calculate magnification

Posted by xlancelot on Feb 10, 2014; 4:39pm
URL: http://imagej.273.s1.nabble.com/calculate-magnification-tp5006474.html

Hi everybody,

i would like to calculate the magnification of my image

i took an image of a mark with actual size 3 mm using my webcam

image resolution is 1600x1200 and the webcam is using 2 MP cmos sensor  

now how can i calculate the magnification between the mark real size and the mark shown form the image ?

sorry for my bad english

thank you