Title: 3D-imaging of boulders using a solid-state 2D profilometer: case study for autonomous robotic rock breaker

Authors: Ilpo Niskanen; Santeri Lampinen; Matti Immonen; Lauri Hallman; Martti Mikkonen; Jarno Karvinen; Juha Kostamovaara; Jouni Mattila; Rauno Heikkilä

Addresses: Faculty of Technology, Civil Engineering Research, University of Oulu, P.O. Box 4000, FI-90014 Oulu, Finland ' Rambooms Oy, Yrittäjänkatu 10, FI-15170 Lahti, Finland ' Faculty of Technology, Civil Engineering Research, University of Oulu, P.O. Box 4000, FI-90014 Oulu, Finland ' Faculty of Information Technology and Electrical Engineering, Circuits and Systems Research Unit, University of Oulu, P.O. Box 7300, FI-90014 Oulu, Finland ' A-Perustus Oy, Linnunrata 14, 90440 Kempele Finland ' Faculty of Technology, Fibre and Particle Engineering, University of Oulu, P.O. Box 4300, FI-90014, Oulu, Finland ' Faculty of Information Technology and Electrical Engineering, Circuits and Systems Research Unit, University of Oulu, P.O. Box 7300, FI-90014 Oulu, Finland ' Tampere University, ATME FI-33101, Tampere, Finland ' Faculty of Technology, Civil Engineering Research, University of Oulu, P.O. Box 4000, FI-90014 Oulu, Finland

Abstract: Measurements of a boulder's fundamental physical properties like volume and shape can offer valuable insights for secondary breaking of boulders by a robotic rock breaker. This study analysed boulder shapes using a pulsed time-of-flight (TOF) solid-state laser profilometer. The 3D surface of boulders was reconstructed creating triangular meshes from point clouds provided by the profilometer. The main advantages of the 2D profilometer are the good measurement precision and accuracy, high speed, small size, real-time measurement capability, low weight, eye-safety, and lack of moving parts. The results indicate that a 3D map facilitates boulder diagnostics, aids in decision making, and represents a step towards a fully integrated autonomous robotic rock breaker in the mining industry. The present procedure is not only restricted to boulders, but it has also potential for other targets in industries that require precise determination of shapes for decision making.

Keywords: time-of-flight profilometer; stereo camera; boulder; robotic rock breaker; point cloud; shape.

DOI: 10.1504/IJMME.2023.131601

International Journal of Mining and Mineral Engineering, 2023 Vol.14 No.1, pp.55 - 68

Accepted: 29 Nov 2022
Published online: 20 Jun 2023 *