Logluv TIFF
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Logluv TIFF is an encoding used for storing high dynamic range imaging data inside a TIFF image.
Logluv TIFF's design solves two specific problems: storing high dynamic image data and doing so within a reasonable amount of space. Traditional image format generally stores pixel data in 24 bits, with 8 bits for each color component. This limited the possible colors to subsection of all visible colors. Using a triplet of floats to represent RGB was a viable a solution, but it trippled the size of the file. To solve both of these problems - and a few others, Logluv TIFF uses 15 bits per component to store the pixel, making it 48 bits per pixel. Instead of using RGB, Logluv uses a color space derived from CIELuv.
One of the other drawbacks of 24 bit RGB was the linerization of the colors. This made it difficult to adjust the tonal quality of the color without adjust the color itself. Logluv uses a logarithmic scale to store its components. This made it extremely well suited for handling HDR data.
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[edit] Usage
Logluv TIFF has widespread use in HDRI applications such as IBL, image based lighting.
Reading and writing of Logluv TIFF images can be handled via libtiff. libtiff is freely available in both source and various binary packages for different platforms.
[edit] Resources
HDRI, by Reinhard et. al has a discussion regarding Logluv Tiff in the 3rd chapter.
For those looking for Logluv images, they are numerous example on Greg Ward Larson's page.
[edit] See also
- HDRI Image Format Comparison.