THE COMPARISON OF 2D AND 3D DETECTORS FOR TLS DATA REGISTRATION – PRELIMINARY RESULTS

Abstract. This paper presents the analysis of possible methods of a terrestrial laser scanning (TLS) data registration using 2D/3D detectors and descriptors. The developed approach, where point clouds are processed in form of panoramic images, orthoimages and 3D data, was described. The accuracy of the registration process was preliminary verified. The two approaches were analysed and compared: the 2D SIFT (Scale-Invariant Feature Transform) detector and descriptor with the rasterized TLS data and the 3D SIFT detector with the 3D FPFH (Fast Point Feature Histograms) descriptor. The feature points were found and preliminary matched using the OpenCV and PCL (Point Cloud Library) libraries. In order to find the best point cloud representation for the registration process, both the percentage and distribution of the correctly detected and matched points were analysed. The materials consisted of the point clouds of two chambers from the Museum of King John III’s Palace in Wilanów. They were acquired using the Z+F 5006h and 5003 TLS scanners. The performed analysis showed that the lowest RMSE values were for the 2D detectors and orthoimages. However, in the case of the point number and distribution, better results were obtained for using the 3D detector.