Posted by
Herbie-3 on
Sep 05, 2013; 10:26pm
URL: http://imagej.273.s1.nabble.com/Automating-Image-Processing-and-Problems-with-FFTJ-tp5004660p5004692.html
Aaron,
I'm still not perfectly sure about the format of your images.
Are they really only one pixel wide or high (single pixel high row or
wide column)?
If so, I see no way to get the corresponding Fourier transform by using
FFTJ. Did you try this successfully? FFTJ requires that rows and columns
are greater than one!
If you have images on larger supports that only vary in one dimension
and are constant in the other, then FFTJ will do the job.
With respect to the image size and DFT versus FFT:
Why don't you pad your images? DFT is rather slow and using the next
larger square-sized power of two support most often will pay.
Best
Herbie
__________________________________________
On 05.09.13 23:29, Aaron Hendrickson wrote:
> Brian,
>
> Thank you for the code and additional information; it was very useful to
> know.
>
> Herbie and Michael,
>
> The reason I have been using FFTJ is because it returns a DFT in my case.
> The images I am using are originally 2-d images of double slit laser
> interference patterns that are captured to evaluate the MTF of the image
> sensor under test. I am aiming to measure the PS of each row or column
> (depending on if test is MTF in vertical or horizontal direction) then
> average them together and determine the frequency of the interference
> pattern and its modulation. If I remember correctly (which I might not)
> when I made a PS from a single row image in ImageJ's FFT option, I got the
> 1-d PS displayed as a 2-D array. Also, I know FFTJ returns a PS of the
> same size as the original image and was not scaled in an way (which I
> liked). That is why I am trying to do this analysis through FFTJ and hence
> the problem I had trying to record it. That said, do you know of how the
> source ode of FFTJ would have to be modified to do the batch processing I
> need?
>
> Respectfully,
> Aaron
>
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