Posted by
michael shaffer on
Apr 09, 2006; 12:23pm
URL: http://imagej.273.s1.nabble.com/applying-a-binary-as-a-selection-tp3703129p3703131.html
Gabriel Landini writes ...
> On Saturday 08 April 2006 13:52, michael shaffer wrote:
>
> > Presumably, what is selected with ImageJ is only what is
> > available to the binary thresholding. However, I cannot
> > find a way to apply the step#1 thresholding to step#2
> > (e.g., similar to copying a binary to a Photoshop alpha
> > channel).
>
> You can use a different image to store the result, or use an
> array, or even convert the greyscale to rgb (witthout
> weighting) and use another plane for storing the results.
Pardon my ignorance, but I fail to see how these methods would expose to
the binary thresholding ONLY selected pixels. For example, other softwares
have demonstrated that simply converting non-selected pixels to black or
white biases the histogram the thresholding works with(?)
Thank you for your other references :o)
Genuinely, Michael Shaffer :o)
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>
> > Preliminary work with another sof e has revealed "minimum error"
> > thresholding (e.g., Kittler) seems to work best for my
> task. I would
> > like to find this technique available as a ImageJ plug-in.
>
> This site has some C code for the kittler algorithm.
>
http://emre.uta.edu/ImageProcessingComputerVisionSoftware.htm> It should be posible to convert it to Java.
>
> > "Maximum entropy"
> > thresholding works well too, but I am finding the method
> described by
> > Shannon to work Better than Johannsen. Is there a specific
> reference
> > for the maximum entropy method available for ImageJ?
>
> Ask Jarek Sacha, I think he wrote the plugin. Perhaps it is
> this one (also code in the same site):
> Kapur J.N., Sahoo P.K., and Wong A.K.C. (1985) "A New Method
> for Gray-level Picture Thresholding Using the Entropy of the
> Histogram" Graphical Models and Image Processing, 29: 273-285
>
> I hope it helps.
> Cheers,
>
> G.
>
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