On 07/11/2018 11:17 AM, Marcel Brouillet wrote:
> I read about demosaic-ing and did my RAW-101 class :-). I'm still a noob on
> this. I understand the process would involve a RAW sticher, the PTO being
> generated on some initial set of (rough) converted files. Yet...
> Vladimir, why do you have the need to separate the colors ? Can't the
> stitching be done on the array of Bayer data ?
I was thinking about something similar to "Bayer drizzle" algorithm
(soory, right now I can't find any good explanationon fof it, the
information on google is rather fragmented)
The input is bayer data, output is normal RGB image.
> Care has to be taken that
> red values be distorted and only put in red positions in the resulting
> array, before mixed with other red values from other distorted arrays. But
> then the resulting array is a giant RAW array, a panoramic RAW, that needs
> to be de-mosaic'ed, white-balanced, noise-reduced, etc... The advantage
> (quite certainly not worth the development, but theoretical) being that you
> handle the RAW processing on the entire pano, afterwards.
> In other words, programmatic care has to be taken that « *The next problem
> is that after remapping the Bayer pattern is destroyed* » be avoided.
> I foresee a possible objection, that raw values only have sense in relative
> values within a single shot, and that two shots do not share the same
> numeric conversion origins (i.e. measurement offset, inconsistent
> calibration of the A-to-N converter). Is that so ?
I see no advantage in saving output as Bayer data. For example
Rawtherapee handles tif files almost the same as raws.
> Le lundi 9 juillet 2018 20:53:52 UTC+2, T. Modes a écrit :
>> Am Montag, 9. Juli 2018 16:02:06 UTC+2 schrieb nadv...@suse.cz:
>>> It might be possible to convert the mosaic data to independent channels
>>> with transparency:
>>> I don't see any principal problem with processing such images with nona
>>> and enblend.
>> If you do it this way each color will get different interpolation for each
>> color (because different alpha channels) and this will results in color
>> The next problem is that after remapping the Bayer pattern is destroyed.
>> With the destroyed Bayer pattern it because impossible (or at least very
>> difficult) for the RAW converter to demosaic the data now to get the final
>> (An alternative approach would be to demosaic the image data, then remap
>> the data and then mosaic the data again to get the RAW again. But then you
>> will loose resolution. So this is a no go.)
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