Well, this is embarrassing. When mentioning there is no documentation about it and there is.
As mentioned in my mail, when I "discovered" this (Christmas holiday), your enfuse reference manual was not "published" yet and I couldn't find documentation about the topic. Later on (February) I started reading your document and at about 50% I got interested in focus blending and skipped to that section thereby missing the section about noise reduction. After last weekend (having released ImageFuser 0.6) I got back to the "noise reduction" and decided to write something about it. I feel embarrassed because I have been working on your document converting it to the wiki and I completely overlooked the section about noise reduction. Off course, at that moment I only focussed on the conversion itself. 2009/4/11 cspiel <[email protected]> > Harry - > > On Apr 10, 7:30 pm, Harry van der Wolf <[email protected]> wrote: > > --- snip --- > > > I also use enfuse quite often for noise reduction, both for normal > photo's, > > bracketed sets and darker panorama's. > > > > I can't find any documentation related to that on the web, not even on > the > > enblend/enfuse project home page [4], so I assume it is a little known or > > even unknown fact. > > The very document you are citing, namely the new > Enfuse documentation features a section on noise > reduction called "6.2 Repetition – Noise Reduction": > > > http://wiki.panotools.org/Enfuse_reference_manual#Repetition_.E2.80.93_Noise_Reduction > > And there is a section on Enfuse's weighting > algorithm, where section "3.1.1 Weighted > Average" in particular mentions the limiting > case of an "arithmetic average". > > > > --- snip --- > > > I assume this enfuse functionality is an undiscovered gem as it has never > > been the purpose of the enfuse tool. It's just a nice side effect, and a > > very effective one. > > Prior art. > > > > I think it is very nice functionality. I know most camera's nowadays have > > noise reduction systems but I find these inferior to enfuse. > > It is not quite fair to compare the noise > reduction of a camera that works on just one > image with the multi-image technique you put to > work with Enfuse. > > Moreover, the in-camera noise reduction systems > are not necessarily based on averaging or > k-selection (read: median) algorithms. > Dark-frame subtraction is common, though. > I never pretended it to be a fair comparison (as it isn't). The in-camera noise reduction is getting better and it is handy and sometimes works well. I didn't discuss or compare the technique (for which I'm not knowledgable enough), I wrote about results: in-camera noise reduction is (currently) inferior to the enfuse image stack approach. Nothing more, nothing less. > > > > I assume you can even improve the result with the enfuse expert options, > > but this is also an area I'm just beginning to discover. > > To my knowledge there is not even an Expert > Option to improve on the averaging. > > We have several possibilities to get you closer > to the cigar. > > (1) Offer different exposure weight functions. > > This one is easy. On the command line, I can > imagine something like > --wExposure=1.0:gaussian > --wExposure=1.0:double-exponential > --wExposure=1.0:distance > where the part after the colon selects the > weighting function over the normalized luminance > interval. Internally, the weighting functions > already are functors... > > (2) Offer different weight contribution functions. > > Currently, we use "--SoftMask" to let contribute _every_ > pixel according to its weight ("democracy" -- well, > kind of), and "--HardMask" where only the pixel > with the largest weight contributes > ("monarchy"). > > As you might know, I plan an extension for the > staging branch of Enblend/Enfuse > > https://code.launchpad.net/~cspiel/enblend/staging<https://code.launchpad.net/%7Ecspiel/enblend/staging> > that lets the user choose between hard mask and > soft mask with a (quasi-)continuous parameter. > > I don't know whether we need (1), but hey, this > is what "staging" is intended for: experiments, > tests, and improvements. > > > Best, > Chris > Thanks for your additional information. I just wanted to give a quick "hands on" example. I do feel embarrassed though that I didn't do a better "literature research" the last few days before writing my mail and example. Especially as I have been working on the conversion of your document (as mentioned). Hoi, Harry --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "hugin and other free panoramic software" group. A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/hugin-ptx -~----------~----~----~----~------~----~------~--~---
