Abstract
In this work, we introduce a novel calibration technique based on a
hanging chain curve replacing the checkerboard-based methods. It is a
known physical phenomenon that a hanging chain or a flexible rope under
gravity can be modeled by a special curve called catenary. Therefore,
instead of the commonly-used planar calibrator, we propose using
multiple shots of a catenary-shaped chain for calibration. This approach
can solve the out-of-focus problem which is faced in checkerboard
calibration methods when the size of the board is not large enough.
Although enlarging a planar calibrator increases the manufacturing time
and cost, a simple label chain can create large planar areas as precise
as a rigid checkerboard, is easily foldable and transportable. We
compare the results of our proposed approach against the widely used
checkerboardbased calibration as well as the state-of-the-art
calibration methods and show that catenary-based calibration is much
more accurate than checkerboard-based calibration by a very large margin
and is also very competitive among the other approaches.