Measuring RGB average values in an ROI

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Measuring RGB average values in an ROI

Jon Harman-3
Hi,
Just checking if there is a simple way to get the average R,G,B values
in a color image inside of an ROI.  I know that I could split the image
into R, G, B images then copy the ROI into each and calculate the
average gray.  That seems to be a pain.  Is there anything easier?

Thanks,
Jon

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Re: Measuring RGB average values in an ROI

Rasband, Wayne (NIH/NIMH) [E]
On Feb 17, 2015, at 6:52 PM, Jon Harman <[hidden email]> wrote:
>
> Hi,
> Just checking if there is a simple way to get the average R,G,B values in a color image inside of an ROI.  I know that I could split the image into R, G, B images then copy the ROI into each and calculate the average gray.  That seems to be a pain.  Is there anything easier?

Use the Plugins>Analyze>RGB Measure command, which runs the MeasureRGB macro, available at

    http://imagej.nih.gov/ij/macros/MeasureRGB.txt

Or convert the RGB image to a composite image using Image>Color>Make Composite and press “m”, “>”, “m”, “>” and “m”. “m” is the keyboard shortcut for the Anlayze>Measure command and “>” is the keyboard shortcut for Image>Stacks>Next Slice.

-wayne
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Re: Measuring RGB average values in an ROI

Jon Harman-3
Hi Wayne,
Thanks, that is easy.  My next question is:
Is there an RGB multiply macro or plugin that multiplys the RGB channels
by different scalers and correctly deals with the 8 bit values, i.e.
prevents going over 255.

Jon

On 2/17/2015 4:17 PM, Rasband, Wayne (NIH/NIMH) [E] wrote:

> On Feb 17, 2015, at 6:52 PM, Jon Harman <[hidden email]> wrote:
>>
>> Hi,
>> Just checking if there is a simple way to get the average R,G,B values in a color image inside of an ROI.  I know that I could split the image into R, G, B images then copy the ROI into each and calculate the average gray.  That seems to be a pain.  Is there anything easier?
>
> Use the Plugins>Analyze>RGB Measure command, which runs the MeasureRGB macro, available at
>
>      http://imagej.nih.gov/ij/macros/MeasureRGB.txt
>
> Or convert the RGB image to a composite image using Image>Color>Make Composite and press “m”, “>”, “m”, “>” and “m”. “m” is the keyboard shortcut for the Anlayze>Measure command and “>” is the keyboard shortcut for Image>Stacks>Next Slice.
>
> -wayne
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>

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Re: Measuring RGB average values in an ROI

Michael Schmid
Hi Jon,

for doing it manually, you can use for this, when you select the Red, Green and Blue channels.
To multiply with x, set the range to 0-(255/x), then press 'Apply'

As far as I know, Image>Adjust>Color Balance is not macro-recordable. In a macro, you would typically convert the image to Composite, manipulate the channels as desired, and convert back to RGB.

Michael
________________________________________________________________
On Feb 18, 2015, at 18:26, Jon Harman wrote:

> Hi Wayne,
> Thanks, that is easy.  My next question is:
> Is there an RGB multiply macro or plugin that multiplys the RGB channels by different scalers and correctly deals with the 8 bit values, i.e. prevents going over 255.
>
> Jon
>
> On 2/17/2015 4:17 PM, Rasband, Wayne (NIH/NIMH) [E] wrote:
>> On Feb 17, 2015, at 6:52 PM, Jon Harman <[hidden email]> wrote:
>>>
>>> Hi,
>>> Just checking if there is a simple way to get the average R,G,B values in a color image inside of an ROI.  I know that I could split the image into R, G, B images then copy the ROI into each and calculate the average gray.  That seems to be a pain.  Is there anything easier?
>>
>> Use the Plugins>Analyze>RGB Measure command, which runs the MeasureRGB macro, available at
>>
>>     http://imagej.nih.gov/ij/macros/MeasureRGB.txt
>>
>> Or convert the RGB image to a composite image using Image>Color>Make Composite and press “m”, “>”, “m”, “>” and “m”. “m” is the keyboard shortcut for the Anlayze>Measure command and “>” is the keyboard shortcut for Image>Stacks>Next Slice.
>>
>> -wayne
>> --
>> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>>
>
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html

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