Feret measurements

Posted by Rodrigo Gonçalves-4 on
URL: http://imagej.273.s1.nabble.com/Feret-measurements-tp5000233.html

Hi guys,

I found that the definition of the Feret's measurements might change for different software/webpages.

To test how ImageJ goes with this, I opened a new image in Fiji under Windows, created a 'perfect' circle pressing CTRL to keep the ratio aspect, and then filled it and measured it.

The max and min Feret's look ok, but then I have FeretX and FeretY which I don't fully understand.

From the ImageJ user guide (http://rsbweb.nih.gov/ij/docs/user-guide.pdf and http://rsbweb.nih.gov/ij/docs/guide/146-30.html) I would expect to obtain the length of the object’s projection in the X (FeretX) and Y (FeretY) direction. If this is correct, then in a perfect circle MaxFeret, MinFeret, FeretX, FeretY should all have the same value, right? Because I expect the projection of a circle on the X axis will equal de circle's diameter, is that so?

But I get a Feret's diameter = 288 while FeretX and FeretY are 78 and 73, respectively.

What am I missing here?

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Rodrigo J. Gonçalves

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