DjVu is among the most established of image-compression technologies that allows easy circulation of scanned documents across the web. DjVu is the preferred scanning medium for communicating digitalized documents and photographs. It also helps content-developers to scan colored pages from magazines, manuals, books, catalogs and newspapers besides getting amazingly clear images of historical documents. This is the reason why DjVu has been widely accepted by institutions that regularly require data to be converted from the hardcopy to the scanned format. This includes libraries, research institutes and government agencies handling large-scale documentation that often need to share their archives in the online mode. However, this doesn’t mean that DjVu isn’t suitable for the business world.
In fact, an increasing presence of DjVu among companies has been noted since it helps workplaces to distribute documents using the localized intranet and instantly share scanned documents with co-workers in offshore offices. Today, the development aspect and distribution of DjVu technology is being handled as an open standard at Caminova Incorporated. DjVu now presents standard file format specifications along with open-source implementation for the encoder and decoder. It’s also compatible with many PDF conversion services, which helps expand its use in corporate digitization.
The increasing use of DjVu among businesses is not surprising, since companies do realize that paper-based information too represents significant invested value in terms of the manpower hours spent on creating such records apart from the creative, indexing and storage costs. With DjVu, businesses are assured that the high resolution required to sustain the readability of the text is guaranteed and the quality of images is sustained, i.e. at par with the original copy. DjVu also offers a great degree of customization. For instance, in some locations, bigger files can be too difficult to download, so the resolution can be decreased in DjVu to achieve reasonable scanning quality without the quality being compromised because of limited download speeds.
In this manner, DjVu has been able to blend quality, practicality and legibility without forfeiting the quality aspect. The progressive nature of DjVu can be evaluated by the fact that nearly all the widely-used web formats, including GIF, JPEG and PNG are quite restricted in terms of providing large images at decent resolution scales, while DjVu doesn’t forfeit quality in any way. DjVu boats have enviable compression ratios that are usually 5-to-10 times higher than such conventional web formats. These benefits are often compared with newer compression technologies like JBIG2 compression, which is widely used in PDF optimization.
Even when compared with TIFF, the resolution quality of DjVu is between 3-to-8 times better. For instance, pages scanned at 300 DPI in color can be easily compressed between 30 and 100 KB files via DjVu. In regard to fully-colored documents and those containing images that also include text, DjVu files are at least five-times smaller than a JPEG file in the same capacity. Similarly, DjVu files are about three-to-eight times smaller than black-and-white PDF files.
Apart from handling scanned documents, DjVu is equally dexterous at creating electronic images in the PDF format. To make it easier for users, DjVu plug-ins are now available on most of the popular web browsers. The plug-ins allow easy zooming and panning of document images. This tool also combines a surprisingly easy fly decompression technology that allows images needing 25 MB of RAM to be compressed to the extent that they require only about 2 MB of RAM!
Conventional image viewing software is a bit impractical for creating high-resolution images since they often tend to exceed the memory limitations of the PC’s configuration. This often causes unwanted disk swapping, but DjVu is smart enough not to decompress the whole image. Instead, it maintains the image in a compact form, i.e. in the PC’s memory, and then decompresses only the parts that are displayed on the screen—‘real-time decompression’ as per the user’s preferences.
What makes DjVu so advanced is its ability to separate an image into a foreground and a background layer. The conventional image compression methods tend to degrade the image quality when handling acute color transitions that are often found among high-contrast parts of the image. With DjVu, the text is separated from the background, ensuring that the readability of the text is maintained at high resolution, while the simultaneous compression of backgrounds at lower resolution helps to customize the image size.