LMS uses a negative feedback to diminish the error by altering the filter coefficients in the way of the negative of the gradient vector
to get the least mean square error (MSE).
The direction of an edge at an arbitrary point (x, y) is orthogonal to the direction, [theta](x, y), of the gradient vector
at the point.
The improved cost function integrates both modulus and phase components of the gradient vector
and then combines them with SAD cost, leading to a superior accuracy.
However, there exist boundary problems on computing the gradient vector
of powers for derivative based methods.
At each point in space (FIGURE 1) where there exists a heat flux vector and temperature gradient vector
, the Bn scalar at that point is calculated as:
7) Finally, the gradient vector
is normalized and threshold to a particular level for display of edge map information.
which shows that X is a gradient vector
field in the sense of Okumura (see ).
The direction of the gradient vector
is combined with the light-direction vector to produce a shading effect in which boundaries facing the light source are enhanced and those facing away from the light source are diminished.
They define the components of the gradient vector
Having fixed a certain direction, we should consider the scalar product of the unit vector of this direction and gradient vector
To make the final result relatively insensitive to the initial conditions, Xu and Prince 8,9] proposed the Gradient Vector
Field (GVF) model, which allows for flexible initialization of the snake and helps convergence to boundary concavities.
One of the significant variables is the angular difference among the velocity vector and the gap thickness gradient vector