  The ability to open a door is essential for robots to perform home-serving
and rescuing tasks. A substantial problem is to obtain the necessary parameters
such as the width of the door and the length of the handle. Many researchers
utilize computer vision techniques to extract the parameters automatically
which lead to fine but not very stable results because of the complexity of the
environment. We propose a method that utilizes an RGBD sensor and a GUI for
users to 'point' at the target region with a mouse to acquire 3D information.
Algorithms that can extract important parameters from the selected points are
designed. To avoid large internal force induced by the misalignment of the
robot orientation and the normal of the door plane, we design a module that can
compute the normal of the plane by pointing at three non-collinear points and
then drive the robot to the desired orientation. We carried out experiments on
real robot. The result shows that the designed GUI and algorithms can help find
the necessary parameters stably and get the robot prepared for further
operations.
