principal axis

(redirected from Principal axes)
Also found in: Dictionary, Thesaurus, Encyclopedia.

principal axis

In optics, a line that passes through the optical center or nodal point of a lens perpendicular to the surface of the lens.
See also: axis
References in periodicals archive ?
This condition implies that the attitude motion in three dimensions is controlled by applying nonlinear control methods utilizing nonholonomic constraint of a FFRB unless the inertial moments of principal axes I and II are equal.
Again, it has been demonstrated that the presented method has a potential to overcome a critical hurdle of not-cutting principal axes in defected virtual organ of injured side.
Based on absolute and central moments of the obtained 3D bone volumes, the proposed method takes the principal axes as feature descriptors and computes them starting from the inertial matrix.
Once the principal components are obtained, [[lambda].sub.1], along with the principal axes, [[bar.v].sub.i], they together explain the variation of the data, which are ordered as a Pareto diagram, selecting exclusively that set of components p that explain at least 80% of the variation in the data.
From (10)~(12), the corresponding component formulation of (17) relative to the Eulerian principal axes is
A big advantage of acoustic birefringence is that no reference state is required, but we must pay attention to the principal axes of the materials and the principal axes of the applied stresses.
76.1% of this is summarized in the first five principal axes (Figure 2).
There is one longitudinal wave and two transverse waves in each of the principal axes, which are related to material density and wave velocity by [C.sub.ii] = [v.sup.2.sub.ii][rho]; the density of the culm is obtained by volumetric methods [19, 20].
In those classes the principal axes of the natural and electrooptic birefringence coincide.
Correspondence analysis determines the principal axes of inertia and for each axis the corresponding eigenvalue, which is the same as the inertia of the cloud in the direction of the axis.
We consider the principal axes of the outer clad to coincide with the optical axis along the z-direction, and the extraordinary principal axis attains a radial orientation.
The principal axes are eigenvectors of the inertia tensor matrix of cluster markers.