KR102529805B1 - Face Recognition System unaffected disturbing light - Google Patents

Abstract

The present invention includes a camera for photographing a user's face, a storage unit in which a plurality of polarization filters are stored, at least one illuminance sensor for detecting an illuminance environment of a place where the face recognition system is installed, and a front end of the camera. Selecting at least one or more of a plurality of polarization filters stored in the storage unit based on a filter mounting portion installed in the housing to which at least one polarization filter is mounted and an illumination environment sensed by the illuminance sensor and inserting the filter into the filter mounting unit and a filter selector to be fixed, wherein the illuminance sensor is fixedly installed on the front upper part of the face recognition system, and is selectively attached to the front lower part, side surface, lower surface, and rear surface according to the installation location of the face recognition system. The polarization filter is a face recognition system robust against external light, characterized in that it has a polarization element in the center and is a protective layer attached to the upper and lower surfaces of the polarization element and an adhesive, a reflector and a surface-treated circular polarization filter on top of the protective layer. can provide.

Description

Face Recognition System unaffected disturbing light}

The present invention relates to a face recognition system that is robust against ambient light.

The external light referred to in the face recognition system is a general term for light incident from a light source to the camera in a forward direction, light incident from a light source reflected by a reflector and entering the camera, and light scattered from the same reflector.

As specific examples of disturbance light, it is classified into DC disturbance light of sunlight or incandescent lamp and AC disturbance light of inverter fluorescent lamp or LED lighting. In particular, when DC disturbance light is incident on the camera, the photoelectric sensor rises to the saturation voltage level, causing serious noise in the camera image.

Since AC disturbance light has a frequency component similar to the self-emission period required for detection by the photoelectric sensor, white burnout occurs in the camera image.

Therefore, in order to develop a face recognition system that is robust against ambient light, it is essential to understand the characteristics of light and to secure countermeasures under conditions of various types of light sources such as illuminance, luminous intensity, incident angle, and scattered light.

KR 10-887183 B1

The present invention provides a face recognition system robust against ambient light that can efficiently cope with ambient light that frequently occurs in operation of the face recognition system exposed to various environments.

In addition, the present invention minimizes the interference of external light by using polarization used in LCD and OLED and a wide range of applications, and at the same time, automatic attachment and detachment of the polarization filter by reflecting critical conditions such as whether or not the polarization filter is involved according to various lighting conditions Alternatively, a face recognition system robust against external light capable of being manually attached or detached is provided.

In order to achieve the above object to be solved, a face recognition system robust against external light according to an embodiment of the present invention includes a camera for photographing a user's face, a storage unit in which a plurality of polarization filters are stored, and the face recognition At least one illuminance sensor for detecting the illuminance environment of the place where the system is installed, a filter mounting portion installed at the front end of the camera and having at least one polarization filter attached thereto, and based on the illuminance environment sensed by the illuminance sensor and a filter selection unit for selecting at least one polarization filter from among a plurality of polarization filters stored in the storage unit and inserting and fixing the polarization filter into the filter mounting unit, wherein the illuminance sensor is fixedly installed on an upper front portion of the face recognition system, and the face recognition Depending on the installation location of the system, it is selectively attached to the front lower part, side surface, and rear surface, and the polarization filter has a polarizing element in the center, a protective layer attached to the upper and lower surfaces of the polarizing element, and an adhesive on top of the protective layer. , a reflector and a surface-treated circular polarization filter.
According to an embodiment of the present invention, the face recognition system manages a table in which storage position information of the polarization filter stored in the storage unit is stored, and the filter selection unit corresponds to the illumination environment sensed by the illumination sensor. After retrieving storage position information of the polarization filter from the table, one polarization filter may be selected in the storage unit based on this search.

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According to the above-described embodiments of the present invention, the installation site of the face recognition system is a place vulnerable to ambient light, and if it is affected by it, the face recognition that can automatically mount/detach the selective polarization filter according to time or can be mounted at all times. By providing the system, a decrease in face recognition rate due to ambient light can be prevented.

1 is a diagram showing the configuration of a face recognition system robust against ambient light according to an embodiment of the present invention.
2 is a diagram for explaining the structure of a polarization filter applied to a face recognition system according to an embodiment of the present invention.
3 to 5 are diagrams for explaining a structure and method for mounting an illuminance sensor in a face recognition system according to an embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The detailed descriptions that follow are provided to provide a comprehensive understanding of the methods, devices and/or systems described herein. However, this is only an example and the present invention is not limited thereto.

In describing the embodiments of the present invention, if it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or operator. Therefore, the definition should be made based on the contents throughout this specification. Terminology used in the detailed description is only for describing the embodiments of the present invention and should in no way be limiting.

Hereinafter, a face recognition system robust against external light according to an embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a diagram showing the configuration of a face recognition system robust against external light according to an embodiment of the present invention, and FIG. 2 describes the structure of a polarization filter to be applied to the face recognition system robust against external light according to an embodiment of the present invention. 3 to 5 are diagrams for explaining a structure and method for mounting an illuminance sensor in a face recognition system according to an embodiment of the present invention.

As shown in FIGS. 1 to 5 , the face recognition system 100 according to an embodiment of the present invention includes a storage unit 110 in which a plurality of polarization filters 112 are stored, and a plurality of storage units 110 stored therein. A filter selection unit 122 for selecting at least one of the polarization filters 112 of the camera 50 and inserting and mounting the filter mounting unit 120 installed at the front end of the camera 50, a memory 124 in which a table is stored, and the like may be included. there is.
Here, storage position information in which the polarization filter 112 to be applied according to the illuminance environment is stored may be set in the table. Through this, the filter selection unit 122 of the face recognition system 100 detects the illuminance environment using the illuminance sensor 130, searches for storage location information in the table based on this, and searches storage location information corresponding to the searched storage location information. By pulling out the polarization filter 112 from the accommodating unit 110 and inserting and mounting the polarization filter 112 in the filter mounting unit 120 , the face recognition system 100 minimizing the influence of ambient light can be implemented.

The polarization filter 112 to be applied to the face recognition system 100 according to an embodiment of the present invention may be manufactured using an anti-reflective adhesive polarizing film. Specifically, as shown in FIG. 2, the polarization filter 112 has a three-layer structure, a polarization element (PVA: Poly Vynyl Alcohol) 112a is located in the center, and the upper and lower surfaces of the polarization element 112a Protection layers (TAC: Tri Acetyl Cellulose) 112b and 112c may be stacked, respectively.
In addition, an adhesive, a reflector, surface treatment, and the like may be added to the protective layer of the polarization filter 112 .
In an embodiment of the present invention, a circular polarization filter having no directivity may be used as the polarization filter 112 according to the experiment below.

Prior to the experiment, a circular polarization filter and a linear polarization filter are prepared. Circular polarization filters do not have directionality, but since linear polarization filters have directionality, it is necessary to identify and direct the attachment surface of the film.

Prepare a laboratory glass slide to which the film will be attached. Select glass slides that are positively charged and uncoated to improve adhesion. If the thickness of the slide is not constant due to the chromatic aberration of the glass, an error may occur in the experimental data due to the error caused by the chromatic aberration. Therefore, in order to reduce errors caused by chromatic aberration, the thickness should be set to about 0.1 to 0.2 mm as a standard.

A polarizing film is attached to the slide. Linear polarization and circular polarization are attached to the slide according to each specification, and a circular polarization filter of 20 to 50 nanometers and a linear polarization filter of 20 to 50 nanometers are selected.

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In the experiment for the method of overcoming disturbance light using the polarization filter 112, the main part is to prepare a polarization filter suitable for specifications and to prepare an illumination system that reproduces disturbance light. In order to implement a lighting system for reproducing external light, a laboratory consisting of four light sources, a precursor light source, a face recognition system 100, and scales for distance measurement (100, 150, 200) is configured as ambient light reproduction lighting, and the laboratory Through this, the experiment is conducted according to the following experimental method.

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The experiment method is to investigate the recognition rate by being closer to the camera 50 for face recognition by 50 cm at an initial distance of 200 cm. Face recognition is performed three times in each condition, and the face recognition score for each implementation is recorded.

Therefore, after the recognition experiment is performed three times without the polarization filter 112 attached, the recognition experiment is performed three times with the polarization filter 112 attached. For the experiment, the disturbance light is reproduced, and the illuminance value for each disturbance light is measured and recorded. When the roughness value is recorded, the experiment is conducted by the following procedure.

Prior to this experiment, the illuminance measurement for each of 15 lighting conditions is preceded before the experiment is conducted. The measured illuminance values are shown in the table below.

[Table 1]

Although the previous experiment was repeated with the polarization filter 112 installed, the advantages and disadvantages of the linear polarization filter and the circular polarization filter were sought in the previous experiment. In the case of a circular polarization filter, it does not have directionality, but since there is a distinction between front and back, it can be seen that the filtering effect is different depending on the division before and after.

The linear polarization filter is divided into a horizontal filter and a vertical filter, and when these two filters are overlapped, it is possible to completely block light by adjusting the angle. The advantage of the linear polarization filter is that if the direction is set at right angles to the incident angle of the disturbance light, it can completely block the disturbance light, but the disturbance light can have various incident angles and has the variability that the incident angle can change from time to time, so a single filter cannot operate. difficult. Therefore, it was found that if the angle is finely adjusted by overlapping the two filters, the external light blocking is effective, but the versatility cannot be secured, and it is difficult to automatically perform the fine angle adjustment.

Therefore, in the embodiment of the present invention, a face recognition system 100 that is robust against external light was implemented using a circular polarization filter, and experiments were conducted through this.
The experimental data according to the experimental results are shown in Table 2 below.
[Table 2]

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In Table 2, 100 N/F means a distance of 100 cm (1 meter), No Filter, that is, no polarization filter is installed. And 100 F/S means 100cm (1 meter), Filter Setup, that is, the polarization filter is installed. The numbers represent recognition attempts and recognition scores. Since the recognition threshold is 65 points, a score less than 65 is regarded as a recognition failure.

Recognition experiments were conducted 3 times under 15 lighting conditions at each distance and whether or not the filter was installed. For example, 100 N/F light 1: 94, 92, 91 to 94, 92, 91 is the recognition score three times. Over 65 points, recognition is successful, but 100 N/F light 15: 53, 57, 55 is 3 Since all of the turns are less than 65 points, they are all examples of failed recognition.

Recognition failed all three times under the lighting condition of 15 times without a polarizing filter at a distance of 100 N/F, that is, at a distance of 1 meter, but under the same lighting condition with a polarizing filter installed at a distance of 1 meter at a distance of 100 S/F, recognition failed three times. all succeeded

Under the conditions of 150 N/F, that is, 1.5 meters apart and no polarizing filter, recognition failed under lighting conditions 10, 12, 13, and 15, but under 150 F/S conditions, 1.5 meters apart, and polarizing filters. In the installation condition, recognition was successful in all lighting conditions.

In the condition of 200 N/F, that is, no polarizing filter at a distance of 2 meters, recognition failed under lighting conditions of 10, 12, 13, and 15, but under the condition of 200 F/S, 2 meters apart, and a polarizing filter In the installation condition, recognition was successful in all lighting conditions.

In conclusion, it can be seen that the recognition rate is superior in a state where the polarization filter 112 is not mounted in most lighting conditions at a short distance within 1 meter. However, under the lighting condition of No. 15, that is, under the condition that both left 1 and 2 (light 1-1 and light 1-2) and right 1 and 2 (light 2-1 and light 2-2) are ON, the polarization filter 112 It was recognized when installed.

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Separately, it can be seen that as the distance from the recognition device increases, that is, 1.5 meters or 2 meters or more, the recognition score is higher when the polarization filter is installed.

As shown in FIGS. 3 to 5 , the face recognition system 100 according to an embodiment of the present invention further includes a plurality of illuminance sensors 130 for sensing the illuminance environment of the place where the face recognition system 100 is installed. can be provided Specifically, the face recognition system 100 may have the illuminance sensor 130 attached to the top, bottom, bottom, rear, and side surfaces of the front.
In particular, the face recognition system 100 according to an embodiment of the present invention has installation terminals 130a to which the illuminance sensor 130 can be attached or detached to the lower part, lower surface, rear surface, and side surface of the front, and the installation terminal 130a Through this, the illuminance sensor 130 can be attached or detached.
That is, depending on the installation location of the face recognition system 100, that is, the ambient light, the illuminance sensor 130 can be selectively installed. That is, the face recognition system 100 has two illuminance sensors 130 on the upper part of the front ) is fixedly installed, and an installation terminal 130a into which the illuminance sensor 130 can be plugged in is provided at the upper and lower ends of the rear portion, and three installation terminals 130a are provided on the side portion, Two installation terminals 130a may be provided on the lower surface.
In addition, the face recognition system 100 may be provided with two installation terminals 130a to which the illuminance sensor 130 may be mounted at the lower front portion.
Through this structure, the face recognition system 100 according to an embodiment of the present invention detects an illuminance environment through a plurality of illuminance sensors 130, selects one of a plurality of polarization filters 112 according to the illuminance environment, and filters the filter. By attaching it to the mounting unit 120, the effect of ambient light can be minimized and the face recognition rate can be increased.

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The above description of the present application is for illustrative purposes, and those skilled in the art will understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present application. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts thereof should be construed as being included in the scope of the present application. .

50: camera
100: face recognition system
110: storage unit
112: polarization filter
120: filter mounting part
122: filter selection unit
124: memory
130: illuminance sensor
130a: installation terminal

Claims (2)

A face recognition system for recognizing a face,
A camera for photographing a user's face;
A storage unit in which a plurality of polarization filters are stored;
at least one illuminance sensor for detecting an illuminance environment of a place where the face recognition system is installed;
a filter mounting portion installed at a front end of the camera and having at least one polarization filter mounted thereon;
a table in which storage position information of the polarization filter stored in the storage unit to be applied according to the illuminance environment is stored;
Based on the illuminance environment sensed by the illuminance sensor, select at least one or more of the plurality of polarization filters stored in the accommodating unit and insert and fix them into the filter mounting portion, corresponding to the illuminance environment sensed by the illuminance sensor. a filter selection unit for searching storage position information of the polarization filter in the table and then selecting a polarization filter in the storage unit based on the retrieved information;
Installation terminals to which illuminance sensors can be installed on the upper and lower ends of the rear face of the face recognition system, installation terminals to which three illuminance sensors can be mounted on the side of the face recognition system, and two illuminance sensors on the lower surface It has an installation terminal that can be mounted,
The illuminance sensor is fixedly installed on the front upper part of the face recognition system, and is detachable from installation terminals provided on the upper and lower parts of the rear part and the side and lower parts according to the installation location of the face recognition system,
The polarization filter is a circular polarization filter having a polarization element in a central portion, a protective layer attached to upper and lower surfaces of the polarization element, and an adhesive, a reflector, and a surface treatment on the upper part of the protective layer. system. delete

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