• Journal of the Korea Society of Computer and Information
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• v.16 no.1
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• pp.61-69
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• 2011

This paper proposes a new algorithm that improve color component of compensated image using Retinex method for back-light image. A back-light image has two regions, one of the region is too bright and the other one is too dark. If an back-light image is improved contrast using Retinex method, it loses color information in the part of brightness of the image. In order to make up loss information, proposed algorithm adds color components from original image. The histogram can be divided three parts that brightness, darkness, midway using K-mean (k=3) algorithm. For the brightness, it is used color information of the original image. For the darkness, it is converted using by Retinex method. The midway region is mixed between original image and Retinex result image in the ratio of histogram. The ratio is determined by distance from dark area. The proposed algorithm was tested on nature back-light images to evaluate performance, and the experimental result shows that proposed algorithm is more robust than original Retinex algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.629-635
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• 2017

In this paper, we proposed a nonlinear synthesis filter for noise reduction to reduce the effects of Gaussian noise and impulse noise. When the centralization of the local mask is judged to be Gaussian noise by the noise judgment, the weight value of the weight filter are applied differently according to the spatial weight filter and the pixel change by using the sample variance in the local mask. And if it is determined as the impulse noise, we proposed an algorithm that applies different weights of local histogram weight filter and standard median filter according to noise density of mask. In order to evaluate the performance of the proposed filter algorithm, we used PSNR(peak signal to noise ratio) and compared existing methods and proposed filter algorithm in the mixed noise environment with Gaussian noise, impulsive noise, and two noises mixed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.11
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• pp.2029-2036
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• 2017

Currently, the demand for multimedia services is increasing with the rapid development of the digital age. Image data is corrupted by various noises and typical noise is mainly AWGN, salt and pepper noise and the complex noise that these two noises are mixed. Therefore, in this paper, the noise is processed by classifying AWGN and salt and pepper noise through noise judgment. In the case of AWGN, the outputs of spatial weighted filter and pixel change weighted filter are composed and processed, and the composite weights are applied differently according to the standard deviation of the local mask. In the case of salt and pepper noise, cubic spline interpolation and local histogram weighted filters are composed and processed. This study suggested the multiple image restoration filter algorithm which is processed by applying different composite weights according to the salt and pepper noise density of the local mask.

• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.1289-1303
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• 2010

The need for statistical process control to check the performance of a process is becoming more important in chemical and pharmaceutical industries. This study illustrates the method to determine whether a process is in control and how to produce and interpret control charts. In the experiment, a stream of green dyed water and a stream of pure water were continuously mixed in the process. The concentration of the dye solution was measured before and after the mixer via a spectrophotometer. The in-line mixer provided benefits to the dye and water mixture but not for the stock dye solution. The control charts were analyzed, and the pre-mixer process was in control for both the stock and mixed solutions. The R and X-bar charts showed virtually all of the points within control limits, and there were no patterns in the X-bar charts to suggest nonrandom data. However, the post-mixer process was shown to be out of control. While the R charts showed variability within the control limits, the X-bar charts were out of control and showed a steady increase in values, suggesting that the data was nonrandom. This steady increase in dye concentration was due to discontinuous, non-steady state flow. To improve the experiment in the future, a mixer could be inserted into the stock dye tank. The mixer would ensure that the dye concentration of the stock solution is more uniform prior to entering the pre-mixer ow cell. Overall, this would create a better standard to judge the water and dye mixture data against as well.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.175-177
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• 2010

본 논문에서는 MPEG 의 3차원 비디오 시스템의 표준 깊이정보 맵에 대한 효율적인 부호화를 위하여 전처리 방법을 제안한다. 현재 3차원 비디오 부호화(3DVC)에 대한 표준화가 진행 중에 있지만 아직 깊이정보 맵의 부호화 방법에 대한 표준이 확정되지 않은 상태이다. 제안하는 기법에서는 우선, 입력된 깊이정보 맵에 대하여 원래의 히스토그램 분포를 가우시안 혼합모델(GMM)기반의 EM 군집화 기법에 의한 방법으로 분리 후, 분리된 히스토그램을 기반으로 깊이정보 맵을 여러 개의 영상으로 분리한다. 그 후 분리된 각각의 영상을 배경과 객체에 따라 다른 조건의 mean shift filter로 필터링한다. 결과적으로 영상내의 각 영역 경계는 최대한 살리면서 영역내의 화소 값에 대해서는 평균 연산을 취하여 부호화시 효율을 극대화 하고자 하였다. 실험조건은 $1024{\times}768$ 영상에 대해서 50 프레임으로 H.264/AVC base 프로파일로 부호화를 진행하였다. 최종 실험결과 bit rate는 대략 23% ~ 26% 정도 감소하고 부호화 시간도 다소 줄어드는 것을 확인 할 수 있었다.

• Journal of the Korean Society of Visualization
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• v.14 no.3
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• pp.32-37
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• 2016

In this study, the mixing process of two distinct flow is numerically investigated. Two flow with different physical properties (resin and hardener) are mixed through the opposing mixing jets. At a high pressure mixing process, the high speed flow is provided by two in-line nozzles. In the case of numerical modeling, Reynolds-Averaged Navier-Stokes Equations (RANS) is conducted to model the flow pattern inside the chamber. Additionally, SST k-omega turbulence model is selected to predict the kinetic energy of flow in impingement zone. The results show that mixing of two distinct flows would be efficient if the velocity of jet is high enough and nozzle diameter is a predominant parameter. Also, this velocity would create higher shear stress between two distinct flows which increases the mixing quality as well as strength of formed vortices. Eventually, the histogram of concentration fraction of resin is examined in order to show the quality of mixing and the range of concentration fractions in the output of chamber.

• Journal of IKEEE
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• v.26 no.2
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• pp.292-298
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• 2022

There is a limit to improving the image quality through global processing of images taken under backlighting because too bright and dark parts are mixed in one scene. This paper introduces a method to improve the quality of a photo by making two virtual images that improve the dark and bright areas of a backlit photo, and fusing them with the original image into a Laplacian pyramid. The proposed method reduces the computational burden by using histogram stretching and gamma transformation that can be simplified with LUT when creating the two virtual images. In addition, in order to obtain a color-enhanced image, contrast conversion was performed only on the luminance using the HSV coordinate system. The proposed technique showed its effectiveness by calculating several NIQA indicators using standard image data sets.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.327-334
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• 2024

In this paper, we developed a system with a near-infrared LED light source with a wavelength of 950nm to acquire palm vein images and a white LED light source to acquire palm creases based on Raspberry Pi. In addition, we implemented a unique pattern-extractable image processing technology that can prevent counterfeiting and enhance security of mixed creases and palmprints through image pre-processing (Gray scaling, Histogram Equalization, Blurring, Thresholding, Thinning) for the acquired vein and palm images, and secured a source technology that can be used in a security-enhanced system.

• Progress in Medical Physics
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• v.16 no.3
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• pp.148-154
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• 2005

Since the output of retina for visual stimulus is carried by neurons of very diverse functional properties, it is not adequate to use conventional single electrode for recording the retinal action potential. For this purpose, we used newly developed multichannel recording system for monitoring the simultaneous electrical activities of many neurons in a functioning piece of retina. Retinal action potentials are recorded with an extra-cellular planar array of 60 microelectrodes. In studying the collective activity of the ganglion cell population it is essential to recognize basic functional distinctions between individual neurons. Therefore, it is necessary to detect and to classify the action potential of each ganglion cell out of mixed signal. We programmed M-files with MATLAB for this sorting process. This processing is mandatory for further analysis, e.g. poststimulus time histogram (PSTH), auto-correlogram, and cross-correlogram. We established MATLAB based protocol for waveform classification and verified that this approach was effective as an initial spike sorting method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.1
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• pp.169-178
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• 2010

The main purpose of this study is to evaluate the feasibility and the accuracy of ASTER DEM and SRTM DEM covering 99% of the earth surface using large-scale Digital Topographic Map in mountainous area(Sokcho), mixed area(Jinan, mountainous area and even land area) and even land area(Anyang). We made DEM using contour lines of 1:5,000 Digital Topographic Map of study area and also acquired ASTER DEM and SRTM DEM of their corresponding area. In order to verify accuracy of DEM, this study compared ASTER DEM and SRTM DEM data using 15m resolution DEM generated from contour lines of Digital Topographic Map as basis for each study area. To evaluate the accuracy of ASTER and SRTM DEM data, statistical such as RMSE and correlation were calculated and histogram and scatter plot were drawn. The analysis result shows that, both ASTER DEM and SRTM DEM have high accuracy but in aspects of future availability, ASTER DEM covering larger areas bas relatively more potential than SRTM data.