Efficient scan matching method using direction distribution

An efficient scan matching method that uses direction distributions of two-dimensional laser scans is proposed. Using line fitting with each point in the scan, together with the neighbouring two points, the distribution of these line directions is computed. The direction distribution represents a measure of the geometric tendency of the scan, and this can be used to compute similarities between scans. This approach can be applied to select scans in a scan database that have high probabilities of being closely aligned with the current scan. Moreover, an initial estimate of the rotational displacement between two scans can be obtained, and scan matching can be accomplished efficiently even with a large rotational displacement between scans.