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particles missed by Particle Analysis

Posted by Glen MacDonald-2 on Feb 18, 2009; 12:01am
URL: http://imagej.273.s1.nabble.com/Re-IMAGEJ-Digest-14-Feb-2009-to-15-Feb-2009-2009-45-tp3693650p3693653.html

Hello,
A colleague is recording the swimming motions of zebrafish larvae in  
response to water flow, using  a macro lens on a CCD camera.  We need  
to determine the angle of orientation relative to the x-axis. The  
larvae are thresholded in a timelapse stack and Analyze Particles  
provides the information, with parameters set for exclude edges,  
minimum size and circularity below .26 (the larvae resemble small  
nails at this magnification with a tapered body and a bulge at the  
head).

Analyze Particles correctly identifies about 25 larvae in each frame  
of the timelapse.  But, 3-5 larvae are not measured in each frame.  
The display of the best fit ellipses and numbering the thresholded  
larvae by result line identifies the missed larvae.  Individual  
measurement of the missed larvae indicates they meet all criteria for  
particle analysis.  In some instances, a larva may not have changed  
position for several frames, yet will have been measured in some  
frames, but not in others.


Thanks,
Glen



Glen MacDonald
Core for Communication Research
Virginia Merrill Bloedel Hearing Research Center
Box 357923
University of Washington
Seattle, WA 98195-7923  USA
(206) 616-4156
[hidden email]

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