Angle measurement by FFT

Posted by Oky on
URL: http://imagej.273.s1.nabble.com/Angle-measurement-by-FFT-tp5002228.html

Dear ImageJ users,

I have been trying to measure orientation of fine lines in an image
utilizing FFT.

My idea can be summarized by following steps.
1. select a ROI for angle measurement (MFAmeasurement.jpg)
2. Run FFT (MFA-ROI.tif)
3. Find peak positions from the FFT result
4. Get angle and spacing information from the peak position in the FFT
result

I have confirmed that it is possible to apply my idea to get angle
measurement. It was very encouraging.

So I have made a very simple macro to do angle measurement automatically,
but I am stuck at step 4 because I don't know how to extract angle and
spacing information from the FFT result.

I could get intensity information not angle or spacing. In the manual for
FFT function in ImageJ I can read the information from the status bar of
ImageJ. However, I still could not find how to retrieve the angle and
spacing information in a macro.

Is there someone already has done this kind of measurement? Any advice
would be helpful for me to solve this issue.

Thank you very much for your kind advice in advance.
[image: Inline image 1]
Best regards,

Ohkyung Kwon

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