On Thursday 03 Apr 2014 16:37:11 you wrote:
> Hi,
> I have read a interesting article about using watershed to do
> segmentation by Steve of Mathworks:
>
http://blogs.mathworks.com/steve/2013/11/19/watershed-transform-question-fro> m-tech-support/
>
> I want to use ImageJ to perform the same task on the same image in the
> article.
>
> I use the watershed plugin of ImageJ, and the operations is like
>
http://rsb.info.nih.gov/ij/plugins/watershed.html describes: "invert image
> (Edit/Invert), calculate the distance transform (Process/Binary/Distance
> Map), invert result, apply Watershed."
>
> However, after calculating the distance transform, the result image is
> not a BINARY image, so I can't apply the watershed filter. Am I operate
> wrong? Any suggestions?
You need to apply the original watershed algorithm which works on greyscale,
not the one built in IJ (which really should be called "Watershed separation"
or something like that). Daniel Sage has one plugin to do this in his page.
http://bigwww.epfl.ch/sage/soft/watershed/You want the Watershed Dams.
Below is an example of how to call Daniel's plugin to only get the dams, and
the Extended Minima can be computed with a macro from the Morphology
collection here:
http://www.mecourse.com/landinig/software/software.html====================================================
import ij.*;
import imageware.*;
import watershedflooding.*;
import ij.gui.*;
/**
* Class MacroWatershed_.
*
* Easy example of calling watershed methods.
*
* @author Daniel Sage
* Biomedical Imaging Group
* Swiss Federal Institute of Technology Lausanne
* EPFL, CH-1015 Lausanne, Switzerland
*
* modified by G. Landini to use min and max
*
*/
public class WatershedDams_ {
public WatershedDams_() {
int minLevel =0;// (int) gd.getNextNumber();
int maxLevel =255;// (int) gd.getNextNumber();
boolean connectivity4 = false; //gd.getNextBoolean (); // false=8
// Get the input image
ImagePlus imp = WindowManager.getCurrentImage();
if (imp == null) {
IJ.error("No image!");
return;
}
if (imp.getType() != ImagePlus.GRAY8 && imp.getType() !=
ImagePlus.GRAY32) {
IJ.error("Require a 8-bit or 32-bit image.");
return;
}
ImageWare image = Builder.wrap(imp);
// Start the watershed segmentation
boolean displayProgressionMessage = false;
Watershed watershed = new Watershed(displayProgressionMessage);
watershed.doWatershed(image, connectivity4, minLevel, maxLevel);
ImagePlus dams = watershed.getDams();
dams.show();
}
}
====================================================
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