• Journal of Korea Society of Industrial Information Systems
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• v.12 no.1
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• pp.39-45
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• 2007

In this paper, we present a new postprocessing algorithm using interpolation and signal adaptive filter according to the each block characteristic which is acquired in block classification process. We applied blocking artifact reduction algorithm for four neighbor low frequency block and ringing artifacts is removed with preserving edges by applying a signal adaptive filter in high frequency block based on edge map. The computer simulation results confirmed a better performance by the proposed method in both the subjective and objective image qualities.

• Journal of the Korean Professional Engineers Association
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• v.37 no.2
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• pp.58-61
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• 2004

황사는 중국과 몽골의 건조지역으로부터 바람에 의해 수송되어 날아오는 먼지 현상이다. 이 먼지현상은 이따금 멀리 북미대륙까지(Husar 등, 2001) 이동한 것이 위성영상으로 확인되며, 캐나다(McKendry 등, 2001)에서도 실제 관측되기도 한다. 요즘에는 이 먼지가 인체와 기후에 미치는 염려를 하는 사람이 많아지며, 이를 예측하는 연구가 시도되기도 한다. 우리나라에서 과거에 기록된 황사현상은 있을까？ 있다면, 얼마나 되며, 최근과 비교하면 무엇이 다른가？ 삼국시대의 역사 기록인 삼국사기와 고려시대의 고려사, 조선시대의 조선왕조실록과 증보문헌비고 속에 기록된 지난 약 2천년간의 기록을 정리해보았다. 또한 기존의 와다유우지(Wada, 1917)와 다무라센노스케(Tamura, 1983)의 조사결과도 참고하여, 우리나라에서의 관측된 황사기록을 가능한 많이 찾고, 확인하여, 과거 우리나라의 황사현상을 되짚어 보았다.

• Journal of Broadcast Engineering
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• v.13 no.5
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• pp.651-661
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• 2008

This paper proposes a novel contrast enhancement (CE) algorithm for color images using the modified error diffusion (ED). After conventional color histogram equalization (HE), artifacts such as false contours are produced in the contrast enhanced image. The proposed CE algorithm using the modified ED consists of two parts: CE and ED. In the first part, a low-contrast input image is enhanced by the conventional HE method. In the second part, we use the modified ED algorithm. The inputs of the second part are the average and scaled difference images of the original color input image and the HE image, in which the scaled color difference image is diffused by the ED algorithm. In the proposed algorithm, the modified ED algorithm reduces the artifacts produced in the HE image, and increases the number of color levels. Computer simulations with a number of low-contrast color images show the effectiveness of the proposed CE method in terms of the visual quality as well as the probability mass function. It can be used as a post-processing for CE with simultaneous artifact reduction in various display devices.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.389-395
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• 2018

The study attempted to use computed tomography images to determine the usefulness of the reduction in the axial reduction algorithm in the event of a metallic artifacts reduction in the image of the beam-hardening effect, which is known as the most effective method of reducing metallic artifact reduction in the image and the reduction of the metal produced in this study. As a result, the result is increased to 140 kVp to reduce the value of the CT value by 0.02 to 0.05 %, resulting in decreased axial effect (P > 0.05). The CT value decreased from 12.4 to 26.9 % when applied to the reduction of the metallic. 12.4 to 26.9 % (p<0.05). In addition, in the qualitative assessment by the clinical trial evaluation, it was assessed as 1.8 points after applying the MAR algorithm, In the resolution of resolution and contrast evaluations, the estimation of the decrease in metallic artifact effects was assessed as the metal was assessed to be scored 7.2 points after the MAR algorithm was evaluated. Therefore, in case of artifacts due to irreversible beam hardening effect, it is useful to reduce artifacts caused by beam hardening effect by using various methods derived from existing researches and scanning by applying the metal artifact reduction algorithm proposed in this experiment.

• The Journal of Korean Association of Computer Education
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• v.13 no.4
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• pp.77-86
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• 2010

In this paper, we propose a real time post-processing visual enhancement technique to reduce the blocking artifacts in block based DCT decoded image for mobile devices that have allocation of the restricted resource. In order to reduce the blocking artifacts effectively even while preserving the image edge to the utmost, the proposed algorithm uses the deblocking filtering or the directional filtering according to the edge detection of the each pixel. After it is discriminated that the pixel to apply the deblocking filtering belongs again to the monotonous area, the weighted average filter with the adaptive mask is applied for the pixel to remove the blocking artifacts. On the other hand, a new directional filter is utilized to get rid of staircase noise and preserve the original edge component. Experimental results show that the proposed algorithm produces better results than those of the conventional algorithms in both subjective and objective qualities.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.18-26
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• 2009

Image resolution enhancement algorithm is a basic technique for image enlargement and restoration. The main problem is the image quality degradation such as blurring or blocking effects. In this paper, we propose loss information estimation and image resolution enhancement method using low level interpolation method. In the proposed method, loss information is computed by downsampling -interpolation process of obtained low resolution image. We estimate loss information of high resolution image using interpolation of the computed loss information. Lastly, we add up interpolated high resolution image and the estimated loss information which is applied a weight factor. Our experiments obtained the average PSNR 1.4dB which is improved results better than conventional algorithm. Also subjective image quality is more clearness and distinctness. The proposed method may be helpful for various video applications which required improvement of image.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.4
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• pp.87-92
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• 2004

Digital halftoning is to quantize a grayscale image to binary image. The error diffusion halftoning generates high quality bilevel image. But that also has some defects such as warms effect, sharpening and etc. To reduce these defects, Kite proposed the modified threshold modulation that has a parameter to control sharpening. Nevertheless some degradation left near edges with large luminance change. In this paver, we propose a method to control the parameter in proportional to local edge magnitude. The results of computer simulation show more reductions of the sharpening in the halftone image. Especially there are great improvement of quality near edges with large luminance change.

• Journal of Broadcast Engineering
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• v.14 no.2
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• pp.197-209
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• 2009

Stereoscopic video delivers depth perception to users contrary to 2D video. Therefore, we need to develop a new video quality assessment model for stereoscopic video. In this paper, we propose a new method for objective assessment of stereoscopic video. The proposed method detects blocking artifacts and degradation in edge regions such as in conventional video quality assessment model. And it detects video quality difference between views using depth information for efficient quality prediction. We performed subjective assessment of stereoscopic video to check the performance of the proposed method, and we confirmed that the proposed algorithm is superior to the existing method in PSNR in respect to correlation with results of the subjective assessment.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.4
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• pp.423-430
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• 2002

When JPEG, a standard of stopped image compression, is high compressed, the image is severely blocked. Since JPEG performs compression after taking DCT(Discrete Cosine Transform). It has a defect that the quality of image becomes low with aliasing in the case of high compression. Though transformation cipher method can have high compression rate, flame nay happen to quality of image by transformation and reverse transformation. In this paper, we use wavelet transform and fractal theory in order to solve these problems. After we apply these two methods to stopped image, we can get some good results, improvement of speed and compression rate, and elimination of blocking appearance. Besides, we show quality of restoration image is better than established one.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.580-584
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• 2005

One of the problems of panoramic image stitching methods is that its computational cost is so high that the image processing required usually cannot be done in real-time. Real-time performance is important in applications such as video surveillance becausewe must see current scenes. But it takes more than several seconds to calculate transform coefficients between images. Panoramic VR technologies such as Apple QuickTime VR have problem that distorts images of top and bottom. This paper presents a fast stitching method and a methpd reducing distortions of top and bottom in cubic panoramic image.