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Re: RMS error [message #39374 is a reply to message #39358]

Wed, 12 May 2004 08:11

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

Paul Van Delst <paul.vandelst@noaa.gov> writes:

> Craig Markwardt wrote:
>> David Fanning <david@dfanning.com> writes:
>>
>>
>>> Julio writes:
>>>
>>>
>>>> I'd like to calculate Root Mean Square error using a base image and a
>>>> secondary image. How can I do that? Clues are welcome!
>>>
>>> rms_error = Sqrt( Total((img_1 - img2)^2)/N_Elements(img_1) )
>>
>>
>> Hey David, I'll pile on too. The problem I see with the above
>> expression is that there could be an offset between the two images,
>> which you are including in your TOTAL expression, and hence biasing
>> the rms value.
>
> Errmm... isn't that intended? RMS errors include the bias. Std deviations don't. At any
> rate, that's how I use 'em. This is what I've got on my wall:

It's a good question for the original poster!

Craig

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Craig B. Markwardt, Ph.D. EMAIL: craigmnet@REMOVEcow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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[Message index]

		Re: RMS error By: David Fanning on Thu, 13 May 2004 06:36
		Re: RMS error By: julio on Thu, 13 May 2004 06:22
		Re: RMS error By: Craig Markwardt on Wed, 12 May 2004 08:11
		Re: RMS error By: James Kuyper on Wed, 12 May 2004 08:02
		Re: RMS error By: Paul Van Delst[1] on Wed, 12 May 2004 07:56
		Re: RMS error By: David Fanning on Wed, 12 May 2004 07:42
		Re: RMS error By: Craig Markwardt on Wed, 12 May 2004 07:13
		Re: RMS error By: David Fanning on Tue, 11 May 2004 16:23
		Re: RMS error By: Rick Towler on Tue, 11 May 2004 15:34
		Re: RMS error By: David Fanning on Tue, 11 May 2004 14:14

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