Posted by
Michael Schmid on
Mar 27, 2017; 3:46pm
URL: http://imagej.273.s1.nabble.com/Calculator-Plus-tp5018377p5018387.html
Hi Thomas,
if you want to subtract 16-bit data and get a signed result, the easiest
is using Process>Image Calculator and select "32-bit (float) result".
The other option is 'difference' instead of 'subtract' mode, it will
give you the absolute value of the difference.
By the way, if you save a 16-bit image as jpg, it will be converted to 8
bits on all programs that I am aware of.
Michael
________________________________________________________________
On 27/03/2017 13:50, Thomas Eschner wrote:
> Dear all,
>
> I am trying to illustrate artefacts introduced by storing files as
> jpg by showing the difference of two identical 16-bit images, one
> stored as jpg and one as tiff.
>
> With Calculator Plus, setting e.g. Subtract with k1 = 1 and k2 = 16,
> I end up with files having their values set to 65535 exclusively.
>
> Only with k2 = 0 I seem to get more or less reasonable results, but I
> lose negative values.
>
> Could please anybody give me a hint?
>
> Thank you.
>
> Kind regards, Thomas
>
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http://imagej.nih.gov/ij/list.html>
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