Matterport 3D digitization
Archéotech SA has acquired a new type of sensor to help with the data capture of interior spaces by combining high definition photography in HDR and 6 short-ranged laser sensors (range of 5-6 meters).
The sensor is moved within the space that needs measuring. As the survey goes along on the site, the different stations are automatically georeferenced in relation to each other. For each position, the sensor records the space at 360 degrees on the horizontal plan, and at +80 and -80 degrees on the vertical plan. A capture usually takes 60 seconds.
The data capture is controlled with an iPad Pro linked to the sensor via a Wi-Fi connection; the inputter remotely pilots the digitization, which allows him or her not to be on the scene during the measurements. Once the station is georeferenced, the sensor can be moved to the next position. If the software cannot geolocalize a station, the inputter is informed on site and can then choose a new viewpoint closer to the former one but with more similarities to the previous stations.
The data capture conditions exclude places with activity or moving elements: it is indeed preferable to have no change in the overlapping scenes’ morphology. Outside data capture in plain light must also be avoided.
Once the 3D model has been acquired, the Web interface of the app lets you move around the site in the same fashion as Google Street View; the circles on the floor match the different positions of the scanner: each station can be visualized by turning on a 360° angle and looking down to the floor or up to the ceiling. The app helps document visible elements by adding labels leading to Web pages that describe such or such object, every object’s quote can be extracted from any view.
Exploiting the scatter plots
The colorized scatter plots obtained by the Tango device are exported in XYZ or in E57 (standard Leica format): they can be opened with the EDF’s Open Source Cloud Compare app (www.danielgm.net/cc/release/). Each zone of the plot can be extracted to form an independent object. The Cloud Compare program lets you:
• extract the X, Y, Z coordinates of any point and measure distances point by point
• measure angles and surfaces
• extract vector profiles from any plan of the space
• visualize the plots in 3D using the anaglyphic method, NVidia Vision or Oculus
• visualize the plots in 3D and calculate orthographies from any viewpoint
• Fast and easy measurements of buildings, excavations or technical infrastructures
• Creation of 3D models of photographic quality
• Possibility of moving around in the 3D model and documenting the place by adding tags and hyperlinks
• Possibility of exploiting the scatter plots thus obtained
Fields of intervention
Heritage, museography, architecture, historical reconstruction, urbanism, archaeology, maintenance