Re: Screen thresholded objects for in/out of focus

Posted by Herbie on Aug 07, 2018; 7:13am
URL: http://imagej.273.s1.nabble.com/Screen-thresholded-objects-for-in-out-of-focus-tp5021054p5021057.html

Good day Timothy,

absolute focus judgments are difficult, relative judgments* are rather
easy to accomplish.

*If you have a focus series you can use LaPlace filtering followed by
power/energy evaluation.

In your case, the problem is that relative judgments appear limited to
in-image comparisons but the cells will most likely have different shape
etc.

I doubt that there is a simple *and* reliable way to do what you want,
except the un-sharp cells are strongly out of focus.

Regards

Herbie

::::::::::::::::::::::::::::::::::::::::::::::::::
Am 06.08.18 um 21:54 schrieb Feinstein, Timothy N:

> Hello,
>
> I have a field of non-touching fluorescent objects that are segmented by thresholding, and I want to discard objects which are out of focus.  In-focus objects (cilia) should have a clear and straight edge that an algorithm like Modulation Transfer Function should be able to detect.  However, MTF plugins are overkill for my needs and they don't seem like they'd be easy to incorporate into a macro script.  I need a single number that represents the sharp-ness or focused-ness of each cilium, so that a macro can automatically discard fuzzy cilia before measuring them.  I like, for example, the Gaussian gradient function in Matlab, but I'm not sure something similar is available in ImageJ.
>
> Any suggestions would be appreciated.  Thanks!
>
>
> TF
>
> Timothy Feinstein, Ph.D.
> Research Scientist
> Department of Developmental Biology
> University of Pittsburgh

--
ImageJ mailing list: http://imagej.nih.gov/ij/list.html