Alpine iLX-W650 Owner's Manual page 40

Distance guidance mark
The distance guides represent the ground level distance from the rear
bumper. It is difficult to accurately estimate the distance to objects above
ground level.
In the following example, the distance to A is 0.5 m and the distance to B
is 1 m.
<Screen>
<Positions of A, B and C>
about 1 m
In the screen, according to the distance guidance marks, the
truck seems to be parked about 1 m away (at the position B).
In actual fact, however, if you reversed to position A, you
would collide with the truck.
In the screen, positions A, B and C seem to be located in order
of proximity. However, in actual fact, the position A and C are
the same distance, and B is farther away than positions A and
C.
• The car width extension mark represents the distance to the road
surface. The distance to an object on the road is not accurately
represented by the guides.
Error between the screen and the actual road surface
In the following conditions, errors are produced between the screen
guidance and the actual road surface. (The illustrations represent a case
when the camera is installed in the standard position.)
When there is a steep upward slope behind the car
(example)
<Screen>
Distance guidance marks
40
-EN
<Situation of the car>
The distance guidance mark represents the distance to a flat
road surface. Therefore in the case of an upward slope
C
behind the car, the distance guides are displayed closer to
B
the rear bumper than the actual distance. For example, if
A (about 0.5 m)
there is an obstacle on the upward slope, it may appear
farther away than its actual position.
Also, an error may occur between the guidance and the
actual path of the car on the road surface.
When there is a steep downward slope behind the car
(example)
<Screen>
<Situation of the car>
In the case of a downward slope behind the car, the distance
guides are displayed farther from the rear bumper than the
actual distance.
If there is an obstacle on the downward slope, it seems closer
than its actual position.
Also, an error may occur between the guidance and the
actual path of the car on the road surface.
Actual distances
Error Error
Error Error