Currently, 3D sensing is a
technology that helps to measure distance
or construct a 3D map of a real life scene.
The sensing hardware use two devices – a
light transmitter and a light receiver – to
collect depth data distance.
Technically,there are three approaches to making these
calculations—time of fight, structured light,
and stereo vision. The first two are active
range strategies (used in nature by bats,
whales, and so on) while stereo vision is a
passive range approach (used in nature by
humans, cats, and owls).
The active approaches tend to be the best
fit for AR applications because they deliver more
accurate depth data and perform better in a
low light or even no light environments.
Selecting which active approach to go with
is tricky. Time of fight involves counting the
time a photon takes to come back from the
object in a scene, while structured light
involves projecting a pattern and then
observing how it is disturbed when hitting
objects in a scene.
Both approaches have their pros and cons,
and selecting which to
go with depends on the required
specifcation and on cost and safety
To simplify though, time of
fight performs best in longer ranges like
outdoor AR use cases while structured light
really performs well in shorter ranges under
six metres and benefts from high precision,
which makes it more useful for indoor AR
applications and facial recognition