Agriculture Reference
In-Depth Information
information usually output by stereo cameras follows the general definition of
cam-
era coordinates
, which places the origin at the optical center of one of both lenses
(manufacturer choice), and makes the
X
c
Y
c
plane coincident with the image plane.
This arrangement leaves the third coordinate (
z
c
) to represent the depth of the image,
as it will always be perpendicular to the image plane (
X
c
Y
c
). The definition of camera
coordinates, depicted in Figure 12.4b, may be useful for certain applications, but
tends to be inconvenient for the majority of needs faced by off-road vehicles. To
begin with, the origin of heights is directly related to the height at which the camera
has been installed, rather than related to a general unchangeable reference such as
(a)
Z
y
O
g
(0, 0, 0)
Y
X
z
P
(
x, y, z
)
x
Z
(b)
camera
X
c
O
c
(0, 0, 0)
φ
Y
c
h
c
P
z
Y
O
g
(0, 0, 0)
y
FIGURE 12.4
Coordinate systems and transformations: (a) ground coordinates; (b) trans-
formation from camera coordinates to ground coordinates.
