The camera itself shoots away at a rate of 30 images every second, non stop. By constantly checking the road horizon up to 100 metres ahead, FCS can spot such things as road signs and lane markings.
Then that clever software kicks in, analysing the images at break neck speed. If it spots what it knows to be a road sign shape it will then use a system based around a colour comparison algorithm to determine numbers for example. Once FCS is happy it is a 50 miles per hour speed limit sign, say, it will notify the driver of the impending limit by way of a warning on the instrument panel.
At the moment I understand these to be visual warnings, although Vauxhall will use audio as well when it comes to lane detection. FCS can use the same technology to calculate when you are veering out of your lane by keeping an eye on the road markings. Do this and you get the full audio warning experience.
Still a little too much like a nagging back seat driver for me, as I'd rather not be distracted by my car reminding me how to drive. And that could be the real problem as the next logical step is to link such a system into the voice controls that are increasingly found in top end vehicles.
Can you imagine your car actually telling you to slow down or straighten up, and while you are at it to sit up straight as well?