Posted by
Herbie on
URL: http://imagej.273.s1.nabble.com/About-automatic-thresholding-program-implemented-in-ImageJ-tp5024552p5024553.html
Greetings Takamasa Kitaoji,
your questions appears being to the point but beware that my answers may
not be really satisfying...
A1. & A2.
Be aware of the fact that the automatic threshold schemes mainly serve
the purpose of getting *reproducible* results from *similar* images.
This means that if you have found a scheme that gives the expected
results for a typical sample image, you should not change the scheme for
other images of the same kind.
The decision if a threshold scheme is reasonable for a certain kind of
images is up to you.
Thresholding means perhaps the most dramatic information reduction for
signals that you can think of. It is up to you to decide what parts of
your images are to be maintained and which are not. According to your
decision, a scheme must be chosen.
A3.
This happens only for very few threshold schemes (perhaps only one) and
it is *not* a bug.
As far as I know, all automatic threshold schemes are based on the
information contained in the gray-value histograms of images. The
algorithms use the histograms to decide at which gray-value the
threshold is to be set. An iterative algorithm may not converge because
the histogram data doesn't allow it find a final single threshold value.
Regards
Herbie
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Am 31.03.21 um 05:29 schrieb Takamasa Kitaoji:
> Respected ImageJ researchers, I have some questions about automatic
> thresholding program to ask you.
> Questions are as follows;
>
> Q1. How do I know the threshold automatically set based on each algorism is
> reasonable or not?
>
> Q2. Among 16 automatic thresholding algorisms, how do you decide which
> algorithm to use for image analysis?
>
> Q3. In image analysis by automatic thresholding method, I sometimes
> encounter an error that the window of ImageJ shows“threshold not found
> after 10000 iterations”. Are there any specific conditions when this kind
> of error occurs? Is this some kind of bug?
>
> I’m looking forward to hearing from you.
>
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