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
---
Windows, c'est un peu comme le beaujolais nouveau :
a chaque nouvelle cuvee on sait que ce sera degueulasse,
mais on en prend quand meme par masochisme.
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