Re: Integrated Density and Image Scale

Posted by Gabriel Landini on Mar 31, 2008; 10:37pm
URL: http://imagej.273.s1.nabble.com/Integrated-Density-and-Image-Scale-tp3696720p3696725.html

On Monday 31 March 2008 19:27:58 Christophe Leterrier wrote:
>  My question is : what is the meaning of
> the ID in case of a scaled image ? This is not "The sum of the values of
> the pixels in the image or selection" anymore, right ?

I had a look at this and noted that the values returned are scaled by the
factor that converts the pixels to area units, so the differences in ID
between different particles are still maintained despite that the values are
different.

> And what intensity
> is taken for each square micrometer to compute such a scaled ID ?

I think that it is still the pixel values (if there is no greyscale
calibration).
I had also a look at an old Optimas manual, and found that the grey value can
also be specified in engineering units.  So I checked this in IJ and indeed
if one does greyscale calibration, then the ID will have a different value as
well.

Cheers

G.