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Re: Adding a stack of array in quadrature sum [message #65630] Sat, 14 March 2009 09:54 Go to next message
David Fanning is currently offline  David Fanning
Messages: 11724
Registered: August 2001
Senior Member
joerhee@gmail.com writes:

> I'm working on a stack of image array in which I need to calculate
> quadrature sum of each pixel. I'd like to know if there is any
> program that does it or if anybody know an efficient way to do it.

Assuming that a "quadrature sum" is the square root
of the sum of the squares, I think something like this
would work:

qsum = SQRT( Total(stack^2, 3) )

This assumes that the third dimension is the number of
images in the stack.

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
Re: Adding a stack of array in quadrature sum [message #66267 is a reply to message #65630] Fri, 24 April 2009 13:02 Go to previous message
joerhee is currently offline  joerhee
Messages: 2
Registered: March 2009
Junior Member
On Mar 14, 9:54 am, David Fanning <n...@dfanning.com> wrote:
> joer...@gmail.com writes:
>> I'm working on a stack of image array in which I need to calculate
>> quadrature sum of each pixel.  I'd like to know if there is any
>> program that does it or if anybody know an efficient way to do it.
>
> Assuming that a "quadrature sum" is the square root
> of the sum of the squares, I think something like this
> would work:
>
>    qsum = SQRT( Total(stack^2, 3) )
>
> This assumes that the third dimension is the number of
> images in the stack.
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")

Thank you so much!
That was exactly what I needed.

Joseph
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