• Journal of Broadcast Engineering
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• v.13 no.5
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• pp.760-770
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• 2008

Though flash images are in general less noisy and present details better than no-flash images, they may sometimes be unnaturally saturated to white/gray-tone and have ridiculously strong shadows around the foreground objects due to the strong flashlight. In this paper, we propose a new algorithm to improve the color quality of the flash images by transfer of the color information of the same-scene no-flash images. The proposed algorithm preserves the vivid edges and the clean details of the flash image while transferring natural colors of the no-flash image, so that it makes the constructed images of the better subjective quality. The performance of the proposed algorithm is verified by experiment which applied to the two types of images with different noise levels.

• Journal of Korea Multimedia Society
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• v.8 no.4
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• pp.516-524
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• 2005

In this paper, a new watermarking scheme based on the POCS theory and human visual system is proposed. Using the POCS theory, watermarks are embedded into imperceptible image regions such as edge and strong texture area in the spatial domain. Also it is inserted into middle frequency band in the transform domain to achieve the robustness against compression and filtering, etc. In addition, different gain factors are employed into blocks classified by considering texture masking effect. By doing so, the proposed method has a novel property of having both the imperceptibility and the robustness simultaneously. Simulation results show that the proposed method has an excellent performance better than conventional approaches.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.10
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• pp.789-796
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• 2006

An unpaired many-to-many k-disjoint nth cover (k-DPC) of a graph G is a set of k disjoint paths joining k distinct sources and sinks in which each vertex of G is covered by a path. Here, a source can be freely matched to a sink. In this paper, we investigate unpaired many-to-many DPC's in a subclass of hpercube-like interconnection networks, called restricted HL-graphs, and show that every n-dimensional restricted HL-graph, $(m{\geq}3)$, with f or less faulty elements (vertices and/or edges) has an unpaired many-to-many k-DPC for any $f{\geq}0\;and\;k{\geq}1\;with\;f+k{\leq}m-2$.

• Journal of Broadcast Engineering
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• v.13 no.6
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• pp.849-858
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• 2008

In this paper, a no-reference perceptual metric is proposed for image quality assessment. It measures the amount of overall blockiness and blurring of the image and evaluates the amount of ringing, staircase, and mosaic noises around the strong edges. Finally, the individual scores are combined by a fuzzy integral to generate the final quality score of the image. The quality scores obtained by the proposed algorithm show strong relationship with the MOS(Mean Opinion Score) values by experts.

• Journal of Korea Multimedia Society
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• v.5 no.2
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• pp.147-157
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• 2002

Noise in image sequences is visually offensive and may mask important image detail. In addition to degradation of visual quality, the noise pattern increases the entropy of the image, and thus hinders effective compression. This paper proposes a spatial and a temporal joint filters to reduce the noise by jointly connecting two adaptive noise reducers with different characteristics, and we also propose an IIR-type 3D noise reduction litter scheme connecting the spatial and the temporal joint filters. The proposed 3D IIR filter not only strongly removes noise in uniform image regions while preserving edges and details but also effectively suppresses temporal flicker caused by noise. Experimental results show that the proposed scheme improves subjective quality as well as objective quality as compared with the various noise filtering techniques.

• Journal of the Korea Society of Computer and Information
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• v.4 no.4
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• pp.77-85
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• 1999

In this paper. improved the formula of Kass. First of all, improved initial guess inside and outside of an object. So, prevent the of shrink, find more easily and faster the contour of object. Secondly, proposed the algorithm which moved to local minimum with the improvement of formula of the internal energy and $3{times}3$ matrix. Process the noise of local minimum with use of medial filtering. In third, process the phenomenon which edge points gather one point with imposing energy to the energy term. Improve the algorithm to find the contour precisely with the use of threshold. The result of these improvements, make an initial guess easily and find the contour of objects which have higher curvature. Improve the speed of process by reducing the repetition of feedback system.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.598-600
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• 2005

본 논문은 MPEG-4 기반의 모바일 비디오 서비스 환경에서 발생하는 화질열화 현상의 하나인 블륵킹 현상을 제거하는 기법을 제안한다. 제안된 기법은 전처리 과정과 3가지 모드의 디블록킹 필터 및 후처리 과정으로 구성되어 있으며 각 모드는 블록경계의 특성에 따라 적용된다. 모드 1은 블록경계의 양쪽 모두가 평탄한 경우에 해당하며 가장 강한 필터를 적용한다. 모드 2는 블록경계의 한쪽만 평탄한 경우이고 이때는 비대칭 필터를 적용한다. 모드 3은 블록경계를 중심으로 양쪽 모두 복잡한 경우이고, 이 경우에는 블록경계의 주파수 특성을 고려하여 화소값을 보정한다. 전처리 과정에서는 각 필터의 모드를 올바르게 선택하도록 블록 내부의 불필요한 신호를 제거하고, 후처리 과정에서는 대각선 에지와 블록의 모서리가 만나는 경우 발생하는 corner outlier를 제거하여 주관적 화질을 향상시킨다. 실험결과에서 제안한 방법이 PSNR 관점에서 후처리 과정을 거치지 않는 비디오의 경우와 비교하여 약 0.7dB, MPEG-4 디블록킹 결과와 비교하여 약 0.4dB 향상됨을 보인다.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.1
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• pp.40-51
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• 2009

A paired many-to-many k-disjoint path cover (paired k-DPC) of a graph G is a set of k disjoint paths joining k distinct source-sink pairs in which each vertex of G is covered by a path. In this paper, we investigate disjoint path covers in recursive circulants G($cd^m$,d) with $d{\geq}3$ and tori, and show that provided the number of faulty elements (vertices and/or edges) is f or less, every nonbipartite recursive circulant and torus of degree $\delta$ has a paired k-DPC for any f and $k{\geq}1$ with $f+2k{\leq}{\delta}-1$.

• The KIPS Transactions:PartA
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• v.11A no.3
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• pp.189-198
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• 2004

We consider the fault hamiltonian properties of m ${\times}$ n meshes with two wraparound links on the first row and the last row, denoted by M$_2$(m,n), (m$\geq$2, n$\geq$3). M$_2$(m,n), which is bipartite, with a single faulty link has a fault-free path of length mn-l(mn-2) between arbitrary two nodes if they both belong to the different(same) partite set. Compared with the previous works of P$_{m}$ ${\times}$C$_{n}$ , it also has these hamiltonian properties. Our result show that two additional wraparound links are sufficient for an m${\times}$n mesh to have such properties rather than m wraparound links. Also, M$_2$(m,n) is a spanning subgraph of many interconnection networks such as multidimensional meshes, recursive circulants, hypercubes, double loop networks, and k-ary n-cubcs. Thus, our results can be applied to discover fault-hamiltonicity of such interconnection networks. By applying hamiltonian properties of M$_2$(m,n) to 3-dimensional meshes, recursive circulants, and hypercubes, we obtain fault hamiltonian properties of these networks.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.2
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• pp.32-43
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• 2004

In this paper, a system which can effectively recognize the plate image extracted from camera set on a moving car is proposed. To extract car licence plate from moving vehicles, multiple candidates are maintained based on the strong vertical edges which are found in the region of car licence plate. A candidate region is selected among them based on the ratio of background and characters. We also make a comparative study of recognition performance between support vector machines and modular neural networks. The experimental results lead us to the conclusion that the former is superior to the latter. For a better recognition rate, a simple method combining the support vector machine with modular neural network where the output of the latter is used as the input of the former is suggested and evaluated. As we expected, the hybrid one shows the best result among those three methods we have mentioned.