P-compressed Quadtrees for Image Storing

The expanding role of database systems is now faced with a new application field, i.e. large image-file management. Composite documents in the Office Automation environment often include images (e.g. graphs, drawings, illustrated or handwritten documents, and so on), as well as alphanumeric and other coded data. Images are stored on mass storage after conversion into a long sequence of bits, performed by scanner devices. Bit-map images are then compressed either using run-length encoding techniques or quadtree-based techniques. The goal of this paper is to show how quadtree-encoded images, which usually require more storage than run-length encodings, can be compressed using a new technique, named P-compression, which is effective for typical Office Automation documents.