Re: fluorescence ratio

Posted by Giulia Falivelli on Sep 03, 2009; 12:11am
URL: http://imagej.273.s1.nabble.com/fluorescence-ratio-tp3691315p3691317.html

Hi John,
Thanks for helping.
Sorry, should I set a threshold before calculate the mean fluorescence?

Giulia

On Wed, Sep 2, 2009 at 4:53 PM, John Oreopoulos <[hidden email]
> wrote:

> Giulia,
>
> First, go to Analyze->Set Measurements and make sure "Mean Gray Value" is
> checked.
> Next, draw a region of interest on your image with the Rectangular
> Selection tool (or circular or freehand tools if your imaging situation
> demands it. To get the mean pixel intensity value within your region of
> interest, click Analyze->Measure, and the result will appear as a number in
> a results window.
>
> Move the region of interest to your other cell compartment where you want
> to measure the intensity value and do the same thing. Now you can take these
> two numbers and calculate a ratio by simple division.
>
> Beyond that, if you require automation/repetition or more complex/multiple
> regions of interest to be examined, you may want to try writing a macro that
> does this for you. Try looking through the long list of plugins available on
> the main ImageJ website and see if there is any plugin out there that
> already does this. None come to mind immediately, but perhaps there is a
> calcium imaging plugin that might do the trick for you. Hopefully someone
> else here on the server can suggest one.
>
> John Oreopoulos
>
>
>
> On 2-Sep-09, at 7:42 PM, Giulia Falivelli wrote:
>
>  Hi All,
>>
>> I am new in Image J.
>> Does anybody know how to calculate the fluorescence ration between two
>> different cells compartement?
>> Or how to calculate the mean grey value of a specific ROI?
>> Thank you very much.
>>
>> Giulia
>>
>