Abstract
Sensor-based sorting provides state-of-the-art solutions for sorting cohesive, granular materials. Typically, involved sensors, illumination, implementation of data analysis and other components are designed and chosen according to the sorting task at hand. A common property of conventional systems is the utilization of scanning sensors. However, the usage of area-scan cameras has recently been proposed. When observing objects at multiple time points, the corresponding paths can be reconstructed by using multiobject tracking. This in turn allows to accurately estimate the point in time and position at which any object will reach the separation stage of the optical sorter and hence contributes to decreasing the error in physical separation. In this paper, it is proposed to further exploit motion information for the purpose of material characterization. By deriving suitable features from the motion information, we show that high classification performance is obtained for an exemplary classification task. The approach therefore contributes towards decreasing the detection error of sorting systems.
Zusammenfassung
Für die Sortierung von kohäsiven, granularen Materialien entspricht die sensorgestützte Sortierung dem Stand der Technik. Die Auswahl geeigneter Systemkomponenten, wie etwa Sensorik, Beleuchtung, oder die Realisierung der Datenauswertung, orientiert sich bei der Entwicklung entsprechender Systeme an der konkreten Sortieraufgabe, die es zu lösen gilt. Eine Gemeinsamkeit findet sich im Einsatz scannender Sensoren. Jüngst wurde jedoch der Einsatz von Flächenkameras vorgeschlagen. Durch die Beobachtung von Objekten zu mehreren Zeitpunkten besteht die Möglichkeit, deren Bewegungspfade zu verfolgen. Dies erlaubt eine präzise Schätzung der Position und des Zeitpunkts, zu welchem ein Objekt die Trennstufe des Systems erreicht und hilft somit dabei, den Fehler in der physikalischen Separation zu verringern. In dieser Veröffentlichung wird vorgeschlagen, diese Bewegungsinformation ebenfalls zur Charakterisierung von Materialien zu verwenden. Durch die Ableitung geeigneter Merkmale zeigen wir exemplarisch für eine Klassifikationsaufgabe, dass hierdurch gute Ergebnisse erzielt werden können. Der vorgestellte Ansatz trägt damit zur Verringerung des Erkennungsfehlers in Sortiersystemen bei.
About the authors
Georg Maier is with the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation IOSB, Karlsruhe, Germany. His research interests include different aspects of image processing, in particular algorithmic aspects, with a focus on real-time capabilities.
Fraunhofer Institute of Optronics, System Technologies and Image Exploitation IOSB, Fraunhoferstraße 1, 76131 Karlsruhe, Germany
Florian Pfaff is a research assistant at the Intelligent Sensor-Actuator-Systems Laboratory at the Karlsruhe Institute of Technology. His research interests include a variety of estimation problems such as nonlinear filtering, multitarget tracking, and estimation in the presence of both stochastic and non-stochastic uncertainties.
Karlsruhe Institute of Technology, Institut für Anthropomatik und Robotik, Adenauerring 2, 76131 Karlsruhe, Germany
Florian Becker is a student at the Karlsruhe Institute of Technology (KIT) and a research assistant at the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB) in Karlsruhe. His research interests include computer vision and algorithm engineering.
Fraunhofer Institute of Optronics, System Technologies and Image Exploitation IOSB, Fraunhoferstraße 1, 76131 Karlsruhe, Germany
Christoph Pieper is a research assistant at the Department of Energy Plant Technology at the Ruhr University Bochum. His research interests include numerical simulation of fluidized particle systems with the Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD).
Ruhr-Universität Bochum, Universitätsstraße 150, IC 2/111, 44780 Bochum, Germany
Robin Gruna is research group manager at the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation IOSB in Karlsruhe. His research interests include hyperspectral imaging, machine vision, computational illumination and chemometrics.
Fraunhofer Institute of Optronics, System Technologies and Image Exploitation IOSB, Fraunhoferstraße 1, 76131 Karlsruhe, Germany
Benjamin Noack received his diploma in computer science from the Karlsruhe Institute of Technology (KIT), Germany, in 2009. Afterwards, he obtained his Ph.D. in 2013 at the Intelligent Sensor-Actuator-Systems Laboratory, Karlsruhe Institute of Technology (KIT), Germany. Since 2013 he is a senior researcher at the Karlsruhe Institute of Technology (KIT), Germany. His research interests are in the areas of multi-sensor data fusion, distributed and decentralized Kalman filtering, combined stochastic and set-membership approaches to state estimation, and event-based systems.
Karlsruhe Institute of Technology, Institut für Anthropomatik und Robotik, Adenauerring 2, 76131 Karlsruhe, Germany
Harald Kruggel-Emden is professor and head of the department of Mechanical Process Engineering and Solids Processing at the Technical University of Berlin. His research interests include Discrete Element Modelling with coupled fluid flow, material preparation and drying technology, bulk solids handling and chemical looping combustion.
TU Berlin, Mechanische Verfahrenstechnik und Aufbereitung, Sekr. BH 11, Ernst-Reuter-Platz 1, 10587 Berlin, Germany
Thomas Längle is adjunct professor at the Karlsruhe Institute of Technology (KIT), Karlsruhe, and the head of the business unit “Vision Based Inspection Systems” (SPR) at the Fraunhofer IOSB in Karlsruhe, Germany. His research interests include different aspects of image processing and real-time algorithms for inspection systems.
Fraunhofer Institute of Optronics, System Technologies and Image Exploitation IOSB, Fraunhoferstraße 1, 76131 Karlsruhe, Germany
Uwe D. Hanebeck is a chaired professor of Computer Science at the Karlsruhe Institute of Technology (KIT) in Germany and director of the Intelligent Sensor-Actuator-Systems Laboratory (ISAS). He obtained his Ph.D. degree in 1997 and his habilitation degree in 2003, both in Electrical Engineering from the Technical University in Munich, Germany. His research interests are in the areas of information fusion, nonlinear state estimation, stochastic modeling, system identification, and control with a strong emphasis on theory-driven approaches based on stochastic system theory and uncertainty models. He is author and coauthor of more than 400 publications in various high-ranking journals and conferences and an IEEE Fellow.
Karlsruhe Institute of Technology, Institut für Anthropomatik und Robotik, Adenauerring 2, 76131 Karlsruhe, Germany
Siegmar Wirtz is the deputy head of the Department of Energy Plant Technology at the Ruhr University Bochum. His research interests include numerical simulation of reactive gas-solid flows, extension of commercial CFD-Codes, Discrete Element Modelling with coupled fluid flow.
Ruhr-Universität Bochum, Universitätsstraße 150, IC 2/111, 44780 Bochum, Germany
Viktor Scherer is the head of the Department of Energy Plant Technology at the Ruhr University Bochum. His research interests include energetic conversion of fossil fuels and biomass as well as related industrial applications and experimental and theoretical investigation of energy and high temperature processes.
Ruhr-Universität Bochum, Universitätsstraße 150, IC 2/111, 44780 Bochum, Germany
Jürgen Beyerer is full professor for informatics at the Institute for Anthropomatics and Robotics at the Karlsruhe Institute of Technology KIT since March 2004 and director of the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation IOSB in Ettlingen, Karlsruhe, Ilmenau and Lemgo. Research interests include automated visual inspection, signal and image processing, variable image acquisition and processing, active vision, metrology, information theory, fusion of data and information from heterogeneous sources, system theory, autonomous systems and automation.
Fraunhofer Institute of Optronics, System Technologies and Image Exploitation IOSB, Fraunhoferstraße 1, 76131 Karlsruhe, Germany
Acknowledgement
IGF project 18798 N of research association Forschungs-Gesellschaft Verfahrens-Technik e.V. (GVT) was supported by the AiF under a program for promoting the Industrial Community Research and Development (IGF) by the Federal Ministry for Economic Affairs and Energy on the basis of a resolution of the German Bundestag.
©2017 Walter de Gruyter Berlin/Boston
