[gst-devel] Looking for someone who can code a (small ?) app for me…

Etienne Toffin etoffin at ulb.ac.be
Fri Apr 11 11:22:59 CEST 2008

Hi there,

I'm a PhD student in Biology, working in Brussels (Belgium). I'm  
looking for a dev who would have some time to spent in coding a small  
video app based on python and gstreamer for my lab. Here's the problem  
I want/have to solve…

I'm working in a lab where the main interest is studying collective  
behaviours, such as collective food retrieval or nest digging in ants,  
group decision-making in cockroaches… that have already been used in  
several topics such as informatics (has anybody heard about ant-based  
algorithms ?). Such studies need two main kinds of data corresponding  
to the macro and micro-level of the phenomenon : collective and  
individual behaviours. Those data allows us to understand how  
complexity emerges from individuals behaviours and interactions. (THAT  

(HERE'S THE MORE TECHNICAL BACKGROUND) Basically, we make some of our  
measurements by using some programs to compute nest area (region- 
growth segmentation) or to follow big enough insects individuals  
trajectories (tracking) for example.
However, the large majority of individual behaviours have to be  
measured by hand as they need "human assessment" to say wether or not  
the behaviour occurs (a small ant that takes a soil pellet and drop it  
after wandering in the experimental setup). In this case, we don't  
have softwares that help us in getting those informations and we have  
to perform a prehistoric-workflow as following :
- watching the video (on a computer… we can at least do that) and  
waiting for a given behaviour to occur (for example an ant beginning  
to drink at a food source),
- pausing the video when the behaviour occurs and writing the given  
time on a sheet,
- playing again until the next awaited behaviour is seen (the ant  
stops drinking), then pausing and writing again the time on the sheet,
- when video watching is done, entering all the values into a text  
file or something else…
Such way of working is very tiring, boring (and all of those bad  
adjectives in -ing)… If you consider that what I gave to you is a  
simple measurements sequence and that a lot of different behaviours  
and measures can be needed (such as the ant cartesian coordinates when  
the behaviour occurs…) you can easily imagine that it's a hard and  
stupid work…

So I thought about writing a small video program that would be an all- 
in-one software :
- video player (with precise controls such as frame by frame playing;  
allowing video or image stacks playing)
- keyboard shortcuts that can be easily defined for a behaviour (for  
example Ctrl-D for "ant begins to drink" and Ctrl-L for "ant stops  
drinking and leaves the food source")
- mouse ability to click on the video where the behaviour occurs (to  
measure the cartesian coordinates)
- recording of the time where shortcuts are entered and the cartesian  
coordinates of the ant showing the behaviour
- timeline where already recorded values are shown as the video file  
is replayed (it's often necessary to make our measurements in several  
times as there can be a lot of ants to observe at once)
- interface allowing video calibration : sometimes we have to film the  
experiment not from above and the experimental setup is then deformed  
on the video (circle becomes an ellipsis). Then we need a simple  
calibration interface to automatically convert the measured  
coordinates in real coordinates
This software would be written with Gstreamer and Python (I've heard  
that it would be the best solution) and could be used on Linux, OSX  
and Windows.

There doesn't exist any FREE software at this time and all the  
existing ones are quite expensive (Noldus products for those who know  
them). And you all know the benefits from free softwares. I know a lot  
of people who work with the same pre-informatic-era methods and would  
appreciate that kind of software…

So, here are my questions :
1. is anybody here interested in writing such program ?
2. does anybody know somedy who can fullfill the question 1. condition ?

Fundamental research is not only made of laboratories that have a lot  
of money to spend in expensive softwares and work with industries… The  
large majority of the labs are quite poor (considering our needs).  
Your help will be very very useful.

Thanks for your replys,

Etienne Toffin
Etienne Toffin, PhD Student
Unit of Social Ecology
Université Libre de Bruxelles, CP 231
Boulevard du Triomphe
B-1050 Brussels

Tel: +32(0)2/650.55.30
Fax: +32(0)/650.59.87
Skype: etienne_titou

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