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

Böhler, Wolfgang

Bibliographic data

Monograph

Persistent identifier:: 830281592

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

Sub title:: September, 1 - 2, 2002, Corfu, Greece

Scope:: 159 Seiten

Year of publication:: 2002

Place of publication:: Thessaloniki

Publisher of the original:: Publ. ZITI

Identifier (digital):: 830281592

Illustration:: Illustrationen

Signature of the source:: T 15 B 1303

Language:: English

Additional Notes:: Literaturangaben

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Böhler, Wolfgang

Corporations:: International Workshop on Scanning for Cultural Heritage Recording, 2002, Kerkira; ICOMOS/ISPRS Committee for Documentation of Cultural Heritage

Adapter:: International Workshop on Scanning for Cultural Heritage Recording, 2002, Kerkira; ICOMOS/ISPRS Committee for Documentation of Cultural Heritage

Founder of work:: International Workshop on Scanning for Cultural Heritage Recording, 2002, Kerkira; ICOMOS/ISPRS Committee for Documentation of Cultural Heritage

Other corporate:: International Workshop on Scanning for Cultural Heritage Recording, 2002, Kerkira; ICOMOS/ISPRS Committee for Documentation of Cultural Heritage

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2015

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: 5. PROJECTS AND EXPERIENCES

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: THEALASERMETRY: A HYBRID APPROACH TO DOCUMENTATION OF SITES AND ARTEFACTS. Claude E. Borg and Joseph A. Cannataci

Document type:: Monograph

Structure type:: Chapter

'll is relatively low. The beam diameter or spot size is also considerably large then for the two other systems included in the tests. However, the LMS-Z210 has a much larger field of view than the ILRIS-3D and the Cyrax. With help of a laptop computer connected to the system and the Riegls 3D-RiScan software, the scanner functionality is controlled and measurements from the scans are processed and visualised. The 3D-RiScan software also includes tools for exporting of data. The colour information (RGB-value) in each registered point gives possibilities to direct colour textured 3D- model generation, e.g. into VRML models. Cyrax 2500 ILRIS-3D LMS-Z210 Wavelength 532 nm 1540 nm* 905 nm* Min. range 1.5 m - 2 m Max. range 100 m 50 m recommende d to objects with 5%- 100% reflectivity. To objects with 4% reflectivity up to 350 m. To objects with 20% reflectivity up to 800 m. To objects with 10% reflectivity up to 150 m. To objects with 80% reflectivity up to 450 m. Beam diameter < 6 mm from 0 to 50 meter. 15mm@50 meter. 20mm@100 meter. 40mm@short distances. 300mm@100 meter. Single point distance accuracy ±4 mm. ±10 mm. 25mm@25 mm resolution + distance depending error < ±20ppm. Single point position accuracy ±6mm@l .5- 50m range. ±7mm@50m ±10mm@10 0m Minimum (horizontal/ vertical scan increment) 0.005 mrad 0.25 mm point-to- point spacing @50m. 0.17 mrad 8.5 mm point-to- point spacing @50m. 1.256 mrad 62.8 mm point-to-point spacing (2>50m. Field of view (horizontal/ vertical angle) 40°/40° 40740° 333780° Max. data acquisition rate 1000 points per second. 2000 points per second. 28000 points per second. Mean 9330 №7 *The wavelengths of Optech and Riegl are not confirmed. Table 1. System specifications. 2.2.4 Trimble 5600 DR200+ The measurement technique used in DR200+ is based on the pulsed TOF distance measuring. To reduce the influence of background noise a unique method of taking the average of many pulses, and determining the shape of the pulse before the transit time of flight is calculated, increases the accuracy of the system. The distance measuring accuracy of the system is ± 3 mm + 3 ppm from 5 to 200 meter. 2.3 Systems range precision and accuracy To determine the distance measuring accuracy, distances measured with each of the scanner systems were compared to distances measured with a total station. Five test targets were placed in the area to be scanned as in figure 1. S canner Target 3 Target 5 T* ■ ■ ——- Figure 1. Distribution of test targets The distance from the scanner to the first test target was approximately 5 meter. From target 1 to target 2: 5 m From target 1 to target 3: 25 m From target 1 to target 4: 50 m From target 1 to target 5: 80 m Table 2. Approximate distances between test targets. The length of the test room limited the range for which the systems distance measuring accuracy could be tested. At first, one system was placed in position and the area to be scanned, including the five test-targets, was scanned 10 times. Thereafter the second system was approximately placed in the same position and a 10 times scan of the same area was carried out. Finally, the third system went through the same process. All the scans were made within the same day. The test targets were all placed at the same height above the floor and the systems approximate origin were placed at the same height as the centre of the targets. The test targets were levelled and placed as close as possible to be parallel to the position for the systems. After the test-targets had been placed in position, they were left in the same position throughout the whole test. Before scanning, when placed in the actual scanning position, the system as well was levelled. The levelling was done with help of water level equipment since the tested systems was not equipped with any built-in levelling possibilities. Levelling and positioning was done to make sure that the systems measurements were all carried out under almost similar conditions. The test targets are all made of plain wood and considered common material for built environments. Being made by our own the test targets did not favour any of the systems. To be able to identify specific positions on the targets the centre of the target, and a square round the centre, was marked with a thin layer of red aerosol spray-paint (see figure 2). Five specific positions were later used to measure distances between when comparing the scanner system distances with distances measured with the total station. -35-

Access restriction

Copyright

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

Monograph

Chapter

Chapter

Table of contents

Cite and reuse

Monograph

Chapter

Image

Image fragment

Citation links

Citation recommendation