Dear Albrakati,

I would say any image you acquire should store a value in each pixel (eg: from 0-255 for 8-bit images).

In FIJI, you can open these images and select an ROI (region of interest - a rectangle, polygon, or circle where you want to measure).

Then you press M (measure - Menu > Analyze > Measure). This should pop up a Results table in another window.

PS: you can select your desired measurement parameters in Menu > Analyze > Set Measurements...

Cheers from Portugal,

Vítor Yang

Do you mean , how to measure intensity of a main color in an image taken by confocal microscop by imagj sofstware?

Please pass through this link

https://forum.image.sc/t/using-imagej-to-measure-intensity-of-fluorescence/65723

or

https://github.com/mfitzp/theolb/blob/master/imaging/measuring-cell-fluorescence-using-imagej.rst

Best wishes