Computes the directional gradient of an image in a direction specified
by its I and J components. A positive I component points East (the X
direction) and a positive J component points North (the Y direction).
For comparison with the other Compass directional modules, North (0
degrees) is I=0,J=1 and East (90 degrees) is I=1,J=0. The gradient is
computed using a square kernel whose edge length is governed by the
Kernel Size parameter. The Bias parameter adds a constant amount to
the output gradient array. This directional gradient computation is
Digital Image Processing, Gonzales, R.C., Wintz, P.,
Addison Wesley, Second Edition, 1987, pp 176--179.
Port: Img In
Port: I Weight
I component of direction (East).
Port: J Weight
J component of direction (North).
Port: Kernel Size
Length of one side of kernel.
Port: Img Out
Directional gradient image.
© The Numerical Algorithms Group Ltd, Oxford UK. 2000