Abstract Designing of touchless user interface is gaining popularity in various contexts. Users can interact with electronic devices using such interfaces even when their hands are dirty or non-conductive. Also, users with partial physical disability can interact with electronic devices with the help of touchless interfaces. In this paper, we propose a Leap Motion controller-based methodology to facilitate rendering of 2D and 3D shapes on display devices. The proposed method tracks finger movements while users perform natural gestures within the field of view of the motion sensor. Then, trajectories are analyzed to extract extended Npen++ features in 3D. These features capture finger movements during the gestures and they are fed to unidirectional left-to-right Hidden Markov Model (HMM) for training. A one-to-one mapping between gestures and shapes, is proposed. Finally, the shapes corresponding to these gestures are rendered over the display using a typical MuPad supported interface. We have created a dataset of 5400 samples recorded by 10 volunteers. Our dataset contains 18 geometric and 18 non-geometric shapes such as “circle”, “rectangle”, “flower”, “cone”, “sphere”, etc. The proposed method has achieved 92.87 accuracy using a 5-fold cross validation scheme. Experiments reveal that the extended 3D features perform better than the existing 3D features when applied for shape representation and classification. The method can be used for developing diverse HCI applications suitable for smart display devices.
@cite_30: This paper focuses on the 3D shape recovery and augmented reality on elastic objects with self-occlusions handling, using only single view images. Shape recovery from a monocular video sequence is an underconstrained problem and many approaches have been proposed to enforce constraints and resolve the ambiguities. State-of-the art solutions enforce smoothness or geometric constraints, consider specific deformation properties such as inextensibility or resort to shading constraints. However, few of them can handle properly large elastic deformations. We propose in this paper a real-time method that uses a mechanical model and able to handle highly elastic objects. The problem is formulated as an energy minimization problem accounting for a non-linear elastic model constrained by external image points acquired from a monocular camera. This method prevents us from formulating restrictive assumptions and specific constraint terms in the minimization. In addition, we propose to handle self-occluded regions thanks to the ability of mechanical models to provide appropriate predictions of the shape. Our method is compared to existing techniques with experiments conducted on computer-generated and real data that show the effectiveness of recovering and augmenting 3D elastic objects. Additionally, experiments in the context of minimally invasive liver surgery are also provided and results on deformations with the presence of self-occlusions are exposed.
@cite_31: Having a correct posture at the piano requires a lot of practice to master; however, a visual feedback can help students realize potential problems and adopt a better position when playing the instrument. This paper discusses an innovative application of the techniqes used for the 3D visualization of piano performances in any possible view, with the purpose of comparing them to an ideal piano playing. It includes the capture and reconstruction of the 3D motion and posture of a professional piano player so that it may be compared against the posture and movements of students, by overlaying 2D videos of their recital. Issues with respect to displaying data and adding useful interface features are also discussed. The motion can be adjusted to fit measurements of anthropometrical different students, so that learners can see themselves and better understand what position they should adopt while they are at the piano
@cite_45: 
@cite_49: Nowadays tablet devices are considered most important category of information-processing devices, because they attract not only PC users, but also all generation of people including small kids to elderly people. However, 3D graphics is mostly used by games and only few well-known applications exist. In this paper, we propose a new content creation system for interactive 3D animation, which dynamically changes the story dependent on the users' gesture. We introduce a state transition model to efficiently achieve smooth transition of multiple sequence of 3D animations. We also propose a content creation tools which help user to easily make such 3D animation.
@cite_15: This paper describes the international electronic collaboration among students of two universities in order to create a digital educational space for supporting a role playing educational activity. The paper also presents the virtual place that has been implemented in order to transfer the role playing game activity students from the traditional classroom as well as the assessment of the whole activity from the pedagogical and technological viewpoint.
@cite_25: Children with autism spectrum condition (ASC) suffer from deficits or developmental delays in symbolic thinking. In particular, they are often found lacking in pretend play during early childhood. Researchers believe that they encounter difficulty in generating and maintaining mental representation of pretense coupled with the immediate reality. We have developed an interactive system that explores the potential of Augmented Reality (AR) technology to visually conceptualize the representation of pretense within an open-ended play environment. Results from an empirical study involving children with ASC aged 4 to 7 demonstrated a significant improvement of pretend play in terms of frequency, duration and relevance using the AR system in comparison to a non computer-assisted situation. We investigated individual differences, skill transfer, system usability and limitations of the proposed AR system. We discuss design guidelines for future AR systems for children with ASC and other pervasive developmental disorders.
Rendering of 3D shapes has many applications. For example, this can be used for designing therapeutic interfaces @cite_25 , interactive pedagogy @cite_45 @cite_15 , shape learning by kindergarten students @cite_49 , learning art and music @cite_31 , virtual and augmented reality applications @cite_30 etc. Users can perform rendering and transformation of 3D shapes by means of interactive participation through natural gestures.