João Luiz Bernardes

Design and Implementation of a Flexible Hand Gesture Command Interface for Games Based on Computer Vision

This paper describes a command interface for games based on hand gestures defined by postures, movement and location. The large variety of gestures thus possible increases usability by allowing a better match between gesture and action. The system uses computer vision requiring no sensors or markers on the user or background. The analysis of requirements for games, the architecture and implementation are discussed, as well as the results of several tests to evaluate how well each requirement is met.

Integrating the Wii controller with enJine: 3D interfaces extending the frontiers of a didactic game engine

The goal of the work described here is to integrate a 3D input device, the Wii controller, and enJine, a didactic engine, motivated by the growing use of 3D interfaces. This article discusses how this increases enJines didactic and technological potential, and details the adopted solution as a layered architecture. Two interaction styles were tested with the implemented solution. Test results show a variety of data about the controller, confirming that this solution works as desired and that using it to modify a game so it can use the WiiMote as its input device is a simple task.

Robot Arena: An augmented reality platform for game development

Nowadays electronic games are of great importance to the economic sector, to computing, and to academic research, and not are limited to entertainment applications only. Augmented reality is one of the new frontiers to be explored in the search for innovation in gameplay and in interactive interfaces of electronic games. This article presents the research, development, and testing of an infrastructure, called Robot Arena, for the development of innovative games using the spatial augmented reality and new interfaces that this technology brings. Based on horizontal interfaces with elements of hardware and software, Robot ARena has a flexible architecture that enables different ways of interaction and visualization. Another aspect planned for this project is the control and communication of robots, which can be used as avatars in games. A Robot ARena prototype was implemented, tested, and used in the development of two game prototypes, FootBot ARena and TanSpace, which bring new challenges to the infrastructure, such as exploration of the influence of virtual objects on real objects and the application of tangible interfaces.

Fusion4D: 4D Unencumbered Direct Manipulation and Visualization

It is possible to predict that sometime in the future, holographic interactive displays will be available as household commodities, requiring new interaction techniques. Fusion4D is our proposal for unencumbered direct manipulation interfaces involving three dimensions in physical space, as well as a fourth data-dependent dimension (such as time-varying information of an object.) A proof-of-concept prototype has been developed and subjected to user testing. The results of the tests indicate that there are some points for improvement, such as the visualization technology, but the system is well accepted by users.

3D Interaction Accessible to Visually Impaired Users: A Systematic Review

There is currently a large number of visually impaired people in Brazil and worldwide. And just as any citizen they have their rights, including in them the right to education and other services that accelerate the process of social. With advent of technology increasingly virtual environments in three dimensions are being used for various areas. But often these environments are not accessible to visually impaired becoming a digital divide. In this context, a review of interactions in three dimensions accessible to visually impaired people may facilitate the work of researchers and developers to build such accessible applications. This paper presents the results of such a systematic literature review.

The Influences of Culture on User Experience

In the last years, some studies about how cultural differences influences user experience (UX) have started being published. Most of these studies concluded that cultural differences really affect UX. These studies were conducted in different countries, using different methods and led by researches with different cultures. Observing these points, the main objective of this review is to map the work in this area and to suggest a research guideline for similar work. First, a systematic literature review was conducted in the main academic search engines, using many related keywords. The search engines returned 1227 studies and all abstracts were read and evaluated according to the acceptance criteria. Twenty three remaining studies were analyzed in detail. Results showed that the Hofstede’s definition of culture and cultural differences is the most commonly used definition in this area, most studies used questionnaires to evaluate if the culture really influences UX and regarding the results, the majority, 87 %, confirm that it does. Based on this analysis, we identify and propose a guideline to replicate this kind of work in other scenarios. This guideline may represent a significant contribution to the area, perhaps enabling an increase in the number and standardization of certain cross-cultural studies, in the development of new techniques and in the relevance of this subject during UX projects.

Brazilian Cultural Differences and Their Effects on the Web Interfaces User Experience

Having an interface that provides good user experience has become a critical factor for success in information systems. Cultural differences, however, may have a significant impact in this experience, but are seldom taken into account during interface design and evaluation, particularly in Brazil, a multicultural country with continental dimensions. Our goal was to investigate whether the cultural differences between the five socio-economical macro-regions of Brazil are profound enough to impact user experience in web-based interfaces and, if so, how. We performed an experiment with 110 participants, 22 per region, comparing cultural differences elicited by VSM with performance and evaluation of a fictitious Internet Banking System. Cultural differences were identified and correlated with differences in user experience, particularly in regards to the amount of information and colors shown in the interface.

Deformation Method Using Physical Parameters Composed of Different Tissue Structures

In order to achieve the realism required in simulating the physical behavior of tissues during deformation, the methods which allow the use of physical parameters are the most widely employed. This paper presents a method of simulating the deformation of three-dimensional objects that represent human organs through multiple layers of tissue, which utilizes the following physical parameters: modulus of elasticity, thickness and density. The number of layers and the allocation of physical parameters can be set according to the different tissues that make up the human body and the behavior to be simulated. Thus, it is possible to achieve visual realism, realistic haptics and real-time interaction, with acceptable computational cost. For the simulation of medical procedures, both visual realism and haptic technology are required in order to provide the user with sensations similar to those found in real procedures. The organ chosen for the experiments was the breast, and the results obtained in relation to the physical behavior of deformation were acceptable in relation to visual realism and haptics.

Skin Color Segmentation and Levenshtein Distance Recognition of BSL Signs in Video

Sign language automatic recognition is an important research area with open challenges that aims to mitigate the obstacles in the daily lives of people who are deaf or hard of hearing and increase their integration in the predominantly hearing society in which we live. This paper implements, evaluates and discusses strategies for automatic recognition of Brazilian Sign Language (BSL) signs, which ultimately aims to simplify the communication between deaf signing in BSL and listeners who do not know this sign language, accomplished through the processing of digital videos of people communicating in BSL without the use of colored gloves or data gloves and sensors or the requirement of high quality recordings in laboratories with controlled backgrounds or lighting. An approach divided in several stages was developed and all stages of the proposed system can be considered contributions for future works in sign language recognition or those involving image processing, human skin segmentation, object tracking etc. For the skin color based segmentation stage, in particular, several techniques were implemented and compared and the strategy used for sign recognition, exploring the Leveshtein distance and a voting scheme with a binary classifier, is unusual in this area and showed good results. From the original 600 samples of 30 words, chosen for frequency of use and superposition of sign elements to make recognition more complex, the system was able to correctly segment 422 (70%) signs, for which it reached 100% accuracy in recognition using our strategy. This sign database with 600 samples in video of the chosen 30 word vocabulary is another of this work’s contributions and is available upon request to the authors.

Autonomous Identification of Virtual 3D Objects by Visually Impaired Users with Proprioception and Audio Feedback

The World Health Organization estimates that there are 285 million people with severe visual impairment worldwide. With the advent of technology, 3D virtual environments are being increasingly used for several applications. Many of these applications, however, are not accessible to visually impaired users, creating a digital divide. Our goal is to develop a novel and low cost 3D interaction technique to allow the identification of virtual objects with autonomy using only proprioception and hearing. We developed a prototype implementing this technique and conducted preliminary tests with it, first with sighted users, only to test the prototype’s basic functionalities and implementation, and then with a blind user with very promising results since the user was able to correctly and quickly identify virtual objects.