Integrated Density and Image Scale

Posted by lechristophe on Mar 31, 2008; 3:16pm
URL: http://imagej.273.s1.nabble.com/Integrated-Density-and-Image-Scale-tp3696720.html

Dear all,

I have a question about the "Integrated Density" measurement. In the ImageJ
docs it is stated:
*"Integrated Density* - The sum of the values of the pixels in the image or
selection. This is equavalent to the product of *Area* and *Mean Gray Value*
."
This is fine for unscaled images, where the area is expressed in pixels. But
what about scaled images ?

- If i have a 10x10 pixel image with a uniform value of 255 unscaled,
Mean=255, Area=100, Integrated Density=25500. Good.

- The same image with a scale "one pixel=0.1 microns" gives Mean=255,
Area=100, Integrated Density=255. But then ID is not "the sum if the values
of the pixels in the image" as stated in the definition ? So what is the
definition of the integrated density ? I could'nt find a good reference for
this.

Thank you for your help,

Christophe Leterrier