Perception Safety

Question 1

Definition: Perception Safety

Answer 1

Perception of relevant information of the traffic environment by the driver and visibility of the own vehicle for other road users

Question 2

Definition: Lumen

Answer 2

Lumen (lm) - Dimension of luminous flux emitted by a light source

Assesment of the light source

Question 3

Definition: Lux

Answer 3

Lux (lx) - Dimension of the illuminance falling on an object

Assessment of the efficiency

Question 4

Limits of Visual Perception

Answer 4

Physical filters:

• Twilight
• Darkness
• Fog, rain, snow
• Aging and wear of the windscreen
• Reflections onto the carriageway

Physiologicial filters:

• Physiolocigal dazzling
• Faculty of sight and age
• Different viewing distance
• Fatigue

Psychological filters:

• Distance and velocity perception
• Psychological dazzling (Distraction by light source)
• Cognitive tunneling

Question 5

Requirements on Headlamp Systems (High beam light)

Answer 5

Visibility range

• long range
• Sufficient side spreading
• Sufficient height spreading

Question 6

Requirements on Headlamp Systems (Low beam light)

Answer 6

Dazzling safety

• Optical visibility range
• Adjustable cut-off line
• Asymmetrical light distribution

Question 7

Cut-off line

Answer 7

For the right-hand traffic the cut-off line runs horizontally to the left, away from the vehicle axis. To the right it rises at an angle of 15 deg. In the longitudinal direction of the vehicle, the light-dark boundary with the reference to the headlight centre moves downward, lowered by 1% i.e. around 25cm over a distance of 25m.

Above the light-dark boundary is the area of glare. The intensity of the low beam light should not amount to more than 1lx, 25m in front of the vehicle. Within the area of the oncoming traffic, this limit value to only 0,6lx. Below the light-dark boundary, a high intensity of light is desired.

Question 8

Asymmetrical Light Distribution

Answer 8

1. Wide side illumination
2. Selective road illumination
3. Broad road illumination

Question 9

Reflector types

Answer 9

• Paraboloid
• Free-Form (FF)
• Ellipsoid - DE (Projection)
• Super-DE (FF + Projection)

Question 10

Elements of Intelligent Front Lighting

Answer 10

• Dynamic headlamp levelling
• Adaptive headlights
• Bending light
• Adaptive light
• Cornering light

Question 11

Aims of the adaptive headlamp systems

Answer 11

• Better illumination on winding roads
• Headlamps should follow curves
• Better illumination in built-up areas
• Wide-angle light to better illuminate pavements and intersections
• “Cornering light” analogous to bending light
• New high beam with great luminosity and range
• Narrow beam that does not dazzle oncoming traffic

Question 12

Near Infrared (NIR) - Night Vision

Answer 12

• Active night vision system, infrared radiation source is mounted at car front, camera can be mounted within the car
• CCD or CMOS camera captures reflected visible infrared light, image is displayed in cockpit monitors or on a Head-Up display
• Radiation is reflected by objects like visible light, displayed image appears natural like the lighted scenery, image is simple to understand

Question 13

Name six essential components of an automotive headlamp

Answer 13

• Reflector
• Lighting unit
• Housing
• Covering frame
• Cover plate
• Bulb holder

Question 14

Two headlamp principles

Answer 14

• Reflection system: Light is distributed through a reflector
• Projection system: Light is distributed through a lens