Region quadtrees are convenient tools for hierarchical image analysis. Like the related Haar wavelets, they are simple to generate within a fixed calculation time. The clustering at each resolution level requires only local data, yet they deliver intuitive classification results. Although the region quadtree partitioning is very rigid, it can be rapidly computed from arbitrary imagery. This res...

With the widespread use of GPS-enabled mobile devices, an unprecedented amount of trajectory data is becoming available from various sources such as Bikely, GPS-wayPoints, and Uber. The rise of innovative transportation services and recent break-throughs in autonomous vehicles will lead to the continued growth of trajectory data and related applications. Supporting these services in emerging pl...

Quadtree-like pyramids have the advantage of re-suiting in a multiresolution representation where each pyramid node has four unambiguous parents. Such a centered topology guarantees a clearly defined up-projection of labels. This concept has been successfully and extensively used in applications of contour detection, object recognition and segmentation. Unfortunately, the quadtree-like type of ...

An algorithm is presented that performs set operations (e.g., union or intersection) on two unaligned images represented by linear quadtrees. This algorithm seeks to minimize the number of nodes that must be searched for or inserted into the disk-based node lists that represent the trees. Windowing and matching operations can also be cast as unaligned set functions; these operations can then be...

We present a library for parallel block-sparse matrix-matrix multiplication on distributed memory clusters. By using a quadtree matrix representation data locality is exploited without any prior information about the matrix sparsity pattern. A distributed quadtree matrix representation is straightforward to implement due to our recent development of the Chunks and Tasks programming model [Paral...

Panoramic X-Ray images are very popular as a first tool for diagnosis in odontological protocols. Automating the process of analysis of such images is important in order to help dentist procedures. In this process, teeth segmentation from the radiographic images and feature extraction are essential steps. In this paper, we propose a segmentation approach based on mathematical morphology, quadtr...

The latest Geographic Information System (GIS) technology makes it possible to administer the spatial components of daily “business object,” in the corporate database, and apply suitable geographic analysis efficiently in a desktop-focused application. We can use wireless internet technology for transfer process in spatial data from server to client or vice versa. However, the problem in wirele...

Rendering of textured terrain models has become a widely used technique in the field of GIS applications and virtual reality. In this paper, we propose a framework based on tile-pyramid model and linear quadtree tile-index, which enable the real-time rendering of out-of-core terrain data sets while guaranteeing geometric and texture accuracy. The digital elevation model tile pyramid and the ort...

A rate-distortion framework is used to de ne a very low bit rate coding scheme based on quadtree segmentation and optimized selection of motion estimators. This technique achieves maximum reconstructed image quality under the constraint of a target bitrate for the coding of the vector eld and segmentation information . First, a complete scheme is proposed for hybrid 2D and 3D motion estimation ...