Method for Underground Mining Shaft Sensor Data Collection.

The motivation behind this research is the lack of an underground mining shaft data set in the literature in the form of open access. For this reason, our data set can be used for many research purposes such as shaft inspection, 3D measurements, simultaneous localization and mapping, artificial intelligence, etc. The data collection method incorporates rotated Velodyne VLP-16, Velodyne Ultra Puck VLP-32c, Livox Tele-15, IMU Xsens MTi-30 and Faro Focus 3D. The ground truth data were acquired with a geodetic survey including 15 ground control points and 6 Faro Focus 3D terrestrial laser scanner stations of a total 273,784,932 of 3D measurement points. This data set provides an end-user case study of realistic applications in mobile mapping technology. The goal of this research was to fill the gap in the underground mining data set domain. The result is the first open-access data set for an underground mining shaft (shaft depth -300 m).

Affordable Robotic Mobile Mapping System Based on Lidar with Additional Rotating Planar Reflector.

This paper describes an affordable robotic mobile 3D mapping system. It is built with Livox Mid-40 lidar with a conic field of view extended by a custom rotating planar reflector. This 3D sensor is compared with the more expensive Velodyne VLP 16 lidar. It is shown that the proposed sensor reaches satisfactory accuracy and range. Furthermore, it is able to preserve the metric accuracy and non-repetitive scanning pattern of the unmodified sensor. Due to preserving the non-repetitive scan pattern, our system is capable of covering the entire field of view of 38.4 × 360 degrees, which is an added value of conducted research. We show the calibration method, mechanical design, and synchronization details that are necessary to replicate our system. This work extends the applicability of solid-state lidars since the field of view can be reshaped with minimal loss of measurement properties. The solution was part of a system that was evaluated during the 3rd European Robotics Hackathon in the Zwentendorf Nuclear Power Plant. The experimental part of the paper demonstrates that our affordable robotic mobile 3D mapping system is capable of providing 3D maps of a nuclear facility that are comparable to the more expensive solution.

Calibration of Planar Reflectors Reshaping LiDAR's Field of View.

This paper describes the calibration method for calculating parameters (position and orientation) of planar reflectors reshaping LiDAR's (light detection and ranging) field of view. The calibration method is based on the reflection equation used in the ICP (Iterative Closest Point) optimization. A novel calibration process as the multi-view data registration scheme is proposed; therefore, the poses of the measurement instrument and parameters of planar reflectors are calculated simultaneously. The final metric measurement is more accurate compared with parameters retrieved from the mechanical design. Therefore, it is evident that the calibration process is required for affordable solutions where the mechanical design can differ from the inaccurate assembly. It is shown that the accuracy is less than 20 cm for almost all measurements preserving long-range capabilities. The experiment is performed based on Livox Mid-40 LiDAR augmented with six planar reflectors. The ground-truth data were collected using Z + F IMAGER 5010 3D Terrestrial Laser Scanner. The calibration method is independent of mechanical design and does not require any fiducial markers on the mirrors. This work fulfils the gap between rotating and Solid-State LiDARs since the field of view can be reshaped by planar reflectors, and the proposed method can preserve the metric accuracy. Thus, such discussion concludes the findings. We prepared an open-source project and provided all the necessary data for reproducing the experiments. That includes: Complete open-source code, the mechanical design of reflector assembly and the dataset which was used in this paper.

Propofol-induced injection pain: comparison of a modified propofol emulsion to standard propofol with premixed lidocaine.

Propofol is well known for its association with pain on injection. The most frequently used method to reduce this pain is premixture with lidocaine. Recently, a modified lipid emulsion of propofol containing medium-chain triglycerides (MCT) with long-chain triglycerides (LCT), in contrast to the usual LCT formulation, has been advocated to alleviate pain. In a randomized, prospective, controlled, double-blind study on 222 surgical patients, we compared the effect of the two solutions on the incidence and intensity of injection pain. Patients were randomly allocated to receive either propofol MCT/LCT (group M; n = 109) or standard propofol LCT with the addition of 20 mg of lidocaine (2 mL of lidocaine 1%) to 200 mg of propofol (group L; n = 113). Pain scores were assessed using a verbal analog scale (VAS) ranging from 0-10. Group L was found to have significantly less pain on the injection of propofol (mean VAS, 2.5 +/- 2.9) (mean +/- sd) than group M (mean VAS, 3.8 +/- 3.2; P = 0.002). Regarding postoperative recall of pain on injection, patients in group L indicated significantly less pain (mean VAS, 2.2 +/- 2.4) than patients in group M (mean VAS, 3.0 +/- 2.7; P = 0.02). Premixing of 20 mg of lidocaine (2 mL of lidocaine 1%) to 200 mg of standard propofol LCT causes less pain on injection than propofol MCT/LCT and thus increases patient comfort.