Intertraff WalzCAM User Manual
10
CAMERA INSTALLATION
Mounting and Adjusting the Camera
Once you have secured the camera to the camera-mounting bracket (locally procured), you should find the
camera point of capture accordingly with the WalzCAM model you purchased.
Intertraff manufactures three different types of WalzCAM:
−WalzCAM_16 suitable for license plate capturing at distance of 3 to 5 meters;
−WalzCAM_25 suitable for license plate capturing at distance of 8 to 12 meters;
−WalzCAM_50 suitable for license plate capturing at distance of 18 to 20 meters;
Each model mounts a different LED which is especially suitable for the operating distance assigned.
Using a WalzCAM_16 instead of a WalzCAM 25 may result in a low contrast number plate capturing.
During WalzCAM installation the horizontal and vertical angle should not be greater than 30 degrees. The
lower the angle, the higher will be the recognition rate which can be expected by any number plate
recognition software.
Start by setting up the camera in daylight conditions. This is helped by having a TV monitor available,
connected directly to the camera output, so the result can be immediately seen.
Adjust the aim of the camera with vehicles passing through the point of capturing, so that the number plates
are roughly central in the image. If the camera is offset to the site of the road, the vehicles will appear to
move diagonally through the field of view. They should be central when just passing the point of capturing.
The central point must be adjusted to coincide with the optimum plate image size as the vehicle approaches
or recedes from the camera.
Optimum plate image size
Vertically, the aim should be set so the average vehicle position is about 1/3 up from the bottom of the
picture. This allows large vehicles with higher plate mounting to be in the image. When the camera position
is properly set, tighten the mounting bolts firmly so to prevent movement. When the rest of the system is
working, the camera aim can be checked more accurately and readjusted if necessary.
It is crucial to set the size of the image correctly, either by changing the zoom setting of the lens or by
altering the camera aim. The width of a number plate should be approximately 25% of image width at
the nominal point where it is to be recognized. Intertraff ANPR software is very tolerant of variations in
plate and should work reliably for plate widths between 20% and 30% of the image width.
Adjust the focus of the lens to give a sharp picture at the recognition point. This should be not too
complicated being the WalzCAM lens of a fixed focus although a slight adjustment is always possible.
It’s wise to fix the focus ring when correctly adjusted.
The size of the number plate in the processed images below is correct:
