Posted by
Crowell Elizabeth on
Mar 14, 2011; 3:37pm
URL: http://imagej.273.s1.nabble.com/JACoP-parameter-and-PSF-tp3685080p3685086.html
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. The first step
in my screening procedure is to eliminate "empty" images, so hopefully
this should not be an issue?
However, I am not working with stacks, actually, but with a set of 2D
images!
I apologize for not having specified this in my first email. In the
image set, I simply want to eliminate the out-of-focus images (i.e.
blurry enough to confound analysis) and keep only the sharp ones for
analysis.
I have tried the extended depth-of-field plugin and it is very easy to
use, and gave me beautiful results on the first try. This is far
superior to generating simple projections, evidently. I wish I were
erudite enough to understand how it works, so that I could apply this
principle to my current problem. My problem is not to sort blurry
pixels from sharp pixels in the same image, but to sort blurry images
from sharp images.
Is there a way to apply the wavelet transform concept to sort my images?
Thanks again,
Elizabeth
> In microscopy the problem is worse than standard photography because we deal
> with semi transparent objects in different z planes, so one might not be
> focusing exactly the same thing at various z distances. In such instances,
> defining depth from focus fails (that is there might be highly focused regions
> in more than one z plane).
>
> Cheers
>
> Gabriel
>
--
Elizabeth CROWELL
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