Monitoring of an aluminum melting furnace by means of a 3D light-field camera

The melting process in an aluminum melting furnace cannot be monitored by contact sensors, since the furnace is not accessible due to the high temperatures (more than 700 °C). Therefore, monitoring the melting process by means of optical sensors is investigated for the first time in this research project. This article deals with an innovative optical measuring system that is able to monitor the melting bridge despite the red-hot furnace walls. For this purpose, a light-field camera is installed on top an aluminum melting furnace in order to monitor the process and to control a targeted heat input into the melting furnace using a rotatable burner. The light-field camera used can capture a 3D point cloud with only one image. To achieve this, a separate field of lenses is placed between the image sensor and the main lens, projecting a virtual intermediate image onto the actual image sensor for further data processing. In addition, a self-developed image analysis program serves to monitor the height variation of the aluminum block and any melting rest on the melting bridge of the furnace [1]. Thus, the energy efficiency of the aluminum melting process could be increased by 15 % and the melting time reduced by almost 20 minutes by means of online monitoring.