[lug] Off-topic: Contour line in image problem

[Glenn Murray]

This is off-topic, but I know there are a lot of people in the
graphics and scientific communities who follow this list and may find
this problem interesting.

I have a scientific computing problem and I suspect there is software
out there that does what I am trying to do.  More or less I have to
draw a contour line in an image and find its length.

More specifically, I have black and white jpeg images of a flame, in
profile, in a tube.  I need to know the area of the flame front.  To
find this I (am thinking I) need to draw a line along some (constant)
intensity around the edge of the flame; a line dividing light from
dark, as it were, from the top of the image to the bottom.  Then I
need to know the line's length (from that I could calculate an
estimate of the area).

Ideally the computer would draw this line or I could with a mouse, and
I could mark start and end points.  The line may not reach to the tube
edge, so I may need to extrapolate it.

Do you know of any software to do this sort of thing?  I may end up
writing it myself.  Any help would be greatly appreciated.

Glenn Murray
www.mines.edu/~gmurray/public_html/Welcome.html