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• Sony recommends that the installer visit the site in order to
determine the work to do for the placement of the camera.
• If there is any doubt regarding the positioning of a camera,
it should be placed at the intended spot temporarily (on a
tripod, for example), and the recognition performance of the
software examined with the Web User Interface.
• Cameras must be at a distance of between 4 and 16
meters from the spot where the number plates will be
filmed.
• One camera cannot cover more than one direction. If more
than one direction is to be filmed, even if the lanes are
close to each other, more than one camera must be used.
• A camera cannot be used at the same time to control the
plates and to provide clear and wide-angled images of the
environment of the vehicles. If such images are required by
the end user, the installer should propose one or more
video surveillance context cameras to be synchronized with
the camera(s).
• Vehicles are best controlled from the front otherwise
the reliability rate is not guaranteed.
• The distance between the camera and the barrier must be
long enough so that the barrier is not larger in the image
than a sixth of the screen (in vertical).
• The plates should not be concealed by the barrier when the
vehicles stop in front of the barrier (barrier above or under
the plate).
• The barrier should ideally be in the top part of the image.
• The barrier or sign should not have any type of inscription
which is likely to give a signal similar to that of a number
plate.
• Cameras should be installed in a location providing a
clear view of the plates, without any temporary or
permanent obstacles (pedestrians, vegetation,
vehicles...).
• Avoid strong illumination effects from the sun into the
camera's CCD image sensor. Both direct (strong sunlight in
background) and indirect illumination (by reflection on the
plate or mirror) should be avoided, or if necessary a
camera suitable for such conditions should be used.
• Avoid having the cameras facing directly west or directly
east, especially when the horizon is not blocked by any
construction or vegetation (risk of blinding by the sun rising
or setting).
• Cameras should be installed at a height or to the side in
order to avoid a direct illumination by the vehicles'
headlights, while avoiding excessive angles at the same
time.
• If it is not possible to have a suitable angle, and the camera
might be in the axis of the headlights, place an infrared
filter in front of the lens.
• Do not exceed a vertical angle of 25 degrees.
• Lateral angles should be kept to a minimum by installing
the camera as close as possible to the roadside. This angle
must be less than approximately 20° .
• If the plates are to be controlled while the vehicle is taking
a bend, cameras should be installed on the outside of the
bend.
• If needed, the fixation system of the camera should allow a
three-dimensional positioning.
• The focus of the lenses should be set so that the width of
the plates is one third of the width of the screen when the
plate is at its stopped position (approximately 200 pixels
width).
• If needed, use a high-pass infrared filter that operates
between 800 and 830 nanometers.
• For a good setting, use the Web User Interface provided by
the camera.
• On the sites with a low volume of traffic, it might be useful
for the installer to carry out a test drive with his own vehicle,
and/or to place a number plate on the road at the point
where the focusing should be carried out.
• Plates must be in good horizontality in the images supplied
by the cameras.
• The framing of the plate cameras should be done so that
the plates appear as long as possible in the image.
other
• Verify that the overall installation was carried out correctly,
by checking the plate reading performance in a command
prompt (see Score Function in the Functions page).
• Clean and check the cameras and the housing at regular
intervals.
• The camera doesn't works with square licence plates.
Requirements
Page 12 / 42
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