• Radiation Oncology Journal
• /
• 제18권4호
• /
• pp.345-354
• /
• 2000

목적 : 방사선조사야를 확인하는 보편적인 방법인 linacgram은 저대조도(low contrast)의 영상을 보여주고 있어 정확한 영상을 확인하는데 문제점이 있다. 따라서 본 연구는 linacgram의 대조도를 높이는 저가형 확인방법을 모색하여 영상판독과 조사야 확인에 도움이 되고자 한다. 대상 및 방법: 인체모형을 사용하여 얻어진 필름 영상을 필름전용 스캐너(Diagnostic Pro)를 통해 Optical Density Scan, Histogram Equalized, Linear Histogram Based (HB), Linear Histogram Independent, Linear Optical Density (OD) Logarithmic 및 Power, Square Root scan 방식으로 디지털화 하였다. 각기 다른 방식으로 전산 입력된 영상의 신호분포도를 얻어 signal intensity를 비교한 후 pailette fitting 방식을 통해 영상을 재구성하였고 재구성된 영상을 비교 분석하였다. 실제 치료에서 얻어진 각 인체 부위별 linacgram도 동일한 방법으로 처리한 후 화질 개선도를 알아 보았다. 결과 : 인체모형을 통해 얻어진 영상의 신호 분포영역은 Logarlthmic 방식을 선택했을 때 최소값인 3192가 나왔고 Square Root방식을 사용했을 때 최대값인 21940가 나왔다. 이러한 값들을 모니터 상에서 구현할 수 있는 256 gray scale로 바꾸어 보았을 때 7$\~$30$\%$ 만 사용되어지고 있음을 알수 있었다. Pallette fitting 방식을 통하여 모니터의 최대표현 값인 256 계조도로 Gray Scale Expansion (GSE) 함으로써 모니터가 지원하는 8bit gray scale pallette의 전범위를 사용하여 대조도가 개선되었다. 임상에서 얻어진 각 인체 부위별 무릎관절, 두경부, 폐, 골반영상에서도 GSE 처리하여 얻어진 영상이 해부학적 구조를 판독하는데 도움이 죄었다. 결론 : GSE 영상의 재구성은 대조도를 증가 시킬뿐 아니라 인체내 관심부위의 농도분포를 별도로 재구성할 수 있으므로 이중방사선조사(double exposure)에 의해 발생되는 화질의 저하를 보정함으로써 화질 개선을 가능하게 하였다. Linacgram 화질 개선은 simulation image 및 치료계획에서 발생한 DRR과 multi-layer 중첩영상 분석에 사용할 수 있으며 영상 비교 시 치료부위의 신속하고 정밀한 확인을 가능하게 하였다.

• 전자공학회논문지B
• /
• 제30B권10호
• /
• pp.27-34
• /
• 1993

In this paper, a driver system is designed and implemented to achieve 4-level gray scale CH TFEL(Thin Film ElectroLuminescent) flat panel display. To implement the driver system, commercial EL driver IC chips are used to apply high voltage pulses to the EL panel and a high voltage switching circuit is designed for the EL driver IC. A new method of reducing storage delay time of transistor is proposed to obtain a reliable switching circuit. The controller for EL driver and switching circuit is also designed. The designed driving scheme applicable to EL display with 4-level gray scale is based on the linear characteristics of brightness vs. frequency of AC TFEL. By experiment, it has been shown that the brightness of AC TEFL display with the implemented driving system is controlled by the level of gray scale.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
• /
• pp.1398-1400
• /
• 2005

A novel data driver for passive matrix organic lightemitting devices (PM-OLEDs) with high gray scale images was designed. The proposed circuit consisted of a main current bias circuit as well as sample & hold circuits in each channel of the data driver to compensate a current offset. These results indicate that a data driver designed by using the current offset compensation technique holds promise for poten tial applications in PM-OLED displays with high gray scale images.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2009년도 IWAIT
• /
• pp.38-43
• /
• 2009

The Chinese Ink Painting is an art with long history in Chinese culture. Painters can obtain various kinds of scenery by mixing water and ink properly. These papers provides a colorization technique that can transfer gray scale paintings to color paintings. Various colorization techniques for photorealistic images have good results. But these techniques are uncertainly suitable for Chinese Ink Painting. In our method, users only provide a gray scale Chinese Ink Painting and a similar color Chinese Ink Painting subjectively, system can automatically transfer the color from color painting to gray scale painting. We also provide a method for users to refine the automatically generated result.

• 한국전기전자재료학회논문지
• /
• 제21권4호
• /
• pp.368-375
• /
• 2008

In this paper, we calculated the pixel and all the inter-electrode capacitances in a unit pixel of three kinds of TFT-LCD modes in order to realize the full color image. And we analyzed the effect on applied voltage. We fixed size of sub-pixel and designed a unit pixel of three kinds of TFT-LCD modes. We calculated rigorously the pixel and all the inter-electrode capacitances by the three dimensional simulation. And we expanded one pixel into whole panel using H-SPICE. As a result, we calculated the RMS voltage and kickback voltage which most affect gray scale of the pixel and calculated the number of bit according to permissible range of minimum gray scale using V-T curve.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2001년도 하계학술발표회
• /
• pp.124-125
• /
• 2001

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.2485-2489
• /
• 2005

This paper introduces a new preprocessing scheme to replace original data of gray scale images with particular ordered data so that performance of lossless compression can be improved more efficiently. As a kind of preprocessing technique to maximize performance of entropy encoder, the proposed method converts the input image data into more compressible form. Before encoding a stream of the input image, the proposed preprocessor counts co-occurrence frequencies for neighboring pixel pairs. Then, it replaces each pair of adjacent gray values with particular ordered numbers based on the investigated co-occurrence frequencies. When compressing ordered image using entropy encoder, we can expect to raise compression rate more highly because of enhanced statistical feature of the input image. In this paper, we show that lossless compression rate increased by up to 37.85% when comparing results from compressing preprocessed and non-preprocessed image data using entropy encoder such as Huffman, Arithmetic encoder.

• 산업경영시스템학회지
• /
• 제43권1호
• /
• pp.16-25
• /
• 2020

Vegetation segmentation in a field color image is a process of distinguishing vegetation objects of interests like crops and weeds from a background of soil and/or other residues. The performance of the process is crucial in automatic precision agriculture which includes weed control and crop status monitoring. To facilitate the segmentation, color indices have predominantly been used to transform the color image into its gray-scale image. A thresholding technique like the Otsu method is then applied to distinguish vegetation parts from the background. An obvious demerit of the thresholding based segmentation will be that classification of each pixel into vegetation or background is carried out solely by using the color feature of the pixel itself without taking into account color features of its neighboring pixels. This paper presents a new pixel-based segmentation method which employs a multi-layer perceptron neural network to classify the gray-scale image into vegetation and nonvegetation pixels. The input data of the neural network for each pixel are 2-dimensional gray-level values surrounding the pixel. To generate a gray-scale image from a raw RGB color image, a well-known color index called Excess Green minus Excess Red Index was used. Experimental results using 80 field images of 4 vegetation species demonstrate the superiority of the neural network to existing threshold-based segmentation methods in terms of accuracy, precision, recall, and harmonic mean.

• Journal of the Optical Society of Korea
• /
• 제16권4호
• /
• pp.409-413
• /
• 2012

Off-axis color shift in the dark state and gray scale inversion in an in-plane switching (IPS) liquid crystal display (LCD) device were investigated. Analyses were performed using the Poincar$\acute{e}$ sphere representation. The results show that color shift in the dark state and gray scale inversion in an IPS LCD can be reduced by using a biaxial film. We confirmed the extent of these improvements by measuring the optical performance of a fabricated IPS LCD.

• 한국의류산업학회지
• /
• 제7권5호
• /
• pp.547-552
• /
• 2005

The study has objective in raising value of the gray color as a meaningful color suiting sentiments of modern people by expressing the gray color in various perspective utilizing natural dyes that is natural at the same time having aesthetic color tones. For example, the main ingredient used for coloring black and gray color is the pyrogallol tannin and the gray tone dye can be acquired by combining the tannin with iron. In order to find the suitable condition for processing tannin, UV-Vis part absorption spectrum of Gallapple pyrogallol tannin, dye ability based on temperature and time, reflection rate based on concentration, color changes based on acid treatment and alkali treatment, changes on surface based on concentration or metal mordant condition, and lightfastness were measured. Maximum absorption wavelength (${\lambda}_{max}$) of Gallapple tannin was at around 273 nm, while strong absorption was also observed at below 350 nm. Dye ability of Gallapple tannin is done more easily on silk rather than cellulose fibers such as cotton, while the optimum condition for dyeing was observed to be at $60^{\circ}C$, for 20 minutes. As a result of acid treatment, the color of dye material consist highly of gray tones and showed red tone after the alkali treatment. While it was observed that as dye concentration and metal mordant concentration increased the color changed at counter-clockwise direction on the Y-scale of Munsell's scale of colors. Lightfastness was more on a normal fading. I hope this study opens up possibilities towards presenting gray color expressed from tannin as color with diversity and aesthetic value. In future, comparative study between dye expressed from catechol tannin dye materials will be helpful.