Installation
Sicore II Installation and Commissioning Guide
667/HB/52600/000 Issue 2 Unrestricted
45
6.8.
Alignment
6.8.1.
Alignment Process
In summary the alignment process is as follows:
Note : This process does not require working in the live carriageway
•
Determine Distance D from the Geometry section of this handbook (See para
6.8.1.1)
•
Measure the distance D from the camera down the edge of the road and place an
object (cone / reflective puck) at the edge of the road (see para 6.8.1.2).
•
Align the camera to satisfy the following (see para 6.8.1.3 and para 6.8.1.5):
•
Edge of field of view lines up with cone / reflective puck placed at distance D
•
Centre of camera field of view is on centre of road
•
Camera rotation is set such that plates are reasonably straight in the camera field
of view
The process is described in detail in the following sections
6.8.1.1. Geometry
For any ANPR camera to function optimally it must be installed observing the correct
geometry. The critical geometry factors are as follows:
•
Distance from ANPR camera to Licence Plate – this ensures that the plate is in
focus and is viewed with sufficient resolution for the ANPR process to function
accurately. This also relates directly to the size of the capture zone on the road
and the number of lanes covered.
•
Angle of camera to Licence Plate – this affects the view of the plate and therefore
the ability of the ANPR to distinguish individual characters. Flash performance is
directly affected by plate angle, a large angle reduces reflected IR used by the
camera to detect the presence of a plate.
Sicore II provides a variety of lenses to cover different working distances and hence a wide
range of geometries. In addition to this Sicore II has flexible operational capacity such that
the installation and setup do not require precise measurement or alignment. However it is
important that the basic geometry distances are considered and used for installations.
The following two diagrams show a basic alignment of a camera mounted over a road on a
bridge or gantry. Generally the alignment is made such that the value DCN (Distance Camera
to Number plate) is at the correct distance for the reasons described above. DCS is the