Establishment of a New Quantitative Evaluation Model of the Targets’ Geometry Distribution for Terrestrial Laser Scanning

Abstract

The precision of target-based registration is related to the geometry distribution of targets, while the current method of setting the targets mainly depends on experience, and the impact is only evaluated qualitatively by the findings from empirical experiments and through simulations. In this paper, we propose a new quantitative evaluation model, which is comprised of the rotation dilution of precision ( r D O P , assessing the impact of targets’ geometry distribution on the rotation parameters) and the translation dilution of precision ( t D O P , assessing the impact of targets’ geometry distribution on the translation parameters). Here, the definitions and derivation of relevant formulas of the r D O P and t D O P are given, the experience conclusions are theoretically proven by the model of r D O P and t D O P , and an accurate method for determining the optimal placement location of targets and the scanner is proposed by calculating the minimum value of r D O P and t D O P . Furthermore, we can refer to the model ( r D O P and t D O P ) as a unified model of the geometric distribution evaluation model, which includes the D O P model in GPS.

Challenges and Recommendations for 3d Plant Phenotyping in Agriculture Using Terrestrial Lasers Scanners

“…Also, selecting the right target design and algorithm for center estimation, and assuring a minimum of 100 points per target can further improve the results (Janßen et al, 2019). Moreover, allowing for a minimum of 4 targets visible in each scan is a good practice that assures sufficient redundancy, and it is advisable that visible targets at each viewpoint enclose a large surface area or 3D volume (Yang et al, 2020).…”

Application of TLS Method in Digitization of Bridge Infrastructures: A Path to BrIM Development

“…However, small movements of the bridge during its operation was unavoidable. As the registration precision of multiple scans is affected by both the number of targets and their distribution in the overlapping region [62], on the scan day, a total of 29 targets were strategically placed on and around the Werrington Bridge to facilitate point cloud registration. Five targets were of the spherical type (a purpose-made sphere with a special coating), and 24 were of the planar type (a high-contrast black and white pattern on laminated A4 paper), with a minimum distribution of three common targets in each scan.…”

A New Way for Cartesian Coordinate Transformation and Its Precision Evaluation

“…The rigid body transformation in the Cartesian coordinate system is expressed by Equation (1), in which the coordinates of points in coordinate system-(i + 1) are transformed into those in coordinate system-i using one scale parameter (k), three translation parameters (t x , t y , t z ), and three Euler angle parameters (ω x , ω y , ω z ) [10,23] or three Rodrigue parameters (a, b, c) [4,10,11,22]:…”

“…Coordinate transformation has been widely studied in the literature, with a focus on modeling and parameter estimation. Several different transformation models exist, including the small-rotation-angle transformation model (e.g., bursa model, Molodensky model, and Wuce model) [8,9], and arbitrary-rotation-angle transformation model (e.g., Euler angle model, unit-quaternions model, and Rodrigue matrix model) [9][10][11][12]. At the same time, a range of methods for estimating model parameters have been proposed, including the 7-parameter linear adjustment method [9,11,13,14], 8-parameter linear adjustment method [9,13], 13-parameters linear adjustment method [1], nonlinear estimation method and its improved method [2,15], Procrusters-based direct solutions [16], analytical close-form solutions [6], ill-condition model solution [17,18], and total least squares method based on the errors-in-variables model [13,19,20].…”