An Integrated Flexible Self-calibration Approach for 2D Laser Scanning Range Finders Applied to the Hokuyo UTM-30LX-EW

Abstract

ABSTRACT:The paper presents a flexible approach for the geometric calibration of a 2D infrared laser scanning range finder. It does not require spatial object data, thus avoiding the time-consuming determination of reference distances or coordinates with superior accuracy. The core contribution is the development of an integrated bundle adjustment, based on the flexible principle of a self-calibration. This method facilitates the precise definition of the geometry of the scanning device, including the estimation of range-measurement-specific correction parameters. The integrated calibration routine jointly adjusts distance and angular data from the laser scanning range finder as well as image data from a supporting DSLR camera, and automatically estimates optimum observation weights. The validation process carried out using a Hokuyo UTM-30LX-EW confirms the correctness of the proposed functional and stochastic contexts and allows detailed accuracy analyses. The level of accuracy of the observations is computed by variance component estimation. For the Hokuyo scanner, we obtained 0.2 % of the measured distance in range measurement and 0.2 deg for the angle precision. The RMS error of a 3D coordinate after the calibration becomes 5 mm in lateral and 9 mm in depth direction. Particular challenges have arisen due to a very large elliptical laser beam cross-section of the scanning device used.

Integrated Georeferencing of LiDAR and Camera Data Acquired from a Moving Platform

“…2) The next preparation step is the determination of the relative orientation between laser scanner and camera (platform calibration, bore-sight alignment). This can be done by scanning objects of known geometry such as cones as described in (Mader et. al., 2014).…”

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Uav-Based Acquisition of 3d Point Cloud – A Comparison of a Low-Cost Laser Scanner and SFM-Tools

“…Both were carried out simultaneously in an integrated self-calibration strategy to guarantee a correct calculation with different observation types. An adaptive fully integrated and modularly structured bundle adjustment is shown in (Mader et al, 2014), which was extended with geometric and stochastic models for the determination of lever arm and boresight angles for the particular sensor-UAV combination.…”

Potential of Uav-Based Laser Scanner and Multispectral Camera Data in Building Inspection

“…An integrated self-calibration strategy was developed for a simultaneously estimation of all unknown parameters to guarantee a correct calculation with different observation types (distances, angles, image point measurements with different sensors). For this purpose, an adaptive fully integrated and modularly structured bundle adjustment was implemented (Mader et al, 2014). A variance component estimation ensures an optimal weighting of the observation groups and additional restrictions (Koch, 1999).…”