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20th April 2013, 16:36 | #1 | Link |
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Join Date: Dec 2011
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About Denoisers
I have 3 questions.
1. What is the advantages of temporal, spatial and spatio-temporal denoisers? 2. What is the side effects of temporal, spatial and spatio-temporal denoisers? Temporal - Ghosting and ...? Spatial - Banding and ...? Spatio-Temporal - ...? 3. Good Temporal, Spatial and spatio-temporal denoisers? Last edited by bxyhxyh; 21st April 2013 at 12:23. Reason: word corrected |
20th April 2013, 22:35 | #2 | Link |
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Join Date: Oct 2012
Posts: 176
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Spatial Noise Reduction
A spatial noise reduction filter uses a more complex algorithm than blur/low-pass, attempting to find where on a frame noise is and isn’t, and only trying to remove the noise. In general, spatial noise reduction will try to preserve sharp edges, and remove or reduce noise from flatter areas with a lot of seemingly random fine detail, like grain/gain. The challenge is they can’t always discriminate between static textures, like cloth, and actual noise. Temporal Noise Reduction For real grain/gain removal, you need a temporal filter. That compares a pixel with its spatial neighbors in the current frame and its temporal neighbors in adjacent frames. Since grain/gain is random on every frame, the filter can pick out flecks of detail that change from frame-to-frame (noise) and those that don’t (detail), and thus be much more aggressive about eliminating the former. And since that random noise is the biggest compression killer (fine detail without any motion vectors to take advantage of), this can pay off very nicely. |
21st April 2013, 10:29 | #3 | Link |
I'm Siri
Join Date: Oct 2012
Location: void
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I think temporal denoisers are usually better than spatial denoisers for most sources
my personally favorite temporal denoiser is MDegrain (in MVTools2) because unlike lots of other denoisers,it makes no artifacts even if use a very strong parameter (unless you use a crazily high thSAD,then there'll be ghosting) and if you use strong parameters in other denoisers on some very dirty sources, your clips will usually become like oil painted which is very bad but MDegrain doesn't have this kind of issues |
21st April 2013, 12:09 | #7 | Link |
I'm Siri
Join Date: Oct 2012
Location: void
Posts: 2,633
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something like this maybe help
Code:
a=last g_mask=mt_lut("x 128 >= 255 x 16 <= 0 x 16 - 255 * 112 / ? ?") denoise=smdegrain () mt_merge(a,denoise,g_mask) gradually decrease the strength of denosing if Y value < 128 and do nothing if Y value < 16 Last edited by feisty2; 21st April 2013 at 12:14. |
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