• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.805-808
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• 2005

엔트로피부호화(entropy coding)는 텍스트와 같은 일반적인 데이터들을 효율적으로 압축하는 반면에, 이미지 데이터들에 대해서는 그 성능이 다소 저하된다. 본 논문에서는 이러한 단점을 개선시키기 위한 효율적인 전처리기법(preprocessing technique)을 소개한다. 제안한 전처리기법은 입력된 명암도 등급 이미지를 무손실 압축하기 이전에, 이미지 내에서 인접한 명암도 값들의 발생빈도(occurrence frequency)를 조사한다. 다음으로 각 픽셀 쌍들의 명암도 값들을 발생빈도에 기반한 순서화된 값(ordered number)들로 대체시킨 후, 최종적으로 엔트로피부호화에 의한 압축을 수행한다. 이와 같은 단계들을 거치면서 이미지 데이터의 통계적인 특성(statistical feature)이 보다 강화되기 때문에, 엔트로피부호화에서의 무손실 압축 성능을 효율적으로 개선시킬 수 있다. 실험을 통하여 256 명암도 등급 이미지들을 산술부호화와 허프만부호화를 사용하여 압축한 결과, 제안한 전처리기법이 압축 후 비트율(bit rate)을 최대 37.49%까지 감소시켰음을 확인하였다.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.3
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• pp.107-111
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• 2005

With the increasing use of multimedia technologies, image compression requires higher performance as well as new functionality in the informationized society. Specially, in the specific area of still image encoding in embedded system, a new standard, JPEG2000 that improve various problem of JPEG was developed. This paper proposed a method that reduce quantity of data delivered in EBCOT(Embedded Block Coding with Optimized Truncation) process using SPIHT(Set Partitioning in Hierarchical Trees) Algorithm to optimize selection of threshold from feature of wavelet transform coefficients and to remove sign bit in LL area for the increment of compression efficiency on JPEG2000. The experimental results showed the proposed algorithm achieves more improved bit rate in embedded system.

• Korean Journal of Digital Imaging in Medicine
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• v.8 no.1
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• pp.27-32
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• 2006

The rapid development in digital acquisition technology in radiography has not been accompanied by information regarding optimum radiolographic technique for use with an amorphus silicon flat panel detector. The purpose of our study was to compared imaging characteristics and image quality of an amorphus silicon flat panel detectors for digital chest radiography. All examinations were performed by using an amorphus silicon flat panel detector. Chest radiographs of an chest phantom were obtained with peak kilovoltage values of 60$\sim$150 kVp. Published data ell the effect of x-ray beam energy on imaging characteristics and image qualify when using an amorphus silicon flat panel detector. It is important that radiographers are aware of optimum kVp selection for an amorphus silicon flat panel detector system, particularly for the commonly performed chest examination.

• Journal of Biomedical Engineering Research
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• v.11 no.2
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• pp.217-226
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• 1990

This paper presents a new algorithm that extracted lung region in X-ray and enhanced the region. With a lung region that was extracted by histogram threshold value, it was diffi cult to detect perfect lung boundary. Therefore we presented perfect lung boundary detection method using apex detection and apex region restoration. Also, by applying modified equalization algorithm and presented function to inside of lung region, we want to give help to automatic diagnosis In X-ray chest image. Presented main line trace algorithm gave good result in detection of lung boundary And, as apex detection method using lung row and column gray level average value found more correct place of lung than the rpethod of prior algorithm, we succeeded perfect lung region detection, Also, presented function that had lung region's gray level distribution characteristic was very effective to image enhancement.

• Journal of Fashion Business
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• v.7 no.6
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• pp.10-20
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• 2003

The object of this research is to develop the designs with aesthetics and function for making the uniforms of specialty restaurants of Korean dishes in pursuit of the image of excellent dignity and its result is as follows: As for designs, this research chose the traditional image as the basic concept and made visual Korean lines, colors, and patterns. As for lines, it made visual the curve of the eaves, the straight line of polls, and the fret of windows and doors represented in architecture and applied them, as for color tones, it chose traditional 'Obangsaek', five direction colors. As for the patterns, it symbolized 4 trigrams( Geon, Gon, Gam, and Yi), the cloud pattern, also it tried to get the formative beauty from traditional patchwork wrapping cloth and windows and doors. The expectant effects on the design of Uniform are as follows: First, it offered basic clothes for male and female employees working in the hall and suggested two kinds of skirt and pants for the latter. It tried to find out both the function of pants and the female beauty of skirts by wrapping on pants to eliminate the feeling of rejection towards the style of them, the use of which have been recognized for man only in spite of many merits of them. Second, it sought for the characteristics of shape on collar, breast-tie, and fold etc. of Korean clothes and designed clothes according to each employee's role and finally emphasized their traditional aesthetics.

• Applied Microscopy
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• v.37 no.3
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• pp.199-208
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• 2007

We have made an optical device to study the wave optics phenomena, such as image and diffraction pattern, constructive and destructive interference, by direct operation of laser beam and optical lenses. It consists of laser beam, goniometer, objective lens, intermediate lens, projection lens, CCD system, and computing system. As a result of the performance test, we were able to magnify samples up to 44 times with the resolution of about $5{\mu}m$. It is expected to help EM users understanding more easily principles of transmission electron microscopy (TEM).

• Korean Journal of Optics and Photonics
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• v.17 no.6
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• pp.519-524
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• 2006

In general, the Lohmann-type binary hologram represents its amplitude and phase by using the rectangular cell. In this paper, we adapts a circular cell to represents the amplitude and phase of holograms. In order to compare the characteristics of the circular cell with the rectangular one, we analyzed the results based on the computer simulations and various optical experiments. The results show that a clearer reconstructed image can be obtained by dividing one cell into many pixels. In the case of a uniform reconstructed image, the rectangular cell is better than the circular cell. However, as for the brightness of the reconstructed image, the circular cell is better than the rectangular one.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.711-714
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• 2015

A new technique for image restoration using Weighted cross-shaped median filter with edge-detection algorithm is proposed in this paper. It consists of simple hypothesis test for edge-detection, and makes use of the weighted cross-shape window. This method is applied to noise corrupted image and its results are compared with those of median filters. As for the experimental result, method of weighted cross-shape median filter is superior to other median filters.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.1006-1009
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• 2013

In this paper, a new technique for image enhancement using cross-shaped median filter with edge-detection algorithm is proposed. It consists of simple hypothesis test for edge-detection, and makes use of the cross-shaped window. This method is applied to noise corrupted image and its results are compared with those of median filters. As for the experimental result, method of cross-shaped median filter is superior to other median filters.

• Journal of Magnetics
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• v.22 no.2
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• pp.227-233
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• 2017

The purpose of this study was to evaluate the effects of X-ray photon energy, tissue density, and the kernel essential for image reconstruction on the image quality by measuring HU and noise. Images were obtained by scanning the RMI density phantom within the CT device, and HU and noise were measured as follows: images were obtained by varying the tube voltages, the tube currents and eight different kernels. The greater the voltage-dependent change in the HU value but the noise was decreased. At all densities, changes in the tube current did not exert any significant influence on the HU value, whereas the noise value gradually decreased as the tube current increased. At all densities, changes in the kernel did not exert any significant influence on the HU value. The noise value gradually increased in the lower kernel range, but rapidly increased in the higher kernel range. HU is influenced by voltage and density, and noise is influenced by voltage, current, kernel, and density. This affects contrast resolution and spatial resolution.