• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.450-453
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• 2002

In this paper a Phase-based virtual image encryption and decryption techniques based on a joint transform correlator (JTC) are proposed. In this method, an encrypted image is obtained by multiplying a phase-encoded virtual image that contains no information from the decrypted image with a random phase. Even if this encryption process converts a virtual image into a white-noise-like image, the unauthorized users can permit a counterfeiting of the encrypted image by analyzing the random phase mask using some phase-contrast technique. However, they cannot reconstruct the required image because the virtual image protects the original image from counterfeiting and unauthorized access. The proposed encryption technique does not suffer from strong auto-correlation terms appearing in the output plane. In addition, the reconstructed data can be directly transmitted to a digital system for real-time processing. Based on computer simulations, the proposed encryption technique and decoding system were demonstrated as adequate for optical security applications.

• ETRI Journal
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• 제27권6호
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• pp.708-712
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• 2005

We propose a computational reconstruction technique in large-depth integral imaging where the elemental images have information of three-dimensional objects through real and virtual image fields. In the proposed technique, we reconstruct full volume information from the elemental images through both real and virtual image fields. Here, we use uniform mappings of elemental images with the size of the lenslet regardless of the distance between the lenslet array and reconstruction image plane. To show the feasibility of the proposed reconstruction technique, we perform preliminary experiments and present experimental results.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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• pp.62-63
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• 2003

We propose an improved image encryption and the shift-tolerance method in the Fourier space using a virtual phase image. The encrypted image is obtained by the Fourier transform of the product of a phase-encoded virtual image, not an original image, and a random phase image. We demonstrate the robustness to noise, to data loss and shift of the encrypted image or the Fourier decryption key in the proposed technique.

• 대한전자공학회논문지SD
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• 제40권9호
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• pp.658-665
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• 2003

본 논문에서는 위상 변조된 가상 영상을 이용하여 암호화 수준을 향상시키고 퓨리에 영역에서 잡음이나 변이에 강한 복호화 방법을 제안하였다. 암호화된 영상은 원 영상이 아닌 위상 변조된 가상 영상과 무작위 위상 영상을 곱하여 퓨리에 변환하여 만든다. 따라서 허가되지 않은 사용자가 암호화된 영상을 분석함으로써 있을 수 있는 복제 가능성을 원 영상의 어떤 정보도 포함하지 않은 가상 영상을 사용함으로써 배제할 수 있다. 복호화 과정은 암호화된 영상과 제안한 위상 대응 규칙으로 만들어진 퓨리에 복호화 키를 간섭시킨 후 퓨리에 역변환하여 간단히 원 영상을 재생하고 컴퓨터 모의 실험을 통하여 제안한 방법의 암호화된 영상과 복호화 키 영상에 잡음이나 영상의 절단, 변이가 발생하더라도 원 영상의 복원이 가능함을 확인하였다.

• Journal of the Optical Society of Korea
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• 제6권4호
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• pp.156-160
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• 2002

In this paper, we propose an improved optical security system using three phase-encoded images and the principle of interference. This optical system based on a Mach-Zehnder interferometer consists of one phase-encoded virtual image to be encrypted and two phase-encoded images, en-crypting image and decrypting image, where every pixel in the three images has a phase value of '0'and'$\pi$'. The proposed encryption is performed by the multiplication of an encrypting image and a phase-encoded virtual image which dose not contain any information from the decrypted im-age. Therefore, even if the unauthorized users steal and analyze the encrypted image, they cannot reconstruct the required image. This virtual image protects the original image from counterfeiting and unauthorized access. The decryption of the original image is simply performed by interfering between a reference wave and a direct pixel-to-pixel mapping image of the en crypted image with a decrypting image. Computer simulations confirmed the effectiveness of the proposed optical technique for optical security applications.

• 디지털콘텐츠학회 논문지
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• 제18권1호
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• pp.71-77
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• 2017

가상광고는 컴퓨터 그래픽을 이용하여 스포츠영상과 같은 미디어제작영상에 제품의 이미지, 로고, 선전문구 등을 삽입하는 광고기법이다. 최근 영상처리 기술과 컴퓨터 성능의 상승으로 인해 스포츠영상에 가상광고를 삽입하기 위한 기술적인 요소가 충족되어 영상 내에 가상광고의 삽입이 활발하게 진행되고 있다. 또한 자동적인 가상광고 삽입을 위한 영상 처리 기술이 가상광고 영역에서 중요한 연구 분야로 자리 잡고 있다. 이에 본 논문에서는 스포츠 영상 내에서 자동적으로 가상광고를 삽입하기 위해 영상처리 기법과 기계학습을 활용하여 저정보 영역을 추출하는 방법을 제안한다. 제안 방법은 영상의 밝기 정도를 히스토그램을 통해 분석하고 기계학습 방법을 활용하여 저정보 영역을 추출한다.

• 한국자동차공학회논문집
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• 제8권4호
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• pp.158-168
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• 2000

Vehicle driving simulators can provide engineers with benefits on the development and modification of vehicle models. One of the most important factors to realistic simulations is the fidelity given by a motion system and a real-time visual image generation system. Virtual reality technology has been widely used to achieve high fidelity. In this paper the virtual environment including a visual system like a head-mounted display is developed for a vehicle driving simulator system by employing the virtual reality technique. virtual vehicle and environment models are constructed using the object-oriented analysis and design approach. Accordint to the object model a three dimensional graphic model is developed with CAD tools such as Rhino and Pro/E. For the real-time image generation the optimized IRIS Performer 3D graphics library is embedded with the multi-thread methodology. Compared with the single loop apprach the proposed methodology yields an acceptable image generation speed 20 frames/sec for the simulator.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.41-45
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• 2005

A new algorithm of the image mapping which is a technique of the elemental image generation is proposed. The proposed method is based on the characteristics of the lens array such as the number, the size and the focal length of the elemental lens. The 3D image generated by 3D graphic API such as OpenGL can be directly adopted without the complex adaptation. Since the image mapping using the proposed method can enhance the speed of the elemental image generation, the computer- generated integral imaging system can be applied to virtual reality system.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.631-634
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• 2002

In this paper, we propose an improved optical security system using three phase-encoded images and the principle of interference. This optical system based on a Mach-Zehnder interferometer consists of one phase-encoded virtual image to be encrypted and two phase-encoded images, encrypting image and decrypting image, where every pixel in the three images has a phase value of '0' and '$\pi$'. The proposed encryption is performed by the multiplication of an encrypting image and a phase-encoded virtual image which dose not contain any information from the decrypted image. Therefore, even if the unauthorized users steal and analyze the encrypted image, they cannot reconstruct the required image. This virtual image protects the original image from counterfeiting and unauthorized access.. The decryption of the original image is simply performed by interfering between a reference wave and a direct pixel-to-pixel mapping image of the encrypted image with a decrypting image. Both computer simulations and optical experiments confirmed the effectiveness of the proposed optical technique for optical security applications.

• 정보처리학회논문지B
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• 제13B권7호
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• pp.663-670
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• 2006

실 세계 영상에 가상표적을 효과적으로 전시하여 현실감을 높이려면 먼저 두 세계를 정합한 후 폐색영역을 산출하여 가상객체의 위치를 결정하는 것이 필수적이다. 본 논문에서는 실 영상위에 지정된 경로에 따라 가상표적을 이동시킬 때 발생하는 폐색문제를 해결하는 새로운 방법을 제안한다. 이를 위해 먼저 실험 영역의 DEM을 이용하여 3차원 가상세계를 생성하고 이를 CCD 카메라 영상과 시각적 단서를 이용하여 정합한다. 또한 스네이크 알고리즘과 픽킹 알고리즘을 이용하여 영상에서 폐색 처리될 지점의 3차원 정보를 산출하고 표적이동시 이를 이용하여 폐색문제를 해결하는 방법을 제안하였다 실험에서는 부분적 폐색이 발생하는 환경에서 제안한 방법의 유효성을 입증하였다.