Fwd: automatic detection out-of-focus images
Posted by
"F.Xavier Gómez" on
Mar 14, 2011; 6:32pm
URL: http://imagej.273.s1.nabble.com/Fwd-automatic-detection-out-of-focus-images-tp3685392.html
Dear all,
And the plugin GM-Autofocus.java ?
http://svg.dmi.unict.it/iplab/imagej/Plugins/Autofocus/gmautofocus.htmI used it to select my best focus plane with my stack of fluorescence pictures.
Best Regards,
F.Xavier
> El 14/03/2011, a las 18:05, Gabriel Landini escribió:
>
>> On Monday 14 Mar 2011 15:49:25 Baron, Ken (US SSA) wrote:
>>> Just compress your images with jpeg or probably any image compressor. The
>>> file that is the largest is probably the one with best focus.
>>
>> That would only work if all the images were of the same scene which is not the
>> case here. A "busy" image out of focus may well take more space to store
>> compressed than one with very few objects but well in focus.
>> This would not work either when parts of the image are in focus and others are
>> not.
>> Rather than compressing the image, it would be better to look at the high
>> frequencies (for example in the Fourier space), but even so, this makes sense
>> only when you compare images of the same (or very similar) scene. This would
>> fail when the image is originally lacking high frequency components.
>>
>> Anyway, finding the best focused image requires looking how much focus can be
>> achieved at other focal distances. The eye does it and photo cameras do it
>> that way too.
>> Have a look at various papers on autofocus techniques (which search for the
>> best focused image) to get an idea how these things are implemented.
>> Understanding the technical problem might help realising what can and cannot
>> be achieved under certain constraints.
>>
>> Roca X, Binefa X, Vitria J. New autofocusing algorithm for cytological tissue
>> in a microscopy environment. Optical Engineering 1998;37(2):635-641.
>>
>> Firestone L, Cook K, Culp K, Talsania N, Preston K. Comparison of autofocus
>> methods for automated microscopy. Cytometry 1991;12:195-206.
>>
>> Santos A, Ortiz de Solorzano C, Vaquero JJ, Pena JM, Malpica N, Del Pozo F.
>> Evaluation of autofocus functions in molecular cytogenetic analysis. Journal
>> of Microscopy 1997;188(3):264-272.
>>
>> Pieper RJ, Korpel A. Image processing for extended depth of field. Applied
>> Optics 1983;22(10):1449-1453.
>>
>> I hope this is useful.
>> Regards
>>
>> Gabriel
>