Posted by
Robert Dougherty on
Apr 19, 2007; 12:53pm
URL: http://imagej.273.s1.nabble.com/Fourier-filters-tp3699723p3699724.html
Sandro,
How about this?
newImage("filter", "32-bit Black", 512, 512, 1);
run("Multiply...", "value=0.0000");
run("Add...", "value=1");
makeOval(178, 178, 154, 154);
run("Multiply...", "value=0.0000");
run("Select None");
run("Gaussian Blur...", "radius=20");
run("Bridge (174K)");
run("FFT Options...", " complex do");
imageCalculator("Multiply create 32-bit stack", "Complex of
bridge.gif","filter");
//run("Image Calculator...", "image1=[Complex of bridge.gif]
operation=Multiply image2=filter create 32-bit stack");
run("Inverse FFT");
Bob
-----Original Message-----
From: ImageJ Interest Group [mailto:
[hidden email]] On Behalf Of Sandro
de Luelmo
Sent: Thursday, April 19, 2007 2:27 AM
To:
[hidden email]
Subject: Fourier filters
Hi my name is Sandro de Luelmo and Im working as a teacher and we are
trying to use ImageJ as a pedagogical tool for our students. Its a course
in image processing and we want them to understand the Fourier transform and
how filtering in the frequency domain working in detail.
An exercise that I would like to include could be as follows:
The student should perform a FFT on a image. Save that FFT-image in there
portfolio for later presentation. Open a high-pass filter and save the image
of the filter for later presentation. Multiply the FFT-image with the
high-pass filter and save the result-image for later presentation. Perform a
INVFFT on the result-image and thereby obtain a edge enhanced image compared
to the original image.
Ive tried everything in ImagJ but it is for example impossible to
multiply a FFT-image with a FFT-filter and then inversing it! Is there
anyone that knows if it is possible to achieve the goals I have for this
course? Maybe I could use some plugins or macros for this task??
Best regards
Sandro de Luelmo
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