Proceedings of the CIPA WG 6 International Workshop on Scanning for Cultural Heritage Recording

Böhler, Wolfgang

Bibliographic data

Multivolume work

Persistent identifier:: 1890699608

Title:: Kunstdenkmäler im Grossherzogthum Hessen

Sub title:: Inventarisirung und beschreibende Darstellung der Werke der Architektur, Plastik, Malerei und des Kunstgewerbes bis zum Schluss des XVIII. Jahrhunderts : mit Abbildungen

Type of content:: Inventar

Year of publication:: 1885

Place of publication:: Darmstadt; Hannover

Publisher of the original:: Kommisionsverlag von Arnold Bergstraesser

Identifier (digital):: 1890699608

Language:: German

Additional Notes:: Bände erschienen von 1885 bis 1940

Other Title:: Später unter dem Titel: Die Kunstdenkmäler im Freistaat Hessen. - Die Kunstdenkmäler im Freistaat (Volksstaat) Hessen. - Die Kunstdenkmäler in Hessen. - Die Kunstdenkmäler im Volksstaat Hessen

Publisher of the digital copy:: Technische Informationsbibliothek (TIB)

Document type:: Multivolume work

Volume

Persistent identifier:: 1890722286

Author:: Dammann, Walter Heinrich; Henkelmann, Karl

Title:: Die Kunstdenkmäler des Kreises Bensheim

Sub title:: mit einer Tafel, 286 Abbildungen im Tetx und einer Übersichtskarte des Kreises Bensheim

Scope:: 317 Seiten, 1 gefaltetes Blatt mit Übersichtskarte

DOI:: 10.14463/KXP:1890722286

Year of publication:: 1914

Place of publication:: Darmstadt

Publisher of the original:: Im Großherzoglichen Staatsverlag

Identifier (digital):: 1890722286

Illustration:: Illustrationen, Karten

Signature of the source:: a 3395(A,4)

Language:: German

Other Title:: Nebentitel: Kreis Bensheim; A: Provinz Starkenburg

Usage licence:: Public Domain Mark 1.0

Publisher of the digital copy:: Technische Informationsbibliothek (TIB)

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2024

Document type:: Volume

Collection:: Architecture; Arts

Chapter

Title:: LORSCH

Document type:: Multivolume work

Structure type:: Chapter

-22- merged data set is shown in Figure 8. The side view clarifies that the undercuts were well digitized. Figure 9. 3D-Projection of Diplodocus camegii A very challenging device was a dinosaur skeleton of a Diplodocus camegii at the Museum of Nature Humboldt - University of Berlin. The skeleton had a length of 25 m and was 5 m high. 21 laser scanner images were taken. These independent data sets were transformed into one common coordinate system by adjustment procedures. Figure 9 shows the final result in 3D-projection. The skeleton is imaged by 861021 laser measurement points. 4. PROCESSING OF LASER SCANNER DATA The presented examples make clear that laser scanners generate point clouds with a large amount of data which cannot be processed by standard CAD programs. This chapter addresses the problems of processing the data so that they can be input into CAD software packages and of generating NC-programs for re-production in archaeology. Solutions for merging effectively independent laser scanner images into one common coordinate system will be presented. 4.1 Procedures for Merging Laser Scanner Images The previous chapters clarified that several independent laser scanner images must be merged when the object is larger than the field of view of the laser scanner or the object exhibits undercuts. A very straightforward solution is using identical points in the overlapping area of neighboring images. This requires that these points appear with high contrast. In cases where identical points cannot be identified on the object itself so called reference spheres can be applied (Wehr, 2001). Using these aids very precise results can be yielded. The Cartesian coordinates that are the result of the digitizing of freeform objects by the 4D-LM are transformed into object coordinates by a special software postprocessor. The coordinates may now be processed as either NC-commands for copymilling (duplicating milling) and rapid prototyping machines or in the data format for the sculptured surface modeller. 4.2 Postprocessing of Object Coordinates for Copymilling and Rapid Prototyping Machines A special software functionality is developed for the calculation and determination of loop contours out of the digitised data. Figure 10 and 11 illustrate the method for the estimation of the contours for the front digitised view of the glass head in figure 6. In further steps of research while analyzing NC-programs of copymilling machines, we found out that the coordinates of the cutter center point represent a set of loop contours. This means that the calculated contours could be transformed directly to NC Programs. This method presents a simple way of how even non experts in CAD/CAM systems could generate and produce a 3D-modell. Figure 10. Estimation of the contours A more advanced method is to carry out the merging after surface modelling. The tooling and moulding industry currently models the work pieces mathematically through Computer Aided Design/Computer Aided Manufacturing- (CAD/CAM) systems. Unfortunately the analytical description of such objects is not sufficient for practical applications. Here the computer space and time complexity must be increased to achieve the approximation and interpolation necessary. Digitizing a sculptured surface results in a very high amount of Figure 11. Estimation of the contours data (Giga Bytes of space in the main memory system). The computation performance of existing CAD/CAM-systems is insufficient for the processing of this data. A data reduction is required to solve this problem. A data reduction of more than 80% can be achieved depending on the complexity of the workpiece by computing spline -curves and -surfaces using the following algorithms bicubic Bezier, polynomial representation (Coons), B-Spline,

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