SMR No.: ME019-030001-
Monument Type: Megalithic Art
There are more than 300 decorated stones in the great tombs of Knowth, the greatest concentration of megalithic art in Europe. Some of the more dramatic designs are on the orthostats in the passages at the approach to the chambers.
Orthostat 49; also known as the Guardian Stone, is situated in the eastern passage tomb at Knowth. The stone is decorated with an anthropomorphic figure.
3D Capture Method: Close range Scanning
3D Capture Description: The Artec EVA scanner is used to generate high resolution models of surfaces with small scale detail. The Artec EVA uses structured light to record. A forensics tent is used to create a controlled lighting environment and ensure measurement can proceed regardless of the weather when used outdoors. Scanning is undertaken with the fastest speed setting (15 frames per second) and with a minimum 400 mm depth of field. The data is recorded with sufficient overlap between scans to ensure easy registration.
- Resolution 0.5 mm
- Accuracy 0.1 mm
- Accuracy over distance 0.03% over 100 cm
- Texture Resolution 1.3 mp
- Colours 24 bpp
- Light Source flash bulb (no laser)
- Video frame rate 16 fps Exposure time 0.0002 s
Post-processing is done in Artec Studio 9 software: individual scans are edited, aligned, before a final surface is generated using global registration, fusion, and a small objects filter algorithm. If required, a textured surface can also be created. The model is exported from Artec Studio 9 as an .obj file. For dissemination purposes a 3D pdf of the model is generated using Geomagic Studio 2012.
Data Processing Software: Artec Studio 9 & Geomagic Studio