Dependants:
OpenCV >2.3
potrace 

get_contour.py: 2 params - path&filename of image to process and tuple of size to resize image before processing
defaults are:

def get_contour(Img_PathandFilename = 'temp_image_file', resize_dim=(640,480) ):

...
...

right now just saves SVG to current directory:
os.system('potrace --svg -k 0.1 contour_image.bmp -o object_contour.svg')

if called from python it returns SVG image:
return SVG_to_return