Special treatment for dark regions?
Posted: Thu Jun 14, 2007 12:07 pm
Question(s):
There exists a Shadow Smoother filter for VirtualDub. This reduces detail in shadows. Does (or could) NeatVideo include such a process? If not then should I apply the filter before or after NV?
At first I guess it should be applied "after" since it would presumably alter the noise profile (since in my case the only useful noise profiling areas in my frame are in shadows), but then again a cleaner shadow would presumably work better for temporal filtering. A dilemma!
Also are there any other recommended ways of reducing detail more strongly in dark areas than in lighter ones?
Background:
I focus on the problem of dark areas because certain key parts of my footage were shot (by a Sony Z1, subsequently deinterlaced) at extremely low light, which when brightened up (using HRDAGC filter in AviSynth) has resulted in some mostly-horizontal green streaks (like "tendrils of green mist...") slowly drifting across the dark areas. HDRAGC has a "shadows" flag, supposed to enhance shadows, but in my case it had no obvious effect (I guess those tendrils were too bright). This artefact is extremely hard to remove without at the same time geting the plastic/blurry side-effect on people's faces etc.
On the other hand "Shadows Smoother", towards its maximum settings, does at least make some visible degree of reduction in this effect in the dark areas, hence my original question.
I realise I am pushing the boundaries of possibility here, but is there anything that NeatVideo can do or could do (in a future version) about the Z1's "green mist" (assuming my scene doesn't contain real green mist)?
Many thanks,
There exists a Shadow Smoother filter for VirtualDub. This reduces detail in shadows. Does (or could) NeatVideo include such a process? If not then should I apply the filter before or after NV?
At first I guess it should be applied "after" since it would presumably alter the noise profile (since in my case the only useful noise profiling areas in my frame are in shadows), but then again a cleaner shadow would presumably work better for temporal filtering. A dilemma!
Also are there any other recommended ways of reducing detail more strongly in dark areas than in lighter ones?
Background:
I focus on the problem of dark areas because certain key parts of my footage were shot (by a Sony Z1, subsequently deinterlaced) at extremely low light, which when brightened up (using HRDAGC filter in AviSynth) has resulted in some mostly-horizontal green streaks (like "tendrils of green mist...") slowly drifting across the dark areas. HDRAGC has a "shadows" flag, supposed to enhance shadows, but in my case it had no obvious effect (I guess those tendrils were too bright). This artefact is extremely hard to remove without at the same time geting the plastic/blurry side-effect on people's faces etc.
On the other hand "Shadows Smoother", towards its maximum settings, does at least make some visible degree of reduction in this effect in the dark areas, hence my original question.
I realise I am pushing the boundaries of possibility here, but is there anything that NeatVideo can do or could do (in a future version) about the Z1's "green mist" (assuming my scene doesn't contain real green mist)?
Many thanks,