Regions within contour defined regions

(second time lucky!)

I was wondering if anyone could help me with this. I am using edge detection
algorithms to determine regions in an image;
and these regions are bounded by contours - a shame that I can't output the
vertices of the regions to disk for further
analysis for flood fills etc.
Anyway, what I am interested in is this: the edge detection routine defines
other areas/regions encompassed by other
regions and I was wondering if there was a way of determing if a region is
contained by another region?

Thanks

Paul


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