How does the Audi A6's Pre-Sense City System work?

I've heard about the Pre-Sense City system on the Audi A6, but I'm not sure how it actually works. Can someone explain it to me?

The Pre-Sense City system uses a combination of radar and front cameras to detect potential collisions with objects and pedestrians in front of the vehicle. If a potential collision is detected, the system will first issue an audible and visual warning to the driver, and if necessary can also apply emergency braking to help avoid or mitigate the impact.

I've personally used the Pre-Sense City system in my own Audi A6, and it has saved me from potential accidents on multiple occasions. It's a highly advanced and reliable system.