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Bae K.,Korean German Institute of Technology | Kim H.,Chonbuk National University
International Journal of Multimedia and Ubiquitous Engineering | Year: 2013

The conventional search methods have computational complexity problem and imprecision problem in correspondence matching process. To resolve these problems, we propose how to effectively make feature space (distance map) and how to rapidly search the optimal point correspondence. The proposed distance map named Voronoi distance map is a 2-Dimensional surface that contains the distance information between each element(x-y coordinates) of image and the nearest feature point. The proposed distance map is efficiently created based on the priority-based calculation algorithm. The general distance calculation algorithm has a time complexity of O(w * h * n). (w = width, h = height, n = the number of feature points) whereas the priority-based distance calculation algorithm is a effective method with a computational cost of O(w * h * logn). Also, The partition search algorithm is a efficient method that can detect corresponding points very rapidly because this method can reduce the search range by a quarter at a time. Experimental results show that the proposed method outperforms conventional methods in reducing computation time and detecting the optimal correspondence. © 2013 SERSC. Source

Jang S.,Yonsei University | Yang J.,Korean German Institute of Technology | Kim D.K.,Yonsei University
IEEE Communications Letters | Year: 2010

We study a joint optimal design of transceiver and relaying architecture in terms of mean square error (MSE) performance for multi-user multiple-input multiple-output (MIMO) relaying system. We show a duality relationship in the design of MSE-optimal transceiver and relaying architecture. Based on that, we devise an alternating algorithm, which converges and provides a suboptimal joint design of transceiver and relaying. By simulation, we show that the proposed joint design improves on the average MSE performance of the existing transceiver and relaying architectures. © 2010 IEEE. Source

Kim H.,Korean German Institute of Technology | Lee S.,Sungkyunkwan University
Proceedings - IEEE International Conference on Robotics and Automation | Year: 2010

This paper presents a novel line matching method based on the intersection context of coplanar line pairs especially working in poorly textured indoor scenes. To overcome the matching ambiguity of single line segments, intersecting line pairs in 2D images are utilized for line matching. Coplanarity of the intersecting line pairs and their corresponding intersection context discriminate true intersecting line pairs from false intersecting ones in 3D world. Compared to previous approaches, the proposed method can match line segments and estimate camera geometry simultaneously not knowing camera geometry in advance or not considering topological relations of all line segments. Comparison studies and experimental results prove the accuracy and speed of the proposed method in real world situations. ©2010 IEEE. Source

Lee Y.-B.,Sungkyunkwan University | Choi Y.-J.,Korean German Institute of Technology | Kim M.-H.,Ewha Womans University
Computers in Biology and Medicine | Year: 2010

The intima-media thickness (IMT) of the carotid artery, obtained from B-mode ultrasound images, has recently been proposed as one of the most useful indices of atherosclerosis and can also be used to predict major cardiovascular events. Ultrasonic measurements of the IMT are conventionally obtained by time-consuming manual tracing of the interfaces between tissue layers. We propose a computerized method to detect the boundary of the intima-media complex using a directional Haar-like filter that can account for the slope of the boundary in an image. The directional Haar-like filter extracts a directional boundary feature as an image feature in the region of interest, which is used to compute a cost function. A cost function includes not only the directional Haar-like filtering value but also the geometric continuity that is computed for every pixel in the region of interest. The optimal boundary pixels are detected by using a dynamic programming approach that searches for the pixel that minimizes the cost function in each column of the image. We compared the performance of the proposed method with that of manual methods performed by two radiologists. The results showed that our approach produces very similar results to those based on manual tracing, and there was no statistically significant difference between the IMT measurements segmented manually and those analyzed using our method. © 2010 Elsevier Ltd. Source

Kim J.,Yonsei University | Choe Y.,Yonsei University | Kim Y.-G.,Korean German Institute of Technology
Digest of Technical Papers - IEEE International Conference on Consumer Electronics | Year: 2013

The recursive quad-tree structure of Coding Unit (CU) in HEVC can improve coding efficiency while the encoding complexity is increased significantly. In this paper, a fast CU size decision algorithm to reduce the complexity of HEVC intra coding is proposed. It introduces the early termination method based on the statistics of rate-distortion costs in CU splitting process. Experimental results show the encoding time can be reduced by 24% on average without significant loss of BD-rate. © 2013 IEEE. Source

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