The position and angles of a Camera Station. The orientation of a Camera Station defines the position of and the pointing direction of the camera at the time of exposure of a photograph. Orientation can also refer to the process of determining the orientation of one or more Camera Stations.
The following sections describe the orientation angles and coordinate system.
Euler Angles: Omega, Phi, Kappa
The direction of view and rotation of each Camera Station is defined by three Euler angles called omega , phi , and kappa . These angles define the rotation of the camera from a default position. These positions and angles are defined in terms of a right-handed coordinate system.
Imagine the object you are measuring is sitting on the XY plane of a Cartesian coordinate system. Imagine the film or CCD that is used to image the object also has a coordinate system in which the XY plane lies on the imaging surface and the Z axis lies along the optical axis of the camera.
If you line-up the coordinate system of the camera with the coordinate system of the object you have the camera's default position.
In the following figure, you are looking through the back of the camera towards the object coordinate frame when the camera is in its default position (that is omega, phi and kappa all equal zero) :
To rotate the camera into the desired orientation in the object coordinate frame, we first rotate the camera omega degrees around the X axis (right-handed, in other words positive rotation rotates the Y axis towards the Z axis), then phi degrees about the camera's new Y axis (positive rotates the Z axis towards the X axis), and lastly kappa degrees about the camera's new Z axis (positive rotates the X axis towards the Y axis). The following figure shows the rotation of the positive values of each angle and the order:
