Augmented Reality Measurement Recorder for Magnetic Fields

Status:

completed 04/2023

Aims:

The hazard potential of magnetic fields at the workplace is relatively difficult for workers to determine since the fields are not visible. Arrangements governing the distance between the hazard and workers for protection of the latter, such as persons fitted with cardiac pacemakers, cannot always be implemented in practice without difficulty if the fields are not clearly demarcated. Visualization of the fields can provide a better understanding of the exposure situation and thus improve workplace safety.

In practice however, creating sketches (for example) often proves time-consuming, and the two-dimensional representation is not always readily comprehensible. The aim of the AURA project (augmented reality transducer for magnetic fields) was therefore to use augmented reality technology to display measurements of magnetic flux densities directly in a smartphone's video display. The measurements are displayed automatically during measurement on a field source; visualization therefore entails no additional effort. Images and videos of the workplace onto which the measured fields and the required safety distances are projected can be made available to the workers following measurement. This enables the workers to understand the exposure situation easily and assess where they can work safely.

Activities/Methods:

In the project, a prototype implementation of the combination of a magnetic field strength meter and a smartphone with augmented reality technology was tested and developed further. Different forms of visualization were compared to ensure the simplest and most effective display possible of measured values and safety distances. The prototype was presented at training events and in dialogue with the German Social Accident Insurance Institutions, and feedback obtained for use in further development. The augmented reality technology employed was continuously improved, and the simultaneous viewing of the virtual objects on different devices is now possible. Studies further examined whether, once measurements have been performed on installations, the data obtained can be stored in such a way that they can still be displayed automatically within an augmented reality at the same installation at a later time. As part of a master's thesis, the expected spatial accuracy of the measurements in various scenarios was ascertained.

Video: AURA in an example in the field

Demonstration video (non-accessible format)

The video shows the results of a master's thesis carried out as part of the AURA project. A smartphone is connected to a measuring device for magnetic fields and the video image of the smartphone spatially correctly shows recorded measurements at a resistance welding system. The measured values are visualised as colour-coded spheres, with the colours (green to red) indicating whether permissible values according to a selected set of rules have been exceeded. The augmented reality technology of the smartphone makes it possible to change the position of the smartphone while the measured values in the video image continue to be displayed at the correct position in the room. Safety distances to be observed are visualised in an easily understandable way by means of a cube and the scene can be viewed simultaneously from a different perspective with a second smartphone. An investigation showed that the understanding of the exposure situation is improved by AURA images.

Results:

The AURA system was developed in the context of a master's thesis on the basis of a prototype. Field test insights were regularly incorporated into the system development and optimisation process. This made it possible to develop a simple user interface and an easy-to-understand content presentation concept. The numerous practical tests involving AURA indicated that the system’s spatial precision is accurate enough to generate results that are useful for occupational safety.

The open source ARCore software development kit and an online real-time database made it possible to view the augmented reality scene simultaneously from a different perspective with a second smartphone. This makes it possible for both the person taking the measurement and another person to quickly and easily assess the exposure situation. With this technology it is theoretically also possible to return to the installation at a later time and view the scene again. However, this topic was not explored further in the project.

All AURA system functions are clearly explained in a video on the IFA website for the project.

An online survey about the AURA system was conducted as part of the master’s thesis. It showed that images created with AURA can improve people’s understanding of an exposure situation, which subsequently can improve occupational safety. For example, the survey showed that respondents with access to AURA images made significantly fewer errors on safety-related questions than respondents who only had a classic measurement report without AURA images available. For further details, please refer to the publications.

The AURA system has been regularly used in seminars on low-frequency electromagnetic fields organised by the German Social Accident Insurance Institution for the energy, textile, electrical and media products sectors (BG ETEM) since March 2022. It allows participants to gain a better understanding of the size of the present magnetic fields and the required safety distances. It is also used for measurements by the IFA and the images obtained serve to improve the comprehensibility of the measurement reports.

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