Posted by
dscho on
Mar 14, 2011; 5:28pm
URL: http://imagej.273.s1.nabble.com/JACoP-parameter-and-PSF-tp3685080p3685087.html
Hi,
On Mon, 14 Mar 2011, Crowell Elizabeth wrote:
> Hello ImageJ list members, Dan, Gabriel,
>
> Gabriel Landini a écrit :
> > > Has anyone developed an algorithm in ImageJ for determining if an
> > > image is out-of-focus?
> >
> > In addition to the links that Dan provided, be aware that there is no
> > method to say with certainty if one single arbitrary photo is in focus
> > unless you know in advance the image contents. For example, a photo of
> > a field that has no high frequency features might be impossible to
> > tell apart from another which is out of focus
>
> I think I understand the problem: if my image does not contain any real
> objects, then it cannot be determined if it is in-focus.
Even if it contains any real objects, it is hard to tell whether fuzziness
stems from out-of-focus effects or from the real optical properties of
your specimen; there are many reasons for "blurred" images in addition to
non-optimal focus. In general, therefore, your problem is not solvable.
Having said that, if you know what your specimen should look like, you may
be able to define a measure that describes "out-of-focusness".
The plugins mentioned so far typically do a good job when the optimal
focus results in sharp edges (or at least sharper ones than in
out-of-focus images), but do keep in mind that all of those methods work
on multiple planes of the _same_ specimen.
Ciao,
Johannes