A system and method that determines the direction of an edge in a video
image using a gradient of the edge in a first direction and a gradient of
the edge in a second direction. The system uses the sign of the product
of the gradient in the first direction and the gradient in the second
direction along with a ratio of multiples of the two gradients to
determine the direction of the edge. The direction may correspond to an
angle range, where the ratio of the gradients corresponds to a
trigonometric function of the angle of the edge.