A. MethodThe major drawback of mono

A. Method
The major drawback of mono camera system, including
systems based on optical mice chips, is the assumption that
the ground is flat. Usually the clearance between the camera
and the surface is held constant by mechanical design, as in
an optical mouse. This method is not suitable for an outdoor
mobile robot on an agricultural field. A stereo camera setup
and epipolar geometry provides a measurement of the
distance between the camera and to the point evaluated. This
is used to compensate for the errors caused by differences in
heights. This method will also provide an easy way to
calibrate the system. Only one stereo pair is analyzed so the
heading of the robot is assumed to be known. Methods for
obtaining direction using by omnidirecitonal camera is
explained in [10] or by a row following system in [3].
The cameras are mounted perpendicular to the ground
according to Fig. 2. This mounting will provide maximum
translation between images and hence no projection of
images to a ground plane is needed. Further the position is
only measured in 2D.

A. Method
The major drawback of mono camera system, including
systems based on optical mice chips, is the assumption that
the ground is flat. Usually the clearance between the camera
and the surface is held constant by mechanical design, as in
an optical mouse. This method is not suitable for an outdoor
mobile robot on an agricultural field. A stereo camera setup
and epipolar geometry provides a measurement of the
distance between the camera and to the point evaluated. This
is used to compensate for the errors caused by differences in
heights. This method will also provide an easy way to
calibrate the system. Only one stereo pair is analyzed so the
heading of the robot is assumed to be known. Methods for
obtaining direction using by omnidirecitonal camera is
explained in [10] or by a row following system in [3].
The cameras are mounted perpendicular to the ground
according to Fig. 2. This mounting will provide maximum
translation between images and hence no projection of
images to a ground plane is needed. Further the position is
only measured in 2D.

A. Method
The major drawback of mono camera system, including
systems based on optical mice chips, is the assumption that
the ground is flat. Usually the clearance between the camera
and the surface is held constant by mechanical design, as in
an optical mouse. This method is not suitable for an outdoor
mobile robot on an agricultural field. A stereo camera setup
and epipolar geometry provides a measurement of the
distance between the camera and to the point evaluated. This
is used to compensate for the errors caused by differences in
heights. This method will also provide an easy way to
calibrate the system. Only one stereo pair is analyzed so the
heading of the robot is assumed to be known. Methods for
obtaining direction using by omnidirecitonal camera is
explained in [10] or by a row following system in [3].
The cameras are mounted perpendicular to the ground
according to Fig. 2. This mounting will provide maximum
translation between images and hence no projection of
images to a ground plane is needed. Further the position is
only measured in 2D.