• Information and Communications Magazine
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• v.33 no.10
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• pp.10-16
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• 2016

IEEE 802.15.7 VLC(Visible Light Communication) 규격 이후에 카메라 기반 ISC(Image Sensor Communication) 관련 개정 필요성이 제기되어서 현재 IEEE 802.15.7m OWC(Optical Wireless Communication) TG가 표준화를 진행 중에 있다. 2016년 5월에 결정된 Baseline Document D0를 기반으로 LiFi(Light Fidelity), OCC(Optical Camera Communication) 및 LED-ID(LED Identification) 기술로 간단하게 분류하고 각 핵심 변조 기법을 소개한다. 5세대 이동통신과 함께 사용될 수 있는 다양한 IoT/ M2M 응용 서비스(LED, 디지털사이니지, 방송, 자동차 안전, 디스플레이 등)들이 포함되어 있다. 국내에서 혁신적인 비즈니스 모델 발굴과 국내 산/학/연/관이 협력하여 가시광, 적외선 및 자외선 분야에서 적극적인 연구개발이 있어야 할 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.9
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• pp.797-801
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• 2013

Visible light communication (VLC) is a rapidly growing area of research and applications, due to the potential and predicted high efficiency of bandwidth. One of the key challenges in VLC technology is the choice of devices which are going to be deployed VLC features. Smartphone rationally uses the most widely deployed visible light sensor i.e. image sensor in camera, which could be used to receive the intensity modulated data. Image sensor based VLC system would be the most deployable scenario but initially the capacity was not much attractive compared with photodetector based VLC system. Here, the spatial multiplexing is proposed in MIMO based VLC system to increase the system capacity by utilizing the property of spatial separation of optical light sources in smartphone's camera module. The active pixels of imaging plane act as the multiple receivers which could be able to use on MIMO spatial multiplexing to enhance the system performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2415-2423
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• 1999

We propose a new optical method which conceals the data of authorized persons by encryption before they are stored or compared in the pattern recognition system for security systems. This proposed security system is made up of two subsystems : a proposed optical encryption system and a pattern recognition system based on the JTC which has been shown to perform well. In this system, each image of authorized persons as a reference image is stored in memory units through the proposed encryption system. And if a fingerprint image is placed in the input plane of this security system for access to a restricted area, the image is encoded by the encryption system then compared with the encrypted reference image. Therefore because the captured input image and the reference data are encrypted, it is difficult to decrypt the image if one does not know the encryption key bit stream. The basic idea is that the input image is encrypted by performing optical XOR operations with the key bit stream that is generated by digital encryption algorithms. The optical XOR operations between the key bit stream and the input image are performed by the polarization encoding method using the polarization characteristics of LCDs. The results of XOR operations which are detected by a CCD camera should be used as an input to the JTC for comparison with a data base. We have verified the idea proposed here with computer simulations and the simulation results were also shown.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.480-483
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• 2018

In this paper, we study the interference canceling and image sensing processing technology of multiple light sources for high speed transmission in CMOS sensor based visible light communication system. To improve transmission capacity in optical camera communications via image sensors, different data must be transmitted simultaneously from each LED. However, multiple LED light source environments for high-speed transmission can cause interference between adjacent LEDs. In this case, since the visible light communication system generally uses intensity modulation, when a plurality of LEDs transmit data at the same time, it is difficult to accurately detect the respective LEDs due to the light scattering interference of the adjacent LEDs. In order to solve this problem, the ON / OFF state of many LEDs of the light source is accurately recognized by using a dual CMOS sensor, and the spectral estimation technique and the pixel image signal processing technique of each LED are proposed. This technique can accurately recognize multiple LED pixels and improve the total average bit error rate and throughput of a MISO-VLC system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1320-1327
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• 2009

In stereoscopy using stereo camera system, the representative factors inducing stereoscopic depth distortions have been reported such as the inter camera distance, the convergence angle and the depth resolution. The image distance is just known to us as a factor related in optical system. In a point of view of depth distortion, it will be a factor inducing a stereoscopic depth distortion. In this paper, we focused on the proof of our opinion that the image distance is one of the weighted factors inducing depth distortion under orthostereoscopic condition.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4A
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• pp.371-382
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• 2002

A camera model with optical axes parallel has been widely used for stereo vision applications. A pair of input ages are obtained from a convergent-looking stereo camera model based on the human visual system in this per, and each image is divided into quadrant regions with respect to the fixation point. The reasoning of quadrant partitions is based on the human visual system and is proven by a geometrical method. Image patches : constructed from the right and left stereo images. A modified cepstrum filter is applied to the patches and disparity vectors are determined by peak detection algorithm. The three-dimensional information for synthetic ages is obtained from the measured disparity and the convergent stereo camera model. It is shown that the experimental results of the proposed method for various stereo images are accurate around the fixation point like the human visual system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10C
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• pp.829-835
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• 2008

Recently, 3D integral imaging system, which is well known as an auto-stereoscopic 3D display method, has been gaining great attention amongst researchers. The integral imaging is a promising 3D display technology since it is able to deliver continuous viewing points, full parallax, and full color view to the observers in space. In this paper, we propose a novel interactive 3D integral imaging system using a single camera. The user interface is implemented by adding a camera in the conventional integral imaging system. To show the possibility of the proposed system, we implement the optical setup and present the preliminary results. To our best knowledge, this is the first time to study an interactive 3D integral imaging.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.10
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• pp.934-940
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• 1991

A modified quantizing method is introduced to teach single layer learning algorithm, which is implemented optically. The proposed optical system consists of input masks, holographic diffraction grating. LCD and CCD camera. The 2 dimensional interconnections between input neurons and output neurons are realized using holographic phase grating, which is fabricated for equal intensity distribution of diffraction orders. The two gray levels of LCD act as binary weights for each interconnection. The weights are compensated according to the learning algorithm in which the amount of weights to be compensated is determined by comparing the output patterns with target patterns. The learning process is iterated until the predetermined conditions are satisfied. Optical experiments are performed for two learning rates, 0.5 and 0.9 and the experimental results show that the proposed system is useful for optical neural networks.

• Journal of Satellite, Information and Communications
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• v.11 no.1
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• pp.21-25
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• 2016

In this paper, we propose an algorithm for optimal selection of communications for smart lighting in heterogeneous networks. The smart lighting can be used for information communications and lighting simultaneously. To improve BER performance of smart lighting in heterogeneous networks, it adaptively selects a communication method among OCC, Wi-Fi, BLE based on distance between sensors and smart lightings, low power consumption for user requirements, operating time of smart lighting in Line-of-Sight(LOS)/Non-LOS channels. Thus, simulation results demonstrate effectiveness of the proposed algorithm contrary to baseline methods in LOS/NLOS channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.353-364
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• 2002

In this paper, a new onto-digital stereo object-tracking system using hierarchical digital algorithms and optical BPEJTC is proposed. This proposed system can adaptively track a moving target by controlling the convergence of stereo camera. firstly, the target is detected through the background matching of the sequential input images by using optical BPEJTC and then the target area is segmented by using the target projection mask which is composed by hierarchical digital processing of image subtraction, logical operation and morphological filtering. Secondly, the location's coordinate of the moving target object for each of the sequential input frames can be extracted through carrying out optical BPEJTC between the reference image of the target region mask and the stereo input image. Finally, the convergence and pan/tilt of stereo camera can be sequentially controlled by using these target coordinate values and the target can be kept in tracking. Also, a possibility of real-time implementation of the adaptive stereo object tracking system is suggested through optically implementing the proposed target extraction and convergence control algorithms.