OpenCv2: Using HoughLinesP raises " is not a numpy array"
Found it: 
I don't have the same opencv version on my robot and on my computer !
For the records calling HoughLinesP:

works fine on 2.4.5 and 2.4.6
leads to "<unknown> is not a numpy array" with version $Rev: 4557 $
Using HoughLinesP raises  "<'unknown'> is not a numpy array", but my array is really a numpy array.
It works on one of my computer, but not on my robot...