• Journal of the Institute of Electronics and Information Engineers
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• 제52권10호
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• pp.16-20
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• 2015

We propose three multi-level modulation codes of the code rate 1/2 for holographic data storage considered as a promising candidate for next generation storage systems. Since a pixel with multi-levels can represent more than 1 bit, it is possible to increase the storage capacity and have many codewords. Thus, we can choose a code that the minimum distance is as far as possible. When we compare the codes with the code rate 1/2, the performance of the code with small number of levels is better than that of large number of levels.

• Proceedings of the KSRS Conference
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.252-256
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• 1998

Accurate mapping of satellite images is one of the most important Parts in many remote sensing applications. Since the position and the attitude of a satellite during image acquisition cannot be determined accurately enough, it is normal to have several hundred meters' ground-mapping errors in the systematically corrected images. The users which require a pixel-level or a sub-pixel level mapping accuracy for high-resolution satellite images must use a number of Ground Control Points (GCPs). In this paper, the performance of two geometric correction algorithms is tested and compared. One is the polynomial warping algorithm which is simple and popular enough to be implemented in most of the commercial satellite image processing software. The other is full camera modelling algorithm using Physical orbit-sensor-Earth geometry which is used in satellite image data receiving, pre-processing and distribution stations. Several criteria were considered for the performance analysis : ultimate correction accuracy, GCP representatibility, number of GCPs required, convergence speed, sensitiveness to inaccurate GCPs, usefulness of the correction results. This paper focuses on the usefulness of the precision correction algorithm for regular image pre-processing operations. This means that not only final correction accuracy but also the number of GCPs and their spatial distribution required for an image correction are important factors. Both correction algorithms were implemented and will be used for the precision correction of KITSAT-3 images.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2008년도 춘계학술대회 및 기술 세미나 논문집 디스플레이 광소자
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• pp.42-42
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• 2008

Considerable attention has been focused on the applications of flexible liquid crystal (LC)-based displays because of their many potential advantages, such as portability, durability, light weight, thin packaging, flexibility, and low power consumption. To develop flexible LCDs that are capable of delivering high-quality moving images, like conventional glass-substrate LCDs, the LC device structure must have a stable alignment layer of LC molecules, concurrently support uniform cell gaps, and tightly bind two flexible substrates under external tension. However, stable LC molecular alignment has not been achieved because of the layerless LC alignment, and consequently high-quality images cannot be guaranteed. To solve these critical problems, we have proposed a PDMS pixel-wall based bonding method via the IB irradiation was developed for fasten the two substrates together strongly and maintain uniform cell gaps. The effect of the IB irradiation on PDMS with PI surface was also evaluated by side structure configuration and a result of x-ray photoelectron spectroscopic analysis of PDMS interlayer as a function of binder with substrates. large number of PDMS pixel-walls are tightly fastened to the surface of each flexible substrate and could maintain a constant cell gap between the LC molecules without using any other epoxy or polymer. To enhance the electro-optical performance of the LC device, we applied an alignment method that creates pretilt angle on the PI surface via ion beam irradiation. Using this approach, our flexible LCDs have a contrast ratio of 132:1 and a response time of about 15 ms, resulting in highly reliable electro-optical performance in the bent state, comparable to that of glass-substrate LCDs.

• Journal of the Institute of Electronics and Information Engineers
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• 제50권10호
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• pp.135-141
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• 2013

In this paper, we installed three high brightness red, green, and blue LED in one socket and made one pixel unit. And we also developed the full-color display board module and control unit which can express various images such as text, graphics, video image with the combination of pixel units and a number of modules. LED display driver module have a driver circuit within the combination of the RGB pixel dot on unit area. These modules of the existing form can be high priced because of implementation a fixed resolution in specific space and installation space. To overcome these shortcomings, we developed a LED driver and LED pixel modules free in array at random pitch intervals. Display board module of this paper enabled to display smoothly video image which have many data processing quantity through dragging data speed up 36 frames per second. Also there are an effect which is provided more clear image because of improving the flickering of the existing display board.

• Journal of Sensor Science and Technology
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• 제27권3호
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• pp.160-164
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• 2018

In this paper, a wide dynamic range complementary metal-oxide-semiconductor (CMOS) image sensor with the adjustable sensitivity by using cascode metal-oxide-semiconductor field-effect transistor (MOSFET) and inverter is proposed. The characteristics of the CMOS image sensor were analyzed through experimental results. The proposed active pixel sensor consists of eight transistors operated under various light intensity conditions. The cascode MOSFET is operated as the constant current source. The current generated from the cascode MOSFET varies with the light intensity. The proposed CMOS image sensor has wide dynamic range under the high illumination owing to logarithmic response to the light intensity. In the proposed active pixel sensor, a CMOS inverter is added. The role of the CMOS inverter is to determine either the conventional mode or the wide dynamic range mode. The cascode MOSFET let the current flow the current if the CMOS inverter is turned on. The number of pixels is $140(H){\times}180(V)$ and the CMOS image sensor architecture is composed of a pixel array, multiplexer (MUX), shift registers, and biasing circuits. The sensor was fabricated using $0.35{\mu}m$ 2-poly 4-metal CMOS standard process.

• Journal of Korea Multimedia Society
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• 제19권6호
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• pp.990-1002
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• 2016

In this paper, we propose a new compression method for the edge image by analyzing the characteristics and the distribution of pixel values of the edge image. The pixel values of the edge image have the Gaussian distribution around '0', and most of the pixel values are `0`. By these analyses we suggest the Zero-Based codec that expresses all values in a CU by a single bit flag. Also, in order to reduce the computational complexity of the proposed codec, the block partition and the intra-prediction techniques are proposed by using edge information like the number of each edge direction, the distribution and the amplitude of a major edge direction in the CU. Experimental results show that the proposed codec leads to a slighter distortion in Y domain than that of HEVC, but has far faster processing speed up to 53 times while it maintains the similar image quality compared to HEVC.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1994-1998
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• 2005

Characteristic analysis of the depth measurement system with a laser, a camera and a rotating mirror has been done and the parameter calibration technique for it has been proposed. In the proposed depth measurement system, the laser beam is reflected to the object by the rotating mirror and again the position of the laser beam is observed through the same mirror by the camera. The depth of the object pointed by the laser beam is computed depending on the pixel position on the CCD. There involved several number of internal and external parameters such as inter-pixel distance, focal length, position and orientation of the system components in the depth measurement error. In this paper, it is shown through the error sensitivity analysis of the parameters that the most important parameters in the sense of error sources are the angle of the laser beam and the inter pixel distance. The calibration techniques to minimize the effect of such major parameters are proposed.

• Journal of the Korean Society of Visualization
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• 제9권1호
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• pp.36-41
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• 2011

It is highly needed to measure the dissolved oxygen (DO) concentration field in water for a variety of purposes such as biological, industrial, environmental monitoring and medical application. Application of PSP (Pressure Sensitive Paint) which is sensitive to oxygen concentration has been carried out to measure DO concentration field using PtOEP/PS film and intensity based method under the UV-LEDs illumination. A micro round water jet having 100% of DO was obliquely impinged on to a PtOEP/PS film coated plate placed in a 0% of DO water container. DO concentration fields on the impinging plate were quantitatively visualized with a $2.94\;{\mu}m$ of spatial resolution. Through pixel-by-pixel calibration, uncertainty of each pixel by different sensitivity, different dye concentration and non-uniformity of illumination was removed. It is demonstrated that the high DO concentration region was coincided with the impingement area. The DO concentration gradient due to DO diffusion was affected by Reynolds number.

• Journal of Computing Science and Engineering
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• 제11권3호
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• pp.79-91
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• 2017

In this paper, the abdominal-deformation measurement scheme is conducted on a shape-flexible mannequin using the DIC technique in a stereo-vision system. Firstly, during the integer-pixel displacement search, a novel fractal dimension based on an adaptive-ellipse subset area is developed to track an integer pixel between the reference and deformed images. Secondly, at the subpixel registration, a new mutual-learning adaptive particle swarm optimization (MLADPSO) algorithm is employed to locate the subpixel precisely. Dynamic adjustments of the particle flight velocities that are according to the deformation extent of each interest point are utilized for enhancing the accuracy of the subpixel registration. A test is performed on the abdominal-deformation measurement of the shape-flexible mannequin. The experiment results indicate that under the guarantee of its measurement accuracy without the cause of any loss, the time-consumption of the proposed scheme is significantly more efficient than that of the conventional method, particularly in the case of a large number of interest points.

• The Transactions of the Korean Institute of Electrical Engineers D
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• 제54권3호
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• pp.148-155
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• 2005

A seam-line determination algorithm is proposed to determine image border-line in mosaicing using the transformation of gray value differences and dynamic programming. Since visually good border-line is the one along which pixel differences are as small as possible, it can be determined in association with an optimal path finding algorithm. A well-known effective optimal path finding algorithm is the Dynamic Programming (DP). Direct application of the dynamic programming to the seam-line determination causes the distance effect, in which seam-line is affected by its length as well as the gray value difference. In this paper, an adaptive cost transform algorithm with which the distance effect is suppressed is proposed in order to utilize the dynamic programming on the transformed pixel difference space. Also, a figure of merit which is the summation of fixed number of the biggest pixel difference on the seam-line (SFBPD) is suggested as an evaluation measure of seamlines. The performance of the proposed algorithm has been tested in both quantitively and visually on various kinds of images.