Patent Application
20140160541
This application claims the benefit of priority of Korean Patent Application Nos. 10-2012-0142164 filed on Dec. 7, 2012 and 10-2013-0149022 filed on Dec. 3, 2013, which is incorporated by reference in its entirety herein.
1. Field of the Invention
The present invention relates to a method for recording a holographic image in a photosensitive material such as a hologram film and determining whether the holographic image is forged.
2. Discussion of the Related Art
A hologram is generated by a method that generates an object beam and a reference beam are generated by using a coherent laser beam and irradiates the generated beams to a hologram photosensitive material such as a silver halide film or a photopolymer film to record an interference fringe.
A holographic recording method includes reflection holography and transmission holography and is determined by an illumination direction of the reference beam. When white light or light having a specific wavelength is illuminated to the hologram generated by such a program by means of an illumination device, the recorded image is reconstructed to observe a stereoscopic recorded image. Making the hologram in related art concentrates on enhancement of a method of reconstructing a clear holographic image by illuminating the reference beam at an appropriate angle.
In this case, only when a direction of light used as an illumination needs to coincide with a direction in recording, the clear holographic image can be reconstructed with maximum efficiency and only when a wavelength of light also coincides with a wavelength of a light source used in recording, the clear image can be reconstructed.
Contrary to this, when the direction of the reference beam and the direction of the illumination do not coincide with each other or a wavelength of the reference beam and a wavelength of illumination light do not coincide with each other, the recorded image is not reconstructed.
Therefore, when such a characteristic is utilized, an image or a pattern which can be observed only at a specific angle or a specific wavelength can be reconstructed and can be utilized as security identification means by using the reconstructed image or pattern. Further, this method can be applied even in recording multiple images in a material under a condition having a different characteristic of the reference beam and thereafter, selectively observing only a desired image by using the illumination device having a wavelength and direction control function.
An object of the present invention is to provide a holographic image identification method in which an image is changed depending on an illumination characteristic as a method for preventing forgery by substituting a document or a photograph which is easily forged through duplication or copying.
Further, another object of the present invention is to provide a method that can selectively observe only a desired image by using an illumination device having a wavelength and direction control function after recording multiple images in a material.
In order to achieve the objects, in accordance with an embodiment of the present invention, an apparatus for identifying authenticity of a holographic image may identify the authenticity by comparing a holographic image reconstructed by irradiating light having the same characteristic as an irradiation characteristic of a first reference beam used in generating the holographic image with an original image.
The apparatus for identifying authenticity of a holographic image may include: a light irradiation unit reconstructing the holographic image by irradiating light to the holographic image; a control unit controlling an irradiation characteristic of the light irradiated to the holographic image; and an authenticity judging unit judging the authenticity by comparing the reconstructed holographic image with the original image.
The control unit may control light having the same irradiation angle and wavelength as the first reference beam to a recording material to the holographic image.
The authenticity judging unit may include a reconstructed image acquiring unit acquiring the reconstructed holographic image; and a judgment unit judging the authenticity of the holographic image by judging whether similarity between the acquired holographic image and the original image is equal to or more than a reference value.
The judgment unit may judge the authenticity based on at least one of depth information of the acquired holographic image, object occlusion associated information, and feature point information.
The judgment unit may judge the authenticity of the holographic image by detecting a depth value of a feature point in the acquired holographic image or determine the authenticity of the holographic image based on inter-depth values or inter-placement relationship of a plurality of feature points.
In order to achieve the objects, in accordance with another embodiment of the present invention, a method for identifying authenticity of a holographic image may include identifying the authenticity by comparing a holographic image reconstructed by irradiating light having the same characteristic as a characteristic of a first reference beam used in generating the holographic image with an original hologram image.
In order to achieve the objects, in accordance with yet another embodiment of the present invention, an apparatus for selectively reconstructing a first holographic image including a plurality of holographic images may selectively reconstruct at least one holographic image among the plurality of holographic images by irradiating light by using light irradiation means capable of an irradiation angle and a wavelength of light to a first holographic image generated by using reference beams having different characteristics with respect to a plurality of original images.
The apparatus for selectively reconstructing a first holographic image may include: a light irradiation unit reconstructing the holographic image by irradiating light to the holographic image; and a control unit controlling an irradiation characteristic of the light irradiated to the holographic image, and the control unit may control an irradiation angle and a wavelength of light irradiated to correspond to an irradiation angle and a wavelength of at least one reference beam among the plurality of holographic images included in the first holographic image.
Information associated with the irradiation angle and the wavelength of the reference beam may be received from the outside or input through a user interface and an irradiation angle and a wavelength of light may be controlled based on the received or input information.
The apparatus for selectively reconstructing a first holographic image may code an element associated with reconstruction of the holographic image to provide the coded element as image identification information.
The apparatus for selectively reconstructing a first holographic image may identify the authenticity by comparing a holographic image reconstructed by irradiating light having the same characteristic as an irradiation characteristic of a reference beam used in generating the first holographic image with an original image.
In order to achieve the objects, in accordance with still another embodiment of the present invention, a method for selectively reconstructing a first holographic image including a plurality of holographic images may include selectively reconstructing at least one holographic image among the plurality of holographic images by irradiating light by using light irradiation means capable of an irradiation angle and a wavelength of light to a first holographic image generated by using reference beams having different characteristics with respect to a plurality of original images.
In order to achieve the objects, in accordance with still yet another embodiment of the present invention, a system for selectively reconstructing a first holographic image including a plurality of holographic images may include: a holographic image generation apparatus generating a first holographic image by using reference beams having different characteristics with respect to a plurality of original images; and a holographic image reconstruction apparatus selectively reconstructing at least one holographic image among the plurality of holographic images by irradiating light by using light irradiation means capable of controlling an irradiation angle and a wavelength of light with respect to the generated first holographic image.
The holographic image generation apparatus may provide characteristic information of reference beams used in the plurality of original images to the holographic image reconstruction apparatus and the holographic image reconstruction apparatus controls an irradiation angle and a wavelength of light irradiated to a holographic image based on the reference beam characteristic information.
The holographic image reconstruction apparatus may identify authenticity by comparing a holographic image reconstructed by irradiating light having the same characteristic as an irradiation characteristic of a reference beam used in generating the first holographic image and an original image.
According to an apparatus and a method of holographic image forgery identification, since an image or a pattern is recorded by using a reference beam having a specific angle and a specific laser wavelength band at the time of making a hologram, duplication or copying for forgery is not easy.
Further, since authenticity is determined in spite of the duplication or copying, the forgery is prevented.
Moreover, since an observed image has a unique characteristic according to a reference beam control characteristic, a recorded hologram is applied to an identification card or a money or a document to determine authenticity thereof to be utilized as a security tool and applied in selectively observing a desired image by using an illumination device having a wavelength and direction control function after recording multiple images in a material.
The present invention may have various modifications and various embodiments and specific embodiments will be illustrated in the drawings and described in detail.
However, this does not limit the present invention within specific embodiments, and it should be understood that the present invention covers all the modifications, equivalents and replacements within the idea and technical scope of the present invention.
Terminologies such as first or second may be used to describe various components but the components are not limited by the above terminologies. The above terminologies are used only to discriminate one component from the other component. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component. A terminology such as and/or includes a combination of a plurality of associated items or any item of the plurality of associated items.
It should be understood that, when it is described that an element is “coupled” or “connected” to another element, the element may be “directly coupled” or “directly connected” to the another element or “coupled” or “connected” to the another element through a third element. In contrast, it should be understood that, when it is described that an element is “directly coupled” or “directly connected” to another element, it is understood that no element is not present between the element and the another element.
Terms used in the present application are used only to describe specific embodiments, and are not intended to limit the present invention. A singular form may include a plural form if there is no clearly opposite meaning in the context. In the present application, it should be understood that term “include” indicates that a feature, a number, a step, an operation, a component, a part or the combination thereof described in the specification is present, but does not exclude a possibility of presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations, in advance.
If it is not contrarily defined, all terms used herein including technological or scientific terms have the same meaning as those generally understood by a person with ordinary skill in the art. Terms which are defined in a generally used dictionary should be interpreted to have the same meaning as the meaning in the context of the related art but are not interpreted as an ideally or excessively formal meaning if it is not clearly defined in the present invention.
Hereinafter, a preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, like reference numerals refer to like elements for easy overall understanding and a duplicated description of like elements will be omitted.
Referring to
The holographic image reconstruction apparatus 120 may identify whether a target holographic image is forged. The holographic image reconstruction apparatus 120 may irradiate a beam having the same characteristic as the irradiation characteristic of the reference beam used when the holographic image generation apparatus 110 makes the holographic image to the target holographic image, in order to identify whether the target holographic image is forged. In this case, the irradiation characteristic of the reference beam may be determined by an irradiation angle between the reference beam and the recording material and a wavelength of the reference beam. Further, information on the irradiation characteristic of the reference beam may be acquired from the holographic image generation apparatus 110 by wired/wireless communication. The holographic image reconstruction apparatus 120 irradiates a beam having the same characteristic as the reference beam to the target holographic image to reconstruct the holographic image. Herein, a term “reconstruction” may be used as a concept including outputting, observation, and the like of an image. The holographic image reconstruction apparatus 120 acquires the reconstructed holographic image through a camera, and the like and judges the similarity between the acquired image and the original image by comparing the acquired image with the original image to judge whether the acquired image is forged. In this case, information on the original image may be acquired form the holographic image generation apparatus 110. Alternatively, the output original image may be captured and acquired.
Referring to
The laser light source unit 220 may generate a laser beam having a desired wavelength characteristic by selecting a desired wavelength for lasers having various wavelengths by using a shutter, a wave plate and a polarizer, a filter and a beam combiner, and the like and controlling the intensity of each wavelength. Further, the laser light source unit may perform even a function to expand the laser beam and generate a collimated beam. The generated beam is provided to the object beam generation unit 230 to form the object beam and provided to the reference beam generation unit 260 to form the reference beam.
The object beam generation unit 230 may generate the object beam and converge and irradiate the generated object beam in the recording material, based on the laser beam provided from the laser light source unit 220 and an image output from the image output unit 210. In more detail, the object beam generation unit 230 may perform a function to generate an object beam modulated depending on an image loaded to a spatial light modulator (SLM) which is a spatial light modulator and a function to converge and irradiate the object beam on the recording material (for example, a holographic film) through a converging lens which is an objective lens.
The control unit 240 may control the image output unit 210, the laser light source unit 220, the object beam generation unit 230, the material transportation unit 250, and the reference beam generation unit 260. The control unit 240 may control the image output unit 210 to output a recorded image to generate the holographic image. Further, the control unit 240 may control a characteristic (for example, a wavelength) of the laser beam by controlling the laser light source unit 220. The control unit 240 may control a movement speed of the recording material by controlling the material transportation unit 250. The control unit 240 may control the irradiation angle and the wavelength characteristic of the reference beam for generating the holographic image by controlling the reference beam generation unit 260. The characteristic information may be stored in a data storage unit (for example, an RAM/ROM or other storages) (not illustrated) and in some cases, the characteristic information may be transmitted to other apparatuses through a communication unit (not illustrated).
The material transportation unit (translation stage) 250 performs a function to accurately photosense the object beam and the reference beam at a desired film (material) position by transporting the hologram recording material.
The reference beam generation unit 260 makes the reference beam be incident in the recording material (for example, the holographic film) at a desired angle by controlling a wavelength of the collimated beam generated by the laser light source unit 220 and the intensity of the beam for each wavelength to perform a function to form an interference fringe between the object beam and the reference beam. In this case, since a holographic image may be generated, which has a different interference fringe depending on the wavelength and the irradiation angle of the reference beam which is incident and becomes an important characteristic in determining whether the holographic image is forged at the time of reconstructing the holographic image, a reference beam control characteristic needs to be precisely controlled by the control unit 240 and related information may be stored in the data storage unit. This may be determined by a predetermined wavelength and a predetermined irradiation angle. Hereinafter, a function to control the wavelength and the irradiation angle of the reference beam will be described in detail with reference to
The user interface 270 receives an input from the user and provides the received input to the control unit 240. The user may input information on a desired image. Further, information associated with a change of a user's set-up of the reference beam control characteristic may be input by the user.
Referring to
The laser light source unit 220 may primarily include red, green, and blue lasers. The respective lasers are transmitted to each of the object beam generation unit 230 and the reference beam generation unit 260 through a BS which is a beam splitter. Constitutions of each of the object beam generation unit 230 and the reference beam generation unit 260 may control select a desired wavelength and the intensity of each wavelength. The constitutions will be described below.
A wavelength control performing unit 410 that controls a part associated with the wavelength may include a shutter, a wave plate, and a polarizer. In detail, the wavelength control performing unit 410 may selectively perform opening and shielding functions for lasers having various wavelengths such as red, green, and blue by means of the shutter. As a result, it may be determined whether a corresponding wavelength band is used. The intensity of an output beam may be determined by using the wave plate and the polarizer.
The wavelength-controlled beam may determine an optical path through a mirror and beams having various wavelengths may be collected into one by using a beam combiner, and the like to output the corresponding beam. A desired wavelength may be selected and the intensity of each wavelength may be controlled and a laser beam having desired wavelength and intensity characteristics may be generated, through such a process. According to another embodiment of the present invention, the shutter, the wave plate, and the polarizer are connected to the respective lasers to be controlled, respectively.
Referring to
In a process of generating the holographic image, an image F(i, j) output through an image output unit 510 is input into a spatial light modulator (SLM) of an object beam generation unit 520 to output modulated light encoded with an appropriate image brightness value. The object wave generation unit 520 converges and irradiates the output modulated light onto a holographic image photosensitive film 505.
A reference beam generation unit 560 may generate a reference beam laser L(λ, θ) of which a wavelength (λ) and an angle (θ) are controlled by a control unit 540. The object beam interferes with the generated laser L(λ, θ) and image F(i, j) to generate the interference fringe and the interference fringe is recorded in the photosensitive film 505, and as a result, a holographic image 580 H(λ, θ) may be finally generated. The holographic image may be expressed as H(λ, θ)=F(i, j)*L(λ, θ). The holographic image reconstruction apparatus may determine whether the generated holographic image is forged.
Referring to
The control unit 620 may control the light irradiation unit 610, the authenticity judgment unit 630, and the receiving unit 640. The control unit 620 may control the light irradiation characteristic of the light irradiation unit 610 based on reference beam characteristic information received through the receiving unit 640. The control unit 620 may control the light irradiation unit 610 to irradiate the same light to the holographic image based on information associated with the wavelength and the irradiation angle of the reference beam used in making the holographic image.
The authenticity judgment unit 630 may include an image acquiring unit 632 and a judgment unit 634. The image acquiring unit 632 may acquire a shape of the target holographic image reconstructed by irradiating light through the camera, and the like. The image acquiring unit 632 may include at least one of a CCD element, a CCD camera, a stereo camera, and multiple cameras (two or more horizontally placed camera groups). The image acquiring unit 632 may be used to acquire original image information. For example, the reconstructed target holographic image or the original image may be acquired by using the CCD element or the CCD camera. Since the reconstructed target holographic image may be reconstructed differently depending on the characteristic of the irradiated light, it may be determined whether the image is forged by acquiring the reconstructed image when the same light as the reference beam is irradiated.
The judgment unit 634 compares the reconstructed holographic image acquired through the image acquiring unit 632 with the original image to judge whether the holographic image is forged. A detailed description will be described below with reference to
The receiving unit 640 may receive information from the outside. The receiving unit 640 may receive the reference beam characteristic information from the holographic image generation apparatus or other apparatuses. Herein, the other apparatuses may be apparatuses such as a server, and the like, which manage the reference beam characteristic information corresponding to a specific image. Further, the receiving unit 640 may receive from the holographic image generation apparatus or other apparatuses original image information required to determine whether the specific image is forged. In this case, apparatuses that receive the reference beam characteristic information and the original image information need not particularly be the same as each other. Information may be received from different databases. The receiving unit 640 may transmit the received information to the control unit 620 or the judgment unit 634. A transmitting unit (not illustrated) corresponding to the receiving unit 640 may transmit an information request signal to the holographic image generation apparatus or other apparatuses in order to acquire the reference beam characteristic information or the original image information. In some cases, as described above, the original image information may be acquired through the image acquiring unit 632.
The user interface 650 may be used to change a user's set-up associated with reconstruction of the hologram. The user interface 650 may change the user's set-up by receiving an input from the user. The user may input the reference beam characteristic information personally and the information input through the user interface 650 may be transmitted to the control unit 620. Further, the user may change a reference value for judging whether the specific image is authentic, which is used in the judgment unit 634 through the user interface 650.
Referring to
Referring to
According to a result of the image comparison, when a difference value is equal to or more than a reference value (threshold) (S840), it may be judged that the acquired image is forged (S850) and if not, it may be judged that the acquired image is not forged (S855). That is, when similarity (a degree in which both images are the same as each other) is equal to or more than the reference value, it is judged that both images are the same as each other to judge that the acquired image is not forged and when the similarity is equal to or less than the reference value, both images are not the same as each other to judge that the acquired image is forged. The reference value for the difference value or the reference value for the similarity may be changed through a user's set-up.
Referring to
Referring to
In some cases, when the holographic image reconstruction apparatus receives a reconstruction request of a specific image through the user interface, the holographic image reconstruction apparatus may control the requested image to be reconstructed by automatically irradiating an illumination having an irradiation angle and a wavelength corresponding to the specific image to a first holographic image. For example, when the user requests reconstructing image 2, a control unit (not illustrated) controls an illumination corresponding to an irradiation characteristic of a reference beam used in making image 2 to the first holographic image to selectively reconstruct image 2.
According to yet another embodiment of the present invention, the image selectively reconstructed based on characteristic information of the reference beam used in making the first holographic image is compared with the original image to determine whether the holographic image is forged. For example, a specific angle or a specific angle characteristic may be used as means for identifying whether the holographic image is forged.
Referring to
While the invention has been shown and described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2012-0142164 | Dec 2012 | KR | national |
| 10-2013-0149022 | Dec 2013 | KR | national |
