# Investigating the Learning Process of Folk Dances Using Mobile Augmented Reality
## 2 Background  
Various applications for dance learning purposes have been proposed using different technologies. [PERSON] et al. [8] developed a 3D viewer for watching the dance. Interaction is provided by change of the point of view and zoom level or control of the speed are available. Another interface for dance learning is presented in [9] includes functionalities like start, stop, zoom, focus, change camera position, change speed. Creating game-like application is also a popular way to encourage specific behaviors and increase motivation and engagement [10]. Examples of game-like environments and interfaces can be found in [4; 11; 12]. They all propose similar way of learning; avatar of the teacher is shown, and user is supposed to imitate teacher's movements. User's movements are streamed to the application and feedback is given in form of score with corresponding message. Once the task is completed successfully, user can go to the next step.  
VR offers an alternative experimental way how dance(s) can be taught. [PERSON] et al. [13] proposed a cave automatic virtual environment (CAVE) for ballet dance training. The environment consists of projectors screens placed to walls of room-sized cube where user can watch the virtual teacher and replicate movements. Training system based on the motion capture and VR technologies is presented in [14]. Virtual teacher's movements are projected on the wall screen and user must imitate movements. In another prototype VR simulator users can preview folk dance segments performed by  
Figure 1: Workflow for learning procedure.  
Figure 2: Workflow for data analysis.  
a 3D avatar and repeat them [15]. Intuitive feedback based on comparison with the template motions is provided. Folk dance training is described in [16]. Head-mounted device (HMD) was used for the dance presentation in VR. Users' movements were captured and compared to the teacher's, and feedback is given in real time. Moreover, a VR application used the 3D computer-generated animation of teacher's movements [17]. [PERSON] in [18] presented a method for controlling a virtual partner's motion based on a performance capture process. A hidden Markov model (HMM) was trained to learn the structure of the dance motions and during the runtime system predicts the progress of the user's motion. To understand naturalness of synchronized motion and the control the user has on a partner's synthesized motion, a user study was conducted.  
AR has been also experimentally used in entertainment and dances [1; 19]. A conceptual tool for simulated dancing uses smart glasses to project virtual dancers in the environment [20]. Multi and single-user scenarios are proposed. In prior two users dance together while not being present physically in the same room, and in latter user dances with avatars that have a predesigned animation. A large-scale AR mirror for user training is presented where the mirror allows users to see their movements providing them visual feedback [21]. In [22], AR is used to present virtual dancer as an instructor or a dance partner and enables user to see their body movements as an external observer. [PERSON] et al. [23] adapted and integrated AR related tools to enhance the emotion involved in cultural performances. As a part of work, stage in a live performance was augmented, and dance was an application case.  
Our prototype, presented in [24], offers users the ability to visualize the avatar of professional dancer with prerecorded animation as shown in Figure 3. Users can switch between different part of the dance without any restrictions. There is no need to complete one step to proceed to the next one so that users can organize the learning procedure in their own pace. In addition, music of the dance is available so that they can coordinate their movements according to it. Similarly to [8; 9], it is possible to change the speed and/or play/pause the dance and offer a personalized experience.