• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.2
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• pp.108-120
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• 1989

The paper describes a new algorithm for reducing the edge degradation of a vector quantization(VQ) in low rates. This algorithm exploits several codebooks, one of which is adaptively selected by standard deviation(SD) of the vector currently being coded. Also, SD search method for reducing the complexity of codebook search is proposed. As a result, a proposed VQ has good performance anout 30 dB PSNR in the 0.4-0.7 bpp range.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.3
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• pp.148-155
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• 2003

In this paper, a nonlinear anisotropic filtering method without the loss of important information happened due to the repeated filtering in magnetic resonance images is proposed. First of all original images are divided into four regions, e.g., SPR(Strong Plain Region), EPR(Easy Plain Region), SER(Strong Edge Region), and EER(Easy Edge Region). An optimal template among multiple templates is selected, then the nonlinear anisotropic filtering based on the template is applied in pixel by pixel basis. In the proposed algorithm, filtering strength of EER containing important information is adjusted very weak and filtering strength for remaining regions is also adjusted according to the degree of the importance. In spite of repeated filtering, resulting images by the proposed method could still preserve anatomy information of original images without any degradation. Compared to the existing nonlinear anisotropic filtering, the proposed filtering method with multiple templates provides higher reliability for filtered images.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.5
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• pp.382-393
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• 1991

In this paper, we propose a method for recognizing printed Korean characters using the Preceding Layer Driven multi-layer perceptron. The new learning algorithm which assigns the weight values to an integer and makes use of the transfer function as the step function was presented to design the hardware. We obtained 522 Korean character-image as an experimental object through scanner with 600DPI resolution. The preprocessing for feature extraction of Korean character is the separation of individual character, noise elimination smoothing, thinnig, edge point extraction, branch point extraction, and stroke segmentation. The used feature data are the number of edge points and their shapes, the number of branch points, and the number of strokes with 8 directions.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.329-330
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• 2006

This paper presents a recovery technique for images with block-based corruption by transmission losses. Conventional methods that do not consider edge directions can cause blocked blurring artifacts. In this paper, we present a block recovery scheme using Haar wavelet features. The adaptive selection of neighboring blocks is performed based on the energy ratio f wavelet subbands. The lost blocks are recovered by linear interpolation in the spatial domain using selected block pairs. The proposed directional recovery method is effective for the strong edge because it exploits the varying neighboring blocks adaptively according to the edges and the directional information in the image. The proposed method outperforms the previous methods that used only a predefined set of neighboring blocks.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.4
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• pp.189-196
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• 2013

This paper presents a two-stage approach to detect pedestrians in video sequences taken from a moving vehicle. The first stage is a preprocessing step, in which potential pedestrians are hypothesized. During the preprocessing step, a difference image is constructed using a global motion estimation, vertical and horizontal edge maps are extracted, and the color difference between the road and pedestrians are determined to create candidate regions where pedestrians may be present. The candidate regions are refined further using the vertical edge symmetry features of the pedestrians' legs. In the next stage, each hypothesis is verified using the integral channel features and an AdaBoost classifier. In this stage, a decision is made as to whether or not each candidate region contains a pedestrian. The proposed algorithm was tested on a range of dataset images and showed good performance.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.762-769
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• 2016

The dynamic modulation transfer function (MTF) for image degradation caused by sinusoidal vibration is formulated based on a Bessel function of the first kind. The presented method makes it possible to obtain an analytical MTF expression derived for arbitrary frequency sinusoidal vibration. The error obtained by the use of finite order sum approximations instead of infinite sums is investigated in detail. Dynamic MTF exhibits a stronger random behavior for low frequency vibration than high frequency vibration. The calculated MTFs agree well with the measured MTFs with the slant edge method in imaging experiments. With the proposed formula, allowable amplitudes of any frequency vibration are easily calculated. This is practical for the analysis and design of the line-of-sight stabilization system in the remote sensing camera.

• Journal of Digital Contents Society
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• v.5 no.1
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• pp.79-86
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• 2004

In this paper we implemented the Real Time Contrast Enhancer for image quality enhancement of moving picture. Also we proposed adaptive contrast method that use mean and variance of input video signal. The Designed the contrast Enhancer is measured in comparison with conventional picture and interfaced to 30inch TFT LCD TV of the LG Electronics.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.131-134
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• 2011

영상에서 경계선의 추출의 저수준 영상 처리에서 매우 중요하다. 하지만 대다수의 경계선 추출 방법들은 노이즈들의 영역이 많기 때문에 효율적이지 못하고 영상이 서로 다르기 때문에 유연하지 못하다. 본 논문에서는 이러한 문제 해결을 위하여 우선 노이즈 감소 단계를 제시한다. 그리고 점진적인 변화 폭의 히스토그램과 내부 클래스 최소 변이상의 양쪽 임계값들을 자동으로 선택하도록 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.449-451
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• 2000

본 논문에서는 내용기반 이미지 검색 시스템을 제작하기 위하여 필수적으로 선행되어야 하는 이미지의 영역구분에 대한 새로운 방법인 경계값을 이용한 영역추출 방법을 소개한다. 빠르고 정확한 이미지 검색엔진을 구현하기 위하여 질의의 결과가 될 이미지들은 전처리기에 의하여 모든 영역을 추출한 뒤 각각의 영역에 따른 특성(feature)를 저장하고 있어야 한다. 정확한 질의 결과를 얻기 위하여는 정확히 영역을 추출할 수 있고 그 특성도 추출할 수 있는 전처리기를 사용하여야 한다. 또한 정확도만을 중시하여 너무 복잡한 알고리즘을 사용한다면 그 또한 실용적이지 못하게 된다. 경계값을 이용한 영역추출 방법은 이미지의 각 점에 대한 경계값(edge value)을 이용하여 그 경계값이 작은 점으로부터 시작하여 경계값이 큰 점들을 병합해 가면서 인접한 영역간의 크기, 색상 등을 고려하여 각각의 영역을 구분해 낸다. 이 방법의 가장 큰 특징은 텍스쳐(texture)를 제외한 일반적인 영역뿐 아니라 텍스쳐 포함하는 영역도 추출할 수 있는 점과 빠른 처리 속도에 있다.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.431-434
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• 2003

In this paper, we propose an efficient method not only f3r producing accurate region segmentation, solving the over-segmentation problem of watershed algorithm but also f3r reducing post-processing time by reducing computation loads. Through this proposed method, region segmentation of neighboring objects and discrimination of similar intensities were effectively obtained. Input image of watershed algorithm has used the derivative-based detectors such as Sobel and Canny. But proposed method uses the pixels-similarity-based detector, that is, SUSAN. By adopting this proposed method, we can reduce the noise problem and solve the problem of over-segmentation and not lose the edge information of objects. We also propose Zero-Crossing SUSAN. With Zero-Crossing SUSAN, the edge localization, times and computation loads can be improved over those obtained from existing SUSAN