  A set of fundamental matrices relating pairs of cameras in some configuration
can be represented as edges of a "viewing graph". Whether or not these
fundamental matrices are generically sufficient to recover the global camera
configuration depends on the structure of this graph. We study
characterizations of "solvable" viewing graphs and present several new results
that can be applied to determine which pairs of views may be used to recover
all camera parameters. We also discuss strategies for verifying the solvability
of a graph computationally.
