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Pedro Alejandro Herve Fernandez Carrera Licenciatura en
              Cs.Biologicas
Hi, my problem is either to simple or to dificult, i?m working on isopod
behaviour and i?m recording the movement, i?ve managed to convert my avi
files in to a series of pictures (jpg), but i can?t make the mesurements, the
video that the program makes is to fast and i can?t measure the distance that
the isopod moves.
if someone knows how to slow down the series of pictures, or even better if
someone knows how can i make the analisis automaticly

thank?s a lot

bye
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Re: Help

jiho
hi,

Le 27 juil. 05, à 23:04, Pedro Alejandro Herve Fernandez Carrera
Licenciatura en Cs.Biologicas a écrit :

> Hi, my problem is either to simple or to dificult, i´m working on
> isopod
> behaviour and i´m recording the movement, i´ve managed to convert my
> avi
> files in to a series of pictures (jpg), but i can´t make the
> mesurements, the
> video that the program makes is to fast and i can´t measure the
> distance that
> the isopod moves.
> if someone knows how to slow down the series of pictures, or even
> better if
> someone knows how can i make the analisis automaticly

I'm doint this with fish larvae: record a video, slow it down = extract
a frame every second, record the mouvement.

Video part:
I do this with mplayer/mencoder, an open source utility found on all
platforms a typical command line would be
mencoder source_video.??? -nosound -ovc lavc -ofps 1 -o
destination_video.avi
the ofps parameters sets the numer of frames per second of the
destination video (here: one frame per second)
then I export the images to pgm files (because they load very quickly
in imageJ) but you can export them to JPG if you prefer.
mplayer -vo pnm:pgm destination_video.avi
I do all this in a bash script that runs on linux or mac os X platforms.

Tracking part:
Depending on your source material this can be automatic. if your images
are completely still except for the isopods, if you have few isopods
(one is even better ;-) ), and if the luminosity and contrast of all
the video are identic, you can make this automatic. Check the Mtrack2
plugin on the web. There was a demo and a how to somewhere with a video
of some small insects in a Petri box.
If you cannot meet the requierements, you have to track tehm manually
and you can do this with the manual tracking plugin.

hope that helps.

JiHO
---
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