Yellow patches left after filtering very noisy image

raven-au · Post by **raven-au** » Wed Mar 07, 2007 12:25 pm

Hi all,

First I have to say Neat Image does an excellent job.

I've been experimenting with taking photos in low light at high ISO and I
get neally high noise levels (obviously) and Neat Image does a great
job of reducing the noise. However, when processing a RAW image,
the one thing I can't seem to improve much are very low frequency
yellow patches, mostly in showy areas. If I save in JPEG the in camera
priocessor seems to be able to reduce these reasonably well but then
I have other quality problems with the images.

So, can anyone enlighten me as to what this yellow stuff is and is there
any way I can reduce it with Neat Image.

Ian

Post by **NITeam** » Wed Mar 07, 2007 3:52 pm

Ian,

Have you already tried the "Very low freq" option in the noise filter?

Vlad

raven-au · Post by **raven-au** » Wed Mar 07, 2007 4:08 pm

NITeam wrote:Ian,

Have you already tried the "Very low freq" option in the noise filter?

Vlad

Yes. It helps a little, perhaps about 20%.

Ian

Post by **NITeam** » Wed Mar 07, 2007 4:38 pm

I guess a more accurate profiling could help in this case, though it is not easy to tell without actual samples.

Vlad

raven-au · Post by **raven-au** » Wed Mar 07, 2007 4:56 pm

NITeam wrote:I guess a more accurate profiling could help in this case, though it is not easy to tell without actual samples.

Vlad

NI claims a 98% quality for this particular image others with similar
ISO and shutter times have usually had a lower quility rating.
I don't really want to post this one though as it's a family member who
didn't want their photo taken anyway.

I should be able to get another image with similar characteristics, give
me a while to get it together and I'll post it. But the the TIFF images would
be about 35MB each. Would before and after clips of a couple of shadows
areas be enough?

Ian

Post by **NITeam** » Wed Mar 07, 2007 5:07 pm

Probably not enough because I would not be able to check which area was used for profiling. Do you control what is used for analysis by Auto Profile?

Vlad

raven-au · Post by **raven-au** » Sat Mar 10, 2007 7:27 am

NITeam wrote:Probably not enough because I would not be able to check which area was used for profiling. Do you control what is used for analysis by Auto Profile?

Vlad

Never mind, this has to be related to the RAW conversion.

Ian