Re: effect of magnification on area measurements

Posted by Nathaniel Ryckman on Apr 15, 2011; 6:20pm
URL: http://imagej.273.s1.nabble.com/effect-of-magnification-on-area-measurements-tp3684968p3684971.html

My guess is that you used the same scale for both the 40x and 10x image?

You'll have to use a different scale for each of those images. One scale will be 4x greater than the other scale.

Basically your picture is broken up into a grid of pixels (dots). You have to specify the length that each dot represents. In the 40x image, the grid of pixels hasn't changed (aka your resolution), but the amount of distance that each dot represents has changed.

Cheuk Tam wrote

Dear ImageJ Community,

I am new to ImageJ and am using it to measure the area of DAB-stained
cells.  I tried measuring the area of the same cell at different
magnifications (and set the scale to the respective stage micrometer
images), but I found the area measurements yielded different numbers.  The
40X objective had an area that was about 4-fold smaller than the 10X
objective image.  Is this because the resolution and the number of pixels in
each image are different?  If so, which area measurement is the accurate
one?   Thank you for your help.

-Cheuk