HDRi (data format)
The proprietary HDRi data format is a 64bit (color) or 32bit (greyscale) data format for saving RAW data of HDR scans including infrared data in a TIFF container developed by LaserSoft Imaging.[1][2]
Data format
| Format | Encoding | Compression | Color space | Color depth (Bit per pixel) | Dynamic range (Dimensions of 10) | Relative gradation |
|---|---|---|---|---|---|---|
| HDRi (.tif, .tiff) | RGB (linear) | none | RGB | 64 = 48 + 16 (infrared channel) | 4,8 | 0,0014% |
| RGB (linear) | none | RGB | 32 = 16 + 16 (Infrared channel) | 4,8 | 0,0014% |
Description
Some image scanners, especially film scanners provide an additional infrared channel. The data it collects during a scan can be used for image optimization, e.g. for scratch and dust removal. The infrared RAW data and the usual image RAW data get saved in the HDRi data format, where 16bit per color channel are used for every pixel and additional 16bit for the infrared channel. Thus, a HDRI color file devotes resources of 64bit per pixel and a HDRi greyscale file 32bit per pixel.
Application
The infrared RAW data is saved lossless with the image RAW data. Therefore it isn't necessary to process them while scanning. This facilitates the digitalization of larger archives. Afterwards, the so filed originals can be post processed at any time with dust and scratch removal, possibly in batch mode.
See also
- High dynamic range imaging
- Infrared cleaning
- SilverFast
References
- ↑ it-enquierer.com: Article on HRDi and iSRD
- ↑ silverfast.com: HDRi - 64bit RAW data including infrared channel
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