please help me understand the difference between Luma noise and Chroma noise

[Amateur]

i think this is one (of the probably many) reasons why i can't seem to utilize fft3dfilter in a better way. if i could get a couple screenshots showing me what is chroma noise and what is luma noise that would be great.

what i DO understand is that luma is the lighting of the image (the black/white/grey detail of the image) while chroma is the color on top of this image. is this even correct? what i don't understand is on an image that is colorful, how do i know if the noise i see is luma or chroma? i just throw a filter at it and hope the image looks better.

[setarip_old]

I've got to believe that searching the Doom9 Forum coupled with a wider-covering Googlesearch will provide you with the answers you seek...

[Amateur]

i did search on here first but i only get people talking about problems that they know are chroma noise. my problem is i don't know if i can differentiate chroma noise from luma noise since i'm not that experienced. not to mention i get 350 results when typing in "chroma noise" so it's a little overwhelming

[mikegarven]

Actually it's very simple:

Luminance is the video level only of just the back and white part of a video signal.

Chroma is just another word for color.

So if you have noise in the Luminance, the picture looks noisy in a grayish way, like an old black and white move.
If you have noise in the Chroma, then the color looks unstable like an old VHS tape.

Mike

[Amateur]

do you happen to have a source that has both where i could see the difference of corrected luma noise (leaving chroma noise) next to an image of corrected chroma noise (leaving luma noise)? i think that would help me the most.

doing a google search of chroma noise gives me results about cameras and shows charts and explanations but no screenshots which is what i am needing the most.

[poisondeathray]

It's "color noise" ; have a look at any low light footage

Here's an example in this thread
http://forum.doom9.org/showthread.php?t=159566

http://i55.tinypic.com/2qb7hg3.png

[GrofLuigi]

Maybe better seen deinterlaced...

http://img534.imageshack.us/img534/3378/sampleg.gif

Ignore the horizontal lines, look at the big blotches of color on the wall.

I'm officially donating it as a teaching aid of all picture defects known to human kind. :)

GL

[Amateur]

so in my footage here (http://www.mediafire.com/?x00gd15q78qbyda) do i have chroma noise? the noise in it doesn't appear to be multi-colored like the above examples, but it seems like setting plane=3 gets rid of a lot more noise than plane=0 for my fft3dfilter.

also curious if my script is a good one or do i use an outrageous amount of filters (i have four different smoothers because it seems like each one helps shrink the size of my lossless png)? if there are some suggestions to better adjust one or two of these filters to speed up my script but give the same result, that would be wonderful.

LoadPlugin("C:\Program Files (x86)\MeGUI\tools\dgindex\DGDecode.dll")
DGDecode_mpeg2source("F:\Videos\TV Shows\The Jetsons\s1e1\VTS_01_1.d2v", cpu=4, info=3)
LoadPlugin("C:\Program Files (x86)\MeGUI\tools\avisynth_plugin\ColorMatrix.dll")
ColorMatrix(hints=true, interlaced=true, threads=0)
LoadPlugin("C:\Program Files (x86)\MeGUI\tools\avisynth_plugin\TIVTC.dll")

tfm(order=1).tdecimate()

removegrain(mode=1)

crop( 0, 0, -2, 0)
LanczosResize(640,480)

dfttest()
fft3dfilter(sigma=2, bt=5, bw=32, bh=32, ow=16, oh=16, sharpen=0.4, plane=3)
deen("a3d",4,7,9)
fluxsmootht(9)

lsfmod(strength=200)

Spline36Resize(last.width*2,last.height*2)
aWarpSharp2(thresh=160, blur=3, type=0, depth=10, chroma=4)
FastLineDarken(strength=150,luma_cap=225,thinning=0)
aWarpSharp2(thresh=160, blur=3, type=0, depth=10, chroma=4)
Spline36Resize(last.width/2,last.height/2)

maa()

tweak(sat=1.25)




(i feel like i should have a degree in this stuff to fully understand it)

[Ghitulescu]

i think this is one (of the probably many) reasons why i can't seem to utilize fft3dfilter in a better way. if i could get a couple screenshots showing me what is chroma noise and what is luma noise that would be great.

I've got to believe that searching the Doom9 Forum coupled with a wider-covering Googlesearch will provide you with the answers you seek...

i did search on here first but i only get people talking about problems that they know are chroma noise. my problem is i don't know if i can differentiate chroma noise from luma noise since i'm not that experienced. not to mention i get 350 results when typing in "chroma noise" so it's a little overwhelming

I was not overwhelmed by having a look at the very first item in google

-> http://www.cambridgeincolour.com/tutorials/image-noise2.htm

[Amateur]

hey thank you for that. what was your search term? i tried luma noise, examples of luma noise, luma noise vs. chroma noise...i don't get that link. thank you for it though because it's a good link. i'm bookmarking it.

any chance i could have people critique my script? it has given me a decent result but it's pretty slow and i'm willing to bet if one or two of the smoothing filters is tweaked, i wouldn't have to use four or five smoothing filters.