Night View Assist, function - GF54.30-P-0005GR
MODEL 166 up to model year 2016 with CODE 610 (Night View Assist)
Function requirements, general
- Terminal 15 ON
- Rain/light sensor detects "Twilight" or "Night" when exterior lights switch is in "A" or "Manual driving lights" position.
- Vehicle in forward movement (speed v ≤260 km/h)
- Low beams ON (for night mode)
The electronic ignition lock control unit sends the circuit 15 status to the Night View Assist control unit via chassis CAN 2.
The request to "switch on low beams" can only be issued with a circuit 15 ON status. The electronic ignition lock control unit sends the circuit 15 status over the interior CAN to the SAM control unit.
The SAM control unit reads in the status of the exterior lights switch directly.
Night View Assist, general
The Night View Assist detects people and objects in the area immediately in front of the vehicle before they are recognizable in conventional headlamp light cones. The Night View Assist camera is located in the upper area of the windshield for this purpose. This is designed for infrared light and records the path the road in front of the vehicle as soon as twilight sets in. The Night View Assistant camera recording range corresponds to the view through the windshield when the high beams are switched on. After the picture data are processed by the Night View Assist control unit, they are transferred to the Audio/COMAND display to be displayed.
The Night View Assist camera operates like a conventional camera although with an extended Infrared light spectrum. The picture data are therefore also displayed when the infrared illumination is not activated.
The windshield must be permeable to infrared light in the field of view of the Night View Assist camera (possible disturbing influences would be: fogging, blocking film, black print, adhesive labels, stone chipping, icing up or dirt).
The Night View Assist system differentiates between the following operating modes depending on the level of ambient brightness:
- Twilight mode
- Night mode
In twilight mode the pictures recorded by the Night View Assist camera are shown in the Audio/COMAND display.
In night mode, as of a vehicle speed of v = 15 km/h the infrared lamps in the front lamp units are additionally switched on. The road in front of the vehicle is then illuminated with infrared light up to s = 150 m.
Because infrared light is invisible to the human eye, oncoming traffic is not dazzled. The Night View Assist system also detects persons on or near the road surface outside built-up areas. The people detected are shown highlighted by photo edges in the Audio/COMAND display. This function is called "Intelligent Night View" (night view with person detection). Person detection in front of the vehicle is possible up to a distance of s = 90 m.
Display on Audio/COMAND display in twilight mode
Display on Audio/COMAND display in night mode ("Intelligent Night View" with person detection)
Function sequence for Night View Assist
The Night View Assist system is activated or deactivated manually by pressing the Night View Assist button. The SAM control unit reads in the status of the Night View Assist button directly and sends this to the COMAND controller unit via interior CAN and to the Night View Assist control unit via interior CAN, electronic ignition lock control unit and chassis CAN 2. The COMAND controller unit then switches over the Audio/COMAND display. In addition, the Night View Assist control unit sends the status of the Night View Assist to the COMAND controller unit via chassis CAN 2, electronic ignition lock control unit and interior CAN.
The Audio/COMAND display now shows the picture data recorded by the Night View Assist camera and processed by the Night View Assist control unit. For this purpose, the Night View Assist control unit actuates the Night View Assist camera over a direct line, which then transmits the recorded picture data via a digital video Interface (direct lines) to the Night View Assist control unit.
The Night View Assist control unit prepares the brightness spread. Extremely bright picture areas that could dazzle the driver are thus filtered out here.
The Night View Assist control unit then sends the processed picture data over an analog video interface (direct line) to the COMAND controller unit. The COMAND controller unit then transmits this via an LVDS line to the Audio/COMAND display.
The picture area and the brightness of the display can be adjusted via the Audio/COMAND control panel. The relevant requests are transmitted to the COMAND controller unit by the Audio/COMAND control panel via the telematics CAN.
When the Night View Assist system is activated, the picture data are continuously sent to the COMAND controller unit.
However, the display of the pictures is suppressed by the COMAND controller unit under the following conditions:
- Engage gear range "R" (activation of reversing camera (with CODE 218 (Reversing camera))
- Application change (e.g. when operating the audio system or telephony)
The following input factors are read in and evaluated by the Night View Assist control unit:
- Status of rain/light sensor
- Vehicle speed
- Exterior lights status (low beams on in night mode)
- Picture data of Night View Assist camera
- Light source detection (for person detection)
Status of rain/light sensor:
The ambient brightness is sensed by the rain and light sensor. The SAM control unit reads in the status of the rain and light sensor over the roof LIN and sends this over the interior CAN, electronic ignition lock control unit and chassis CAN 2 to the Night View Assist control unit.
A distinction is made between the following brightness values:
- Day: Night View Assist inactive
- Twilight: Twilight mode
- Night: Night mode
Vehicle speed:
The vehicle speed is calculated on the basis of the wheel speeds. The wheel speeds are detected by the rpm sensors. The Electronic Stability Program control unit directly reads in the signals from the rpm sensors and sends them over the chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 to the instrument cluster. The instrument cluster calculates the vehicle speed to be displayed and transmits this via chassis CAN 2 to the Night View Assist control unit.
Exterior lights status (low beams on in night mode):
The SAM control unit determines the status of the exterior lights through the position of the exterior lights switch or based on the signals from the rain/light sensor, when the exterior lights switch is in position "A". The SAM control unit transmits this via interior CAN, the electronic ignition lock control unit and chassis CAN 2 to the Night View Assist control unit.
Picture data of Night View Assist camera:
The Night View Assist camera transmits the picture data via direct lines (digital video interface) to the Night View Assist control unit.
After replacement of the windshield or a component of the Night View Assist, the Night View Assist camera must be recalibrated.
Light source detection (for person detection):
The multifunction camera distinguishes between light sources on vehicles and static light sources (e.g. street lamps). If the multifunction camera identifies static light sources in the vehicle's surroundings, the "Intelligent Night View" function is deactivated. For this purpose, the multifunction camera transmits corresponding information via chassis CAN 2 to the Night View Assist control unit.
The Night View Assist control unit evaluates the input factors, activates the Night View Assist system and switches between twilight and night modes depending on the level of ambient brightness.
Twilight mode:
When the rain/light sensor evaluates the ambient brightness as twilight, the Night View Assist camera records the path of the road surface without additional infrared illumination.
Night mode:
In night mode, as of a vehicle speed of v = 15 km/h the infrared lamps in the front lamp units are additionally actuated. Light emitting diodes (LEDs) are used to generate the infrared light.
The infrared lights are actuated by the headlamp control unit. The Night View Assist control unit sends the "infrared lights on" request over the chassis CAN 2 to the headlamp control unit. The headlamp control unit transmits this request via headlamp LIN to the front LED exterior lights actuation modules, which then actuate the infrared lights.
The function of the infrared lights is monitored by the front LED exterior lights actuation modules. The front LED exterior lights actuation modules send corresponding information via headlamp LIN, headlamp control unit, chassis CAN 2, electronic ignition lock control unit and interior CAN to the SAM control unit. The SAM control unit forwards this via interior CAN, the electronic ignition lock control unit and chassis CAN 2 to the Night View Assist control unit.
In addition, the front LED exterior lights actuation modules actuate the fan motors 1 of the front lamp unit. This prevents overheating of the LEDs and of the plastic housing of the front lamp units as a result of high outside temperatures and/or high actuation currents.
If the vehicle speed drops below v = 5 km/h, the infrared lights are switched off.
Function test of LEDs:
The infrared light function test is carried out using a diagnostic tester and is possible for approx. t = 10 s. A repeat of the function test is only possible after t = 5 min. Hold a white surface (e.g. a piece of white paper) in front of the infrared lamps for this. If the infrared lights are OK, a reddish/green shimmer can be seen on the white surface.
When the Night View Assist detects people on or near the road surface in night mode, these are highlighted with photo edges and displayed on the Audio/COMAND display. For this it has to be defined whether the vehicle is in a town or on a non-illuminated country road. This is accomplished by evaluating the data from the multifunction camera (light source detection).
Function notes:
Due to the limits of the system, the person detection may interpret incorrectly, e.g. objects may be detected as persons and displayed with highlighted photo edges. The identification rate drops off with increasingly unfavorable conditions (e.g. strong backlighting, rain, snow, bright background or very darkly clothed people) and individuals are not shown highlighted.
Malfunctions of the Night View Assist system are communicated to the driver through the multifunction display. Here, a distinction is made between user-related and system-related messages.
The example messages listed in the following tables are transmitted by the Night View Assist control unit via chassis CAN 2 to the instrument cluster.
| User-related messages | Meaning |
|---|---|
| "Night View Assist not in gear range R" | Gear range "R" is engaged. |
| "Night View Assist light ON or AUTO not in gear range R" | Gear range "R" is engaged, Rotary light switch not in position "A" or "Manual driving lights" |
| "Night View Assist lights ON or AUTO" | Rotary light switch not in position "A" or "Manual driving lights" |
| "No Night View Assist display over x km/h" | Speed over v = 260 km/h |
| System-related messages | Meaning |
|---|---|
| "Night View Assist is started" | Night View Assist is being initialized. |
| "Night View Assist inoperative" | Faulty connection in the analog video interface, Faulty Controller Area Network (CAN communication), Infrared LEDs defective |
| "Night View Assist currently not available" | Night View Assist camera shut off due to overheating, Temporary interruption of control or data line of Night View Assist camera |
| "Night View Assist in darkness only" | Rain/light sensor sends "Day". |
| "Night View Assist available again" | Temporary source of fault has been eliminated. |
| Electrical function schematic, Night View Assist | PE54.30-P-2053-97NAA |
| Overview of system components for driver assistance systems | GF54.00-P-9998GR |