  We present a method for determining surface flows from solar images based
upon optical flow techniques. We apply the method to sets of images obtained by
a variety of solar imagers to assess its performance. The {\tt opflow3d}
procedure is shown to extract accurate velocity estimates when provided perfect
test data and quickly generates results consistent with completely distinct
methods when applied on global scales. We also validate it in detail by
comparing it to an established method when applied to high-resolution datasets
and find that it provides comparable results without the need to tune, filter
or otherwise preprocess the images before its application.
