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Exaggeration Factor for FFT

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Melissa on 30 Dec 2013
Commented: Melissa on 30 Dec 2013
Good Afternoon All and Happy New Years!!
I was just wondering if anyone could assist me or provide me with a reference on what exactly an exaggeration factor is in regards to the FFT. I am calculating the fourier coefficients of a distorted cylinder using its polar coordinates. (radius and angles). I created an interpolation function by matlab spline of these two variables (radius and angles) and then use the fft matlab function to find the real and imaginary terms for the coefficients and when trying to compare my results to an existing program they have input variables called the default exaggeration function and the default dz and I am unsure what they are referencing.
Any suggestions?

Answers (1)

Walter Roberson
Walter Roberson on 30 Dec 2013
My speculation would be that the program you are comparing against is plotting results. In cases where you expect a change in z values that is relatively small compared to the x and y range, you might want to exaggerate the z (scale it up) in order to be more easily understood. Like
surf(X, Y, exaggeration_factor * Z)
The dz I would speculate to be the interval at which it samples the Z for plotting (or calculation) purposes.
  1 Comment
Melissa on 30 Dec 2013
Thanks Walter, that does make sense since plotting is involved and the displacements are rather small. My values for the coefficients dont match though either so I was thinking that this may have been the reason.

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