How to measure color

Posted by L Holman on Oct 01, 2007; 3:34pm
URL: http://imagej.273.s1.nabble.com/How-to-measure-color-tp3698285.html

Good day to all!

I would be very grateful for any help with the following problem. I am using a
fluorescent stain to make live cells stain green and dead cells stain red, and
attempting to quantify the proportion of dead cells. I was wondering if ImageJ
can be used for this purpose, e.g. returning a figure for the number/brightness
of red and green pixels.

A simpler method might be to replace all the red (or green) in the image with
black (using Photoshop), and convert the image to greyscale. I could then
measure the average luminosity of the picture (I know this possible with other
image analysis software such as Optimas). Is there a facility to measure the
luminosity (i.e. average brightness of all pixels in a designated area) in
ImageJ? I could not find one in the help, but such measurements are fairly
commonly used in the life sciences.

Thanks in advance for any help and ideas, they are much appreciated.

Luke Holman, University of Sheffield.