Posted by
Kashif Zeeshan on
Aug 29, 2008; 7:56am
URL: http://imagej.273.s1.nabble.com/Integrated-Density-tp3695254p3695257.html
Thanks to all for the reply. In fact, my aim is to determine the density of
each object. I thought that I choose the wrong option. Instead of
calculating integrated density, I should have measure mean gray value which
shows the density. Correct me please if I am wrong. For the moment, I will
divide the integrated density values by area values to have the density (or
mean gray values). Can you kindly tell me what will be the unit of the
density or gray values here.
Cordially.
Kashif ZEESHAN
-----Message d'origine-----
De : ImageJ Interest Group [mailto:
[hidden email]] De la part de Ben
Tupper
Envoyé : vendredi 29 août 2008 02:52
À :
[hidden email]
Objet : Re: Integrated Density?
On Aug 28, 2008, at 12:01 PM, Kashif Zeeshan wrote:
> Hello experts,
>
> Can you kindly help me to understand the term "Integrated Density".
> I read
> the documentation of ImageJ which says that this is the sum of all the
> pixels or equals to the product of Area and Mean Gray Value. But it
> is very
> confusing for me. How we will interpret this? What is the
> difference between
> density and integrated density in this regard? Is this term
> "integrated
> density" is same as "density"? My aim is to compare the different
> media
> giving different forms of fungi according to the density of the
> pellets
> found in each medium and also if this is possible then I want to
> classify
> the pellets in a medium according to the density i.e., I want to
> classify
> pellets as less dense, average dense and dense.
> Any help will be highly appreciated.
>
> Kashif ZEESHAN
On Aug 28, 2008, at 7:22 PM, Robert Dougherty wrote:
> Kashif,
>
> Maybe this will help: density is an intensive quantity and
> integrated density is an extensive quantity. See Wikipedia for an
> explanation of extensive and intensive quantities.
>
Hi,
I find it a bit hard to untangle the questions posed. But here are
couple of thoughts...
(1) Be sure that you understand what the documentation actually says,
"The sum of the values of the pixels in the image or selection." In
your case, it means that it sums the gray values of each pellet found
- it is a measure of "grayness" on an individual particle or
selection. (see
http://rsb.info.nih.gov/ij/docs/menus/analyze.html#set )
(2) Your description of pellet counting could be used to measure a
density of population - for example, X pellets per square cm. You can
use ImageJ for this purpose. For that you could analyze the image
and retrieve either the number of pellets found. Dividing the pellet
count by the image area will give you the population density. If you
want to discriminate density patterns within an image, then you might
want to dig deeper by retrieving the centroids of each pellet. You
could divide the image into quadrants of known area and get the
population density in each quadrant, etc.
If I follow you correctly, I don't think you want the Integrated
Density as you won't care how dark each pellet is.
Cheers,
Ben
Ben Tupper
Bigelow Laboratory for Ocean Science
180 McKown Point Road
POB 475
West Boothbay Harbor, ME 04575