• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.9
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• pp.538-545
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• 2000

In this paper we proposed a new map construction and path planning method for mobile robot. In our proposed method first we introduced triangular representation map that mobile robot can navigate through shorter path and flexible motion instead of grid representation map for mobile robot navigation. method in which robot can navigate complete space through as short path as possible in unknown environment is proposed. Finally we proposed new path planning method in a quadtree representation map. To evaluate the performance of our proposed new path planning method in a quadtree representation map. To evaluate the performance of our proposed triangular representation map it was compared with the existing distance transform path planning method. And we considered complete coverage navigation and new path planning method through several examples.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.183-186
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• 2008

All measures to cope with flooding rely on flood predictions to some extent, and the effectiveness of these measures is dependent on the quality of flood predictions. It is important to track properly the movements of the river-bankline in numerical modeling because the location of it varies continuously in the flood inundation. In this study, the wet and dry treatment is used to describe the moving river-bankline accurately (Cho, 1996). An oscillatory flow motion in a parabolic basin is used to validate the performance of the developed model based on quadtree grids. As a result of a simulation, a reasonable agreement is observed with analytical and Cho's results.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.7
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• pp.793-801
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• 1992

This paper proposes a method of extracting connected strokes and characters in a Hangeul document image represented by a quadtree. Connected strokes are extracted by examining adjacency for each node of a black region to the side of east and south. Then, each character is extracted by the sizes and the relations of connected strokes. This is done by iterative vertical and horizontal manipulation. The result shows all characters are extracted in the same sequence as that of context with space and time efficiency.

• Journal of the Korea Society for Simulation
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• v.10 no.3
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• pp.95-103
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• 2001

Rendering of 3D terrain data in real-time is difficult because of its large scale. So, it is necessary to use level-of-detail(LOD) that uses fewer data, but makes almost similar image to the original. We present an algorithm for real-time LOD generation and rendering of 3D terrain data. The algorithm applies wavelet transform to the terrain data, and then generates quadtree based view-dependent LOD using wavelet coefficients that are the output of wavelet transform. It also uses frame-to-frame coherence and view culling for high frame rates.

• Water for future
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• v.33 no.3
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• pp.68-73
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• 2000

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.3
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• pp.134-142
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• 2002

Quadtree, which is a hierarchical data structure, is a very important data structure to represent binary images. The linear quadtree representation as a way to store a quadtree is efficient to save space compared with other representations. Therefore, it has been widely studied to develop efficient algorithms to execute operations related with quadtrees. The window operation is one of important geometry operations in image processing, which extracts a sub-image indicated by a window in the image. In this paper, we present an algorithm to perform the window operation of binary images represented by quadtrees, using three-dimensional $n{\times}n{\times}n$ processors on RMESH(Reconfigurable MESH). This algorithm has constant-time complexity by using efficient basic operations to route the locational codes of quardtree on the hierarchical structure of $n{\times}n{\times}n$ RMESH.

• Journal of Broadcast Engineering
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• v.9 no.3
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• pp.257-273
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• 2004

In stereoscopic or multi-view three dimensional display systems, the synthesis of intermediate sequences is inevitably needed to assure look-around capability and continuous motion parallax so that it could enhance comfortable 3D perception. The quadtree-based disparity estimation is one of the most remarkable methods for synthesis of Intermediate sequences due to the simplicity of its algorithm and hardware implementation. In this paper, we propose two ideas in order to reduce the annoying flicker at the object boundaries of synthesized intermediate sequences by quadtree-based disparity estimation. First, new split-scheme provides more consistent auadtree-splitting during the disparity estimation. Secondly, adaptive temporal smoothing using correlation between present frame and previous one relieves error of disparity estimation. Two proposed Ideas are tested by using several stereoscopic sequences, and the annoying flickering is remarkably reduced by them.

• Journal of Korea Multimedia Society
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• v.15 no.4
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• pp.485-491
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• 2012

This paper proposes 'Coding Unit Tree' based on quadtree efficiently with motion vector to represent splitting information of a Coding Unit (CU) in HEVC. The new international video coding, High Efficiency Video Coding (HEVC), adopts various techniques and new unit concept: CU, Prediction Unit (PU), and Transform Unit (TU). The basic coding unit, CU is larger than macroblock of H.264/AVC and it splits to process image-based quadtree with a hierarchical structure. However, in case that there are complex motions in CU, the more signaling bits with motion information need to be transmitted. This structure provides a flexibility and a base for a optimization, but there are overhead about splitting information. This paper analyzes those signals and proposes a new algorithm which removes those redundancy. The proposed algorithm utilizes a type code, a dominant value, and residue values at a node in quadtree to remove the addition bits. Type code represents a structure of an image tree and the two values represent a node value. The results show that the proposed algorithm gains 13.6% bit-rate reduction over the HM-1.0.

• The KIPS Transactions:PartB
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• v.9B no.1
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• pp.77-82
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• 2002

Progressive image transmission involves a progressive increase in the image resolution at the receiver from a lower to a higher resolution during the transmission of data. This is an effective way of using a limited transmission channel, because, after estimating the value of the data in the early transmission period, a decision can be made whether or not to proceed with the transmission of the remaining part. To realize more effective progressive image transmission, the current thesis divides an image into bit planes and then re-organizes each plane into a complementary quadtree structure. As a result, by transmitting the data on each bit plane and each level of the complementary quadtree in the appropriate order, the basic image contents can be understood with less data in the early period of transmission.

• Journal of Korea Game Society
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• v.7 no.1
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• pp.43-52
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• 2007

This article describes a new contribution culling method for fast rendering of complex huge urban scenes. A view frustum culling technique is used for fast rendering of complex scenes. To support the levels-of-detail, we subdivide the image regions and construct a weighted quadtree. Only visible objects at the current camera position contributes the current quadtree and the weight is assigned to each object in the quadtree. The weight is proportional to the image area of the projected object, so large buildings in the far distance are less likely to be culled out than small buildings in the near distance. The rendering time is nearly constant not depending on the number of visible objects. The proposed method has applied to a new metropolitan region which is currently under development. Experimental results showed that the rendering quality of the proposed method is barely distinguishable from the rendering quality of the original method, while the proposed method reduces the number of polygons by about 9%. Experimental results showed that the proposed rendering method is appropriate for real-time rendering applications of complex huge scenes.