Object Detection Description and Operation (Traffic Sign Assist)
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Object Detection Description and Operation (Traffic Sign Assist)
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The traffic sign assistant is a convenience detects designated traffic signs via the vehicle direction camera control module and displays them in the driver information center.
The traffic sign assistant is made up of the following components:
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Vehicle direction camera control module
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Instrument Panel Cluster
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Vehicle Direction Camera Control Module
If the vehicle is driving, the camera observes the road borders inside it's field of view. The camera is able to see the scene inside it's field of view, which is 40° horizontal and 26° vertical. The camera is designed in a kind, that it can see traffic signs up to a distance of 10 m (33 ft) in front of the vehicle. It can also see traffic signs up to a horizontal distance of 8.5 m (28 ft) and a height of 6 m (20 ft). Traffic signs which are not in the field of view can not be detected.
Inside the field of view the camera constantly searches for traffic signs. If the camera detects a traffic sign, it will permanently check the quality of the detection, when the traffic sign is coming closer. The position of the traffic sign is calculated and computed with other information like vehicle speed, lane information and other seen traffic signs. By this the camera is able to estimate, whether the seen traffic sign is a valid one. If the traffic sign is a valid one, it will be reported to the driver in the moment when it leaves the field of view, i.e. 10 m (33 ft) in front of the car.
Instrument Panel Cluster
The control unit for camera monitoring of vehicle direction sends messages to the instrument group via the CAN bus. For this reason the traffic signs are shown in the driver information centre. On the page TRAFFIC SIGN DETECTION the last recognized traffic sign will be displayed. Speed limits and no passing signs are displayed as popup on each page of the driver information center menu.
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Traffic Sign Assist Operation
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The following traffic signs will be detected:
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No overtaking for passenger cars
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End of no overtaking for passenger cars
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End of all restrictions
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End of speed limit zone
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No passing signs have priority above speed limits. Combinations of both signs in the driver information center are possible.
The traffic sign assist will be active and ready to assist, if the vehicle speed is higher than 10 km/h (6 MPH). It will remain active at day until a speed of 200 km/h (124 MPH). At night the visibility of traffic signs is decreased at higher speed. Therefore the traffic sign assist will be deactivated at night when the speed is above 140 km/h (87 MPH).
If the system is deactivated because of too low or too high speed, the speed limit information is cleared and the blank page is shown. Even if the system is active again, it will show the blank page until the next valid traffic sign is detected. As soon as the speed becomes slower than 55 km/h (34 MPH) the display also will be reseted and the content of the traffic sign page will be cleared.
The content of the traffic sign page is also cleared during driving by pushing the SET/CLR button on the turn signal lever.
When one of the following conditions are met, the system does not operate correctly:
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The area of the windshield, where the camera is located, is not clean.
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Traffic signs are completely or partially covered or badly discernible.
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There are bad environmental conditions like strong rain, snow, direct sun or shadows.
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Traffic signs are incorrectly mounted or damaged.
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Traffic signs do not comply with the Vienna Convention on traffic signs.
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Traffic Sign Assist Driver Information Center Messages
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TRAFFIC SIGN DETECTION FAILURE
The driver information center displays TRAFFIC SIGN DETECTION FAILURE when the parking assist control module detects a malfunction in the traffic sign assist and the system is disabled.
NO TRAFFIC SIGN DETECTION DUE TO WEATHER or NO TRAFFIC SIGN DETECTION - SENSOR BLOCKED
These messages are displayed if the windshield is not clean or there are bad environmental conditions like strong rain, snow, direct sun or shadows.
