  We present a fast method for generating random samples according to a
variable density Poisson-disc distribution. A minimum threshold distance is
used to create a background grid array for keeping track of those points that
might affect any new candidate point; this reduces the number of conflicts that
must be checked before acceptance of a new point, thus reducing the number of
computations required. We demonstrate the algorithm's ability to generate
variable density Poisson-disc sampling patterns according to a parameterized
function, including patterns where the variations in density are a function of
direction. We further show that these sampling patterns are appropriate for
compressed sensing applications. Finally, we present a method to generate
patterns with a specific acceleration rate.
