# Reflections on the Limited Pervasiveness of Augmented Reality in Industrial Sectors
## 1 Introduction  
Information for human interaction is available for access at any time and place, allowing operators to change settings or maintainers to perform maintenance and monitoring of tasks in real time with a high level of situational awareness. However, due to the flow of information and the need for operators and maintainers to access different systems for service support, there is a change of behavior and professional profile in progress. In terms of human factors, education for industry 4.0 goes through the process of understanding the best technologies and procedural approaches, so that the human being reaches the expected levels of efficiency and safety. Several experiments are being carried out, indicating that there is much space for innovation through technological/procedural development. One of the technologies being tested is the use of Augmented Reality (AR). By delivering to the operator/maintainer a set of contextualized digital information, AR introduces computer-generated elements and objects overlapping the view of the real world [1], showing a significant amount of information, depending on the set of symbols associated with the environment of interest [2]. However, AR technology is not restricted to the hardware/software for personal use, but a whole range of applications, culminating in the delivery of the fused information, projected on the real world from the perspective of the user's interest. Consequently, although the available technologies are not new (some date back decades), the arrangement linked to the advent of the Internet of Things (IoT) [3],providing an information flow not previously available, has given a set of processes that have brought novelty, being the junction what makes an environment conducive to innovation using AR. Despite the wide range of AR applications in several market segments and the consequential forecast of market expansion (Figure 1), recent research on the use of AR technology in industrial environments has shown that major problems such as hardware and software development, weight, ergonomics, limited user acceptance, visual fatigue and concentration, data transfer, integration, security, content creation, adaptive instructions, marker tracking reliability, and cost [4] still exist. There is no specific hardware and software solution that solves all the applications demands in the industry, and the definition of symbols needs to be done contextually and depending on the type of operation/activity to be performed. The manufacturing industry is concerned with the process of transforming raw materials into finished goods with added value. In such a way, AR can contribute, giving information that is not available in terms the user could not perceive by their own senses [6]. Several studies have proved that visual instructions are easier to be understood than text instructions [7; 8]. Process monitoring and control, real-time evaluation of plant layout, plant and machinery maintenance, and plant and building construction for enhancing industrial safety, are some of the recent developments in AR for manufacturing [6; 9]. In terms of activities for AR usage in manufacturing, the most prominent are assembly and maintenance [10]. Maintenance is frequently associated to application fields like remote assistance and training, while assembly is also frequently associated to training [6]. This perspective provides the interpretation that applications of augmented reality technologies are the tip of the iceberg of a set of processes and technologies to meet an operational demand within the industry. It is not something specific to manufacturing, but it is clear the tendency to determine the compilation of necessary information during a set of activities that are naturally organized together to achieve the overall performance of a desired task.