, receives the fog transmission loss amount from the fog transmission loss measurement unit 300, and controls the transmission amount of the laser signal based on the fog transmission loss amount;
A retroreflective plate 101 that reflects the laser signal transmitted from the laser sensor;
And a fog transmission loss measurement unit (300) that receives the laser signal reflected from the retroreflective plate, measures the amount of fog transmission loss, and transmits it to the intrusion detection sensor unit.
According to claim 1,
The intrusion detection sensor unit 200,
Control the output by controlling the output power variable circuit 202 based on the received signal amplification rate received from the fog transmission loss measurement unit 300 and transmit the difference between the current and past laser received signal light amount to the received signal amplification variable circuit MCU 201 to be;
An output power variable circuit 202 for varying the output power by the control signal of the MCU and inputting it to the pulse laser transmission driver 203;
A pulse laser transmission driver 203 for receiving the output power signal from the output power variable circuit and causing the pulse laser transmitter to transmit a laser;
A pulse laser transmitter 204 for receiving a signal from a pulse laser transmission driver and transmitting a laser;
A pulse laser receiver 206 that transmits a received signal input as being reflected by the laser signal from the retroreflective plate to the received signal amplification variable circuit 205;
And receiving the output signal of the pulse laser receiver to vary the amplification factor for the laser received signal based on the difference between the current and past laser received signals input from the fog transmission loss measurement unit 300 to the MCU 201. A reflector-based laser sensor having immunity to fog, characterized in that it consists of a variable amplification circuit 205 to receive the signal amplification rate to the MCU.
According to claim 1,
The fog transmission loss measurement unit 300,
A continuous wave laser transmission driver 301 for measuring the amount of laser loss caused by fog, and allowing the continuous wave laser transmitter 302 to continuously transmit the laser by a control signal of the MCU;
A continuous wave laser transmitter 302 for continuously transmitting a laser according to the signal of the continuous wave laser transmission driver;
A continuous wave laser receiving unit 304 into which the laser signal transmitted from the continuous wave laser transmitting unit is reflected and input from the retroreflective plate;
And a comparator (303) that transmits a difference in the received signal light amount to the MCU comparing the current received amount received from the continuous wave laser receiving unit 304 with the past received amount received from the MCU. Branch is a reflector-based laser sensor.
According to claim 2,
The pulse laser transmission unit 204,
Reflector-based laser sensor having a resistance to fog, characterized by consisting of a laser diode and an optical lens.
According to claim 2,
The pulse laser receiver 206,
Reflector-based laser sensor having a resistance to fog, characterized by consisting of a photodiode and an optical lens.

The method of claim 2
The amplification rate of the received signal amplification variable circuit,
A reflector-based laser sensor with fog immunity, characterized by being controlled by an MCU based on the signal-to-noise ratio (SNR).
According to claim 2,
The amount of transmission loss,
A reflector-based laser sensor having resistance to fog, characterized in that it is the same as the laser output power amplification factor to be compensated in the output power variable circuit.
A method for detecting an intruder using a reflector-based laser sensor having resistance to fog for easily and stably detecting an intruder in a fog,
The intruder detection method using the reflector-based laser sensor having the resistance to fog,
A step in which the MCU of the intrusion detection sensor unit drives the continuous wave laser transmission driver to transmit the continuous wave laser to the retroreflector (S11);
A step S12 in which the retroreflective plate reflects the continuous wave laser;
A continuous wave laser receiving unit receiving the continuous wave laser reflected from the retroreflective plate and transmitting the continuous wave laser reception amount to the MCU (S13);
A step in which the MCU periodically stores the received amount of continuous wave laser and compares the received amount of continuous wave laser with the received amount of continuous wave laser received immediately before, and calculates a loss amount, which is a difference in received light amount by fog in the current state (S14);
The MCU increases the amplification factor of the output power variable circuit at the transmitting end of the intrusion detection sensor unit based on the amount of loss (S15);
Transmitting a pulse laser signal to a retroreflector based on the increased amplification factor of the output power variable circuit (S16);
A step (S17) of the pulse laser receiving unit receiving the pulse laser signal reflected from the retroreflective plate and transmitting the received pulse laser signal to the variable receiving signal amplifying circuit;
A step in which the received signal amplification variable circuit whose amplification rate is adjusted by the MCU transmits the received laser signal to the MCU (S18);
And a step (S19) of determining whether or not chip particles invade in a fog situation based on the received laser signal from the MCU, the method for detecting an intruder using a reflector-based laser sensor having resistance to fog.
The method of claim 8,
The intruder detection method using the reflector-based laser sensor having the resistance to fog,
A method of detecting an intruder using a reflector-based laser sensor that is resistant to fog, characterized in that it adjusts the amplification rate of the transmitting and receiving end in consideration of the laser loss for the current standby state while continuously running in real time.
The method of claim 8,
The amount of transmission loss of the laser

silver,

Intruder detection method using a reflector-based laser sensor having a resistance to fog, characterized in that can be calculated by.
Where σ is the attenuation factor due to fog, and R is the distance between the laser sensor and the retroreflector.
The method of claim 8,
The amplification rate of the received signal amplification variable circuit,
A method of detecting an intruder using a reflector-based laser sensor having immunity to fog, characterized by being controlled by an MCU based on a signal-to-noise ratio (SNR).
The method of claim 10,
The σ is,

Intruder detection method using a reflector-based laser sensor having a resistance to fog, characterized in that can be calculated by.
Here, V ₀ is the continuous wave laser received signal voltage level when there is no fog, Vm is the received voltage level of the continuous wave laser when there is fog, λnm is the wavelength of the continuous wave laser used, and q is the size distribution of the fog particles (size distribntion ), Visibility is the visible distance concentration.
The method of claim 12,
Q is,

Intruder detection method using a reflector-based laser sensor having a resistance to fog, characterized in that can be calculated by.
The method according to any one of claims 8 to 13,
The amount of transmission loss,
A method for detecting an intruder using a reflector-based laser sensor having immunity to fog, characterized in that it is the same as the laser output power amplification factor to be compensated by the variable output power circuit.

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