Comparison of the Depth Accuracy of a Plenoptic Camera and a Stereo Camera System in Spatially Tracking Single Refuse-derived Fuel Particles in a Drop Shaft

With the development of depth cameras in the last decades, several cameras are able to acquire 3D information of the captured scenes, such as plenoptic camera and stereo camera system. Because of the differences in principle and construction of various depth cameras, different cameras own particular advantages and disadvantages. Therefore, a comprehensive and detailed comparison of different cameras is essential to select the right camera for the application. Our research compared the depth accuracy and stability of a stereo camera system and a plenoptic camera by monitoring the settling processes of various refuse-derived fuel particles in a drop shaft. The particles are detected at first using detection approaches, and the particle detections are subsequently associated in accordance with data association algorithms. The spatial particle trajectories are obtained by the tracking-by-detection approach, based on which the performances of the cameras are evaluated

A Novel Plenoptic Camera-Based Measurement System for the Investigation into Flight and Combustion Behavior of Refuse-Derived Fuel Particles

In the past several decades, refuse-derived fuels (RDFs) have been widely applied in industrial combustion processes, for instance, in cement production. Since RDF is composed of various waste fractions with complex shapes, its flight and combustion behaviors can be relatively complicated. In this paper, we present a novel plenoptic camera-based spatial measurement system that uses image processing approaches to determine the dwell time, the space-sliced velocity in the depth direction, and the ignition time of various applied RDF fractions based on the obtained images. The image processing approach follows the concept of tracking-by-detection and includes a novel combined detection method, a 2.5D multiple particle tracking algorithm, and a postprocessing framework to tackle the issues in the initial tracking results. The thereby obtained complete spatial fuel trajectories enable the analysis of the flight behaviors elaborated in the paper. The acquired particles’ properties (duration, velocity, and ignition time) reversely prove the availability and applicability of the developed measurement system. The adequacy and accuracy of the proposed novel measurement system are validated by the experiments of detecting and tracking burning and nonburning fuel particles in a rotary kiln. This new measurement system and the provided experimental results can benefit a better understanding of the RDF’s combustion for future research