hom_mat2d_rotate_local — Add a rotation to a homogeneous 2D transformation matrix.
hom_mat2d_rotate_local( : : HomMat2D, Phi : HomMat2DRotate)
hom_mat2d_rotate_local adds a rotation by the angle Phi to
the homogeneous 2D transformation matrix HomMat2D and returns the
resulting matrix in HomMat2DRotate. The rotation is described by a
2×2 rotation matrix R. In
contrast to hom_mat2d_rotate, it is performed relative to the local
coordinate system, i.e., the coordinate system described by
HomMat2D; this corresponds to the following chain of transformation
matrices:
The fixed point of the transformation is the origin of the local
coordinate system, i.e., this point remains unchanged when
transformed using HomMat2DRotate.
It should be noted that homogeneous transformation matrices refer to
a general right-handed mathematical coordinate system. If a
homogeneous transformation matrix is used to transform images,
regions, XLD contours, or any other data that has been extracted
from images, the row coordinates of the transformation must be
passed in the x coordinates, while the column coordinates must be
passed in the y coordinates. Consequently, the order of passing row
and column coordinates follows the usual order
(Row,Column). This convention is essential to
obtain a right-handed coordinate system for the transformation of
iconic data, and consequently to ensure in particular that rotations
are performed in the correct mathematical direction.
Note that homogeneous matrices are stored row-by-row as a tuple; the last row is usually not stored because it is identical for all homogeneous matrices that describe an affine transformation. For example, the homogeneous matrix is stored as the tuple [ra, rb, tc, rd, re, tf]. However, it is also possible to process full 3×3 matrices, which represent a projective 2D transformation.
HomMat2D (input_control) hom_mat2d → (real)
Input transformation matrix.
Phi (input_control) angle.rad → (real / integer)
Rotation angle.
Default: 0.78
Suggested values: 0.1, 0.2, 0.3, 0.4, 0.78, 1.57, 3.14
Value range:
0
≤
Phi
≤
6.28318530718
HomMat2DRotate (output_control) hom_mat2d → (real)
Output transformation matrix.
If the parameters are valid, the operator
hom_mat2d_rotate_local returns
2 (
H_MSG_TRUE)
. If necessary, an exception is raised.
hom_mat2d_identity,
hom_mat2d_translate_local,
hom_mat2d_scale_local,
hom_mat2d_rotate_local,
hom_mat2d_slant_local,
hom_mat2d_reflect_local
hom_mat2d_translate_local,
hom_mat2d_scale_local,
hom_mat2d_rotate_local,
hom_mat2d_slant_local,
hom_mat2d_reflect_local
Foundation