# Effect of Augmented Reality Support on Quality Inspection of Welded Structures
## 3 Materials and Methods
### Procedure  
The first variant tested in the experiment was a conventional approach to weldment inspection. In this approach, the inspector relied only on printed inspection documents and performed the inspection in a situation of zero automation. After handing the product to the inspector, the inspector started the identification process. Once the product had been identified, a quality check of the product was performed using technical documentation and control plans. First, the inspector needed to interpret the specifications and quality characteristics prescribed by the designers or technologists. After interpreting these requirements, the quality of the part was compared with the prescribed standards from the technical documentation, and conformity or deviation was assessed. In case of conformity, the part was released for further operations. If a deviation was found, it was returned for repair. The results of this process were recorded in a printed checklist. In this variant, instructions and information were conveyed to users in the traditional manner of a printed drawing and control plan. Control plans and general inspection steps that are commonly used for the parts used in the experiment are not suitable for inexperienced inspectors. In this research, the issue of AR-supported inspection approaches is investigated in terms of, among other things, the experience of the workers with the process. Therefore, participants with and without weldment inspection experience were part of  
Figure 4: A preview of the inspected part in experiment (all dimensions in the drawing are in mm). the experiment. So, instead of conventional inspection documents, modified inspection plans were created for the experiment for the parts in the inspection that are suitable for less experienced participants. These plans were tested on a pilot group of probands who do not have extensive experience in reading welding drawings. All confirmed that the visual layout of the control plan was clear, and that they did not experience any difficulty in navigating the plan. From the control plans produced, a set of documentation was created for product inspection in the experiment, which was the main basis for the implementation of the conventional quality inspection methodology. The preparation of the workstation is shown in Figure 5.  
The materials prepared in this way meant that the inspection process was carried out during the experiment without significant downtime or time loss. With the help of the prepared plans, the users were able to identify the part in a relatively short time, find the relevant printed documentation, and start interpreting it. This interpretation was then compared with the quality level found on the real piece. The second scenario was the proposed AR inspection approach. In this case, the participant was guided interactively through the process from the beginning with the support of the developed AR software. Once the AR scene was started, a video recording of the real scene began as the input for the AR module of the software used. It processed the AR scene with the help of the Vitoria Engine SDK functionalities. With the Vitoria extension, the tracked object acts as a target without the need to add an artificial marker. After the detection and recognition module recognised the tracked object, it deployed the programmed 3D visualisation and user interface created in Unity 3D into the real scene with the help of the tracking module. This environment interactively guides the user through the inspection plan, projects an ideal CAD model onto the real part for an easy comparison of the basic features, and displays the interpretation of the parameters in space on the inspected piece. Conformance decisions are dependent on the judgment of the inspector, who records conformance or deviation from the quality objectives on an AR checklist. This interactively marks the already checked characteristics in an AR scene anchored above the real product being inspected.