Read more
technology news
www.theengineer.co.uk
the real value comes in with a
fusion of multiple sensors much as
you have with the human brain
45 April 2020 / www.theengineer.co.uk
Association found that not one of them
recognised a pedestrian at night, while
collisions were only avoided 40 per cent
of the time during daylight. “Long wave
thermal cameras can solve this problem
and make a real difference to AEB
systems,” notes Posch.
There are two main trends that he
believes will make these systems more
attractive to OEMs. The first is the shift
towards VGA sensors, which offer four
times the resolution of traditional qVGA
systems; the other is the use of a second
sensor, such as radar or visible light,
to work in parallel with the infrared
camera. “That’s when the real value
comes in – with a fusion of multiple
sensors, much as you have with the
human brain,” he concludes.
On test: Bentley Continental GT
To put night vision to the test, we turned
to the Bentley Continental GT.
Admittedly, you can find similar systems
on some far more affordable cars these
days; if you’re going to spend an evening
driving up and down darkened roads in
search of wildlife hiding in the hedges,
however, there are few finer machines in
which to do it. More to the point, the
Bentley’s LED matrix headlamps are
some of the best in the business, so the
night vision system is going to have its
work cut out to spot any hidden hazards.
The Continental GT uses a passive
system, with a thermal camera mounted
on the front of the grille (complete with
its own washer unit to clear dust, grime
and ice). Inside the car, a control unit
analyses the data from the sensor, which
is then sent to the virtual instrument
cluster. It’s displayed as a greyscale
image, with brighter shades representing
higher temperatures. Body heat typically
appears as a vivid white, but the filtering
system works on contrast between the
different areas, so it will still function
with ambient temperatures up to 80
deg C (and down as low as -40 deg C).
What’s more, it looks at emissivity of
the surface, so even two objects at a
completely identical temperature should
theoretically stand out.
The clever bit is the recognition
software. This highlights potential
hazards, with the warning strategy
adjusted to suit different environments,
such as town centres and rural roads,
using data from the navigation system
and the vehicle’s cameras. A yellow
box means that the car has spotted a
moderate hazard, whereas a red box –
accompanied by an audible warning
– means that the car is reaching the
critical stopping distance to avoid a
collision.
“The detection range and
classification varies largely on the
size and shape of the hazard,” explains
Martyn Brookes, advanced driver
assistance engineer at Bentley. “As a
rough guide, it can detect a 1.7 metre tall
stop. “We are developing future
technologies for next generation
systems that will be close linked to other
ADAS functionality,” notes Brookes.
On the road
With the system switched on, we
head off in search of warm bodies. The
first thing you notice is that the shades
in the display are all fairly subdued, so
it doesn’t divert too much attention in a
dark cabin. The sensitivity of the camera
and the sophistication of the filtering
is such that it actually produces a fairly
passable image of the surroundings –
you can pick out bumps in the road and
branches on the trees. Generally, though,
the display fades into your peripheral
vision and you almost forget that it’s
there.
Sure enough, people stand out well
from the background and are almost
always correctly highlighted by the
software. Having failed to spot Bambi en
route we decide to cheat and enlist the
help of Ferne, a five-year old flat coated
retriever, who doubles as a deer leaping
into the road. The system doesn’t seem
to be quite as reliable with animals –
possibly because we’re a little too close
– but it still registers our canine stunt
double more often than not.
So far, I’m impressed rather than
bowled over by the capabilities of the
night vision system. On the drive back,
however, we enter a dimly-lit village
on dipped headlights and a yellow box
suddenly illuminates on the screen. It’s
at that point that I notice a pedestrian
lurking unseen at the side of the road.
For the first time, it feels like the system
has offered something beyond my own
hazard perception. And that’s driving
with fresh eyes and deliberate care.
Of course, the human brain applies
its own degree of filtering. Unlike the
car, I knew we were going to take a
turning long before we reached the
rogue pedestrian. As such, I wouldn’t say
it’s a conclusive victory for technology
over human intuition, but there’s no
question that the system works. Bundled
in an options pack with a suite of other
features – as it is on the Bentley – I can
see the value. It’s relatively unobtrusive
when in use and it’s easy to turn off. And
there’s always the possibility that one
day it might spot something that you
don’t.
pedestrian at distances of between 8
metres and 90 metres. Small animals up
to 1 metre at the withers can be detected
at a distance of 7 metres to 70 metres,
and larger animals up to 2 metres at a
distance of between 13 metres and 140
metres.”
At present, it’s a ‘closed’ device,
which relies solely on infrared sensing
and has no direct control over the
vehicle, although it will prime the
master cylinder if it believes the driver
may need to carry out an emergency
The Bentley
system can
detect a 1.7 metre
tall pedestrian
at distances of
between eight and
90 metres, whilst
small animals be
be detected at
distances of seven
to 70 metres
/www.theengineer.co.uk
/www.theengineer.co.uk