Traffic Sign Assist, Function - GF54.30-P-0010FR
Model 257, 290
up to model year 2021
with code 504 (Speed sign recognition)
Model 257, 290
up to model year 2021
with code 513 (Road sign recognition system)
Shown on model 257, 290
Function requirements in general
- Terminal 15R On:
The electronic ignition lock control unit sends the circuit 15 status over the chassis FlexRay to the stereo multifunction camera or over the periphery CAN to the mono multifunction camera.
Traffic Sign Assist, general
Traffic Sign Assist is implemented to match the equipment into the mono multifunction camera or into the stereo multifunction camera. The multifunction camera records the signposted speed limits including additional characters, e.g. at the edge of the road, on overhead signs or at construction sites. The data are displayed in the instrument cluster and, with code 463 (Head-up Display), in the head-up display. The display in the instrument cluster's multifunction display can switched on or off on the head unit.
Additionally, with code 513 (Traffic Sign Assist),
- the data are compared with the information of the navigation system and also shown in the navigation map view in the Audio/COMAND display.
- no-passing signs and their termination signs are recorded and displayed.
- for no-entry zones with corresponding signage, a visual warning and a warning tone are emitted in the instrument cluster.
A visual warning and warning tones can also be issued when a speed limit is exceeded, and can be selected and configured using the head unit. The following options are available for navigating in the control menu:
- Except with code 446 (Touchpad only), navigation can be performed using the Audio/COMAND control panel. The Audio/COMAND control panel transmits the relevant control signals via the telematics CAN to the head unit.
- With code 446 (Touchpad only) or code 448 (Touchpad), navigation can be performed using the touchpad. The touchpad sends the relevant operation signals to the head unit via the telematics CAN.
- Navigation can be performed by voice control. The driver hands-free system microphone is read directly by the head unit.
- Navigation can be performed via the head unit finger navigation pad and the "Back" button on the steering wheel. The corresponding operation signals are sent by the head unit finger navigation pad and the "Back" button over the steering wheel electronics, steering wheel CAN, steering column tube module control unit, suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the head unit.
- With code 246 (Analog clock), the control menu can be called up with the Vehicle button in the upper control panel control unit. The status of the Vehicle button is sent by the upper control panel control unit over the LCP-LIN, the Audio/COMAND control panel (except code 446 (Touchpad only)) or touchpad (with code 446 (Touchpad only)) and the telematics CAN to the head unit.
The head unit sends the status of the operating mode over the user interface CAN, electronic ignition lock control unit and the chassis FlexRay to the stereo multifunction camera or over the user interface CAN, electronic ignition lock control unit and the periphery CAN to the mono multifunction camera.
The driver can select the following operating modes:
- Visual warning
- Visual warning and warning tones
- Off
Display in instrument cluster (depiction of the detected traffic sign is country-specific)
A maximum of two speed limits and an additional traffic sign are shown at the same time. If several speed limits are detected, the lowest speed limit is displayed.
Shown on Audio/COMAND display (with code 513 (Traffic Sign Assist)), system language German (the detected traffic signs are shown on a country-specific basis)
The display on the Audio/COMAND display (with code 513 (Traffic Sign Assist)) is only performed in the map view of the navigation system and can be switched on or off using the head unit menu.
The mono multifunction camera or the stereo multifunction camera evaluates the following input factors among other things:
- Signal "Engine running" or "Drive train operational"
- Map data (with code 513 (Traffic Sign Assist))
- Direction of travel vehicle speed and yaw rate
- Steering wheel angle
- Windshield wiper active
- Outside temperature
- Trailer recognition (with CODE 550 (Trailer hitch))
"Engine running" or "Drive train operational" signal:
The CDI control unit or the ME-SFI [ME] control unit sends the "Engine running" or "Drive train operational" signal via drive train CAN drivetrain control unit and chassis FlexRay to the stereo multifunction camera or via drive train CAN, drivetrain control unit and periphery CAN to the mono multifunction camera.
Map data (with code 513 (Traffic Sign Assist)):
The map data is used for checking the plausibility of the object detected by the multifunction camera as well as for fading out displayed speed limits when the vehicle is driven into built-up areas. The map data are sent by the head unit over the user interface CAN electronic ignition lock control unit and the chassis FlexRay to the stereo multifunction camera or over the user interface CAN, electronic ignition lock control unit and the periphery CAN to the mono multifunction camera.
Direction of travel, vehicle speed and yaw rate:
Information on direction of travel and vehicle speed are derived from the wheel speed and wheel rotation direction signals.
The yaw behavior is detected by the acceleration sensor integrated into the Supplemental Restraint System control unit. The supplemental restraint system control unit sends the corresponding values via the vehicle dynamics CAN to the Electronic Stability Program control unit.
The Electronic Stability Program control unit sends all relevant information via chassis FlexRay to the stereo multifunction camera or via chassis FlexRay, electronic ignition lock control unit and periphery CAN to the mono multifunction camera.
Steering wheel angle:
The steering angle is recorded by the steering wheel angle sensor. The steering column tube module control unit reads in the signals from the steering wheel angle sensor directly and sends information about the steering wheel angle via the chassis FlexRay to the stereo multifunction camera or via the chassis FlexRay, electronic ignition lock control unit and periphery CAN to the mono multifunction camera.
Windshield wiper active:
The front SAM control unit controls the windshield wiper system. With the windshield wiper switched on, the front SAM control unit sends the "Windshield wiper active" status via the interior CAN, electronic ignition lock control unit and chassis FlexRay to the stereo multifunction camera or via the interior CAN, electronic ignition lock control unit and periphery CAN to the mono multifunction camera.
Outside temperature:
The outside temperature is recorded by the outside temperature sensor. The front SAM control unit reads in the outside temperature sensor signal directly, uses this to calculate the outside temperature and sends this via interior CAN, electronic ignition lock control unit and user interface CAN to the instrument cluster. The instrument cluster calculates the outside temperature displayed and sends this over the user interface CAN, electronic ignition lock control unit and chassis FlexRay to the stereo multifunction camera or over the user interface CAN, electronic ignition lock control unit and periphery CAN to the mono multifunction camera.
Trailer recognition (with code 550 (Trailer hitch)):
If a trailer is detected, the trailer recognition control unit sends the "Trailer detected" status over the interior CAN, electronic ignition lock control unit and the chassis FlexRay to the stereo multifunction camera or over the interior CAN, electronic ignition lock control unit and the periphery CAN to the mono multifunction camera.
Function sequence for Traffic Sign Assist
At a horizontal angular coverage of ∠ = 46° the multifunction camera records pictures during the journey of the traffic signs over or at the side of the road. Traffic Sign Assist is continuously active in the background. In other words, the corresponding traffic signs are permanently recorded and evaluated by the multifunction camera [MFK]. The recorded picture data are sent to the integrated picture recognition module which compares them against the stored data records and assigns the traffic signs to the respective valid road traffic regulations. The picture recognition module of the multifunction camera assigns a specific credibility to all results.
The national regulations for the design and attachment of traffic signs are taken into account for this.
The multifunction camera records all picture objects and evaluates circular as well as square contours. Speed limits, prohibitory and derestriction signs including additional restrictions in countries with signage according to the Vienna convention, in the USA and Canada are accordingly detected. Non-relevant signs (supplementary signs that, e.g. are relevant for a turnoff lane) are suppressed. If the navigation system is active, supplementary signs will be shown immediately if they are relevant for the currently active navigation.
Possible additional signs include limits in wet conditions or when towing a trailer. If, for example, the "windshield wipers active" status is received by the multifunction camera and a permissible maximum speed with additional restriction "in the wet" is registered, the detected permissible maximum speed is shown in the instrument cluster. The permissible maximum speed is not viewed to be relevant as long as the "windshield wipers active" status is not read in.
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. After evaluating the data, the detected traffic signs are shown on the multifunction display of the instrument cluster and, with code 513 (Traffic Sign Assist), also on the Audio/COMAND display. Information about the currently permissible speed or the currently valid prohibitions is thus available to the driver.
The multifunction camera also combines the information about speed limit to form an event if the information is contradictory.
Vehicles except code 23P (Driving Assistance Package):
The mono multifunction camera sends corresponding requests to display the currently detected traffic sign and a warning message to the instrument cluster and, with code 513 (Traffic Sign Assist), also to the head unit via the peripherals CAN, electronic ignition lock control unit and the user interface CAN.
Vehicles with code 23P (Driving Assistance Package):
The stereo multifunction camera sends corresponding requests to display the currently detected traffic sign and a warning message to the instrument cluster and, with code 513 (Traffic Sign Assist), also to the head unit via the suspension FlexRay, electronic ignition lock control unit and the user interface CAN.
With code 513 (Traffic Sign Assist), the head unit actuates the Audio/COMAND display via the telematics CAN and transmits the corresponding data via the HSVL line.
Vehicles with code 463 (Head-up display):
The instrument cluster sends the corresponding data over the HSVL line to the head-up display. The head-up display projects the corresponding data onto the windshield in the driver's field of view.
If the multifunction camera with code 513 (Traffic Sign Assist) detects a no-entry sign when entering a freeway or expressway in the opposite direction to the direction of travel (scenario of motorist driving the wrong way), the no-entry sign is shown on the multifunction display of the instrument cluster and on the Audio/COMAND display. A "Check direction of travel!" warning message is displayed in the multifunction display and warning tones are also issued over the instrument cluster speaker, which is actuated directly by the instrument cluster.
The acoustic warning message can be acknowledged at the earliest after t = 5 s.
In the event of a fault, the following messages are shown on the multifunction display:
- "System currently not available" (e.g. camera field of view fogged up)
- "System nonfunctional" (e.g. multifunction camera or navigation system malfunction)
- "Field of view camera blocked, Traffic Sign Assist nonfunctional"
Display on the instrument cluster
Traffic signs recognized by the multifunction camera (example displays)
Representation of derestriction signs
The following events cause the derestriction sign to be displayed (J):
- Passing by a derestriction sign (F) and no further maximum permissible speeds
In no passing areas, the prohibition sign is removed from the display when a no passing derestriction signs is passed (I).
In addition the multifunction camera evaluates information on the area around the vehicle and on the vehicle's own movement.
These include:
- Distance and angle to other road users and objects recorded by the multifunction camera itself
- Vehicle movement and yaw behavior
- Head unit map data (with code 513 (Traffic Sign Assist))
With code 513 (Traffic Sign Assist), the attributes verified in the digital map of the navigation system are also evaluated.
Model 257 290
up to model year 2021
with code 513 (Road sign recognition system)
The map data are used to evaluate the national availability. The national availability may be able to be extended and therefore it matches the current software release
Model 257, 290
up to model year 2021
with code 513 (Road sign recognition system)
Because speed limits are subject to alteration, the digital map data has to be regularly updated.
Map data processing with code 513 (Traffic Sign Assist):
Information on the classification of roads and regional development is deduced from the map data provided by the head unit. By this means the system recognizes that the vehicle is leaving a road for which a speed limit identified earlier was displayed.
When changing from an undeveloped area to a built-up area, the speed limit of the map data is used. As the town/village limits do not always match the built-up area markings from the navigation map, the display of the last detected speed limit may be faded out too soon or may continue to be shown in the built-up area.
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
Function information and system limits
Below is a list of examples of situations in which the pictures taken by the multifunction camera cannot be evaluated and are not used to display on the multifunction display and on the Audio/COMAND display (with code 513 (Traffic Sign Assist)):
Highway entry/exit signs
Speed limits marked by town/village entry and town/village exit signs or by freeway start and finish signs are not recorded. These traffic signs however, are filed through the road definition feature (e.g. freeway) in the digital navigation map.
Changing traffic signs
Electronically actuated changing traffic signs can be "missed" or interpreted incorrectly. In the event of changing traffic signs that are actuated by pulses or flashes, there may be difference to the picture recording's permanent cycle time, depending on the actuated frequency of the changing traffic signs. As a result only fragments of the changing traffic signs will be recognized.
If the image cannot be uniquely identified as a traffic sign, the speed value that is stored in the digital navigation map is then shown.
Changing traffic signs without circular ring
To enable the detection of changing traffic signs on which the outer circular ring is missing, special detectors have been implemented in the multifunction camera.
This type of display is mainly used in The Netherlands and Belgium.
Horizontal angle of vision of multifunction camera
The horizontal angle of vision of the multifunction camera is limited. Traffic signs erected immediately after junctions, turnoffs which the vehicle takes, can be "missed" by the multifunction camera.
The horizontal angular coverage of the multifunction camera is ∠ a = 46°.
Resolution of multifunction camera
The resolution of the multifunction camera is limited. Traffic signs on wide or multilane roads can be "missed" as they do not reach the size required for clear identification in the evaluation window of the multifunction camera.
The sensitivity and dynamics of the multifunction camera are limited. This results in traffic signs not being recognized under the following conditions:
- Traffic signs with low contrast
- Extreme oncoming lights or lights from the rear
- Low levels of lighting, darkness
The focus and alignment of the multifunction camera are fixed. As a result recorded objects are represented with a movement blur depending on the exposure time.
This movement blur and sensitivity of the multifunction camera limit its usefulness at night. The result of the fixed focus and static alignment is that the traffic signs to be recorded must be completely visible in a small observation time window.
Back-end sections of commercial vehicles - design
Unfavorably designed back-end sections of commercial vehicles may be interpreted as derestriction signs by mistake.
Back-end sections of commercial vehicles - labeling
Signage on the back-end section of commercial vehicles may be interpreted as traffic signs by mistake.
Model 257, 290
up to model year 2021
with code 513 (Road sign recognition system)
During an update or a reset procedure for the head unit, the navigation system data are not available so that fault messages may occur in an individual case.
| Electrical function schematic, traffic sign assist | PE54.30-P-2066-97XBA | ||
| Overview of system components for driver assistance systems | GF54.00-P-9998FR |