Re: FFT along line in image

Posted by Jay Unruh on Oct 23, 2007; 5:34pm
URL: http://imagej.273.s1.nabble.com/FFT-along-line-in-image-tp3698130p3698140.html

I will echo this sentiment.  It would be straightforward to do these
analyses if the line data were available to a plugin.  Unfortunately, one
has to obtain this data through the List button which reduces the data to
three decimal points precision.

Jay
--
Dr. Jay Unruh
Laboratory for Fluorescence Dynamics, Room 3311
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University of California, Irvine
Irvine, CA 92697
Phone: [phone]

> On the contrary, this has everything to do with "image processing":
> there is no reason why "images" have to be 2-D and probably the
> greatest weakness of ImageJ (don't get me wrong - I think it's
> great!) is the inability to assign different scales and meaning to
> different axes of arbritrary dimension.   Yes, there are plugins, but
> this needs to be at the heart of the ImageJ data model.
>
> A sonogram (x=frequency, y=time) is usually displayed as an image.
>
> Rick
>
> On 23 Oct 2007, at 5:10 pm, Gluender wrote:
>
>> Dear Jon Harman,
>>
>> what you are looking for is the 1D Fourier Transformation which has
>> no direct relation to image processing. Consequently, you may have
>> a look at general signal rpocessing software. You will find a lot
>> of free 1D FFT code in the internet. I sometimes use a macro that
>> comes with Kaleidagraph that in turn can be use in a demo mode for
>> free (Mac & Windows versions available).
>>
>>> Hi,
>>>
>>> Is there a plugin to ImageJ that can calculate the FFT along a
>>> line in the image and display the result (say for instance plot
>>> the power spectrum)?
>>>
>>> Jon
>>
>> I suggest to export the line data etc.
>>
>> If precision and computational effort is not an issue you may even
>> apply a 2D FFT to the line (set the rest of the image to zero) and
>> you will get the Fourier spectrum of this line projected in one
>> dimension.
>
>
>
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