Hello Greg, > I tend not to use the -x option for critical work, as it's mostly a > time-saver as opposed to a way to improve accuracy. > > That said, the value range I consider "safe" extends from 27 to 228 in the > 8-bit domain. I have found this empirically to be above the noise floor > (provided the ISO setting is not too high) and below where some cameras > introduce highlight roll-off.
Interesting. Will have to update the heat map on WebHDR, then. It's set to 20 and 200 at the moment. > I cannot use a strict cut-off for image values. Up to 0.2% of the pixels > below the minimum are ignored and 0.05% of pixels above the maximum, > likewise. This avoids issues with stuck pixels, which would otherwise make > the -x option useless. This is also why it is better not to use -x for > critical work, because you may lose the peak highlight in your image if it > happens to be very small. This is probably what happened with my sequences. Since hdrgen copes admirably with completely black frames (as far as the human eye can tell), it's probably best to use them all, rather than make a pre-selection. > Note also that hdrgen would never discard an input exposure off the end > because it was "in range." Only the exposures shorter than first one below > the safe maximum and the exposures longer than last one above the safe > minimum that are considered superfluous. > > I have a Lubuntu installation running under VMWare with gcc version > 4.6.1-9ubuntu3. I could use it to recompile hdrgen if you like, but I'm not > sure what machines it would run on.... That would be absolutely super-fantastic. I understand from http://www.hdrlabs.com/news/index.php?id=8369771879810293991 that the ghost removal in Photosphere is now second to none, and that it can even handle breaking waves and swaying palm trees on tropical beaches. This is really exciting! I volunteer to update the man page, if you like. Thank you so much Axel _______________________________________________ HDRI mailing list [email protected] http://www.radiance-online.org/mailman/listinfo/hdri
