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Re: How to create white noise in IDL? [message #93058 is a reply to message #93053]

Sat, 16 April 2016 15:21

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

On Saturday, April 16, 2016 at 5:51:32 AM UTC-4, Meegle_Jade wrote:
> How to create white noise image in IDL? I have heard about RANDOMN and RANDOMU but do they create white noise?

Typically, white noise is the same as Gaussian deviate noise (RANDOMN). The "whiteness" refers to the power spectrum of the data.

RANDOMU provides uniform deviates. While this *also* will produce noise with a white spectrum, it is not typical. And RANDOMU deviates have a DC bias. The deviates are between 0 and 1 which means the average is 0.5, and this will show up as a non-white DC frequency component.

So for a 100x200 image use RANDOMN(SEED,100,200).

Craig

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[Message index]

		How to create white noise in IDL? By: Sonu Tabitha on Sat, 16 April 2016 02:51
		How to create white noise in IDL? By: Helder Marchetto on Sat, 16 April 2016 07:48
		How to create white noise in IDL? By: Helder Marchetto on Sat, 16 April 2016 12:09
		How to create white noise in IDL? By: Helder Marchetto on Sat, 16 April 2016 12:09
		Re: How to create white noise in IDL? By: Craig Markwardt on Sat, 16 April 2016 15:21

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