create_cam_pose_look_at_point — Create a 3D camera pose from camera center and viewing direction.
create_cam_pose_look_at_point( : : CamPosX, CamPosY, CamPosZ, LookAtX, LookAtY, LookAtZ, RefPlaneNormal, CamRoll : CamPose)
The operator create_cam_pose_look_at_point creates a 3D
camera pose with respect to a world coordinate system based on two
points and the camera roll angle.
The first of the two points defines the position of the optical
center of the camera in the world coordinate system, i.e., the
origin of the camera coordinate system. It is given by its three
coordinates CamPosX, CamPosY, and
CamPosZ. The second of the two points defines the viewing
direction of the camera. It represents the point in the world
coordinate system at which the camera is to look. It is also
specified by its three coordinates LookAtX,
LookAtY, and LookAtZ. Consequently, the second
point lies on the z axis of the camera coordinate system.
Finally, the remaining degree of freedom to be specified is a
rotation of the camera around its z axis, i.e., the roll angle of
the camera. To determine this rotation, the normal of a reference
plane can be specified in RefPlaneNormal, which defines the
reference orientation of the camera. Finally, the camera roll angle
can be specified in CamRoll, which describes a rotation of
the camera around its z axis with respect to its reference
orientation.
The reference plane can be seen as a plane in the world coordinate
system that is parallel to the x axis of the camera (in its
reference orientation, i.e., with a roll angle of 0). In an
alternative interpretation, the normal vector of the reference plane
projected onto the image plane points upwards, i.e., it is mapped to
the negative y axis of the camera coordinate system. The parameter
RefPlaneNormal may take one of the following values:
The reference plane is the yz plane of the world coordinate system. The projected x axis of the world coordinate system points upwards in the image plane.
The reference plane is the yz plane of the world coordinate system. The projected x axis of the world coordinate system points downwards in the image plane.
The reference plane is the xz plane of the world coordinate system. The projected y axis of the world coordinate system points upwards in the image plane.
The reference plane is the xz plane of the world coordinate system. The projected y axis of the world coordinate system points downwards in the image plane.
The reference plane is the xy plane of the world coordinate system. The projected z axis of the world coordinate system points upwards in the image plane.
The reference plane is the xy plane of the world coordinate system. The projected z axis of the world coordinate system points downwards in the image plane.
Alternatively to the above values, an arbitrary normal vector can be
specified in RefPlaneNormal, which is not restricted to the
coordinate axes. For this, a tuple of three values representing the
three components of the normal vector must be passed.
Note that the position of the optical center and the point at which the camera looks must differ from each other. Furthermore, the normal vector of the reference plane and the z axis of the camera must not be parallel. Otherwise, the camera pose is not well-defined.
create_cam_pose_look_at_point is particularly useful if a 3D
object model or a 3D shape model should be visualized from a certain
camera position. In this case, the pose that is created by
create_cam_pose_look_at_point can be passed to
project_object_model_3d or project_shape_model_3d,
respectively.
It is also possible to pass tuples of different length for different input parameters. In this case, internally the maximum number of parameter values over all input control parameters is computed. This number is taken as the number of output camera poses. Then, all input parameters can contain a single value or the same number of values as output camera poses. In the first case, the single value is used for the computation of all camera poses, while in the second case the respective value of the element in the parameter is used for the computation of the corresponding camera pose.
CamPosX (input_control) real(-array) → (real)
X coordinate of the optical center of the camera.
CamPosY (input_control) real(-array) → (real)
Y coordinate of the optical center of the camera.
CamPosZ (input_control) real(-array) → (real)
Z coordinate of the optical center of the camera.
LookAtX (input_control) real(-array) → (real)
X coordinate of the 3D point to which the camera is directed.
LookAtY (input_control) real(-array) → (real)
Y coordinate of the 3D point to which the camera is directed.
LookAtZ (input_control) real(-array) → (real)
Z coordinate of the 3D point to which the camera is directed.
RefPlaneNormal (input_control) string-array → (string / real)
Normal vector of the reference plane (points up).
Default: '-y'
List of values: '-x', '-y', '-z', 'x', 'y', 'z'
CamRoll (input_control) angle.rad(-array) → (real)
Camera roll angle.
Default: 0
CamPose (output_control) pose(-array) → (real / integer)
3D camera pose.
If the parameters are valid, the operator
create_cam_pose_look_at_point returns the value 2 (
H_MSG_TRUE)
. If
necessary an exception is raised. If the parameters are chosen such
that the pose is not well defined, the error 8940 is raised.
convert_point_3d_spher_to_cart
3D Metrology