HDRi (data format)
|Format||Encoding||Compression||Color space||Color depth
(Bit per pixel)
(Dimensions of 10)
|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%|
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.
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.
- it-enquierer.com: Article on HRDi and iSRD