• Journal of Korea Water Resources Association
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• v.53 no.6
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• pp.451-461
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• 2020

Urban flooding due to rapid urbanization has recently become frequent. In this study, a hydraulic model experiment was conducted on Shinwol rainwater storage and drainage system constructed for the first time in South Korea to prevent urban flooding. Experiments were preformed for 55 scenarios, of which 19 overflows occurred. In addition, the video analysis for the scenarios where the overflow occurred showd that the overflow occurred during the process of exhausting the pressurized air in the facility and the undular bore were moving. Results of this study, it was judge that it would be advantageous to maintain a completely drained or full-pipe condition for stable operation of the Shinwol rainwater storage and drainage system for continuous rainfall in the future. And it is necessary to additional research on the correlation for the magnitude of inflow discharge, overflow and undular bore.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.1
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• pp.38-46
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• 2004

Image segmentation is the task which partitions the image into meaningful regions and considered to be one of the most important steps in computer vision and image processing. Image segmentation is also widely used in object-based video compression such as MPEG-4 to extract out the object regions from the given frame. Watershed algorithm is frequently used to obtain the more accurate region boundaries. But, it is well known that the watershed algorithm is extremely sensitive to gradient noise and usually results in oversegmentation. To solve such a problem, we propose an image segmentation method which is robust to noise by using stabilized inverse diffusion equation (SIDE) and is more efficient in segmentation by employing multiresolution approach. In this paper, we apply both the region projection method using labels of adjacent regions and the region merging method based on region adjacency graph (RAG). Experimental results on noisy image show that the oversegmenation is reduced and segmentation efficiency is increased.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1104-1113
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• 2014

Future combat systems can be represented as the NCW (Network Centric Warefare), which is based on the concept of Sensor-to-Shooter. A wireless video sensor networking technology, one of the core components of NCW, has been actively applied for the purpose of tactical surveillance. In such a surveillance sensor network, multi-composite sensors, especially consisting of image sensors are utilized to improve reliability for intrusion detection and enemy tracing. However, these sensors may cause a problem of requiring very high network capacity and energy consumption. In order to alleviate this problem, this paper proposes an image data transmission scheme based on resource reservation. The proposed scheme can make it possible to have more reliable image data transmission by choosing proper multiple interfaces, while trying to control resolution and compression quality of image data based on network resource availability. By the performance analysis using NS-3 simulation, we have confirmed the transmission reliability as well as energy efficiency of the proposed scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.595-598
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• 2005

MPEG-4 Visual is, and international standard for the object-based video compression, designed for supporting a wide range of applications from multimedia communication to HDTV. To control the minimum decoding complexity required at the decoder, the MPEG-4 Visual standard defines the co-called video buffering mechanism, which includes three video buffer models. Among them, the VCV(Video Complexity Verifier) defines the control of the processing speed for decoding of a macroblock, there are two models: VCV and B-VCV distinguishing the boundary and non-boundary MB. This paper presents the evaluation results of decoding complexity by measuring decoding time of a MB for rectangular, arbitrarily shaped video objects and the various types of objects supporting the resolution of HDTV using the optimized MPEG-4 Reference Software. The experimental results shows that decoding complexity varies depending on the coding type and more effective usage of decoding resources may be possible.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.2
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• pp.126-131
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• 2004

Full search algorithm(FA) provides the best performance but this is usually impractical because of the large number of computations required for large search region. Fast search and conventional Boolean matching algorithms reduce computational complexity and data processing time but this algorithms have disadvantages that is difficult of implementation of hardware because of high control overhead and that is less performance than FA. This paper presents new Boolean matching algorithm, called BCBM(Bit Converted Boolean Matching). Proposed algorithm has performance closed to the FA by Boolean only block matching that may be very efficiently implemented in hardware for real time video communication. Simulation results show that the PSNR of the proposed algorithm is about 0.08㏈ loss than FA but is about 0.96∼2.02㏈ gain than fast search algorithm and conventional Boolean matching algorithm.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.3
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• pp.310-315
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• 2004

Image taken in the night can be low-contrast images because of poor environment and image transmission. We propose an algorithm that improves the acquired low-contrast image. MPEG-2 separates chrominance and illuminance, and compresses respectively because human vision is more sensitive to luminance. We extracted illumination and used K-means algorithm to find a proper crossover point automatically. We used K-means algorithm in the viewpoint that the problem of crossover point selection can be considered as the two-category classification problem. We divided an image into two subimages using the crossover point, and applied the histogram equalization method respectively. We used the index of fuzziness to evaluate the degree of improvement. We compare the results of the proposed method with those of other methods.

• The Journal of the Korea Contents Association
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• v.9 no.9
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• pp.1-8
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• 2009

H.264/AVC video coding standard uses the rate distortion optimization method which determines the best coding mode for macroblock(MB) to improve coding efficiency. Whereas RDO selects the best coding mode, it causes the heavy computational burden comparing with previous standards. To reduce the complexity, in this paper, a fast intra prediction mode decision algorithm using directional gradients is proposed. The proposed algorithm is composed of 2-path structure. In the first path, $16{\times}16$ intra prediction mode is determined using directional gradients. In the second path, 3 modes instead of 9 modes are chosen for RDO to decide the best mode for $4{\times}4$ block. Finally, the two modes determined in the two-path decision process are compared to decide the final block mode. Experimental results show that the computation time of the proposed method is decreased to about 77% of the exhaustive mode decision method with negligible quality loss.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.699-706
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• 2008

H.264/AVC is a new international standard for the compression of video images, in which a deblocking filter has been adopted to remoye blocking artifacts. This paper proposes an efficient architecture of deblocking filter in H.264/AVC. By making good use of data dependence between neighboring $4{\times}4$ blocks, the memory sire is reduced and the throughput of the deblocking filter processing is increased. The designed deblocking filter further enhances the parallelism by simultaneously executing horizontal and vertical filtering within a macroblock in pipeline method and adopting overlap between macroblocks. The implementation result shows that the proposed architecture enhances the performance of deblocking filter processing from 1.75 to 4.23 times than that of the conventional deblocking filter. Hence the Proposed architecture of deblocking filter is able to perform real-time deblocking in high-resolution($2048{\times}1024$) video applications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.945-949
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• 2009

This paper proposes an enhanced motion estimation that is one of core parts affecting the coding performance and visual quality in video coding. Although the full search technique, which is the most basic method of the motion estimation, presents the best visual quality, its computational complexity is great, since the search procedures to find the best matched block with each block in the current frame are carried out for all points inside the search area. Thus, various fast algorithms to reduce the computational complexity and maintain good visual quality have been proposed. The PMVFAST adopted the MPEG-4 visual standard produces the visual quality near that by the full search technique with the reduced computational complexity. In this paper, we propose a new motion vector prediction method using median processing. The proposed method reduces the computational complexity for the motion estimation significantly. Experimental results show that the proposed algorithm is faster than the PMVFAST and better than the full search in terms of search speed and average PSNR, respectively.

• Journal of the Korea Society of Computer and Information
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• v.17 no.2
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• pp.177-185
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• 2012

In this paper, we developed the composition system that it can efficiently edit camera recording data, images, office document such as powerpoint data, MS word data etc in real-time and broadcasting system that the file is made by the composition system. In this Study, we developed two kinds of algorithm; Approximate Composition for Optimization (ACFO) and Sequence Composition using Memory Que (SCUMQ). Especially, the system is inexpensive and useful because the system is based on mobile devices and PCs when lectures hope to make video institutional contents. Therefore, it can be contributed for e-learning and m-learning. In addition, the system can be applied to various fields, different kinds of multimedia creation, remote conferencing, and e-commerce.