Lizardtech DjVu v3 reference 0
ISBN: 2005
Год: Lizardtech, a Celartem Company
Количество страниц: 71
Язык: Английский
Формат: DJVU / RAR
Формат файла: RAR
Although the Internet has given us a worldwide infrastructure on which to build the universal library, much of the world knowledge, history, and literature is still trapped on paper in the basements of the world's traditional libraries. Many libraries and content owners are in the process of digitizing their collections. While many such efforts involve the painstaking process of converting paper documents to computer-friendly form, such as SGML based formats, the high cost of such conversions limits their extent. Scanning documents and distributing the resulting images electronically is not only considerably cheaper, but also more faithful to the original document because it preserves its visual aspect.
Despite the quickly improving speed of network connections and computers, the number of scanned document images accessible on the Web today is relatively small. There are several reasons for this.
The first reason is the relatively high cost of scanning anything else but unbound sheets in black and white. This problem is slowly going away with the appearance of fast and low-cost color scanners with sheet feeders.
The second reason is that long-established image compression standards and file formats have proved inadequate for distributing scanned documents at high resolution, particularly color documents. Not only are the file sizes and download times impractical, the decoding and rendering times are also prohibitive. A typical magazine page scanned in color at 100 dpi in JPEG would typically occupy 100 KB to 200 KB, but the text would be hardly readable: insufficient for screen viewing and totally unacceptable for printing. The same page at 300 dpi would have sufficient quality for viewing and printing but the file size would be 300 KB to 1000 KB at best, which is impractical for remote access. Another major problem is that a fully decoded 300 dpi color images of a letter-size page occupies 24 MB of memory and easily causes disk swapping.
The third reason is that digital documents are more than just a collection of individual page images. Pages in a scanned document have a natural serial order. Special provision must be made to ensure that flipping pages be instantaneous and effortless so as to maintain a good user experience. Even more important, most existing document formats force users to download the entire document first before displaying a chosen page. However, users often want to jump to individual pages of the document without waiting for the entire document to download. Efficient browsing requires efficient random page access, fast sequential page flipping, and quick rendering. This can be achieved with a combination of advanced compression, pre-fetching, pre-decoding, caching, and progressive rendering. DjVu decomposes each page into multiple components (text, backgrounds, images, libraries of common shapes.) that may be shared by several pages and downloaded on demand. This allows a suitably designed Dj Vu-viewing application to to handle on-demand downloading, pre-fetching, decoding, caching, and progressive rendering of the page images.
- Color theory and modeling for computer graphics,visualization,and multimedia applicat Levkowitz H.
Imagine a world in which the colors you see do not necessarily represent the correct ones Imagine, when you approach a traffic light, you cannot tell what color the light is Imagine the colors of traffic lights changing from one block to the next one - Introduction to error-correcting codes Purser M.
This book aims to be an introduction to the topic of error-correcting codes, a topic of major importance in digital communication whenever accuracy is critical There are several excellent specialist textbooks (and one or two almost unreadable ones) on the subject, in addition to innumerable articles and papers in the journals - Writing efficient programs Bentley J.
This book is about an approach to building efficient computer systems called writing efficient code" To put the approach in context, we will consider the importance of efficiency in Section 11 and study avenues to efficiency in Section 12 Section 1 - Algorithms Sedgewick R.
This book is intended to survey the most important algorithms in use on computers today and to teach fundamental techniques to the growing number of people who are interested in becoming serious computer users It is appropriate for use as a textbook for a second, third or fourth course in computer science: after students have acquired some programming skills and familiarity with computer systems, but before they have specialized courses in advanced areas of computer science or computer applications