Traffic sign recognition
The multifunction camera recognizes the following traffic signs:
Example displays |
1 | Speed limits |
2 | Speed limits in the form of changing traffic signs |
3 | Derestriction signs (cancellation of double figure and triple figure speed limits, general derestriction) |
4 | Derestriction signs in the form of changing traffic signs |
5 | Traffic sign restricted by supplementary sign |
6 | No-passing signs including derestriction signs |
7 | No-entry signs and regulatory signs on slip roads |
P54.32-9740-82
Additional information for evaluation
Possible supplementary signs can be . Restrictions in the wet or for trailer operation. If, for example, the windshield wiper is activated and a speed limit with additional restriction "in the wet" is detected, this speed limit is displayed.
The speed limit is not viewed to be relevant as long as the windshield wiper is not activated. Supplementary signs not relevant for passenger cars (e.g. speed limits for trucks) will not be shown. The number of these traffic signs amounts to approx. 10 % of all traffic signs.
Representation of derestriction signs
Driving past a derestriction sign (F) with no further speed limits causes the derestriction sign to be displayed (J).
In no-passing zones, the prohibition sign disappears a no-passing derestriction sign is passed (I).
P54.33-4663-73
The multifunction camera also takes into account information from the navigation system (vehicles with Connect 20 multimedia system). Since speed limits may be changed, the digital map data must be updated regularly. Information on the classification of roads and regional development is deduced from the map data. By this means the system recognizes that the vehicle is leaving a road for which a speed limit identified earlier was displayed.
Since the picture recognition system is unable to cancel the display of a speed limit identified outside a town/village when passing a town/village entry sign, use is made of the map data. When changing from an undeveloped area to a built-up area, the speed limit of the map data is used. The town/village limits do not always match the built-up area markings from the map data. As a result, the last displayed speed limit may disappear too soon or continues to be shown in the town/village.
Situations which lead to a failed cancellation or superfluous cancellation of this display are shown in the following pictures:
Representation of town/village limits and built-up area limits |
13 | Local limit is outside the development limits |
14 | Local limit is inside the development limits |
15 | Local limits without development limits |
16 | Local limit is behind the development limit |
A | Outside development area |
B | Inside development area |
C | Distance |
P54.33-2617-75