Imagej Inversion for Dummies

Posted by serka on Aug 11, 2015; 12:27pm
URL: http://imagej.273.s1.nabble.com/Imagej-Inversion-for-Dummies-tp5013978.html

Hi all,

I have two images that I have to logarithmically transform and invert each, and then I have to subtract one image from the other.
To transform I have used process>math>log and to invert I used edit>invert.
The images do not look inverted after I do this, and the mean pixel value on my ROI is exactly the same after each process as it was on the original images, is that correct?
I know that invert LUT inverts the colour but I need the pixel values inverted.

I ask because when I subtract the images I get a completely black image and I'm trying to work out why.

Very confused imageJ novice.