Re: Image quality evaluation

Posted by dscho on Jul 12, 2006; 7:27pm
URL: http://imagej.273.s1.nabble.com/Image-quality-evaluation-tp3695062p3695070.html

Hi,

we used the entropy of the histogram for a long time, and then the entropy
after subtracting a massively blurred version of the image.

However, keep in mind that this (as the Extended Depth of Field plugin at
http://bigwww.epfl.ch/demo/edf/index.html) only measures the _crispness_
of the image.

So it does not actually work well in the presence of noise, since this
adds much more to the crispness than a well focused image. It should work
quite well to autofocus, though, since the amount of noise can be expected
to be fairly constant, no matter how focused the image is (or it should
actually add to the crispness _exactly_ in the case when the image is
focused).

Hth,
Dscho