fix for darkareas missalignment

[KillerInk]

its simple but effective. you have to add +64 to each input pixel and increase the blacklvl +64. due that its easier for the algo to algin correct in dark areas, no more ghosting and visible tiles.

greets

[timothybrooks]

Hi KillerInk,

Thanks for the recommendation! Could you submit a pull request for this? I would be happy to review and accept the change.

[KillerInk]

Hi Timothy

i try to add it to your code, but its untested.

i only use the align and merge part and do it aot compile. im including that complied lib in another project wich get the data direct from the camera and save it back as stacked dng.

also i think there is something wrong.

https://github.com/timothybrooks/hdr-plus/blob/bbcae37ffcc5cec4d3e7069bcab65b699659e57f/src/align.h#L7-L8

[KillerInk]

i wonder where that factor and the diff through 256 come from https://github.com/timothybrooks/hdr-plus/blob/bbcae37ffcc5cec4d3e7069bcab65b699659e57f/src/merge.cpp#L52

https://github.com/timothybrooks/hdr-plus/blob/bbcae37ffcc5cec4d3e7069bcab65b699659e57f/src/merge.cpp#L58

on the left side of the ledder is a figure wich gets smoothed with factor

orginal frame

with factor

factor removed

the factor seems to cause the ghosting in dark areas

[DanielMao2015]

@KillerInk hi, I am still confused about the effect of fact and the normailziation process. Can you help me?