Video Noise at DVinfo.net

Jason Chang · October 23rd, 2003, 10:50 AM

How does video noise occur? Is underexposure the only factor? I know video noise when I see it, but I don't know how to explain the cause of it in technical terms. Please help.

Jason Chang · October 23rd, 2003, 11:38 AM

I've found the answer to my own question.

http://www.cctv-information.co.uk/constant2/sn_ratio.html

Here is a good article on signal-to-noise ratio and it explains the subject very well.

Alex Dunn · October 23rd, 2003, 11:57 AM

Interesting article, but as far as the under-exposed type of noise you mentioned, are you talking about the red and blue fuzz in the black areas, and he general fuzz everywhere else? That may be caused by your gain level. If you're using a Canon XL or GL series, you've got four choices, +0, +6, +12, or +18. In my opinion, any amount of gain causes unacceptable noise. So I always use the manual setting of 0 gain, and if there's not enough light, I get some light or put away the camera and or go home. The cause, as I understand it, is gain takes what light you have and electonically bumps it up. The processor doesn't know what to do when it bumps up underexposed scenes and fills in the blanks with noise.

So, there's noise due to electronic interference (like the article), and then there's the noise created by the gain.

October 23rd, 2003, 10:50 AM	#1
Jason Chang Regular Crew Join Date: Oct 2003 Location: San Diego, CA USA Posts: 163	Video Noise How does video noise occur? Is underexposure the only factor? I know video noise when I see it, but I don't know how to explain the cause of it in technical terms. Please help.

October 23rd, 2003, 11:38 AM	#2
Jason Chang Regular Crew Join Date: Oct 2003 Location: San Diego, CA USA Posts: 163	Video Noise I've found the answer to my own question. http://www.cctv-information.co.uk/constant2/sn_ratio.html Here is a good article on signal-to-noise ratio and it explains the subject very well.

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October 23rd, 2003, 11:57 AM	#3
Alex Dunn Major Player Join Date: Aug 2002 Location: Phoenix, AZ Posts: 202	Interesting article, but as far as the under-exposed type of noise you mentioned, are you talking about the red and blue fuzz in the black areas, and he general fuzz everywhere else? That may be caused by your gain level. If you're using a Canon XL or GL series, you've got four choices, +0, +6, +12, or +18. In my opinion, any amount of gain causes unacceptable noise. So I always use the manual setting of 0 gain, and if there's not enough light, I get some light or put away the camera and or go home. The cause, as I understand it, is gain takes what light you have and electonically bumps it up. The processor doesn't know what to do when it bumps up underexposed scenes and fills in the blanks with noise. So, there's noise due to electronic interference (like the article), and then there's the noise created by the gain.