KR20200018938A - Low power face recognition system using PIR sensor and its control method - Google Patents

Abstract

The present invention relates to an access control system and/or a security system. More specifically, the present invention relates to the access control system and/or the security system using a facial recognition sensor and/or iris. The access control system comprises: a motion monitoring sensor unit including a pyroelectric infrared (PIR) sensor and sensing motions of a person; an infrared LED unit operated by the motion monitoring sensor unit; an image sensor unit photographing by using light emission of the infrared LED unit and obtaining facial and/or iris recognition data; and a control unit controlling access by using the facial and/or iris recognition data of the image sensor unit.

Description

Low power face recognition system using PIR sensor and its control method

The present invention relates to an access control system and / or security system, and more particularly to an access control system and / or security system using a face recognition sensor and / or iris and an access control method using the same.

Access control system and security system that registers face recognition information of individuals to the system by using face recognition sensor that processes the scanned face using infrared LED and image sensor, and controls access through authentication when entering and exiting This is widely used.

The face recognition sensor scans the face by turning on the infrared LED, and uses a method of image processing the face scanned by the image sensor through a system algorithm. The face sensor requires a large number of infrared LEDs because it needs to scan the entire area of the face, and high-power infrared LEDs are used for accurate face recognition.

When the face recognition sensor is continuously turned on, the current consumption is greatly increased due to the large number of high power LEDs, and the high power LED is deteriorated, which causes a problem that the face recognition system does not operate normally.

Various solutions are being developed to solve this problem. Initially, a touch screen was installed and a face recognition sensor was used when a user manually touched the touch screen. However, this method is cumbersome for a person to operate the system directly through touch. In addition to the need for guidance that touch is required because it is operated manually, there is a problem that it is inconvenient to use when it is difficult to touch, for example, holding a bag in hand.

Recently, an access control method using an iris recognition sensor has been developed instead of a face recognition sensor, but this method also basically includes a process of scanning using an infrared LED and an image sensor. Since the eye is found in the face scanned by the image sensor, and then the algorithm is applied to the feature of the iris to process the image, the problem of the existing face recognition sensor is the same.

Accordingly, methods have been developed to enable the face recognition sensor to operate only when a person is located adjacent to be able to photograph a face.

By using an optical sensor (distance sensor), a method has been developed and used to automatically operate the sensor system by lighting an infrared LED only when a person approaches a certain distance. However, in the case of using an optical sensor, the face recognition sensor does not operate correctly under the influence of ambient disturbance light, or there is an inefficiency in which the entire system operates in response to a non-human object.

The problem to be solved by the present invention is to provide an access control system that accurately determines the approach of a person, so that the face sensor or iris recognition sensor can selectively and accurately operate only when the person approaches.

The problem to be solved by the present invention is to provide an access control method to accurately determine the access of the person, so that the face sensor or iris recognition sensor can selectively and accurately operate only when the person approaches.

In order to solve the above problems, the present invention

A motion monitoring sensor unit including a pyroelectric infrared sensor (PIR sensor) and detecting a motion of a person;

An infrared LED unit operated by the motion monitoring sensor unit;

An image sensor unit for photographing by using light emission of the infrared LED unit and obtaining face and / or iris recognition data; And

And a control unit controlling entrance and exit using the face and / or iris body recognition data of the image sensor unit.

In one aspect of the invention,

Recognizing an approach of a human body in a motion monitoring sensor unit including a pyroelectric infrared sensor;

Operating the infrared LED unit by a recognition signal to approach the human body;

Photographing using infrared light of the infrared LED unit;

Extracting face and / or iris recognition data from the captured image; And

And providing access by using the extracted data.

In the present invention, the motion monitoring sensor unit selectively filters a light source generated by the human body from a PlR sensor, a Fresnel lens having a plurality of compartments for condensing light with the PIR sensor, and a light source focused by the Fresnel lens. It may include a filter to.

In the present invention, the PIR sensor may be a sensor for detecting the movement of the object with heat by using the principle that the micro current is generated by the pyroelectric phenomenon when the infrared rays emitted from the object having heat is incident on the pyroelectric element. have.

In the practice of the present invention, the PIR sensor can detect the movement of a heating object emitting a wavelength of 5 to 14 micrometers, preferably an infrared wavelength of 8 to 14 micrometers, and the change in infrared radiation energy At this time, a current can be output and a change can be detected by amplifying the output current with an amplifying circuit.

In a preferred embodiment of the present invention, the PIR sensor is composed of a PIR sensor chip for outputting a fine current when the energy radiated from the human body, and a JFET for changing the current output from the PIR sensor chip into a voltage, the fine output Use an amplification circuit to use The amplifier circuit may be composed of elements such as an op amp, a resistor, and / or a capacitor. The PIR sensor chip and the devices may be embedded in a case where light is blocked except for a filter installation area so as to block the influence of disturbance light.

In the present invention, the Fresnel lens is used to determine the sensing distance and the sensing angle of the PIR sensor.

In the embodiment of the present invention, the Fresnel lens has a hemispherical body shape, a honeycomb-shaped pattern is formed on the outer surface of the body, the lens is formed in each compartment of the pattern on the inner surface of the body signal generated in the compartment Can be collected by section and sent to the PIR sensor.

In a preferred embodiment of the present invention, the Fresnel lens is a hemispherical body is formed in the center of the rectangular plate, so that it can be installed in a narrow range of 1x1 cm ² , it can be coupled to the installation area through the rectangular plate. have.

In the present invention, the filter may be a band pass filter for selectively transmitting only the region corresponding to the infrared wavelength generated at the surface temperature of the human body so as to efficiently recognize the infrared wavelength generated by the human body.

Although not theoretically limited, the surface temperature of the human body is in the range of 32 to 40 ° C., while the peak of the infrared radiation wavelength corresponds to 9.36 micrometers, whereas the wavelength of 5 to 14 micrometers recognized by a general PIR sensor is According to the law of displacement of Vienna, it corresponds to about -66 ℃ ~ 306 ℃. Accordingly, since the PIR sensor reacts to an object or a living thing, such as an animal, which has heat, not to the human body, accuracy can be improved by a band pass filter having a range that can pass only infrared wavelengths generated by the human body. It becomes possible.

In the practice of the present invention, the band pass filter preferably has a pass range of 9.2 to 9.5 micrometers.

In a preferred embodiment of the present invention, the band pass filter is positioned to cover the top surface of the PIR sensor, so that only the infrared wavelength in the range of 9.2 to 9.5 micrometers can be incident on the PIR sensor.

In the present invention, when motion is detected by the motion monitoring sensor unit, infrared LEDs operate in the infrared LED unit, and photographing is performed to recognize the face and / or iris in the face and / or iris recognition sensor unit. The face and / or iris recognition data obtained by photographing is compared with the access authorization data stored in the control unit, and the access is allowed or denied.

In the present invention, the LED unit is arranged in a grid at a predetermined interval around the image sensor unit, and emits infrared rays for image capture.

In the practice of the present invention, the amount of infrared light emitted from the LED unit can be adjusted according to the amount of light around the image sensor unit, more precisely the amount of infrared light in the wavelength range used by the camera for shooting in the ambient light. The amount of infrared light used by the camera in ambient light can be measured by a grape diode having a bandpass filter that selectively transmits only the wavelength used by the camera. Through the measurement, the light amount of the LED portion around the sensor portion is raised to lower the amount of light, and if the light amount around the sensor portion to reduce the amount of light emitted from the LED portion can be taken with a constant light amount.

In a preferred embodiment of the present invention, since the face recognition is performed by extracting a predetermined region by adjusting the amount of infrared light, it is not preferable to adjust the number of LEDs that emit light, and the number of LEDs that emit light remains the same. In the present invention, it is preferable to uniformly reduce or increase the amount of current supplied to a plurality of infrared LEDs to control the amount of infrared light emitted. This content is disclosed in Korean Patent Application No. 10-2018-0024639, which is a prior invention of the present invention, the contents of which are incorporated herein in their entirety.

In the present invention, the image sensor unit may extract the recognition data for recognizing the face from the photographed image, signal it and provide it to the controller. In addition, the data for recognizing the iris may be extracted from the separately captured image.

In the practice of the present invention, the image sensor unit may extract the recognition data using a known algorithm for extracting the face recognition data and / or iris recognition data from the image. The extraction algorithm can be purchased commercially.

In the present invention, the controller may compare the extracted data transmitted from the image sensor unit with the extracted data registered as the access permission in the database, and determine whether to permit access. When the entrance is allowed, an open signal is sent to the door, and the door is opened. When the entrance is denied, the door is kept closed without sending an open signal to the door.

According to the present invention, by applying a PIR sensor to the face and / or iris recognition sensor, the automatic access control system or security that can automatically operate the system only when recognizing a human movement, and can solve the problem of manual operation Provide a system.

According to the present invention, when the PIR sensor is not used to recognize a human motion, the infrared LED is continuously operated for converting all the power into standby power and recognizing the face and / or iris, thereby causing excessive heat generation. , Problems of energy consumption, and LED deterioration can be prevented from occurring.

In addition, by applying a bandpass filter of 9.26um to 9.50um that passes only the wavelengths generated at the temperature of 32-40 ℃ (average 36.5 ℃) of human body, it minimizes the interference of non-human objects or other living things. The accuracy of the sensor can be increased.

1 is a view showing an access control system according to the present invention.
Figure 2 shows a Fresnel lens forming a motion detection unit in the entrance control system according to the present invention. (a) Side view of Fresnel lens, (b) Top view of Fresnel lens, (c) Bottom view of Fresnel lens, (d) Real photo of Fresnel lens in bottom direction.
3 is a picture of the PIR sensor of the access control system according to the present invention.
Figure 4 is a side cross-sectional view of the entrance control system motion detection unit according to the present invention.
5 is a view illustrating an image taken by the entrance control system according to the present invention.
6 is a flowchart illustrating a flow of controlling access by the access control system according to the present invention.

Hereinafter, the present invention will be described in detail through examples. It should be noted that the following examples are not intended to limit the invention, but to illustrate the invention.

As shown in FIG. 1, the access control system 10 according to the present invention includes a motion detection sensor unit 100 that detects a motion of an occupant and an infrared ray that emits infrared light by a signal of the motion detection sensor unit 100. An infrared LED unit 200 made of LEDs, an image sensor unit 300 for photographing a face of a person using infrared light emitted from the infrared LED unit, and extracting recognition data of a face and / or iris, and an image sensor The control unit 400 is configured to apply access by comparing the face and / or iris recognition data extracted from the unit with the stored data.

As shown in FIGS. 1 to 6, the motion monitoring sensor unit 100 detects a motion of an occupant and collects infrared rays that are incident, and the Fresnel lens 110. It consists of a band pass filter 120 and the PIR sensor 130 to selectively transmit only the infrared wavelength emitted by the body temperature of the inside of the infrared ray incident through the.

Fresnel lens 110 has a rectangular coupling plate 111 and a hemispherical dome 112 formed in the center of the coupling plate 111. A honeycomb pattern 113 is formed on an outer surface of the hemispherical dome 112, and a convex lens 114 is formed in each section of the pattern on the inner surface of the hemispherical dome 112 to collect infrared light in each section. It is sent to the internal PIR sensor 130. When the object moves, since the amount of infrared light incident on each compartment changes, the PIR sensor 130 may check the operation of the object.

The band pass filter 120 uses a band pass filter having a transmission range of 9.26 um to 9.50 um so that only a wavelength generated at a temperature of 32 to 40 ° C. (average 36.5 ° C.) of the human body can be passed. The band pass filter having the transmission range can be purchased commercially.

The PIR sensor 130 has a cylindrical case 132 having a rectangular window 131 formed at the center of the upper surface. The PIR sensor chip 133 is embedded in the cylindrical case 132. The band pass filter 120 is installed in the rectangular window 131, and the infrared light entering the interior of the Fresnel lens 110 is transmitted to the PIR sensor chip 133 only through the band pass filter 120.

In the PIR sensor chip 133, a minute current is output when the energy radiated from the human body is detected, the current output from the PIR sensor chip is changed into a voltage through the JFET, and the minute voltage is amplified and output through the amplification circuit. The amplifier circuit is composed of conventional elements such as op amps, resistors, and / or capacitors, and is known to those skilled in the art, and detailed descriptions thereof are omitted here.

In the infrared LED unit 200, a plurality of infrared LEDs are arranged on the left and right sides of the image sensor to emit a specific range of infrared wavelengths suitable for the image sensor. The infrared LEDs constituting the infrared LED unit emit infrared rays having a wavelength that can pass through the band pass filter built in the camera 110, that is, a wavelength belonging to a band pass filter wavelength range, and the intensity of light is controlled by the amount of applied current. Use infrared LED bulbs that can be.

The image sensor unit 300 has a built-in band pass filter of 850 ± 50 nm to transmit only an infrared wavelength suitable for photographing, preferably an infrared ray of 800 to 900 nm, and an infrared LED unit 200, which is an infrared ray having a specific wavelength range. Shooting is done using.

In addition, the image sensor unit 300 measures the amount of light that can pass through the band pass filter built in the image sensor unit 300 using the infrared photodiode 310 so that the amount of light suitable for photographing can be used. And, based on this, by controlling the amount of light emitted from the infrared LEDs to shoot.

In the image sensor unit 300, as shown in FIG. 5, the infrared rays of the infrared LEDs of the infrared LED unit 200 may pass through the band pass filter of the image sensor to the face of the person 500. It emits (320), and photographs the image using the infrared light 320 reflected by the entrance 500 and the infrared light included in the ambient light (330). When the image is taken, an image of the face part is obtained from the captured image, and a feature point of the face and / or iris is extracted from the captured face part image and transmitted to the controller 400.

The controller 400 registers the face and / or iris recognition data extracted from the image sensor unit 300, or compares the registered data with the registered data to authenticate the identity to control access.

The access control system 10 according to the present invention operates as follows.

As shown in Figure 6, the human body sensor detects the movement of the person in the PIR sensor. When a person approaches, infrared wavelengths in the range of 9.26 to 9.50um are generated by the temperature of the human body at 32 to 40 ° C (average 36.5 ° C). This infrared wavelength passes through a Fresnel lens, passes through a band pass filter, and reaches the PIR sensor chip. Infrared light collected by the PIR sensor chip changes in each section of the Fresnel lens according to the human motion, and microcurrents are output, which are converted into voltage and then amplified. When a voltage representing human approach is output from the human body sensor PIR, the system of the face / iris recognition sensor, which is in the standby power state, operates.

Firstly, to scan the image of the face, the infrared LED lights up. The ambient light detects the amount of infrared light used for the camera, adjusts the amount of light emitted by the infrared LED, and captures the infrared light optimized for image capturing.

Next, image processing is performed by applying an image of a face photographed by a microcontroller unit to a specific algorithm. The face image after the image processing is compared with the previously registered face. Matches or disagrees with a registered face and applies it to the access control system or security system.

Comparative Example 1

In the embodiment was configured a system excluding the band pass filter for selectively transmitting only the infrared wavelength emitted by the body temperature of the person. When an object of about 50 degrees (summer car exterior temperature) moved in front of the entrance system, the motion sensor was activated, and the system of face / iris recognition sensor, which was in standby power state, was operated.

Comparative Example 2

In the embodiment was configured a system excluding the band pass filter for selectively transmitting only the infrared wavelength emitted by the body temperature of the person. When an object of about 0 degrees (winter car exterior temperature) moved in front of the entrance system, the motion sensor was activated, and the system of face / iris recognition sensor, which was in standby power state, was operated.

100: motion detection sensor unit
200: LED unit
300: image sensor unit
400: control unit

Claims (10)

A motion monitoring sensor unit including a pyroelectric infrared sensor (PIR sensor) and detecting a motion of a person;
An infrared LED unit operated by the motion monitoring sensor unit;
An image sensor unit for photographing by using light emission of the infrared LED unit and obtaining face and / or iris recognition data; And
And a control unit controlling entrance and exit using the face and / or iris body recognition data of the image sensor unit. The method of claim 1,
The motion monitoring sensor unit may include a PlR sensor, a Fresnel lens having a plurality of compartments for condensing light with the PIR sensor, and a filter for selectively filtering a light source generated in the human body from a light source focused at the Fresnel lens. Access control system characterized by. The method of claim 2,
The PIR sensor is an access control system, characterized in that for detecting the movement of the heating object emitting an infrared wavelength of 8 to 14 micrometers to output a current, and amplifies the output current to the amplifier circuit. The method of claim 3,
The PIR sensor includes a PIR sensor chip; A JFET device for changing a current output from the PIR sensor chip into a voltage; And an amplifier circuit including at least one element selected from the group consisting of an op amp, a resistor, and a capacitor, wherein the access control system is built in a case where light is blocked except for a filter installation area. The method of claim 2,
The Fresnel lens has a hemispherical body formed in the center of the rectangular plate, a honeycomb pattern is formed on the outer surface of the hemispherical body, the lens is formed in each compartment of the pattern on the inner surface of the body Access control system, characterized in that to collect the light generated by the area by the light beam to the PIR sensor. The method of claim 2,
The filter is the access control system, characterized in that the bandpass filter for selectively passing the infrared radiation wavelength emitted in the range of 32 ~ 40 ℃. 7. The access control system according to claim 2 or 6, wherein the band pass filter has a pass range of 9.2 to 9.5 micrometers. The method of claim 2, wherein the motion sensor unit
A hemispherical body is formed in the center of the rectangular plate, a honeycomb pattern is formed on the outer surface of the hemispherical body, and a lens is formed for each section of the pattern on the inner surface of the body to receive light generated in each compartment. A fresnel lens for condensing;
A PIR sensor chip located below the Fresnel lens; A JFET device for changing a current output from the PIR sensor chip into a voltage; A PIR sensor comprising an amplifier circuit including at least one element selected from the group consisting of an op amp, a resistor, and a capacitor, wherein the light is blocked except for a filter installation region; And
And a band pass filter installed in the filter installation area of the PIR sensor and selectively transmitting only the radiation wavelength emitted from the human body from the light source flowing from the Fresnel lens to the PIR sensor. The method according to claim 1 or 2,
The amount of infrared light emitted from the LED unit is controlled according to the amount of infrared light of the camera wavelength range in the ambient light of the image sensor unit. Recognizing an approach of a human body in a motion monitoring sensor unit including a pyroelectric infrared sensor;
Operating the infrared LED unit by a recognition signal to approach the human body;
Photographing using infrared light of the infrared LED unit;
Extracting face and / or iris recognition data from the captured image; And
Granting access using the extracted data;
Access control method including

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