SUMMARY
Airborne laser scanning of the earth surface and other objects on top it yieldsmeasurements of unstructured point clouds in a strip wise manner. Often multiplelength strips with a small overlap are observed, sometimes augmented by a fewcross strips for validation purposes. Due to inaccurate calibration of the entiremeasurement system and due to the limited accuracy of direct geo-referencing (i.e.,the exterior orientation determination) with GPS and IMU, including systematicerrors, adjacent strips may have discrepancies in their overlap. For removing thesediscrepancies strip adjustment algorithms require quantification on these offsets atvarious locations within the overlapping zones. Different methods of stripadjustment are reviewed, followed by the presentation of a general method fordetermining the discrepancies automatically. This method the core of the paper is based on segmenting the point cloud in the overlap. In the examples, mean offsetsbetween neighboring strips in the order of a few centimeters are reconstructed. Theoffsets also show substantial variation along the strip. The method developed fordiscrepancy determination can be applied to height or full 3D strip adjustment andfor approaches using the original measurements, the coordinates of the measuredpoints, or only the offsets between surfaces. An example of strip adjustment usingdiscrepancy observations with the method presented and a discussion of the resultsconclude this paper.