Figure 3
From: 2D-3D Registration of CT Vertebra Volume to Fluoroscopy Projection: A Calibration Model Assessment
Different frame of references employed in the study of the 3D pose estimation of the vertebral model. The main frame of reference (OXYZ) is related to CT slices and patient. The other frame of reference (
) is fixed to the DVF device: where F is the X-ray focal spot, 
and 
axes describe the orientation of the image plane and the 
axis represents the direction connecting 
with the radiographic image centre (focal length). Orientation of the DVF frame of reference is described by a translation vector (e.g., 
in Table 1, which represent the X-ray focal spot coordinates with respect to the CT frame of reference) and the Euler angles (
rotation angles about the axes 
and 
).