Re: detect motion across frames

Posted by Albert Cardona on
URL: http://imagej.273.s1.nabble.com/detect-motion-across-frames-tp3696278p3696280.html

Franklin,


> I have images that resemble clouds and I am also trying to track the motion of clouds from frame-to-frame.  Although my "clouds" are actually clusters of small particles.
>  
> I've been considering using cross-correlation techniques.  I know they will work because I have large structures that move small displacements from frame-to-frame.  Cross-correlating will give the magnitude and direction of the displacement of the structure between frames.  
>  
> Does anyone know if ImageJ has the capability to use cross-correlations to measure the displacement of large structures from frame-to-frame?
>  

Several options:

If a binarized version of your images still contains the clouds as
blobs, you may run a watershed to separate them (as described in Tony
Collins ImageJ manual) and then use any of the ImageJ multiple object
trackers (see plugins page) to track each one separately.

For cross-correlation, we have a very fast library (automatically
parallelized, scales to CPU cores) inside TrakEM2 (
http://www.ini.uzh.ch/~acardona/trakem2.html ). See the mpi.fruitfly
packages:

http://repo.or.cz/w/trakem2.git?a=tree;f=mpi/fruitfly;h=822172d1796eb55345344321229acbcb7928c513;hb=HEAD


You may even use SIFT to extract the clouds as features, and then try to
track each one across the sections. The plumbing is there, but you'd
have to do the tracking yourself, finding a subset of features for each
cloud on each frame ( see some SIFT examples, a plugin and explanations
here : http://www.ini.uzh.ch/~acardona/howto.html#feature_extraction )

Hope that helped.

Albert

--
Albert Cardona
http://www.mcdb.ucla.edu/Research/Hartenstein/acardona