Re: applying a binary as a selection

Posted by Gabriel Landini on Apr 09, 2006; 1:36am
URL: http://imagej.273.s1.nabble.com/applying-a-binary-as-a-selection-tp3703129p3703130.html

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.

> 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.