[Gimp-user] Reducing noise with multiple exposures

[Rich]

Toby Haynes wrote:
> giuliogiuseppecarlo at interfree.it wrote:
>   
>> I'm trying to reduce noise using multiple photos of the very same subject, using both a tripod or simply repeating a scan a number of times ( i have a flatbed scanner with a lot of noise especially in dark areas... )
>>
>> So far i have tried with my old broken camera that had powerful noise at 400 iso  and first results are not bad at all.
>>
>> Samples:
>> http://img90.imageshack.us/img90/6967/prova1wc2.jpg
>> http://img131.imageshack.us/img131/448/prova2xh7.jpg
>> http://img116.imageshack.us/img116/7589/prova3on7.jpg
>> ( heavy purple fringing is probably due to the fact that i choosed 5/7 of the max resolution, 5 mp instead of 7 )
>>   
>>     
> You might consider the Anti-Lameness Engine, which is expressly designed 
> for exactly this sort of task (including re-aligning the images and 
> suppressing noise).
>
> http://auricle.dyndns.org/ALE/
>
> Hugin (http://hugin.sf.net/) is useful if you need to exactly align a 
> number of images prior to any stacking. It can also be used to remove 
> chromatic aberation with a little care (although it's fiddly and time 
> consuming).
Hi

I normally take photos in raw, which seems to eliminate a lot of the 
color noise on long exposures.
My camera is usually okay within 5-10sec exposures, but this time I took 
shots in Jpeg, which then to generate more noise when there is a lot of 
low-level light on a long exposure.
It looks like lint or squiggly lines all throughout the image.

I tried using despeckle, which does a fine job, however, it tends to 
kill the sharpness and distorts anything that was smooth, especially 
circles and droplet edges.
I tried Selective Gaussian, that seems to help with some of the color 
blockiness. 

Is there another method I can use to help eliminate those squiggly 
artifacts?
Would using multiple images help eliminate the noise?



Thanks
Rich

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