A STATISTICAL EVALUATION OF REGISTRATION METHODS USED IN TERRESTRIAL LASER SCANNING IN CULTURAL HERITAGE APPLICATIONS

Abstract

Terrestrial laser scanning (TLS) systems are used during surveying in cultural heritage applications, supported by recent developments in the electronics and computing. The aim of this article is to present a statistical study of the accuracy of registration methods (target (sphere), specific point and surface-matching) used for merged of the scans captured from different scan stations. A Mensi GS 100 terrestrial laser scanner was used to scan an historical building. The point clouds reflecting the building facade were registered using these registration methods and were transformed into the same geodesic coordinate system. A Leica TPS 1200 Total Station was used to measure the coordinates of specific points on the building facade and compare them with the coordinates of the same points using three different scan-registration methods. The t-student test and Analysis of Variance (ANOVA) were used for point-and method-based comparisons, and it was found that the coordinates did not exhibit any statistically significant variation. Better results were obtained with target-based registration methods compared to other methods, and with surface-matching methods compared to methods using specific points. Although the results of the registration methods used in this study had certain similarities, variation in their accuracy was determined to be statistically significant.