Optical Image Encryption and Decryption Considering Wireless Communication Channels

Cho, Myungjin,Lee, In-Ho Korea Information Processing Society 2014 Journal of information processing systems Vol.10 No.2

In this paper, we discuss optical encryption and decryption considering wireless communication channels. In wireless communication systems, the wireless channel causes noise and fading effects of the transmitted information. Optical encryption technique such as double-random-phase encryption (DRPE) is used for encrypting transmitted data. When the encrypted data is transmitted, the information may be lost or distorted because there are a lot of factors such as channel noise, propagation fading, etc. Thus, using digital modulation and maximum likelihood (ML) detection, the noise and fading effects are mitigated, and the encrypted data is estimated well at the receiver. To the best of our knowledge, this is the first report that considers the wireless channel characteristics of the optical encryption technique.

Computational volumetric reconstruction of integral imaging with improved depth resolution considering continuously non-uniform shifting pixels

Cho, Byungwoo,Kopycki, Przemyslaw,Martinez-Corral, Manuel,Cho, Myungjin Elsevier 2018 Optics and lasers in engineering Vol.111 No.-

<P><B>Abstract</B></P> <P>In this paper, we propose a new computational volumetric reconstruction technique of three-dimensional (3D) integral imaging for depth resolution enhancement by using non-uniform and integer-valued shifting pixels. In a typical integral imaging system, 3D images can be recorded and visualized using a lenslet array. In previous studies, many computational reconstruction techniques such as computational volumetric reconstruction and pixel of elemental images rearrangement technique (PERT) have been reported. However, a computational volumetric reconstruction technique has low visual quality and depth resolution because low-resolution elemental images and uniformly distributed shifting pixels are used for reconstruction. Although PERT can enhanced the visual quality of the 3D images, the size of the reconstructed 3D images is different from the original scene. On the other hand, our proposed method uses non-uniformly distributed shifting pixels for reconstruction instead of uniformly distributed shifting pixels. Therefore, the visual quality and depth resolution may be enhanced. Finally, our experimental results show the improvement of depth resolution and visual quality of the reconstructed 3D images.</P> <P><B>Highlights </B></P> <P> <UL> <LI> We present a new reconstruction of integral imaging with integer-valued and non-uniform shifting pixels as shown in Fig. 1. </LI> <LI> However, a conventional computational volumetric reconstruction has high reconstruction error and low depth resolution. </LI> <LI> Furthermore, if the resolution of the elemental images is low, these problems become even bigger. </LI> <LI> We proposed a reconstruction technique to improve depth resolution by using continuously non-uniform shifting pixels. </LI> <LI> Finally, our experimental results as shown in Fig. 2 show the improved depth resolution and reduced reconstruction errors. </LI> </UL> </P>

Optical Image Encryption and Decryption Considering Wireless Communication Channels

( Myungjin Cho ),( In Ho Lee ) 한국정보처리학회 2014 Journal of information processing systems Vol.10 No.2

In this paper, we discuss optical encryption and decryption considering wireless communication channels. In wireless communication systems, the wireless channel causes noise and fading effects of the transmitted information. Optical encryption technique such as double-random-phase encryption (DRPE) is used for encrypting transmitted data. When the encrypted data is transmitted, the information may be lost or distorted because there are a lot of factors such as channel noise, propagation fading, etc. Thus, using digital modulation and maximum likelihood (ML) detection, the noise and fading effects are mitigated, and the encrypted data is estimated well at the receiver. To the best of our knowledge, this is the first report that considers the wireless channel characteristics of the optical encryption technique.

Peplography—a passive 3D photon counting imaging through scattering media

Cho, Myungjin,Javidi, Bahram OPTICAL SOCIETY OF AMERICA 2016 Optics letters Vol.41 No.22

<P>Dynamic imaging through scattering media under natural light is a significant challenge in many applications. To overcome this challenge, we propose a new passive imaging technique in scattering media using statistical estimation and photon counting modeling. We directly detect the ballistic photons from objects in scattering media based on statistical optics and then show experimental results to support our proposed method. We have named the proposed technique 'peplography.' The word comes from Greek words (peplo; 'veiled') and (grafis; 'writing'). The peplography system directly detects ballistic photons associated with the objects from a single peplogram ('veiled image') based on statistical optics, and reconstructs the three-dimensional (3D) peplogram using integral imaging. (C) 2016 Optical Society of America</P>

3차원 집적 영상을 위한 우선순위 전송 기법

조명진(Myungjin Cho),최현호(Hyun-Ho Choi) 한국통신학회 2014 韓國通信學會論文誌 Vol.39 No.5(융합기술)

본 논문에서는 무안경식 3차원 영상처리 기법 중 대표적인 집적 영상 기법을 고려하여 전송 에러를 극복하여 영상 품질을 향상시키는 우선순위 전송 기법을 제안한다. 집적 영상의 각 복셀을 구성하고 있는 픽셀들의 유사성에 기반하여 전송 우선순위를 다르게 설정하고 이에 따라 변조 방식을 다르게 적용한다. 즉, 복셀을 구성하는 해당 픽셀들의 분산값이 작은 경우에는 높은 우선순위를 부여하여 에러에 강인한 특성을 갖는 변조 레벨을 사용하여 전송하고, 복셀을 구성하는 해당 픽셀의 분산값이 큰 경우에는 낮은 우선순위를 부여하여 에러율은 높아지지만 빠른 전송률을 제공하는 변조 기법을 사용하여 전송한다. 우선순위의 구분 없이 동일한 변조 레벨을 사용하는 기존 방식 대비, 우선순위가 높은 중요한 영상 데이터 비트열에 에러에 강인한 변조 레벨을 적용한 제안 방식의 경우에 수신 영상의 peak to sidelobe ratio (PSR)이 개선됨을 확인할 수 있다. In this paper, we consider a representative integral imaging method in glasses-free 3D image processing and propose a prioritized transmission scheme for guaranteeing a received video quality in error-prone environments. According to the correlation of pixels consisting of each voxel of integral image, we set the priority differently and apply the modulation level according to this priority value. That is to say, the corresponding pixels with small variance are set to a high priority and transmitted by using a low level modulation that is robust under transmission errors, but the corresponding pixels with greater variance are set to a lower priority and transmitted by using a high level modulation that has a high bit error rate but fast transmission rate. Result shows that the proposed scheme that applies the error-robust modulation level to the important image bit stream with the high priority improves the peak to sidelobe ratio (PSR) of the received 3D image, compared with a typical method that use the same modulation level without distinction of priorities.

한글 X 윈도우 시스템 및 그래픽 사용자 접속에 관한 연구

조명진(Myungjin Cho),하종성(Jongsung Ha),김판건(Pankeon Kim),전길남(Kilnam Chon) 한국정보과학회 언어공학연구회 1989 한국정보과학회 언어공학연구회 학술발표 논문집 Vol.1989 No.10

3차원 집적 영상의 자유시점 컴퓨터 재생

조기옥 ( Ki-ok Cho ),조명진 ( Myungjin Cho ),김한정 ( Han-jeong Kim ),김상훈 ( Sang-hoon Kim ) 한국정보처리학회 2013 한국정보처리학회 학술대회논문집 Vol.20 No.1

본 논문에서는 집적 영상(Integral imaging)에서 3차원 영상을 자유시점에서 재생하는 방법에 대해 설명한다. 집적 영상은 완전시차와 연속적인 시점을 제공하기 때문에 자유시점 재생을 사용하여 3차원 물체의 측면을 재생할 수 있다. 따라서, 이러한 3차원 데이터를 사용하여 보다 향상된 3차원 영상의 시각화 및 패턴 인식이 가능할 수 있다. 이를 증명하기 위해 컴퓨터 시뮬레이션을 수행하였다.

Taiwan’s Concepts of Military Strategy and Military Power Construction in Response to Chinese Threats

( Myungjin Kim ),( Kwanhaeng Cho ) 한국국방연구원 2022 The Korean Journal of Defense Analysis Vol.34 No.4

The Taiwan Strait poses a risk of war at any time due to a combination of international political factors such as China’s national strength, willingness to unify, Taiwan’s independence, and the U.S.-China leadership competition. In this situation, this paper analyzed the scenario of China’s invasion of Taiwan, and considered the comparison of military power on both sides and the direction of Taiwan’s military power construction. In conclusion, the war in the Taiwan Strait is likely to trigger geopolitical conflicts between the United States and North Korea on the Korean Peninsula, and the ROK will have to respond to diplomatic and security challenges simultaneously. Therefore, we must face up to the fact that tensions and crises between the two sides in the Taiwan Strait are directly linked to the security crisis on the Korean Peninsula. It is necessary to closely monitor the conflict between the two sides and preemptively prepare diplomatic and security response strategies for each situation.

600 MPa급 플럭스 코어드 아크 용접금속의 저온균열에 미치는 예열 온도 및 미세조직의 영향

이명진 ( Myungjin Lee ),조경목 ( Kyungmox Cho ),강남현 ( Namhyun Kang ) 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.4

The influence of preheat and microstructure on cold cracking for high strength and low hydrogen flux cored arc (FCA) weld metal was analyzed using Y-groove test. The weld microstructure consisted of acicular ferrite and martensite. As the preheat temperature increased, the volume fraction of acicular ferrite increased and that of martensite decreased, thereby decreasing the volume expansion during the transformation from austenite to martensite. This result was consequently associated with a reduced cold cracking ratio. Cold cracking progressed mainly along the prior austenite grain boundary of martensite, and the fractograph of cold cracking consisted of intergranular fractures and quasi-cleavage fractures. With increasing the preheat temperature and decreasing the carbon equivalent, the fraction of intergranular fractures decreased and quasi-cleavage fractures increased. The microstructure related with intergranular fractures was martensite; quasi-cleavage fractures were associated with acicular ferrite.

Environmental Specimen Bank and Ecosystem Assessment

Kim, Myungjin,Kim, Jiyeon,Cho, Yongjoo,Yoo, Byungho Korean Society of Environmental Impact Assessment 2009 환경영향평가 Vol.18 No.6

Environmental specimen bank (ESB) is a new tool to assess ecosystem in environmental impact assessment (EIA). ESB looks at changes in the concentration of pollutants in human and environmental specimens over long periods of time through retrospective analysis of archived samples. Korea started to design its National Environmental Specimen Bank (NESB) in 2007 and planned to launch an operational pilot project by 2010. NESB prepares five Standard Operating Procedures (SOPs) of shoots of Red and Korean pine, leaves of Mongolian oak, Pigeon's egg, and Common carp's muscle out of 14 planned specimens in 2009. ESB contributes to monitoring the effectiveness of EIA projects and policies by providing a time capsule through ecosystem assessment of representative species. This study reviews ecosystem assessment in EIA and the ESB establishment in Korea and probes NESB applications in ecosystem assessment.