• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.9C
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• pp.840-848
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• 2007

A multiple description coding (MDC) scheme for 3-D Data is presented. First, a plane-based 3-D data is split into two descriptions, each of which has identical contribution in 3-D surface reconstruction. In order to maximize the visual quality of reconstructed 3-D data, then, plane parameters are modified according to channel error condition. Finally, these descriptions are compressed and transmitted over distinct channels. In decoder, if two descriptions are available, we reconstruct a high quality 3-D data. If only one description is transmitted, however, 3-D surface recovery scheme reduces artifacts on erroneous 3-D surface, yielding a smooth 3-D surface. Therefore, the proposed algorithm guarantees acceptable quality reconstruction of 3-D data even though one channel is totally lost.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.2 s.308
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• pp.63-71
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• 2006

Denoising and reconstruction of color images are extensively studied in the field of computer vision and image processing. Especially, denoising and reconstruction of color face images are more difficult than those of natural images because of the structural characteristics of human faces as well as the subtleties of color interactions. In this paper, we propose a denoising method based on PCA reconstruction for removing complex color noise on human faces, which is not easy to remove by using vectorial color filters. The proposed method is composed of the following five steps: training of canonical eigenface space using PCA, automatic extraction of facial features using active appearance model, relishing of reconstructed color image using bilateral filter, extraction of noise regions using the variance of training data, and reconstruction using partial information of input images (except the noise regions) and blending of the reconstructed image with the original image. Experimental results show that the proposed denoising method maintains the structural characteristics of input faces, while efficiently removing complex color noise.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.6
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• pp.117-124
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• 2008

The approaches to overcome the limited spatial resolution and the limited dynamic range of image sensors have been studied independently. A high resolution image is reconstructed from multiple low resolution observations and a wide dynamic range image is reconstructed from differently exposed multiple low dynamic range in es based on signal processing approach. In practical situations, it is reasonable to address them in a unified context because the recorded image suffers from limitations of both spatial resolution and dynamic range. In this paper, the image acquisition process including limited spatial resolution and limited dynamic range is modelled. With the image acquisition model, the response function of the imaging system is estimated and the single image of which spatial resolution and dynamic range are simultaneously enhanced is obtained. Experimental results indicate that the proposed algorithm outperforms the conventional approaches that perform the high resolution and wide dynamic range reconstruction sequentially with respect to both objective and subjective criteria.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.255-259
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• 2003

In this paper, we propose an improved image encryption and decryption method using a virtual image and a joint transform correlator (JTC). The encrypted image is obtained by the Fourier transform of the product of a virtual-phase image and a random-phase image, and a Fourier transform of the decrypting key generated by the proposed phase assignment rule is used as the Fourier decrypting key. Based on the solution, the original image is reconstructed using JTC in the frequency-domain. The proposed method using a virtual image, which does not contain any information from the original image, prevents the possibility of counterfeiting by unauthorized people. And also the auto-correlation terms, which are the drawback of a JTC system, contribute to reconstructing the original image rather than to disturbing its identification. But because phase-only encryptions are sensitive to noise and scratches, phase errors can be generated in fabricating the encrypted image or the Fourier decrypting key so the errors that are responsible for degradation of the quality of the reconstructed image are analyzed and the solution is demonstrated. Computer simulations show the solution, and the proposed method is very useful for JTC architecture.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.11a
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• pp.193-196
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• 2017

본 논문에서는 콘트라스트 복원 기법을 통한 효과적인 비 제거 알고리즘을 제안한다. 기존의 비 제거 알고리즘은 영상에 나타난 비를 제거하는 과정에서 빗줄기로 인한 콘트라스트 감소 현상을 제거하지 못하는 단점이 존재한다. 이에 본 논문에서는 합성곱 신경망을 이용하여 빗줄기를 제거하는 기존의 알고리즘에 덧붙여 빗줄기로 인해 발생된 콘트라스트 변화량을 추정하여 복원하는 과정을 추가함으로써 기존의 알고리즘보다 효과적으로 비를 제거하는 방법을 제시한다. 실험을 통해 성능을 분석한 결과, 제안하는 알고리즘은 모든 결과 영상에 대하여 기존의 알고리즘에 비해 높은 화질 평가 수치를 나타내었으며 주관적으로도 더 선명한 결과를 보여주었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9C
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• pp.743-747
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• 2010

This paper presents an iterative adaptive hybrid image restoration algorithm for fast convergence. The local variance, mean, and maximum value are used to constrain the solution space. These parameters are computed at each iteration step using partially restored image at each iteration, and they are used to impose the degree of local smoothness on the solution. The resulting iterative algorithm exhibits increased convergence speed and better performance than typical regularized constrained least squares (RCLS) approach.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.417-418
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• 2012

본 논문에서는 3차원 데이터를 이용한 효율적인 실내 공간 표현 기법을 제안한다. 제안하는 기법은 3차원 데이터의 획득과 실내 구조 및 영상 정보를 표현하기 위한 표현 복원으로 구성된다. 3차원 데이터는 레이저 거리 측정기(laser range finder, LRF)와 전방향(omni) 카메라를 통해 획득한 포인트 클라우드 공간 정보와 전방향 텍스쳐 영상으로 구성된다. 실내 구조를 복원하기 위해, 획득한 포인트 클라우드를 복셀 격자 기반의 샘플링 기법을 통해 균일화하고 포아송 표면 재구성(Poisson surface rocoostruction) 기법을 통해 3차원 메쉬를 생성한다. 그리고 전방향 텍스쳐 영상과 3차원 메쉬외 기하학적 관계를 이용한 텍스쳐 매핑 기법을 통해 최종적으로 3차원 메쉬 표면을 복원한다. 실험 결과를 통해 제안하는 기법이 실내 공간을 효과적으로 표현함을 확인한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.29-35
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• 2012

In this paper, it is presented the method of image recovering which existing is only pixel processing, but suggesting method is concluding image clustering overlap degree after classfying around unit fixel to crowd pixel. Concluding overlap degree threshold value is after identifying pattern pixel and grasping geometry structure of sample pattern and deduction of deciding function. distinguishing feature space is above four dimension is reason of not visual observation of pattern structure. consideration of distribution structure is distance of center of crowd pixel, the number of each crowd pattern pixel and standard deviation. The over threshold value elimate the overlap image and the downward is recovered and established dynamic image. memory storage deduction of 20% and elevation of 15% performance is estimated in recovery of image.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.3
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• pp.27-33
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• 2003

The image-based 3D modeling is the technique of generating a 3D graphic model from images acquired using cameras. It is being researched as an alternative technique for the expensive 3D scanner. In this paper, we propose the image-based, 3D modeling system using calibrated stereo cameras. The proposed algorithm for rendering, 3D model consists of three steps, camera calibration, 3D reconstruction, and 3D registration step. In the camera calibration step, we estimate the camera matrix for the image aquisition camera. In the 3D reconstruction step, we calculate 3D coordinates using triangulation from corresponding points of the stereo image. In the 3D registration step, we estimate the transformation matrix that transforms individually reconstructed 3D coordinates to the reference coordinate to render the single 3D model. As shown the result, we generated relatively accurate 3D model.

• Journal of IKEEE
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• v.22 no.1
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• pp.149-155
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• 2018

In this paper, we used ET(Electrical Tomography) for earth resistivity image reconstruction of vertical multi layer underground model. The earth resistivity is analyzed generally as the parallel multi-layer model, however possibly there happens vertical layer model. Here to find the best electrode array in case of vertical layer underground model, Wenner, Schlumberger, and Dipole-dipole electrode arrays, which are well known electrode arrays used in ET, have been tested. And Gauss-Newton algorithm is used in ET inversion. RMS error analysis shows that Wenner electrode array is best in imaging.