BMW 7 Series: System Functions

The BMW Night Vision 2 System Principle

The BMW Night Vision 2 camera is a heat image camera that converts thermal radiation into electronic signals.

The thermal image is converted first by the sensor into electrical signals and then, with the aid of imageprocessing software, into a visible image in the control display or central information display.

The sensor elements alter the resistance in proportion to the temperature. The higher the temperature, the higher the electrical signal and the whiter the pixel will be shown.

Heat radiation is absorbed and dissipated by virtually every solid or liquid body. However, the heat emitted is not visible to the human eye because it is located in the long-wave infrared range. From a physical standpoint, this represents electromagnetic waves with a wavelength of 8 μm to 15 μm. This long-wave infrared radiation is known as Far Infrared (FIR).

The advantage of utilizing radiation in the far infrared range is the greater range compared with near infrared systems (NIR) with a wavelength of 0.7 μm to 1.4 μm. These systems additionally require illumination in precisely this wavelength. Essentially, FIR systems consist of an optical element, a thermal imaging camera, a control unit and a display.

Fig. 56: Identifying BMW Night Vision 2 System Principles

BMW NIGHT VISION 2 SYSTEM LEGENDS

1. Environment ahead of vehicle
2. Optical element
3. Thermal imaging sensor
4. BMW Night Vision 2 control unit
5. Control display

The BMW Night Vision 2 system collects in its front lens the infrared radiation of heat-emitting objects such as persons, animals or vehicles in a specific wave range.

Principle of Pedestrian Detection

The Night Vision 2 control unit is equipped with three processors containing software, which, in addition to image processing for display, execute an automatic person detection function. The software searches the image for objects with human shape and classifies these objects as persons.

Their position, speed and distance to the vehicle are then determined. The risk level is analyzed based on these parameters as well as on the speed and yaw rate of the vehicle and a warning is triggered.

The warning for the driver, indicating persons at risk, is given in the form a corresponding symbol in the central information display CID or head-up display HUD.

Fig. 57: Identifying Symbols On CID

These ranges change with increasing vehicle speed and follow the direction of the vehicle as a function of the current steering angle (yaw rate).

In order not to unnecessarily distract the driver not all persons identified in the image are signalled by a symbol.

Only persons who are in a certain area directly in front of the vehicle are indicated by a symbol.

The system also warns of pedestrians located in an extended area to the left and right of the vehicle and are moving towards the central area (threat of collision).

Fig. 58: Identifying Symbols On HUD

People who are within the central zone are always indicated. Persons in the extended area are only indicated if they are moving in the direction of the central area.

Under optimum conditions, the automatic pedestrian detection function operates at a distance of up to 100 m. At a driving speed in excess of 100 km/h (62 mph), the time between signalling and passing the person and therefore the reaction time for braking and evasive maneuvers is reduced.

Various Forms of Indication

The following table shows the different forms of indication in the two display instruments CID and HUD.

CID AND HUD INDICATIONS REFERENCE CHART

Availability Indicator in CID

The availability of the Night Vision 2 system can be restricted by environmental conditions such as heavy rain, extreme +/- temperatures or fluctuations in light conditions.

Fig. 59: Display Availability Indicator On CID

NOTE: Only non-availability of person detection function is indicated. The symbol corresponds to the "Pedestrian Detection" button in the function bar.

The possible situations for the availability indicator in the CID are listed in the following table.

CID AVAILABILITY INDICATOR DISCRIPTION CHART

Symbols in HUD (Head-up Display)

If a person is detected at a great distance inside the warning range of the system the pedestrian figure will be shown distinctly above the road symbol. This is refered to as long-distance warning.

Fig. 60: Display Long-Distance Warning On HUD

If a person is detected in close range, inside the warning zone of the system, the pedestrian figure will be shown distinctly on the road symbol. This is refered to as short distance warning.

Fig. 61: Display Short-Distance Warning On HUD

Warning in Vehicles w/out HUD

The warning symbol is shown on the CID in vehicles without HUD or with HUD deactivated. In addition, the CID initially flashes yellow 3 times when the warning comes on in order to catch the driver's attention.

The warning is shown as soon as a person enters the warning zone directly ahead of the vehicle or a person crosses the road from the left or from the right.

Sequence of signals

The following graphic shows the exact sequence of warning signals and is designed to illustrate the functional principle in connection with the table.

Fig. 62: Identifying Sequence Of Warning Signals

FUNCTIONAL PRINCIPLE LEGENDS

1. Yellow display
2. Normal display
3. Interval approximately 0.5 seconds
4. The warning symbol remains for as long as there is a pedestrian in the danger zone, but at least 3 seconds

Switch-on Conditions

The BMW Night Vision 2 is activated as soon as the button in the control panel of the driver assist systems BEFAS is pressed.

The following basic conditions can exist:

• The rain/driving lights sensor detects sufficient ambient light and the driving lights are switched off; BMW Night Vision 2 is ready for operation approximately 2 seconds after the button in BEFAS is pressed. A message is shown in the control display during this period of 2 seconds.
• The rain/driving lights sensor detects insufficient ambient light and the driving lights are switched on; BMW Night Vision 2 is ready for operation immediately after the button is pressed. BMW Night Vision 2 cannot be activated when
• The driving lights are switched off
• The rain/driving lights sensor detects insufficient ambient light
• The driving speed is greater than 5 km/h (3 mph).

Once BMW Night Vision 2 has been activated, a message appears in the control display to the effect that the system cannot be used at night without headlights.

Fig. 63: Display Night Vision 2 Button On BEFAS

Operation by iDrive

The individual functions and settings can be selected and activated through the iDrive.

The following settings can be selected on the F01/F02:

• Brightness
• Contrast
• Pedestrian detection.

Fig. 64: Display BMW Night Vision 2 Menu On F01/F02

Calling Up Menu

The "Night Vision 2" menu can only be selected if the system has been activated by pressing the button in the BEFAS.

Providing the preconditions have been met, the menu can be selected as follows:

• Press the controller, the "BMW Night Vision" menu is shown on the control display.
• Select the desired menu item, e.g. "Brightness", by turning the controller.
• Press the controller to activate the function.
• Set the required value and confirm by pressing.

Contrast and Brightness

Both values can be personalized and changed on a scale between 0 % and 100 %.

Fig. 65: Display Adjusting Brightness Screen

Pedestrian Detection

The person detection function can be activated and deactivated.

Visibility

The illumination range in front of the vehicle with low beam is less than 50m/54yd.

Normal driving light illumination by fitted halogen headlights is 100m/109yd.

Fig. 66: Display Activating/Deactivating Person Detection

The high beam illumination range provided by xenon headlights is 150m/164yd. However, people can only be detected in this range if they are wearing reflective clothing.

Night Vision 2 will detect heat-emitting objects in the image up to a distance of about 300m/328yd, regardless of the amount of reflection their clothing gives off.

Automatic pedestrian detection has a maximum range of 100m/109yd. This specified distance is dependent on weather factors.

The range of vision is also reduced in the Night Vision 2 image in the case of thick fog or heavy rain. Night Vision 2 is designed as a supporting system, which provides the driver a better overview of the road conditions ahead of the vehicle.

Fig. 67: Identifying Comparison Of BMW Night Vision 2 Range Of Vision With Different Headlights

NOTE: The driving speed must be adapted to the relevant visibility conditions.

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