Natural corners extraction algorithm in 2D unknown indoor environment with laser sensor

The algorithm of line extraction and corner extraction in unknown indoor environment with laser sensor is presented in this paper. The corners, the intersection point of two line segments and the two endpoints of each line segment extracted from raw sensor data, can be chosen as landmarks to estimate the position of mobile robot or used to do mapping unknown environment without artificial landmarks intentionally. Sufficient landmarks are the precondition for realizing robot localization and Mapping Environment very well. In addition, the covariance matrix of corners, propagated from covariance matrices of line segments, is derived using the first-order Taylor expansion and it is proved by comparing the uncertainty ellipse drawing from the ellipse of line segments and that from covariance matrix of corners in real experiments. Experiment results of line extraction and corner extraction in the complex environment with the HOKUYO laser sensor located on the Pioneer mobile robot are presented to proving the validity of this algorithm.