HDRi (data format)
|Format||Encoding||Compression||Color space|| Color depth|
(Bit per pixel)
| Dynamic range|
(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 16 bits per color channel are used for every pixel and an additional 16 bits for the infrared channel. Thus, a HDRI color file devotes resources of 64 bits per pixel and a HDRi greyscale file 32 bits 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
- silverfast.com: HDRi - 64bit RAW data including infrared channel