KR102160940B1 - 3-Dimensional Facial Recognition System Using Hologram - Google Patents

Abstract

The present invention relates to a three-dimensional facial recognition system using a hologram, and by obtaining a holographic image of a user's face in natural light to perform a facial recognition function, a separate light-emitting unit that irradiates light to the user's face A hologram that can enhance accuracy and security by enabling the system to be configured without any glare or discomfort in use, simplifying and miniaturizing the system configuration, and recognizing a three-dimensional face through a holographic image. It provides a 3D facial recognition system using

Description

3-Dimensional Facial Recognition System Using Hologram}

The present invention relates to a three-dimensional face recognition system using a hologram. In more detail, by acquiring a holographic image of the user's face in natural light to perform the facial recognition function, the system can be configured without a separate light emitting unit that irradiates light to the user's face. The present invention relates to a three-dimensional face recognition system using a hologram that can remove discomfort, simplify and miniaturize a system configuration, and enhance accuracy and security by enabling three-dimensional face recognition through a holographic image.

Recently, 3D 3D imaging technology is expected to have a significant impact as it is widely used in almost all industries such as film, broadcasting, entertainment, aerospace, military, and medical care. Not only is it being talked about in the community, but it is emerging as a national issue related to future research and development.

The 3D stereoscopic image providing technology is largely divided into a glasses-wearing method and a no-glasses method that provides different images to the left and right eyes to feel the depth due to the parallax, and the glasses-wearing method can be further divided into polarized glasses and shuttle glasses. The glasses-free method is a parallax direct image (lenticular, parallax barrier, parallax illumination) that shows different images to the viewer's left and right eyes, like the glasses wearing method, and a cross section of an object to actually create a 3D image in space. There are a volumetric method for continuously reproducing an image, and a holographic method for recording and reproducing wavefront information of a 3D object.

The binocular parallax type 3D image providing technology has fundamental problems such as headache and dizziness for humans, unlike natural 3D images for several reasons. These are all three-dimensional image shooting and display device settings that do not take sufficient consideration of image alignment, optical distortion, three-dimensional effect adjustment, and emotional aspects, flicker phenomenon that occurs when alternately spraying left and right images, and This is caused by distortion of the 3D image itself due to excessive protrusion effect generation.

Holography technology is a method that can fundamentally solve the inconvenience of viewing stereoscopic 3D images caused by the problem of the binocular parallax method. In general, humans perceive a three-dimensional object due to the light hitting the object. If only the light of this object can be generated, it will be possible to reproduce the actual shape of the object. The hologram realizes this, and it uses laser light to make the object wave reflected from the object meet with the laser light from another direction and record it together on a photographic film. At this time, when the two directions of light meet, an interference pattern according to the phase difference of the object wave reflected from each division of the object is generated, and the amplitude and phase of the object are recorded in this interference pattern. A photographic film in which the shape of an object is recorded in the form of an interference pattern is called a hologram. In other words, a hologram is a three-dimensional image recorded on a surface similar to a photographic film by using the interference effect of light caused by two laser beams meeting each other.

Unlike general photography techniques that record only light intensity information, holography acquires and records amplitude and phase information of light propagated from an object. Until now, since there is no sensor capable of directly recording the amplitude and phase information of visible light, related information is acquired indirectly through light interference when acquiring the amplitude and phase information of visible light. Interference is a phenomenon in which two light waves of object light and reference light interact. However, it is difficult to obtain interference fringes unless a laser, which is artificially aligned in amplitude and phase, is difficult to obtain. Thus, lasers were mainly used in holography technology until recently.

However, in the case of using such a laser, it is necessary to block all light other than the laser, so that the hologram cannot be recorded and recorded in an external environment. In order to solve this practical problem, a self-interference method of holography technology has been developed.

In the self-interference holography, interference fringes are obtained by a self-referencing method that divides incident light emitted or reflected from an object according to spatial or polarization state. The divided light waves are modulated into wavefronts with different curvatures under the influence of an interferometer or polarization modulator, and propagate, forming an interference fringe on the image sensor. The interference at this time is free from the conditions of the light source because the twin light waves originating from the light originating from the same time and space occur. Therefore, it is possible to shoot in fluorescent, light bulb, LED, or natural light conditions.

The concept of such self-interference holography technology has been established, but a system that actually implements it has not yet been developed, and it is not applied to actual products, such as applying a complex optical system to separate incident light to form interference fringes. It is not possible.

In the case of holography technology in which all optical parts are aligned on one axis, it has the advantage that the resolution or area of the image sensor can be used as a hologram, but according to the interference formula, in addition to the hologram information of the object, the information of the light source and the twin image of the object ( There is a disadvantage that twin-image) information is recorded together. In order to remove such light source and twin image information from the obtained hologram information, a phase shifting technique is used. If the optical path of the object light or reference light is finely adjusted in 2 to 4 steps by a length less than the wavelength, the phase information is slightly shifted, and the light intensity information is measured at each step and then calculated, the light source and twin image information are converted. The removed complex hologram can be obtained. In the four-step phase shift system, a complex hologram is obtained as shown in Equation 1. In Equation 1, (x,y) is the coordinates of the image sensor surface, I is the image that has been phase-shifted, and Φ is a complex hologram.

Various phase shift systems are being tried for phase shift in holography technology, for example, using equipment that can finely move the mirror of the interferometer in nano units, such as a piezo-actuator, or a spatial light modulator capable of phase modulation. A way to use is being tried. However, these equipments are very expensive and have disadvantages of being sensitive to external environments such as temperature, humidity and vibration, and since they directly modulate the optical path, complete modulation of the phase from 0 to 360 degrees is possible only in a specific wavelength range. There is a disadvantage in that the phase shift error increases as the distance from a specific wavelength increases.

This phase shift system is applied in a manner that sequentially changes the phase of light, and in the above-described four-step phase shift system, one complex hologram has to be obtained by combining the four pieces of information phase shifted in each step. It takes 4 phases of phase shift time to obtain a hologram, and therefore, a hologram for a stationary object can be obtained, but a hologram cannot be obtained for a moving object. In other words, there is a fundamental problem that it is impossible to shoot holographic videos.

On the other hand, recently, with the development of communication and imaging technology, a system using facial recognition is being used for security systems, etc., and the conventional facial recognition system uses a dot projector that projects dot light of a dot pattern onto the user's face. And, when dot light is scattered on the face, the shape is recorded with a camera and used for facial recognition, or three-dimensional information on the face is detected using a TOF (Time of Flight) camera.At this time, light with a short pulse must be continuously emitted. do.

Such a facial recognition system has a light-emitting unit and a light-receiving unit. The light-emitting unit has a problem that the structure is complicated and the manufacturing cost is increased in order to transmit a specific pattern or signal. There are problems such as feeling uncomfortable.

Domestic registered patent No. 10-1467672

The present invention was invented to solve the problems of the prior art, and an object of the present invention is to obtain a holographic image of the user's face in natural light to perform a facial recognition function, thereby irradiating light on the user's face. Since the system can be configured without a separate light emitting unit, glare or inconvenience in use can be eliminated, the system configuration can be simplified and miniaturized, and three-dimensional face recognition is possible through a holographic image for accuracy and security. It is to provide a three-dimensional face recognition system using holograms that can enhance

Another object of the present invention is to obtain a holographic image through infrared light reflected from the user's face by adding a separate infrared light emitting unit, and obtain a general photographed image through visible light, thereby simultaneously providing a general camera function and a face recognition function. It is to provide a three-dimensional face recognition system using a hologram capable of enhancing the accuracy and security of a face recognition function by combining images of these.

The present invention includes a geometric phase lens that is arranged to pass incident light propagating from a user's face portion to change the incident light into left and right polarized light, and a left circularly polarized light receiving the changed left and right circularly polarized light through the geometrical phase lens. And an image sensor for obtaining an interference fringe generated by interference of right-circular polarization, and a self-interference digital holographic unit for acquiring facial hologram data on a user's face by using the interference fringe obtained by the image sensor. And a data determination unit that compares the facial hologram data acquired by the self-interfering digital holographic unit with separate reference hologram data to determine whether they match. It provides a three-dimensional face recognition system using a hologram.

In this case, the 3D facial recognition system using the hologram further includes an infrared light emitting unit capable of irradiating infrared light to the user's face, and the incident light incident on the geometric phase lens of the self-interfering digital holographic unit is It may be infrared light reflected from the facial area.

In addition, the 3D facial recognition system using the hologram further includes an optical splitter capable of separating visible light and infrared light propagating from the user's face portion, and the infrared light separated by the optical splitter is the geometric phase lens. It can be configured to be incident on.

In addition, the 3D facial recognition system using the hologram may further include a visible light image sensor that receives visible light separated by the optical separator.

In addition, an incident lens for condensing incident light propagating from a user's face may be disposed in front of the optical separator.

In addition, the self-interference digital holographic unit, in the process of receiving the left circular polarization and the right circular polarization changed through the geometric phase lens by the image sensor, the left circular polarized light and the right circular polarized light are changed into two linear polarized light to the image sensor. Further comprising a spatially divided phase shifting means disposed in front of the image sensor to receive light, and configured to receive linearly polarized light having a different phase for each of a plurality of divided areas of the light receiving area of the image sensor, and each divided area Interference fringes generated by linearly polarized light of different phases may be simultaneously acquired by the image sensor and combined to obtain one facial hologram data.

In addition, the spatially divided phase shifting means includes a micro polarizing plate array attached to a front surface of the image sensor, and the micro polarizing plate array includes a plurality of fine polarizing plates for converting transmitted light into linearly polarized light. It may be formed in a form arranged to correspond to each.

Further, the divided regions of the image sensor may be formed to correspond to pixels of the image sensor.

In addition, the light transmission axes of each of the fine polarizing plates may be formed to have different angles, so that linearly polarized light passing through each of the fine polarizing plates may have different phases.

In addition, the light transmission axis angles of the plurality of fine polarizing plates may be formed to have any one of four different types of light transmission axis angles sequentially changing by a 45° angle difference.

According to the present invention, by acquiring a holographic image of the user's face in natural light to perform a facial recognition function, the system can be configured without a separate light emitting unit that irradiates light to the user's face, thereby making the user's face dazzle. It is possible to remove the discomfort or inconvenience, simplify and miniaturize the system configuration, and enhance accuracy and security by enabling a three-dimensional face recognition through a holographic image.

In addition, by adding a separate infrared light emitting unit, a hologram image can be obtained through infrared light reflected from the user's face, and a general photographed image can be obtained through visible light, so that a general camera function and a face recognition function can be performed simultaneously. , There is an effect of enhancing the accuracy and security of the facial recognition function by combining these images.

1 and 2 are views exemplarily showing a usage aspect of a three-dimensional facial recognition system using a hologram according to an embodiment of the present invention;
3 is a conceptual diagram conceptually showing the basic configuration of a self-interference digital holographic unit according to an embodiment of the present invention;
4 is a diagram for explaining characteristics of a geometric phase lens according to an embodiment of the present invention;
5 is a conceptual diagram conceptually showing the configuration of a self-interference digital holographic unit to which a spatial division phase shifting means is applied according to an embodiment of the present invention;
6 is a diagram illustrating a detailed configuration of a self-interference digital holographic unit according to an embodiment of the present invention;
7 is a functional block diagram functionally showing the configuration of a 3D facial recognition system using a hologram according to an embodiment of the present invention;
8 is a conceptual diagram showing a configuration of a 3D facial recognition system using a hologram according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to elements of each drawing, it should be noted that the same elements are assigned the same numerals as possible even if they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the subject matter of the present invention, a detailed description thereof will be omitted.

1 and 2 are views exemplarily showing a usage aspect of a 3D facial recognition system using a hologram according to an embodiment of the present invention.

The 3D face recognition system 30 using a hologram according to an embodiment of the present invention is a system for recognizing a user's face, and is mounted on a smart phone 31 as shown in FIG. 1 to recognize the user's face. And, it can be used for purposes such as checking whether a registered user exists. In addition, as shown in FIG. 2, it is mounted in a vehicle interior to recognize the driver's face, and may be used for purposes such as tracking the driver's pupils to prevent the driver's drowsy driving.

Of course, it may be applied to various other devices, for example, an entrance door, and used as a system for recognizing a user's face.

Unlike the prior art, the three-dimensional facial recognition system 30 using such a hologram acquires a holographic image through natural light or infrared light, and not a separate dot light or TOF method, and uses the acquired holographic image for the user's face. To enable 3D recognition, the self-interference digital holographic unit 40 that acquires facial holographic data on the user's face and the facial holographic data acquired through the self-interference digital holographic unit 40 are separately It is configured to include a data determination unit 800 that compares the reference hologram data.

3 is a conceptual diagram conceptually showing the basic configuration of a self-interfering digital holographic unit according to an embodiment of the present invention, and FIG. 4 is a view for explaining the characteristics of a geometric phase lens according to an embodiment of the present invention. 5 is a conceptual diagram conceptually showing the configuration of a self-interfering digital holographic unit to which a spatial division phase shifting means is applied according to an embodiment of the present invention, and FIG. 6 is a self-interfering digital holographic unit according to an embodiment of the present invention. It is a diagram showing a detailed configuration of a graphic unit by way of example.

The self-interference digital holographic unit according to an embodiment of the present invention is a structure that generates and acquires an interference fringe by generating an interference fringe in a self-interference method of incident light propagating from a target object, and is arranged to pass incident light so that the incident light is converted into left and right It may be configured to include a geometrical phase lens 100 to change, and an image sensor 200 that receives the changed left and right circularly polarized light through the geometrical phase lens 100.

In addition, it is configured to further include a spatially divided phase shifting means 700 for changing the left circular polarized light and the right circular polarized light changed through the geometrical phase lens 100 into linear polarized light to be received by the image sensor 200.

First, explaining the principle of a basic self-interference digital holographic unit without the spatial division phase shifting means 700, as shown in FIG. 3, the incident light is left circularly polarized in the process of passing through the geometric phase lens 100. And the right circular polarized light, and an interference fringe is generated by the interference of the changed left circular polarized light and the right circular polarized light. This interference fringe is generated on the image sensor 200 and is obtained by the image sensor 200.

Looking at the geometric phase lens 100 in more detail, the geometric phase lens (Geometric Phase Lens) is a device that functions as a lens by maintaining a specific fixed arrangement of liquid crystals. A typical lens modulates the wavefront of incident light by adjusting the thickness of a medium with different refractive indices to perform dynamic phase modulation to converge or diverge, but a geometrical phase lens is a polarization of light according to the birefringence characteristics of liquid crystals. The difference is that a phase change occurs due to a state change, and accordingly, the wavefront of the incident light is modulated. Since a holographic photographing technique is used when manufacturing a geometric phase lens, a twin-image of the lens surface to be recorded is recorded together, and thus, the lens characteristics have both negative and positive focal lengths.

Such a geometrical phase lens acts as an independent passive optical element because it is permanently oriented according to the alignment layer formed while the photosensitive polymer is cured without the need to electrically move the liquid crystal element. It has the advantage of being very transparent, thin, and easy to manufacture.

In addition, since there is polarization selectivity, when incident light is right circularly polarized, it is changed to left circularly polarized light and converged according to a positive focal length, and when incident light is left circularly polarized, it is changed to right circularly polarized light and radiates according to a negative focal length. When linearly polarized or unpolarized light enters, the energy is divided into half and converges and diverges. At this time, the converging light becomes left-circular polarized light and the divergent light becomes right-circular polarized light.

For reference, circular polarization means that the vibration direction of the electric displacement vector (or magnetic field displacement vector) of the light wave is circular vibration, and the linear polarization is a vibration surface inclined 45° to the main axis of the 1/4 wave plate. The light that passes through the 1/4 wave plate is circularly polarized light when incident with it. Circularly polarized light in which the electric vector of light rotates clockwise when viewed from the observer is called right circularly polarized light, and circularly polarized light that rotates counterclockwise is called left circularly polarized light.

As shown in (a) of FIG. 4, when the right circularly polarized light L2 is incident, the focal point f1 has a positive focal length X1 and is converted to the left circularly polarized light L1, and passes through the geometric phase lens 200. And condensed to the focal point f1. On the other hand, as shown in (b) of FIG. 4, when the left circularly polarized light L1 is incident, the focal point f2 has a negative focal length X1 and is converted to the right circularly polarized light L2, and the geometric phase lens 200 It diverges along a path extending from the focal point f2 through. As shown in (c) of FIG. 4, when linearly polarized or unpolarized light (L) is incident, the energy is divided in half, and some have a positive focal point (f1) and converted into left-circular polarized light (L1). Converge, some have a negative focal point (f2) and are converted to right-circular polarization (L2) and diverge.

Accordingly, the incident light emitted or reflected from the target object 10 passes through the geometric phase lens 100 and is changed into left-circular polarized light and right-circular polarized light. Generated, and the interference fringe is generated on the image sensor 200 and obtained by the image sensor 200.

The self-interference holography unit according to the present invention may obtain information on incident light through information on interference fringes obtained by the image sensor 200. That is, a holographic image may be obtained through the interference fringe acquired by the image sensor 200.

The obtained holographic image may be displayed through a separate hologram display device, and the hologram display device may be applied in various ways.

Meanwhile, as discussed in the background technology, in the case of such a holography technology, information on a light source and twin-image information of an object are recorded together in the image sensor 200 that acquires a holographic image through an interference fringe. Will act as. Therefore, a phase shifting means is provided in order to remove such light source and twin image information from the holographic image. Since the phase shifting means, which is generally studied, is configured in a manner that changes the phase of light in time order, moving objects There is a fundamental problem that filming is impossible.

In an embodiment of the present invention, a space division phase shifting means 700 using a space division method as a phase shifting means is provided.

The spatially divided phase shifting means 700 changes the left circular polarized light and the right circular polarized light into two linear polarized light while the left circular polarized light and the right circular polarized light changed through the geometrical phase lens 100 are received by the image sensor 200. It is disposed in front of the image sensor 200 so that light is received by 200. In this case, the spatially divided phase shifting means 700 is formed so that linearly polarized light having a different phase is received for each divided area obtained by dividing the light receiving area of the image sensor 200 into a plurality of pieces.

In more detail, the spatially divided phase shifting means 700 may include a micro polarizing plate array 710 attached to the front surface of the image sensor 200, and the micro polarizing plate array 710 linearly polarizes transmitted light. A plurality of fine polarizing plates 711 to be converted into are formed in a form in which they are arranged to correspond to a plurality of divided regions of the image sensor 200.

For example, the image sensor 200 has a plurality of pixels, and a divided area for the image sensor 200 may be formed in units of such pixels, and the fine polarizing plate 711 is applied to the pixels of the image sensor 200. Each of the pixels of the image sensor 200 may be formed correspondingly and attached to the front surface of the image sensor 200 in the same arrangement structure as the pixels of the image sensor 200.

The fine polarizing plate 711 is formed in the form of a polarizing plate that converts transmitted light into linearly polarized light. In this case, the fine polarizing plate 711 is formed so that the phase of the linearly polarized light converted through the fine polarizing plate 711 is different for each fine polarizing plate 711. ) Of the light transmission axes a1, a2, a3, and a4 are formed to have different angles.

For example, the angles of the light transmission axes (a1, a2, a3, a4) of the fine polarizing plate 711 are four different types of light transmission axis angles sequentially changing by a 45° angle difference as shown in FIG. 6. It may be formed to have any one of, and through this, the linearly polarized light converted through each of the fine polarizing plates 711 has a phase difference of 45° according to the angle of the light transmission axes a1, a2, a3, and a4. In this case, it is preferable that the number of fine polarizing plates 711 having different types of light transmission axis angles is the same for each type of light transmission axis angle.

According to this configuration, incident light propagating from the target object 10 passes through the geometric phase lens 100 and is changed into left and right polarized light, and the changed left and right polarized light is received by the image sensor 200. It passes through the fine polarizing plate 711 disposed to correspond to the divided area of the image sensor 200, changes into two linearly polarized light, and is received by the image sensor 200 in a linearly polarized state. In this case, an interference fringe is generated by the interference of two linearly polarized light converted from the left circularly polarized light and the right circularly polarized light, and the generated interference fringe is obtained by the image sensor 200. The interference fringes caused by these two linearly polarized light are formed for each of a plurality of fine polarizing plates 711, and each fine polarizing plate 711 has different angles of the light transmission axes a1, a2, a3, and a4 so that the phase of linearly polarized light is As a result, it is possible to simultaneously obtain interference fringes caused by linearly polarized light with four phase shifts.

In other words, in the process of obtaining a holographic image through the interference fringes, a plurality of interference fringes having different phases are generated and acquired by using a phase shifting means to remove noise, and a general phase shifting means changes the phase according to the time order. Whereas it is configured in a changing manner, in an embodiment of the present invention, a plurality of interference fringes having a phase-changed phase may be simultaneously obtained in an embodiment of the present invention.

As described above, interference fringes caused by a plurality of phase-shifted linearly polarized light are simultaneously acquired, and a single complex hologram may be obtained by performing a combination operation.

Therefore, the self-interference digital holographic unit according to an embodiment of the present invention does not sequentially acquire interference fringes caused by phase-shifted linearly polarized light in a time sequence, but simultaneously acquires the interference fringes in a spatially-divided manner. One complex hologram can be obtained. In addition, since multiple phase-shifted interference fringes can be simultaneously acquired with only one recording, holographic videos such as moving objects and objects that change over time, such as living organisms, can be captured in addition to static objects.

In addition, it is possible to obtain an interference fringe for incident light by using a geometric phase lens, which is a simple optical component, and through this, a holographic image can be obtained. It is easy to manufacture, low cost, and can be manufactured in a form that can be miniaturized. Can be expanded in various ways.

In particular, since the fine polarizing plate 711 is applied as the spatially divided phase shifting means 700 and attached to the front of the image sensor 200, a separate optical path for phase shifting is unnecessary, making the entire system more compact. Do.

Meanwhile, a fixed polarizing plate 600 for converting incident light into linearly polarized light may be disposed in front of the geometrical phase lens 100 so that the incident light passes before it is incident on the geometrical phase lens 100.

Even without such a fixed polarizing plate 600, a plurality of phase-shifted interference fringes can be obtained as described above, but by converting the incident light into linearly polarized light through the fixed polarizing plate 600 and entering the geometrical phase lens 100, the left circle The interference of polarized light and right-circular polarized light and the interference of linearly polarized light through the spatially divided phase shifting means 700 may be further strengthened, thereby generating a clearer interference pattern in the image sensor 200.

In addition, an incident lens 300 is provided in front of the fixed polarizing plate 600 so that incident light propagating from the target object 10 passes through the fixed polarizing plate 600 and is incident on the geometric phase lens 100 to condense the incident light. Can be.

The incident lens 300 may be disposed coaxially in front of the fixed polarizing plate 600. Through this, the incident light propagating from the target object 10 passes through the fixed polarizing plate 600 and enters the geometric phase lens 100, which is a part of the incident light radiated in all directions from the target object 10 as described above. It is to be incident on the holographic unit of the invention, and performs the function of an objective lens such as a general camera or microscope.

On the other hand, between the geometrical phase lens 100 and the spatially divided phase shifting means 700 to allow the left and right polarized light changed by the geometrical phase lens 100 to pass, a floating lens ( 400) can be deployed. The floating lens 400 may be selectively disposed by the user according to the product structure of the holographic unit. For example, in the case of a microscope or a telescope, the floating lens 400 may be used to extend an optical path. In addition, the floating lens 400 extends the optical paths of the left and right circularly polarized light so that the interference effect of the left and right circularly polarized light is reinforced to obtain a clearer interference fringe.

7 is a functional block diagram functionally showing a configuration of a 3D facial recognition system using a hologram according to an embodiment of the present invention, and FIG. 8 is a 3D facial recognition system using a hologram according to an embodiment of the present invention. It is a conceptual diagram conceptually showing the configuration of.

The three-dimensional face recognition system 30 using a hologram according to an embodiment of the present invention is the self-interference digital holographic unit 40 and the facial hologram data acquired by the self-interference digital holographic unit 40. It includes a data determination unit 800 that compares with separate reference hologram data to determine whether they match.

As described above, the self-interference digital holographic unit 40 can obtain a holographic image through light propagating from the target object in a natural light state, even if the target object is not irradiated with separate light, according to an embodiment of the present invention. The facial recognition system 30 according to the self-interference digital holographic unit 40 can perform a face recognition function with a simple structure without a separate light emitting unit, and is safe and secure without glare or inconvenience in use by the light emitting unit. You can conveniently perform the facial recognition function.

In particular, since the self-interference digital holographic unit 40 can recognize a user's face in three dimensions, the accuracy and security of face recognition can be further enhanced.

The data determination unit 800 compares the facial hologram data acquired by the self-interfering digital holographic unit 40 with separate reference hologram data. The reference hologram data is hologram data initially registered by the user, and self-interference digital holographic data The holographic image recognized through the unit 40 may be configured to be stored in a separate storage unit as reference hologram data by a user's manipulation.

Meanwhile, the facial recognition system 30 according to an embodiment of the present invention may further include a separate infrared light emitting unit 910 capable of irradiating infrared light onto a user's face.

The infrared light emitting unit 910 may be simply configured as a single infrared LED. Since the infrared light is not visible light, there is no glare or discomfort to the user.

When the infrared light emitting unit 910 is provided, the infrared light is irradiated onto the user's face and then reflected again to be incident on the geometric phase lens 100 of the self-interference digital holographic unit 40, and the geometric phase lens ( 100) is changed into left-circular polarized light and right-circularly polarized light, and an interference fringe resulting from this is obtained by the image sensor 200.

In this case, an optical splitter 920 capable of separating visible and infrared light propagating from the user's face may be further provided, and infrared light separated by the optical splitter 920 is incident on the geometric phase lens 100 It can be configured to be.

That is, in the user's face part, infrared light by the infrared light emitting unit 910 is reflected and propagated, and visible light reflected in natural light is reflected and propagated. Among them, infrared light is separated through the optical separator 920 By making it incident on the phase lens 100, it is possible to stably obtain a holographic image using infrared light.

In this case, a separate visible light image sensor 930 may be provided to receive the visible light separated by the light splitter 920, and since it is possible to take general photographing of the target object through the visible light image sensor 930, this Through this, it can also perform the function as a simple camera.

In addition, the data determination unit 800 performs a facial recognition function by comparing the facial hologram data acquired by the image sensor 200 to which infrared light is received and the reference hologram data to determine whether they match. The visible light image data acquired by the image sensor 200 may be further compared with reference visible light image data to determine whether or not they match.

As described above, by comparing both the hologram image by infrared light and the visible light image by visible light with reference image data, the accuracy of facial recognition can be further improved, and security accordingly can be further enhanced.

The above-described spatial division phase shifting means 700 is disposed in front of the image sensor 200 to which the infrared light is received, and the incident lens 300 includes the optical separator 920 to condense the incident light propagating from the user's face. Can be placed in the front.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

100: geometric phase lens
200: image sensor
300: incident lens
400: floating lens
600: fixed polarizer
700: spatial division phase shifting means
710: micro polarizer array
711: fine polarizer
800: data determination unit
910: infrared light emitting unit
920: optical separator
930: visible light image sensor

Claims (10)

A geometric phase lens that is arranged to pass incident light propagating from the user's face to change the incident light into left and right polarized light, and the left and right polarized light changed through the geometrical phase lens, A self-interference digital holographic unit including an image sensor for obtaining an interference fringe generated by interference, and acquiring facial hologram data on a user's face by using the interference fringe acquired by the image sensor; And
A data determination unit that compares the facial hologram data acquired by the self-interference digital holographic unit with separate reference hologram data to determine whether they match or not
Including,
An infrared light emitting unit capable of irradiating infrared light to the user's face region, and an optical separator capable of separating visible and infrared light propagating from the user's face region are provided, and the infrared light separated by the optical separator is Is incident on the geometric phase lens,
A visible light image sensor for receiving visible light separated by the optical splitter is provided, and the data determination unit determines once again whether the visible light image data obtained by the visible light image sensor is matched by comparing the visible light image data obtained by the visible light image sensor with separate reference visible light image data. ,
The self-interference digital holographic unit
The left and right polarized light changed through the geometrical phase lens is disposed in front of the image sensor so that light is received by the image sensor by changing the left and right circularly polarized light into two linearly polarized light while receiving light from the image sensor, Spatial division phase shifting means formed to receive linearly polarized light having different phases for each of a plurality of divided areas of the light receiving area of the image sensor
3 using a hologram, characterized in that it further comprises, simultaneously obtaining interference fringes generated by linearly polarized light of different phases for each divided region by the image sensor, and combining them to obtain one facial hologram data. Dimensional facial recognition system.
delete delete delete The method of claim 1,
A 3D face recognition system using a hologram, characterized in that an incident lens for condensing incident light propagating from a user's face is disposed in front of the optical separator.
delete The method of claim 1,
The spatial division phase shifting means
Including a micro polarizing plate array attached to the front surface of the image sensor,
The micro polarizing plate array is a three-dimensional face recognition system using a hologram, characterized in that a plurality of fine polarizing plates that convert transmitted light into linearly polarized light are arranged to correspond to a plurality of divided regions of the image sensor.
The method of claim 7,
The three-dimensional face recognition system using a hologram, characterized in that the divided regions of the image sensor are formed to correspond to pixels of the image sensor.
The method of claim 7,
3D facial recognition system using a hologram, characterized in that the light transmission axes of each of the fine polarizing plates are formed to have different angles so that linearly polarized light passing through each of the fine polarizing plates has a different phase.
The method of claim 9,
The three-dimensional face recognition system using a hologram, characterized in that the light transmission axis angles of the plurality of fine polarizing plates are formed to have any one of four different types of light transmission axis angles sequentially changing with a 45° angle difference.

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