Recently, more research has been conducted on moving object databases (MOD). Typically, there are three kinds of data for dynamic attributes in MOD, i.e., historical, current and future. Although many index structures have been developed for the former two types of data, there is not much work to deal with the future data. In particular, the problem of index update has not been addressed with e...

In this paper, we propose an algorithm for neighbors finding in images represented by quadtree data structure. We first present a scheme for addressing image pixels that takes into account the order defined on a quadtree blocks. We study various properties of this method, and then we develop a formula that establishes links between quadtree blocks. Based on these results, we present an efficien...

Progressive, adaptive and hierarchical modes are desirable image coding features. This paper presents a quadtree-pruning pyramid coding scheme satisfying all these objectives. Pyramid coding is an approach suitable for progressive image tramsmission, where the original image is divided into different levels that correspond to successive approximants of the original one. Starting from the origin...

In this paper we present a model and experimental results for performing parallel fractal image compression using circulating pipeline computation and employing a new quadtree recomposition approach. A circular linear array of processors is employed and utilized in a pipelined fashion. In this approach, a modification of the scheme given by Jackson and Blom, quadtree sub-blocks of an image are ...

We consider the problem of building a quadtree subdivision for a set E of n non-intersecting edges in the plane. Our approach is to first build a quadtree on the vertices corresponding to the endpoints of the edges, and then compute the intersections between E and the cells in the subdivision. For any k ≥ 1, we call a K-quadtree a linear compressed quadtree that has O(n/k) cells with O(k) verti...

The quadtree data structure is commonly used in image coding to decompose an image into separate spatial regions to adaptively identify the type of quantizer used in various regions of an image. The authors describe the theory needed to construct quadtree data structures that optimally allocate rate, given a set of quantizers. A Lagrange multiplier method finds these optimal rate allocations wi...

An algorithm is presented to answer window queries in a quadtree-based spatial database environment by retrieving all of the quadtree blocks in the underlying spatial database that cover the quadtree blocks that comprise the window. It works by decomposing the window operation into sub-operations over smaller window partitions. These partitions are the quadtree blocks corresponding to the windo...

In this paper, we present a fractal image compression algorithm employing a new quadtree recomposition (QR) approach. In this approach, quadtree subblocks of an image are iteratively recombined into larger blocks for fractal coding. For complex images, this approach exhibits superior runtime performance, when compared to a classical quadtree decomposition (QD) scheme, while maintaining high del...

In this paper, a new image authentication scheme based on quadtree segmentation is presented. In this scheme, partial digital signature encryption is employed to ascertain the origin of the image. Furthermore, the quadtree structure is imposed on the design of the authentication code. The authentication code consists of the quadtree list and the mean values of the quadtree leaf nodes. The size ...

In this paper we introduce efficient parallel quadtree construction and manipulation algorithms on hypercube multiprocessors. The notion of extended binomial tree is introduced to represent the distributed quadtree structure on a hypercube. By incorporating the geometric property into the distributed quadtree structure, we devise a data assignment scheme which satisfies the multi-level adjacenc...