Browsing by Author "Chen, IP"

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A simple recursive method for converting a chain code into a quadtree with a lookup table
(2001-05-01)
Chen, Z
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Chen, IP
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資訊工程學系
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Department of Computer Science
We present a simple recursive method for converting a chain code into a quadtree. We generate the quadtree black nodes level by level, starting from the finest resolution (i.e. the bottom) level toward the coarsest resolution (i.e. the top) level. Meanwhile, at each resolution level a new object border is revealed after the removal of the black nodes. The chain code elements for this new object border can be easily generated. Thus, the quadtree black nodes and the chain code elements of the new object border are generated side by side and their generations constitute a basic cycle of the conversion process. We show the generations can be done with the aid of a lookup table. Finally, we compare our method with the existing two-phase methods exemplified by Samet's method in terms of the total numbers of major operations including node allocations, node color filling, and node pointer linking. It indicates that our method is conceptually simpler and runs faster. (C) 2001 Elsevier Science B.V. All rights reserved.
Recursive conversion of chain code into quadtree with table lookup
(2000)
Chen, Z
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Chen, IP
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資訊科學與工程研究所
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Institute of Computer Science and Engineering
We present a simple recursive method for converting a chain code into a quadtree representation. We generate the quadtree black nodes recursively from the finest resolution level to the coarsest resolution level. Meanwhile, at each resolution level a new object border is unveiled after the removal of the black nodes. the chain code elements fo this new object border can then be easily generated. Thus, the generation of the quadtree black nodes at one level and the generation of the chain code elements of the new object border both constitute a basic cycle of the conversion process. We also show the generations can be done with the aid of a table lookup. Finally, our method is shown to be better than the well-known Samet's method in terms of the number of color filling operations.
Recursive representation and progressive display of binary objects for efficient network browsing
(1998-01-01)
Chen, IP
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Chen, Z
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資訊科學與工程研究所
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Institute of Computer Science and Engineering
When browsing binary objects in a network environment, data transmission rate, progressive display capability, and view modification under rotation, scaling, and/or translation (R/S/T) changes are the major factors for selection of an appropriate representation model of binary objects. A new half plane based representation and display method of 2D binary objects is proposed. Within this modeling framework, a binary object approximated by a shape of a polygon can be represented as a collection of half planes defined over the edges of the polygon under operations of union and intersection. The basic shape attributes of the object model are the slope and the intercept of the boundary line of the constituent half planes. It is shown that the representation parameters at the parent node is recursively related to those at the child nodes. This recursive relation is crucial for deriving the color of the nodes for progressive object display. Simulation results are provided to illustrate the performance of our method.
Recursive representation and progressive display of binary objects for efficient network browsing
(1998-12-01)
Chen, IP
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Chen, Z
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資訊科學與工程研究所
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Institute of Computer Science and Engineering
When binary objects are browsed in a network environment, data transmission rate, progressive display capability, and view modification under rotation, scaling, and/or translation (R/S/T) are the major factors for selection of an appropriate representation model of binary objects. A new half-plane-based representation and display method for 2D binary objects is proposed. Within this modeling framework, a binary object approximated by a shape of a polygon can be represented as a collection of half-planes defined over the edges of the polygon under operations of union and intersection. The basic shape attributes of the object model are the slope and the y-intercept of the boundary line of the constituent half planes. In the progressive display of the binary object our method adopts the quadtree block subdivision to divide the object image into hierarchical levels of detail (or resolution). Our method determines the color of a quadtree node based on the (angle, intercept) representation parameters. It is shown that the representation parameters at the parent node are recursively related to those at the child nodes, This recursive relation is crucial for deriving the color of the nodes for progressive object display. Lemmas for the node color determination for an object expressed in the form of half-planes, a convex polygon, or a concave polygon are derived step by step. Our method is generally better than many existing methods in terms of data transmission rate, progressive display capability, and view modification under R/S/T variations. Simulation results are provided to illustrate the performance of our method. (C) 1998 Academic Press.
The color appearance of chromatic textures
(2004-10-01)
Hsieh, TJ
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Chen, IP
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交大名義發表
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National Chiao Tung University