#Djvu zone djvulibre pdf#
It allows in particular to convert to DjVu the PDF output of popular OCR programs like FineReader preserving the hidden text layer and some other features. The DjVu GPLed tools are not limited just to the DjVuLibre library, but are being supplemented by various new programs, such as pdf2djvu developed by Jakub Wilk. It relies on the DjVu format, which for some applications is still superior to other modern formats including PDF/A. The paper describes an open-source tool which allows to present end-users with results of advanced language technologies. All the data taken together allow to link the search results to theĪppropriate fragments of the original scans. For every word, instead of grammatical tags, we provide its localization on the page in the form of the line number and its position in the line. In our ,quick and dirty'' approach we treat every page as a single document with the metadata consisting of the name of the document index and the name of the file with the page content. Some preliminary experiments are described in the talk. The Institute of Computer Science of Polish Academy of Sciences. For this purpose we intend to adapt Poliqarp (Polyinterpretation Indexing Query and Retrieval Procesor), a GPLed corpus query tool developed in
#Djvu zone djvulibre how to#
So the question is how to search efficiently the text layer in such large multi-volume works. Another important feature is the ability to store (and serve over Internet) the documents as aįrom the very beginning it has been used also for dictionaries, in particular there are also several Polish dictionaries available in this format. An essential feature of the format is the hidden text layer, usually containing the results of Optical Character Recognition. One of the best formats for scanned documents is DjVu. Compression ratios on scanned US patents at 300dpi are 5.2 to 10.2 times higher than GroupIV with shared dictionaries and 3.6 to 8.5 times higher than GroupIV without shared dictionaries. Shared dictionaries allow 40% typical file size reduction for scanned bitonal documents at 300dpi. This greatly reduces the overall bandwidth requirements. shape dictionaries, or background layers) are loaded as required and cached. Components that are shared across pages (e.g.
Pages are pre-fetched or loaded on demand, allowing users to randomly access pages without downloading the entire document, and without the help of a byte server.
#Djvu zone djvulibre software#
A multithreaded software architecture with smart caching allows individual components to be loaded and pre-decoded and rendered on-demand. Image components include :text images, background images, shape dictionaries shared by multiple pages, OCRed text, and several types of annotations. DjVu document files are merely a list of enriched URLs that point to individual files (or file elements) that contain image components.
We describe the image structure and software architecture that allows the DjVu system to load and render the required components on demand while minimizing the bandwidth requirements, and the memory requirements in the client. Image-based digital documents are composed of multiple pages, each of which may be composed of multiple components such as the test, pictures background, and annotations.
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