Report on the May 2016 ASTM E57.02 Instrument Runoff at NIST, Part 1 � Background Information and Key Findings

Muralikrishnan, Balasubramanian; Rachakonda, Prem K.; Shilling, Katharine Meghan; Lee, Vincent D.; Blackburn, Christopher J.; Sawyer, Daniel S.; Cheok, Geraldine S.; Cournoyer, Luc

doi:10.6028/nist.ir.8152

Cited by 9 publications

(7 citation statements)

References 1 publication

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“…Besides the geometric description, the properties color, material, surface finish, and reflectivity are used to describe the target designs in previous literature [25,44,45]. They are briefly explained in the following: Geometry: In the geometric form of targets, a differentiation is made between plane and spatial targets.…”

Section: Preliminary Considerations Of Target Designsmentioning

confidence: 99%

Decreasing the Uncertainty of the Target Center Estimation at Terrestrial Laser Scanning by Choosing the Best Algorithm and by Improving the Target Design

et al. 2019

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During the registration and georeferencing of terrestrial laser scans, it is common to use targets to mark discrete points. To improve the accuracy of the registration, the uncertainties of the target center estimation (TCE) have to be minimized. The present study examines different factors influencing the precision of the TCE. Here, the focus is on the algorithm and the target design. It is determined that, in general, the uncertainties of the TCE are much smaller than those indicated by the manufacturers. By comparing different algorithms for the first time, it was possible to clearly determine that an algorithm using image correlations yields the smallest standard deviations for the TCE. A comparison of different target designs could not identify an ideal commercially available target. For this reason, a new target, the BOTA8 (BOnn TArget with 8-fold pattern) was developed, which leads to smaller standard deviations than the previous targets. By choosing the best algorithm and improving the target design, standard deviations of 0.5 mm in distance direction and 1.2 arcsec in angular direction for a scan distance up to 100 m were achieved with the laser scanner Leica ScanStation P20. The uncertainties could be reduced by several millimetres and angular seconds compared to the manufacturer’s targets and software.

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Section: Preliminary Considerations Of Target Designsmentioning

confidence: 99%

Decreasing the Uncertainty of the Target Center Estimation at Terrestrial Laser Scanning by Choosing the Best Algorithm and by Improving the Target Design

et al. 2019

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“…In most cases of the indoor TLS calibration, the limiting factor is the ceiling height, and this should be the main guideline when selecting an appropriate facility. In order to increase the sensitivity in a room with limited dimensions, two modifications can be applied-short tripods, allowing the instrument placement only several centimeters above the ground, and mirrors placed on the ceiling, artificially extending the steep lines-of-sight, as already suggested in [41].…”

Section: Discussion Of Sensitivity Analysismentioning

confidence: 99%

“…Figure 2 depicts the latter misalignments excluding the commonly known vertical index offset and rangefinder offset. The parameter nomenclature is adopted from the American National Institute of Standards and Technology (NIST), who originally derived the parametrization and proved it as valid in the run-off experiment, where several leading manufacturers were involved [41]. The readers are referred to Muralikrishnan et al 2015 [22] for more details.…”

Section: Calibration Parametersmentioning

confidence: 99%

Sensitivity Analysis and Minimal Measurement Geometry for the Target-Based Calibration of High-End Panoramic Terrestrial Laser Scanners

2019

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Target-based calibration is the most widely used calibration procedure for terrestrial laser scanners. Nevertheless, the current implementations of this procedure are suboptimal due to the high complexity of their calibration fields. Therefore, designing calibration fields, by selecting optimal target locations with respect to the instrument, is a pending research question. Answering this question would lead to a more efficient and user-friendly calibration, as well as improved calibration results. Herein, we conduct a detailed analysis of the most sensitive target-to-instrument measurement configuration to estimate individual calibration parameters. Based on this analysis, we derive a minimal measurement geometry, sensitive to all mechanical misalignments, relevant for high-end panoramic terrestrial laser scanners. We support our sensitivity analysis by a simulation and empirical experiments followed by a discussion about the advantages and shortcomings of the proposed minimal measurement geometry.

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“…The techniques proposed in this section were developed after analyzing thousands of sphere datasets acquired from six different TLSs. This data was acquired during an instrument runoff [8] performed as part of the ongoing ASTM E57 standards work. The methods we propose here were tested on those datasets to ensure their broad applicability across different TLSs.…”

Section: Methods To Segment Sphere From 3d Scan Data and Obtain Thementioning

confidence: 99%

Methods and considerations to determine sphere center from terrestrial laser scanner point cloud data

Rachakonda

Muralikrishnan

Cournoyer

et al. 2017

Meas. Sci. Technol.

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The Dimensional Metrology Group (DMG) at the National Institute of Standards and Technology (NIST) is performing research to support the development of documentary standards within ASTM E57 committee. This committee is addressing the point-to-point performance evaluation of a subclass of 3D imaging systems called Terrestrial Laser Scanners (TLSs) which are laser-based and use spherical coordinate system. This paper discusses the usage of sphere targets for this effort and methods to minimize the errors due to the determination of their centers. The key contributions of this paper include the methods to segment sphere data from TLS point cloud and the study of some of the factors that influence the determination of sphere centers.

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Report on the May 2016 ASTM E57.02 Instrument Runoff at NIST, Part 1 � Background Information and Key Findings

Cited by 9 publications

References 1 publication

Decreasing the Uncertainty of the Target Center Estimation at Terrestrial Laser Scanning by Choosing the Best Algorithm and by Improving the Target Design

Decreasing the Uncertainty of the Target Center Estimation at Terrestrial Laser Scanning by Choosing the Best Algorithm and by Improving the Target Design

Sensitivity Analysis and Minimal Measurement Geometry for the Target-Based Calibration of High-End Panoramic Terrestrial Laser Scanners

Methods and considerations to determine sphere center from terrestrial laser scanner point cloud data

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