pixel intensity comparisons between areas

[Kathy Su]

Dear All,

I would like to compare GFP expression between 2 areas of a fly wing by
comparing pixel intensities.

Right now I am using the polygon selection to mark out my desired area and
then the measure
function to get the average pixel intensity of the area.

However, I am using a nuclear GFP so much of the area selected is actually
dark space around the
nuclei, which reduces the average pixel values and the accuracy
dramatically. Would there be a
possibility to only select and count pixels for the nuclei and average over
the total nuclei area instead
of the total selected space?

Thank you very much in advance for your help

Cheers

Kathy

[Alicia Piera Alberola]

Dear Kathy,
You can try the following:
-Adjust the threshold of the image.
-Select the area of interest with the polygon.
-Use the analyze particles tool to select and only the nuclei will be  
selected and measured.
Be sure that before you set the mean grey value in set measurements.
Check the scale of the picture for setting the size of the particles  
to analyze.

So you get the average intensity of each nucleus.You can get the  
average for the total nuclei area by clicking summarize in the  
particle analysis window or in the results window(edit/summarize).
I hope it helps
Alicia

> Dear All,
>
> I would like to compare GFP expression between 2 areas of a fly wing by
> comparing pixel intensities.
>
> Right now I am using the polygon selection to mark out my desired area and
> then the measure
> function to get the average pixel intensity of the area.
>
> However, I am using a nuclear GFP so much of the area selected is actually
> dark space around the
> nuclei, which reduces the average pixel values and the accuracy
> dramatically. Would there be a
> possibility to only select and count pixels for the nuclei and average over
> the total nuclei area instead
> of the total selected space?
>
> Thank you very much in advance for your help
>
> Cheers
>
> Kathy
>

Alicia Piera
Lehrstuhl für Experimentalphysik:
Physik weicher Materie und Biophysik
Geschwister-Scholl-Platz 1
80539 München


Tel.: [phone]

Fax: [phone]

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[Guerda Massillon]

  Dear All,

I have a 3D interactive surface plot, I want to change the size of the  
axis number.

Does some one know to do that?

Thanks,

Guerda

*************************************
Guerda Massillon-JL, Ph.D.
Instituto de Física UNAM
A.P. 20-364
01000 DF
MEXICO
Tel:[phone]
Fax:[phone]

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