24. A method as in claim 1 wherein the step of refining an image-based model additionally comprises the steps of: creating multiple pixel representation versions of a given visual image frame, the multiple pixel representation versions being at different levels of image resolution; and using different ones of the pixel representation versions in given iterations.
24. A method as in claim 1 wherein the step of refining an image-based model additionally comprises the steps of: creating multiple pixel representation versions of a given visual image frame, the multiple pixel representation versions being at different levels of image resolution; and using different ones of the pixel representation versions in given iterations. 25. A method as in claim 24 additionally comprising the step of: presenting an interactive display of intermediate results of storing the scene model from a given iteration whereby a user specifies which one of the pixel representation versions is to be used in a subsequent iteration.