Accuracy assessment of airborne laser scanning strips using planar features

ABSTRACT Airborne Laser Scanning (ALS) is widely used in many applications for its high measurement accuracy, fast acquisition capability, and large spatial coverage. Accuracy assessment of the ALS data usually relies on comparing corresponding tie elements, often points or lines, in the overlapping strips. This paper proposes a new approach to strip adjustment and quality assessment of ALS data by using planar features. In the proposed approach a transformation is estimated between two overlapping strips by minimizing the distance between points in one strip and their corresponding plane in the other. The planes and the corresponding points are extracted in a segmentation process. The point-to plane distances are used as observables in the estimation model, where the parameters of a transformation between two strips and their associated quality measures are estimated. We demonstrate the performance of the method on the AHN2 dataset over Zeeland province of The Netherlands. The dataset consists of 13 overlapping strips, from which a total of 522 gable roof and dike slope planes are extracted. The results show planimetric offsets between the strips that range from 3.13 cm to 55.32 cm. These offsets are in agreement with previously reported results using linear features. In addition, we estimated vertical offsets in the order of a few centimeters, which were not estimated in previous studies. The rotation parameters between the strips were also estimated; however, these did not show a significant difference in the orientation of the strips.