360° Camera, Function - GF54.65-P-0007CE
MODEL 204.9 with CODE (501) 360-degree camera as of model year 2013/model refinement package 12
Function requirements, general
- Circuit 15 ON
- 360 degree view function activated via COMAND controller unit
or
- reverse gear (with transmission (711, 716) or gear range "R" engaged (with transmission 722)
The status of circuit 15 is sent by the electronic ignition lock control unit via the interior CAN, front SAM control unit and front end CAN to the 360° camera control unit.
360° camera, general
The 360° camera is a support system which uses four digital cameras to assist the driver when parking and maneuvering and also when driving out of blind exits. There is one camera each on the radiator grille, in the outside mirror housings and in the liftgate.
In addition to the original picture data recorded by the cameras, the 360° camera control unit also calculates an artificial image ("virtual viewpoint").
On the Audio/COMAND display, the vehicle and its surroundings (s = 3 m to front and rear and s = 2.5 m to the ground on the sides) are displayed to the driver as a "top view" (bird's eye view).
The driver is thus supplied with seven split views and two full screen views of areas of the vehicle surroundings which are not visible from within the vehicle.
Camera lenses with a horizontal angle of vision of > 180° and a vertical angle of vision of > 125° supply the required field of view. Dynamic and static guide lines, which represent the vehicle dimensions and driving trajectories (driving paths) based on the steering angle, are displayed in the image to assist the driver.
A maximum of two views can be shown simultaneously on the Audio/COMAND display: the "top view" and additionally a detailed view (e.g. the picture recorded by the 360° rear camera after reverse gear or gear range "R" has been engaged).
For optimal safety during parking and maneuvering, appropriate additional information (e.g. warning elements or vehicle corners at risk) is shown on the Audio/COMAND display. The parking system control unit sends appropriate information regarding the status of the parking system via the chassis CAN, front SAM control unit and front end CAN to the 360° camera control unit which processes this information and then sends the corresponding requests to the Audio/COMAND display.
The 360° camera system operates according to the direction of travel and vehicle speed, therefore requiring these variables to be determined.
The vehicle speed is calculated on the basis of the wheel speeds. The direction of travel is defined by the wheel rotation direction.
Vehicle speed and direction of travel:
For this purpose, the Electronic Stability Program control unit reads in the rpm sensor signals and sends them via the chassis CAN to the instrument cluster and additionally via the chassis CAN, front SAM control unit and front end CAN to the 360° camera control unit. The instrument cluster calculates the vehicle speed to be displayed and sends it via the chassis CAN, front SAM control unit and front end CAN to the 360° camera control unit. The 360° camera control unit uses the signals from the rpm sensors to determine the direction of travel.
The 360° camera system remains active up to a vehicle speed of v < 18 km/h in the case of forward travel.
When this speed limit is exceeded, the 360° camera system is deactivated.
If the vehicle speed then drops back below this speed limit, the 360° camera system is activated again. In the case of reverse travel, the 360° camera system remains active irrespective of the vehicle speed.
Function sequence for 360° camera
The 360° camera system is activated automatically when reverse gear (with transmission 711, 716) or gear range "R" (with transmission 722) is engaged or by pressing the corresponding softkey or the favorite button on the Audio/COMAND control panel.
The Audio/COMAND control panel sends the status of the softkey and favorite button via the telematics CAN, COMAND controller unit, interior CAN, front SAM control unit and front end CAN to the 360° camera control unit.
Automatic activation when reverse gear or gear range "R" is engaged can be deactivated via the system menu of the COMAND controller unit.
The COMAND controller unit sends the corresponding status via the interior CAN, front SAM control unit and front end CAN to the 360° camera control unit.
Vehicles with transmission 711, 716:
Engagement of reverse gear is defined via the status of the backup lamp switch, which is read in directly by the front SAM control unit.
Vehicles with transmission 722:
The request to "Engage gear range R" is defined by the corresponding selector lever position.
The electronic selector lever module control unit sends the selector lever position via drive train CAN, CDI control unit, or ME-SFI [ME] control unit and chassis CAN to the front SAM control unit.
Located in the front SAM control unit are two microprocessors, one for control of basic functions e.g. the exterior lights, and the second for control of the central gateway functions. Both processors communicate with each other internally via interior CAN.
Using the incoming information, the microprocessor which controls the central gateway functions generates the "reverse gear engaged" signal (irrespective of the transmission variant) and sends this signal via the front end CAN to the 360° camera control unit.
After the 360° camera system has been activated, the 360° camera control unit switches on the power supply of the camera. The pictures recorded by the respective camera are read in by the 360° camera control unit via the LVDS line and then processed.
The 360° camera control unit then activates the COMAND controller unit via the front end CAN, front SAM control unit and interior CAN.
The 360° camera control unit transmits the processed pictures as CVBS signals to the COMAND controller unit.
The COMAND controller unit then activates the Audio/COMAND display via the telematics CAN.
To improve the image quality of the displayed driving area, electronic distortion correction is performed by the 360° camera control unit.
The processed data is transmitted by the COMAND controller unit via the LVDS line to the Audio/COMAND display, where it is displayed.
Taking the pictures recorded by the camera, the steering angle and the stored vehicle parameters into consideration, the 360° camera control unit calculates guide lines which are displayed in the documented pictures.
The steering angle is recorded by the steering angle sensor.
The steering column tube module control unit reads in the signals from the steering angle sensor and sends them via the chassis CAN, front SAM control unit and front end CAN to the 360° camera control unit.
The "top view" also displays open doors and/or an open liftgate.
An open front door is detected from the status of the front door rotary tumbler switch in the front door lock.
The respective front door control unit reads in the status of the front door rotary tumbler switch directly and sends it via the interior CAN, front SAM control unit and front end CAN to the 360° camera control unit.
An open rear door is detected from the status of the rear door rotary tumbler switch in the rear door lock.
An open liftgate is detected from the status of the liftgate rotary tumbler switch in the liftgate central locking motor.
The rear SAM control unit reads in the status of the rear door rotary tumbler switch and that of the liftgate rotary tumbler switch directly and sends them via the interior CAN, front SAM control unit and front end CAN to the 360° camera control unit.
The 360° camera control unit evaluates this information and, according to the respective status, displays an open door or an open liftgate in the "top view".
However, the area recorded by the camera in question is removed from the display.
On vehicles with code (249) Automatically dimming inside rearview mirror and outside mirrors including folding outside mirrors, the 360° camera control unit additionally evaluates the position of the outside mirror housings for display of the pictures recorded by the cameras. Using the status of the outside mirror housings (folded in or out), the 360° camera control unit computes the optimum display for the "top view".
The position of the outside mirror housings is sent by the left front door control unit and right front door control unit via the interior CAN, front SAM control unit and front end CAN to the 360° camera control unit.
While the outside mirror housings are being folded in/out, the "top view" is temporarily removed from the display until the display is recomputed.
The views shown on the Audio/COMAND display can be switched over both automatically and manually. The system switches between the rear view and front view automatically according to which gear is engaged or which gear range is selected.
In addition to the automatic selection, the driver can also switch manually between the various detailed views via the COMAND controller unit.
The following views are possible on the Audio/COMAND display:
- Top View + Front View
- Top View + Rear View
- Top View + Side View Forward
- Top View + Side View Backward
- Top View + Top View Front Zoom
- Top View + Top View Rear Zoom
- Top View + Trailer Coupling View (with code (550) Trailer hitch, if trailer is detected)
- Front view full screen
- Rear view full screen
Top View + Front View, shown on model 166
Top View + Rear View, shown on model 166
Top View + Side View Forward, shown on model 166
Top View + Side View Backward, shown on model 166
Top View + Top View Front Zoom, shown on model 166
Top View + Top View Rear Zoom, shown on model 166
Top View + Trailer Coupling View (with code (550) Trailer hitch), shown on model 166
Front View Fullscreen, shown on model 166
Rear View Fullscreen, shown on model 166
System limits:
The 360° camera system has certain limits with regard to its functions and displays. Distortion and "blind spots" can occur. In the "top view", objects outside road level (e.g. vehicles) are displayed with distortion.
Objects in "Front View Full Screen" (left outside mirror 360° camera, right outside mirror 360° camera and front 360° camera active) are also displayed with distortion. The assignment of objects in the picture to how they appear in real-life can therefore be very unusual.
There are different types of "blind spot" depending on the system and model in question. On the one hand, they result from the position of the camera above the respective bumper. Here the 360° camera system loses the field of view directly in front of and behind the vehicle. On the other hand, they can occur because of how the system operates, particularly in the four overlapping areas of the pictures recorded by the cameras during computation of the "top view".
Furthermore, due to the low installation height of the cameras there are areas where only objects close to the ground can be seen. This means, for example, that people are not shown roughly above knee height in the "top view". In both cases, however, additional protection is provided by the parking system.
| Electrical function schematic for 360° camera | PE54.65-P-2060-97FAA | ||
| Overview of system components of parking assistance systems | GF54.00-P-9997CE |