# Effect of Augmented Reality Support on Quality Inspection of Welded Structures
## 3 Materials and Methods
### AR Pilot Software  
For the experimental study, pilot AR software was designed and developed to support users in the inspection of welded products using AR. In this section, the design and development of this tool is briefly presented. One of the first steps in the design of this tool was to collect experiences in the field of quality control of welded products from industrial practice. At the same time, the characteristics and approaches to inspection processes and their support were investigated in the context of practical experience. After examining the practical characteristics of inspection operations, a search for suitable tools for the actual design and development of an AR-supported technological solution was conducted. Attention was paid to game engines, with the help of which it is possible to design AR applications with an interactive user environment. Furthermore, the research focused on methods of tracked object recognition. For data storage, the possibilities of linking the proposed AR solution with a suitable database were investigated. The research also included the possibilities of using CAD software and graphics programs (see below) to design the necessary models and create visualisations and user interfaces. Last but not least, research on the available hardware devices and their possibilities when used in the experiment was carried out. The proposed approach assumes efficient data management and communication between users. Google's Firebase Database was chosen for this function. It is a powerful cloud-based database system that provides interfacing with Unity 3D and offers several features for data storage, synchronisation, and management. Firebase enables real-time data synchronisation and instant updates across devices and users, supporting the interactivity of connected applications. Firebase provides a cloud-based database that allows for data to be stored and managed on servers in a remote data centre. With the help of this database, user identity authentication is also performed. SolidEdge (ST10) and Blender (3.6.4 LTS) software were used to work with 3D CAD models. SolidEdge is a professional powerful software tool that was used to create the necessary models for the experiment. Blender was used to create visualisations of the 3D models. GIMP (2.10.32) and Adobe Illustrator (CS2) were used to create and edit 2D graphics and visualisation elements and the user interface. An example of data creation is shown in Figure 1.  
A combination of Unity 3D and Vuforia Engine was chosen. Vuforia was chosen as an AR-dedicated extension for Unity 3D that works with real-time visual recognition and tracking of markers and objects. It allows objects to be identified and to react to virtual elements to create interactive and realistic AR scenes. In this research, an object recognition method is investigated, which makes it possible to recognise an object without artificially added markers. The tracked object itself then acts as a marker, which Vuforia detects and recognises, then tracks it in space and anchors the programmed visualisation to the real scene. For this method to work properly, a database of parts was created in the Vuforia Model Target Generator extension, for which the prepared models were configured to work properly in AR visualisations. Examples of this configuration are shown in Figure 2.  
Unity 3D is an integrated development environment that offers a wide range of features and tools for creating simulations and applications. It was used to create a tool that interfaces with both the Vuforia and Firebase databases to guide the inspector interactively through the inspection process to support them in identification, the interpretation of prescribed specifications, and the process of deciding whether the inspected product conforms to the quality objectives. Unity and Vuforia are integrated within Unity to create an AR experience.