This paper presents an embedded wavelet packet image coding algorithm which is based on context classification and quadtree ordering (CCAQO). To match up well with the quadtree-based embedded coder, a new cost function for the best basis selection is adopted in discrete wavelet packet transform (DWPT). In addition, combined with the structure of the best wavelet packet basis, a complete quadtre...

We introduce a method for fast quadtree construction on the Graphics Processing Unit (GPU) using a level-by-level approach to quadtree construction. The algorithm is designed to build each subsequent level from the parent nodes of the previous level and thus is suitable for parallelization. Our work is motivated by the use of quadtrees for spactial segmentation of LIDAR data points for grid dig...

The proposed technique combines quadtree-based compression and chaotic-encryption, and can be used for secure image transmission over the internet. The method of quadtree decomposition, an image representation technique, essentially decomposes a given image into its four major quadrants, which are further decomposed progressively. The technique provides for a powerful variable resolution or var...

Instead of maintaining such a decomposition explicitly, it is convenient to construct a compressed quadtree T of the points of P , and every pair, (Ai, Bi) is just a pair of nodes (vi, ui) of T , such that Ai = Pvi and Bi = Pui , where Pv denote the points of P stored in the subtree of v, where v is a node of T . This gives us a compact representation of the distances. We slightly modify the co...

A texture segmentation algorithm is developed, utilizing a wavelet-based multi-resolution analysis of general imagery. The wavelet analysis yields a set of quadtrees, each composed of highhigh (HH), high-low (HL) and low-high (LH) wavelet coefficients. Hidden Markov trees (HMTs) are designed for the quadtree HH, HL and LH wavelet coefficients. Many textures have intricate structure, extending b...

We introduce a method for fast quadtree construction on the Graphics Processing Unit (GPU) using a level-by-level approach to quadtree construction. The algorithm is designed to build each subsequent level from the parent nodes of the previous level, and is thus suitable for parallelization. Our work is motivated by the use of General Purpose GPU (GPGPU) techniques for large data sets generally...

This study is to improve image data compression performance based on variable block-size quadtree image segmentation applied to double predictor differential pulse code modulation (DP–DPCM) image compressive algorithm. The quadtree segmentation method is applied to better allocate image characteristics. A variable block-size double predictor DPCM (VBDP–DPCM) image coding system works on an imag...

The aim of this paper is to present a new indexing technique that provides an efficient support for retrieving and handling spatial data. Traditionally, the mapping between layers (in a thematic point of view) and indexes structures is one to one. Each layer is associated with an index structure. In some previous work, we have presented a data structure, the FI-Quadtree that handles a set of im...

The goal of image segmentation is to partition an image into some homogeneous regions. In this paper, a novel neighborhood-based segmentation approach is proposed. Genetic algorithm is used in the proposed twopass process. In the first pass, an energy function, which is defined based on Markov Random Fields, is minimized. In the second pass, which is optional, segmentation results obtained from...

With a focus on mobile and web mapping, we propose several algorithms for on-the-fly generalization of point data, such as points of interest (POIs) or large point collections. In order to achieve real-time performance we use a quadtree. With their hierarchical structure and progressive levels of detail, indexes of the quadtree family lend themselves as auxiliary data structures to support algo...