Analysis of Uncertainty and Repeatability of a Low-Cost 3D Laser Scanner

Abstract

Portable 3D laser scanners are a valuable tool for compiling elaborate digital collections of archaeological objects and analysing the shapes and dimensions of pieces. Although low-cost desktop 3D laser scanners have powerful capacities, it is important to know their limitations. This paper performs an analysis of the uncertainty and repeatability of the NextEngine TM portable low-cost 3D laser scanner by scanning an object 20 times in two different resolution modes-Macro and Wide. Some dimensions of the object were measured using a digital calliper, and these results were used as the "true" or control data. In comparing the true and the scanned data, we verified that the mean uncertainty in the Macro Mode is approximately half that of the Wide Mode, at ±0.81 mm and ±1.66 mm, respectively. These experimental results are significantly higher than the accuracy specifications provided by the manufacturer. An analysis of repeatability shows that the successive replicates do not match in the same position. The results are better in Macro Mode than in Wide Mode; it is observed that the repeatability factor is slightly larger than the corresponding mode accuracy, with ±0.84 vs. ±0.81 mm in Macro Mode and ±1.82 vs. ±1.66 mm in Wide Mode. We suggest several improvements, such as adding an external reference scale or providing a calibrated object to allow for a self-calibration operation of the scanner.

Analysis of Uncertainty in a Middle-Cost Device for 3D Measurements in BIM Perspective

“…Many studies have carried out such analysis for active measurement techniques [21,22,23] as in the case of passive measurement techniques [4,24,25]. These are deduced in the first case for objects of medium format, with the use of handheld laser scanners, where an accuracy up to 0.1 mm can be achieved [26]; in the second case, using techniques of automated digital photogrammetry, precision is of the order of about 5 mm [27], but with the advantage of a smaller economic cost.…”

The Future of Forensic Biology

“…Other advancement could include use of Fourier Transform Infrared (FTIR) spectroscopy to identify drugs such as cocaine in short span of time which could replace several heavy equipments that require various gases, liquids, and solids [59]. The use of handheld 3-D laser scanners [60,61]and Near-infrared (Near IR) light scanners [62] can also help scientist/police to identify a potential suspect during an investigation. The microfluidic chips on the other hand allow scientists to reduce contamination and build DNA profile at the scene of crime [5][6][7]63].…”

The Suitability of 3D Data: 3D Digitisation of Human Remains

“…Some initial errors that can be encountered are a direct result of the equipment and scan parameters used to produce a digital image. For laser scanning, the quality of the resulting model is affected by the settings used (eg how many scans, point density, and mode) (Polo and Felicísimo 2012), as well as the positioning of the object (Fourie et al 2011), the environmental conditions (Algee-Hewitt and Wheat 2016), and the method used to align individual scans (Fourie et al 2011;Guyomarc'h et al 2012). In 3D photogrammetry, the camera must be calibrated prior to image capture to eliminate distortion, and the final quality of the 3D model is affected by the quantity of images captured (Gallo et al 2014).…”