Precise rejection and material characterisation through image sequence evaluation and multi-object tracking during bulk material sorting
Optical bulk material sorting is considered a key technology for the recycling industry and has a central role in quality control in various industries. It enables, for example, the separation of a granular material stream into several fractions. In many cases, the sorting task consists of cleaning a defined product from foreign bodies, impurities or particles of inferior quality. Examples of applications are found in the sorting of plastic waste, demolition and waste glass shards as well as in the removal of foreign bodies in food and agricultural products. The systems, which are equipped with a wide range of sensor technology, can be used in many different ways. A common feature of all variants is the use of line scanning sensors.
Extension of optical bulk material sorters by motion analysis
As part of an interdisciplinary cooperation project between the Fraunhofer Institute of Optronics, Image Exploitation and System Technologies and System Technology IOSB, the Chair of Intelligent Sensor-Actuator Systems at the Karlsruhe Institute of Technology and the Chair of Energy Systems and Energy Process Technology at the Ruhr University Bochum and the Chair of Mechanical Process Engineering and Processing, Institute of Process Engineering and Chemical Engineering at the TU Berlin, an optical sorting system with area scan camera was developed. By using a high-speed camera, particles contained in the material flow are observed at several points in time and tracked via a multi-object tracking system. By evaluating the movement information, the actuators for rejecting bad material can be controlled much more accurately, thus increasing the sorting quality.
More information can be found on the Fraunhofer project page "Inside Schüttgut".