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RE: filmscanners: GEM & the LS2000
> is GEM available only at the hardware level? or is there a way to do GEM
> post scan? more specifically will i ever be able to take a raw scan
> from the LS2000 and do GEM processing on it?
>From postings I have seen from ASF, the official answer is that ROC and GEM
require ASF to characterize the scanner, but...
In the ROC patent (which should be very similar to how GEM operates) they
discuss how to calibrate the system. Calibration eliminates certain off
diagonal elements from a response matrix that is central to their technique.
These elements result from non linear characteristics of the scanner and
film. Their preferred calibration method starts with a scanner having a
known spectral response, but they also talk about calibrating a system
starting with a known film and deriving the scanner properties.
>From this it looks like ASF should be able to specify a calibration slide
(Kodak Q60 should work) and derive the scanner properties required for ROC
and GEM. Doing it this way would probably result in lower quality results
since there is one extra step in the calibration sequence. It may be that
the processing contained in the shipping versions of ROC and GEM contain
proprietary algorithms not covered in the patent that require direct
knowledge of the scanner.