DJVU

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DJVU is a format by Lizardtech that is more and more widely used for scientific publications.

DjVu (pronounced "déjà vu") is a digital image format with advanced compression technology and high performance value. DjVu allows for the distribution on the Internet and on DVD of very high resolution images of scanned documents, digital documents, and photographs. DjVu viewers are available for web browsers, the desktop, and PDA devices. Its main characteristics is that the compress ratio is about 10x better than in PDF format at the same quality.

One of the main technologies behind DjVu is the ability to separate an image into a background layer (i.e., paper texture and pictures) and foreground layer (text and line drawings). Traditional image compression techniques are fine for simple photographs, but they drastically degrade sharp color transitions between adjacent highly contrasted areas - which is why they render type fonts so poorly. By separating the text from the backgrounds, DjVu can keep the text at high resolution (thereby preserving the sharp edges and maximizing legibility), while at the same time compressing the backgrounds and pictures at lower resolution with a wavelet-based compression technique. DjVu is used by many commercial and non-commercial web sites on the Web today.