Posted by
Joachim Wesner on
May 03, 2006; 8:49am
URL: http://imagej.273.s1.nabble.com/Where-is-the-source-of-Process-Binary-Threshold-tp3702932p3702934.html
HI,
I do not understand exactly what you are asking, the algorithm is the one
called from the "run" method, as with any plugin.
If you ask what the underlying principle is, it´s mentioned in the ImageJ
FAQ, it´s the so called Isodata algorithm:
http://rsb.info.nih.gov/ij/docs/faqs.html:How does "Auto" thresholding work?
The automatic thresholding function used by
Image/Adjust/Threshold and Process/Binary/Threshold divides the
image into objects and background. It does this by taking a
test threshold and computing the average of the pixels at or
below the threshold and pixels above. It then computes the
average of those two, increments the threshold, and repeats the
process. Incrementing stops when the threshold is larger than
the composite average. That is,
threshold = (average background + average objects)/2
The code in ImageJ that implements this function is the
getAutoThreshold() method in the ImageProcessor class.
The online Image Processing Fundamentals tutorial discusses
thresholding techniques. ImageJ uses the Isodata algorithm.
Yili Zhao
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Hi,
it seems that the source for "Process -> Binary -> Threshold" is in
the "ij.plugin.Thresholder" class.
What is the algorithm of this class?
Thanks!
Yili
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