Hand-held 3D laser scanner

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While the development of three-dimensional technologies is advancing rapidly, the collection of high-quality terrain data in remote high-alpine areas remains a challenge. The use of ground-based methods, such as terrestrial laser scanning (TLS) , is made difficult by high investment costs, the portability of large instruments and the energy demand in remote areas. Hand-held 3D laser scanners are an alternative . These are a variant of terrestrial laser scanning (TLS). However, these devices cannot be used flexibly without restrictions and are partly tied to a carrier platform, such as a vehicle. Hand-operated 3D laser scanners (HLS) can be used for areas with steep slopes, landslides and / or rocky surfaces. These serve to convert a real object into a digital form. The scanned data are still available from the recording as point clouds, with each point having a position in space and relating to a coordinate system . The 3D scanners can be divided into stationary and mobile devices. Stationary 3D scanners are devices with large dimensions that are tied to one place. Mobile devices, on the other hand, are smaller in size and can be brought to an immobile object. With the increasing use of laser scanners, the quest for affordable, efficient and user-friendly devices followed. Although some applications require expensive equipment, nowadays many tasks can already be carried out with cheaper and smaller hand-held 3D laser scanners.

When scanning, it is necessary not to change the basic parameters of the environment, such as temperature , humidity and lighting in the room, as this has a great influence on both the calibration of the device and the scan. Before each measurement process, it is necessary to calibrate or test the 3D scanner. In the case of a laser and optical 3D scanner, a calibration plate is scanned at different distances and inclinations. In order to enable an accurate reconstruction and avoid deviation problems, the survey path should form a closed loop so that the same area is scanned at the beginning and at the end of the path.

application areas

Hand-held 3D laser scanners are used in engineering , for example in the reconstruction of objects, in quality control for the control of products in companies, in architecture , in geomorphology , in the multimedia area in the modeling of virtual cities, in art the reconstruction of historical and cultural buildings and statues, in food process modeling and in the medical field.

Cultural sites

For an effective and detailed digitization of cultural sites, measurements from a variety of points of view are necessary. The currently most common way of covering these cultural places is through aerial photographs such as airborne laser scanning or satellite-based recording. However, no detailed recordings can be made at ground level. Such a survey was carried out on Peel Island, 4 km off the Australian coast near Brisbane. The hospital located here is one of the only multicultural sites in Australia and consists of many small huts that serve as accommodation.

geomorphology

Laser scanners are also used for geomorphological issues, such as B. when recording eroding coastlines. The data is collected from the erosion of the cliff base at low water . There is also the option of collecting topographical data by measuring salt marsh gullies . Here a surveyor walks an irregular loop along ridges between ravines .

Food processing

Compact 3D laser scanners are increasingly used in the food industry . Using hand-held 3D laser scanners, it is possible to capture complex and organic shapes in detail in order to develop templates for optimized product and packaging designs.

Test for accuracy and uncertainty

For the user, the accuracies and uncertainties of the hand-held 3D laser scanner are of great importance, which should be specified by the manufacturer with a span, depending on the object or surface. A check can be carried out by scanning an object. On the one hand by assessing the position and extent of the scanned data after several repeated scans and on the other hand by comparing these data in different resolutions . The reference objects (geometric shapes) that are increasingly included or that are available for purchase are used to calibrate handheld laser scanners.

restrictions

Some manufacturers recommend using colored pencils, white hairspray or talc for dark, luminous or transparent objects in order to better capture the scanned objects. However, the use of such aids is often problematic as they are used in certain cultural sites such as B. archaeological excavations are prohibited.

Publications (selection)

  • Anthony CT, Loretta LY Pau, Jonas D., Weigler B. (2015): A pilot study on the use of handheld laser scanner for landform mapping and slope investigation in Hong Kong. Geotechnical Engineering Office, Civil Engineering and Development Department, 101 Princess Margaret Road, Homantin, Kowloon, Hong Kong.
  • Hämmerle M., Höfle B., Fuchs J., Schröder-Ritzrau A., Vollweiler N., Frank N. (2014): Comparison of Kinect and Terrestrial LiDAR Capturing Natural Karst Cave 3-D Objectss.-In: IEEE Geoscience and Remote Sensing Letters 11, 1896-1900
  • James MR, Quinton JN (2014): Ultra-rapid topographic surveying for complex environments: the hand-held mobile laser scanner.-In: Earth Surface Processes and Landforms 39, 138-142
  • Polo M.-E., Angel F. (2012): Analysis of Uncertainty and Repeatability of a Low-Cost 3D Laser Scanner.-In: Sensors (12), 9046-9054.
  • Toth T., Zivcak J. (2014): A Comparison of the Outputs of 3D Scanners.-In: Procedia Engineering 69, 393-401
  • Uyar R., Erdogdu F. (2009): Potential use of 3-dimensional scanners for food process modeling. In: Journal of Food Engineering (93), 337-343.
  • Smith MW, Carrivick JL, Quincey DJ (2016): Structure from motion photogrammetry in physical geography.-In: Progress in Physical Geography 40, 247-275
  • Westoby MJ, Brasington J., Glasser NF, Hambrey MJ, Reynolds JM (2012): Structure-from-Motion 'photogrammetry: A low-cost, effective tool for geoscience applications.-In: Geomorphology 179, 300-314
  • Zlot R., Bosse M., Greenop K., Jarzab Z., Juckes E., Roberts J. (2014): Efficiently capturing large, complex cultural heritage sites with a handheld mobile 3D laser mapping system.-In: Journal of Cultural Heritage 15, 670-678

Individual evidence

  1. ↑ Westoby MJ et al. (2012)
  2. ↑ Anthony CT, Loretta LY Pau, Jonas D., Weigler B. (2015)
  3. ↑ Toth T., Živčák J. (2014)
  4. ↑ Toth T., Živčák J. (2014)
  5. ↑ Zlot R., Bosse M., Greenop K., Jarzab Z., Juckes E., Roberts J. (2014)
  6. ↑ James MR, Quinton JN (2014)
  7. ^ Uyar R., Erdogdu F. (2009)
  8. ↑ Polo M.-E., Angel F. (2012)
  9. ↑ Polo M.-E., Angel F. (2012)