## 1 Introduction  
AR techniques are used extensively in various real world applications for education, training, entertainment, tourism, and cultural heritage [1]. Especially in the education field, AR techniques have completely changed the design and method of learning [2]. Similarly, in the fields of cultural heritage and tourism, the historical places and objects can be reconstructed with the help of AR and VR techniques [3]. The ancient buildings that are not present in normal conditions are possible to visit with AR techniques [4]. AR techniques combine real world scenes and computer-based virtual world scenes and present their combined view to the user [5]. AR technology adds 3D user interactive virtual objects into the physical world [6]. According to the 2010 Horizon Report [7], AR techniques are of two types, marker-based and markerless-based. In marker-based AR techniques,image targets are predefined to visualize virtual content at different places. Target images are scanned with an AR camera (mobile or webcam), and then the system renders 3D visuals on the surface of that image targets in the real world. On the other hand, in the case of markerless-based AR techniques, there are no predefined target images [8]. An AR camera is capable of tracking the surfaces of any physical environment and overlay virtual content. It also utilizes a compass and Global Positioning System (GPS) for location tracking. AR techniques are used in almost every education field [9], such as engineering, medical education, surgical training, arts, designing, and language learning. Using AR-based learning techniques, students are highly motivated for learning activities, and their learning capabilities are significantly enhanced [10]. Students at primary age probably learn from activities where they observe, listen, and explore different things. Students are interested in learning and motivated to attend places, such as school, where they perform physical activities [11]. According to the study [12], techniques utilizing AR results in a better understanding of the concepts. In traditional knowledge transfer methods, a single teacher manages all the teaching processes, and the learning activities are performed face to face with the tutor [13]. The traditional method of learning is quite tedious for students and teachers that have a burden of many students to teach in class and satisfy each student. In traditional methods, learning materials are pen, paper, charts, videos, and presentations. Using these tools, the learning is not so interactive to the users as the AR learning content [14; 15; 16]. In this era of technology, most of the teaching community and researchers are interested in modifying the education system to enhance both the learning and teaching understandings [17]. The learning and teaching methods are greatly developed and expanded, due to technological advancements in recent years [18]. Most studies are now in favor of AR learning and training techniques compared to traditional learning methods [19]. AR learning techniques have several positive impressions on the students in comparison with traditional methods of learning. AR techniques increase students' motivation for learning, teamwork in group tasks, and understanding of the learning content for an extended period [20]. As suggested by the authors of [21], the learning experience becomes more meaningful when more senses are involved. From the children's perspective, a fascinating way of using their senses is through visualization, which is a crucial way to improve and develop their capacity to understand things [22]. Thus, the visualization of 3D graphics is more effective in solving and understanding the problem using all the children's senses. Based on the reasons above, we build a new learning system that utilizes AR technology to improve children's learning skills. Using this system, children can interact with the book contents displayed virtually via smartphones. At earlier ages, engaging primary school students in learning activities is quite a difficult task.