Byungki Cha
Kyushu Institute of Information Sciences
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Publication
Featured researches published by Byungki Cha.
Image and Vision Computing | 2009
Hideaki Kawano; Noriaki Suetake; Byungki Cha; Takashi Aso
We propose an image enlargement method preserving perceptual sharpness, which is achieved by augmenting a low resolution image with high-frequency components from a given image itself. The estimation of high-frequency image components is performed by a codebook built by a decomposition of the given image, i.e. a self-decomposed codebook. The rational that is exploited in this approach is the shape-invariant properties of edges across scales. As a distance measure for matching from the codebook, we employ the Mahalanobis distance which is a local distance measure incorporating pixel correlation. The effectiveness of the proposed method is verified by some image enlargement experiments. Consequently, the experimental results show that the performance of the proposed method is superior to other conventional image enlargement methods objectively and subjectively.
digital image computing: techniques and applications | 2007
Hideaki Kawano; Noriaki Suetake; Byungki Cha; Takashi Aso
We propose a method for constructing an image of high resolution by augmenting a low resolution image with high frequency components from a given image itself. The estimation of high frequency image components is performed by a codebook built by a decomposition of the given image, i.e. self-decomposed codebook. The rational that is exploited in this approach is the shape-invariant properties of edges across scale. As a distance measure for matching from the codebook, we employ a local distance measure incorporating pixel correlation. The effectiveness of the proposed method is verified by some image super-resolution experiments. Consequently, the experimental results show that the performance of the proposed method is superior to other typical image super-resolution methods objectively and subjectively.
acm multimedia | 2006
Suk-Hwan Lee; Ki-Ryong Kwon; Gwang-Seok Jung; Byungki Cha
For real-time animation, keyframe animation that consists of translation, rotation, scaling interpolator nodes is used widely in 3D graphics. This paper presents 3D keyframe animation watermarking based on vertex coordinates in CoordIndex node and keyvalues in PositionInterpolator node for VRML animation. Experimental results verify that the proposed algorithm has the robustness against geometrical attacks and timeline attacks as well as the invisibility.
pacific rim symposium on image and video technology | 2015
Ryosuke Kubota; Hakaru Tamukoh; Hideaki Kawano; Noriaki Suetake; Byungki Cha; Takashi Aso
In this paper, we propose a new color quantization method for generation of the color-reduced images. The proposed method employs a vector error diffusion VED method and a particle swarm optimization PSO. VED method based on Floyd-Steinberg dithering is used for display of the color-reduced image. Furthermore, a color palette used in VED method is optimized by PSO. PSO generates the effective color palette with evaluating a human visibility of the color-reduced image on the display. The validity and the effectiveness of the proposed method are confirmed by some experiments.
pacific-rim symposium on image and video technology | 2010
Hakaru Tamukoh; Hideaki Kawano; Noriaki Suetake; Masatoshi Sekine; Byungki Cha; Takashi Aso
A high-quality image enlargement is achieved by an estimation of high-frequency component. A codebook based method, which consists of a relationship of high and low-frequency image components, is known as one of the high-quality image enlargement. However, it takes too much calculation time, and is not appropriate for a real-time application such as a moving image enlargement. In this paper, we propose a hierarchal predefined codebook which achieves both of a fast calculation and a high-quality image enlargement. First, we define 1,904 code words generated from fundamental edge patterns. Then, the vector quantization is applied to the generated code words, and dividing 1,904 code words into 225 clusters. Finally, we obtain the hierarchal predefined codebook based on the divided code words. Experimental results show that the proposed method achieved both of a fast calculation and a high-quality image enlargement.
international conference on natural computation | 2008
Byungki Cha; Hideaki Kawano; Noriaki Suetake; Takashi Aso
We propose a fast segmentation technique for segmenting natural images into meaningful regions based on a minimum spanning tree (MST) principle. The main idea of the technique comes from the redundancy of MST based image segmentation process. We compared the performance of the proposed technique with the performance of depth first search (DFS) and of the traditional MST. Finally, the simple split and merge method based on the proposed technique is proposed with some natural images of the Berkeley segmentation dataset and compared with our results with humans handi-labeled segmentation results.
Optical Review | 2010
Hideaki Kawano; Hakaru Tamukoh; Noriaki Suetake; Byungki Cha; Takashi Aso
international conference on computer vision theory and applications | 2014
Hakaru Tamukoh; Noriaki Suetake; Hideaki Kawano; Ryosuke Kubota; Byungki Cha; Takashi Aso
대한전자공학회 기타 간행물 | 2008
Hye-Jung Chang; Jun-Hee Kim; Suk-Hwan Lee; Kwang-Seok Moon; Byungki Cha; Ki-Ryong Kwon
world automation congress | 2008
Byungki Cha; Hideaki Kawano; Noriaki Suetake; Takashi Aso