Figure 3: The sinogram pattern of cylindrical specimen and the trajectory, depending on the tilt of the object or the RA. | Scientific Reports
The third and fourth pictures in (a,b and c) show the trajectories of 
. When the 
is on the RA (orange dot in the picture), it is expressed as a dot. In other cases, it is expressed as a circular trajectory (blue circle). (a) The sinogram and the 
trajectory when an object is tilted. Even though the object is tilted, the 
is on the parallel line with the stage in the projection. This is quite a typical occasion where no error is found. (b) The sinogram and the 
trajectory when the RA is vertically tilted. The object rotates around the RA and the line that 
makes are perpendicular to the RA on the projection. (c) The sinogram, its reconstruction and the 
trajectory when the RA has a parallel tilt. The pattern of the sinogram is linear around the center. However, its reconstruction is flawed (shown better in the magnified figure), since the layers are all mixed up at each angle θ. In this case, the collection of 
s in the projection makes an elliptical shape, not a line. The RA is also perpendicular to the major axis of 
trajectory in this case.