Raw versus calibrated integrated density

Posted by IJperson on Oct 18, 2010; 1:03pm
URL: http://imagej.273.s1.nabble.com/Raw-versus-calibrated-integrated-density-tp3686613.html

Hi everyone.

This could well be a misunderstanding on my part, but why are the raw and
calibrated integrated densities different?  I understand the per micron or
per pixel means being different, but isn't the total intensity unit-free?

Here is a quick calculation, where as I calculate it, the total integrated
intensity should be the same. Where have I gone wrong? Is it my
understanding of what 'density' means?

Pix count           Calibration           Cal area
100000              2                       200000
                               
Total Intensity over image
555555
                               
                               
Cal mean    Pix mean
2.777775   5.55555
um-2           pix-2
mean       umean
                               
                               
IntDensity (mean*cal area) RawIntDensity (umean*num pixels)
555555                               555555

Many thanks for the clarification.



                       

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