Re: Image Processing Question

Posted by Pang, Zhengyu (GE Global Research) on
URL: http://imagej.273.s1.nabble.com/Image-Processing-Question-tp3696307p3696308.html

Just answer the statistics part of your question. Adding/substracting a
constant number to your orignal data will not change the standard
deviation.




Hi,

here is what I do for a little plugin in Java:

pic1 - pic2 = result1 --> measure --> min1 = 0

(pic1 +100) - pic2  = result2 --> measure --> min2 = 53

Built-in Plugins give the same results. Is ImageJ setting negative Pixel
values to Zero, since I expected min2=100?

And of course if you do image statistics stdDev (result1) and stdDev
(result2), the results will be different. In my opinion the addition of
an offset is required for the correct calculation of stdDev, but maybe I
am wrong.
Any suggestions on this issue?
Thanks for your help!

Sebi