Finding corresponding spots in the overlap of two digital terrain models derived from airborne laserscanner data is required for two purposes: (i) Strip adjustment: Often the direct georeferencing (via GPS/IMU) of the individual laser strips is not perfect and the remaining (small) errors are to be removed by a strip adjustment. For this adjustment corresponding spots in the strips are required. (ii) Quality control: Often for a certain area several partly overlapping DTMs exist, which are generated from different data at different dates. In order to check the georeferencing of these DTMs the discrepancies between the DTMs in the common overlap should be computed. This again requires the identification of corresponding spots in two different DTMs. In this paper we present a method for deriving corresponding spots in two different overlapping point clouds with very high precision, by applying a robust version of the method of least squares area matching (LSM) on raster data interpolated from laser data (heights and intensity). The inclusion of laser intensity data is particularly useful in areas with little variation in height in order to derive the horizontal shifts between corresponding patches in the two data sets.
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