Dear ImageJ Community,
If possible i kindly ask for help. I would like to measure with imageJ the shown are in Square mm as i have a lenght scale in mm as seen in the picture attached. If you could please tell me how to do this.
Thank you in advance,
D.
Hi @Nadal,
Welcome to the forum (and congrats for your last grand Slam 
)
The best thing to do is to calibrate your images (Images>Properties). Doing this, all you measurements (including area) will be calibrated and her, you result will be expressed as mm².
All this is explained here : Spatial Calibration of an image
Nico
Ps : of course, all this can be automated in a script if you have lots of images
Ciao Nico!
Thank you for your kind reply!
I just calibrated the Image with these steps:
2.Set Scale
Distance in pixel 29
Known Distance 1
Unit of lenght mm
Now if i mark an area usino the Freehand Tool and Measure, do i get squaremm in the Area Field? And could you maybe tell me what in this case mean/min an Max stands for, because i doubt that this area is really 33square mm in reality…so i think i have
an error somewhere.
If you have an idea i would gladly hear it! Greetings from Austria,
Danilo
Hi @Nadal,
Mean, Max and Min are measurements made on pixel greylevels inside ROI.
I’ve tested your print screen image. I find an area in the same range (~40 mm²), so I fell you’re right. Why do you feel this ROI couldn’t be 33mm² ?
Nico
Ciao Nico,
Sorry for the late reply.
Thank you for the doublecheck - i will make some more tests and if in doubt i may write you again 
Thank you a lot for your help!
best wishes froh austria
Danilo
