Re: Advice segmenting a short video

Posted by Anderson, Charles (DNR) on Mar 04, 2014; 9:31pm
URL: http://imagej.273.s1.nabble.com/Advice-segmenting-a-short-video-tp5006685p5006770.html

My error. I let a default program open your images and then saved them; this changed their size and created the weird behavior I encountered. After saving your images correctly, I tried a few things.  

Adjust | AutoThreshold (turning off the white objects on dark background) suggests some threshold methods that might work better than others (Yan looks Ok on each image).  Trying a Gaussian blur with sigma =1 or 2 before using AutoThreshold may help.

You might apply a stronger blur, then find the minima representing the center of the constricted regions, then track movement of that point to estimate velocity and frequency of peristaltic movements, as a different approach.

There must be methods for background segmentation for videos, but I have no experience with them. Good luck.

Charles

________________________________________
From: ImageJ Interest Group [[hidden email]] on behalf of Pedro J Camello [[hidden email]]
Sent: Saturday, March 01, 2014 9:04 AM
To: [hidden email]
Subject: Re: Advice segmenting a short video

Hi Charles,

I´ve been unable to reproduce the behaviour you describe. The images are very small (abount 100 x 30 pixels) so that pixels are perfectly differentiated. I have tried to change from 8 to 16 and 32 bits but I see no difference. I have even made a Plot Profile for a vertical line in my original and in 16 and back-to 8 bit images and the plots are the same.
After the conversion I still have the same problem with automated segmentation/thresholding (in fact, in my first attempts I used 32 bit images)

Thanks for your reply

Pedro

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