Walter Simoes

Usuarios da nova TV Digital Interativa (TVDi), particularmente da TV Inteligente (Smart TV), tem experimentado novas formas de se relacionar com a TV atraves controles remotos que incorporaram mais funcionalidades, controles de deteccao de movimento e os controles atraves de reconhecimento de gestos. Os layouts operados por estes controles tiveram que se adequar as estas novas funcionalidades e apresentam as opcoes de funcionalidades ora por acesso direto (um unico botao), ora pelo acesso indireto (combinacao de botoes), e, neste segundo caso, tornam a atividade de interacao com a TVDi bastante dificil pois exigem um nivel de vivencia com os dispositivos eletronicos de interacao muito elevado. O controle remoto e o dispositivo padrao utilizado para permitir a interacao do usuario com a TV, mas em alguns momentos a sua utilizacao se torna macante e dificil. Neste cenario, o uso dos gestos surge como um modo mais natural e menos invasivo para auxiliar ou substituir o controle remoto c...

Wireless sensor networks have been presented as an alternative to location and navigation systems for the visually impaired in environments where GPS is not effective. However, dealing with the information obtained from these sensors for this purpose may present some challenges. The difficulties described by several authors are related to the oscillation of the signals, which are susceptible to numerous interfering agents such as the scene itself, the presence of people, etc. Therefore, this paper proposes to apply a data fusion of wireless networks with inertial sensors in an experiment protocol to allow its use in the indoor location of visually impaired persons with greater reliability. The methodology adopted was to construct a database obtained from several readings of the wireless sensors and inertial devices, to construct a reference curve and to compare the data of the test readings to this curve and indicate through three models (raw data Moving average and weighted average...

Many applications developed for tracking moving objects apply multiple cameras distributed in the study scenario. However, this form requires a lot of effort to know the time position of the moving object to align the frames at the same time and position. This paper presents a study on the camera space-time alignment to increase the degree of certainty about the location of objects monitored by merging information obtained from cameras and GPS. The results obtained by testing on simulator and a study scenario showed a degree of 98% and 71.42% accuracy. The lower result in the actual scenario was due to GPS signal use limitation. The major contribution of this work is to provide an alternative to future works which propose solutions to the problem of spatiotemporal alignment of cameras without overlapping fields.

This paper presents an audio guided Indoor Navigation Systems built in a wearable device designed to work with a hybrid mapping. This mapping consist of radio frequency markers as well as visual markers located in special places inside known ambient. This system allows blind users a safe guided navigation with quick and low computational complexity. The chosen methodological approach divides the system in two stages: one offline and another online. In offline stage the indoor mapping is made through construction of markers to generate a contextual database that increases the quality of location indication. The online stage, where the indoor navigation is performed, is based on the proximity method, visual pattern recognition, odometry, and ultrasonic perception of barriers. Results showed rates of over 90.0% of the recognition of RF and visual markers with time of 0.4 seconds, as well as over 95.0% of positive ultrasonic perception of obstacles.

This paper presents an indoor navigation wearable system based on visual markers recognition and ultrasonic obstacles perception used as an audio assistance for blind people. In this prototype, visual markers identify the points of interest in the environment; additionally this location status is enriched with information obtained in real time by other sensors. A map lists these points and indicates the distance and direction between closer points, building a virtual path. The blind users wear also glasses built with sensors like RGB camera, ultrasonic, magnetometer, gyroscope, and accelerometer enhancing the amount and quality of the available information. The user navigates freely in the prepared environment identifying the location markers. Based on the origin point information or the location point information and on the gyro sensor value the path to next marker (target) is calculated. To raise the perception of the environment, avoiding possible obstacles, it is used a couple of ultrasonic sensors. The audio assistance provided to the user makes use of an audio bank, with simple known instructions to indicate precisely the desired route and obstacles. Ten blind users tested and evaluated the system. The results showed rates of about 94.92% successful recognition of the markers using only 26 frames per second and 98.33% of ultrasonic obstacles perception disposed between 0.50 meters and 4.0 meters.

This paper presents an indoor navigation system built in a wearable device. The system allows visually impaired users to perform guided audio navigation safe, fast and has a low computational complexity. The methodological approach chosen divides the process into two phases: offline and online. In offline phase, the indoor mapping is done by data fusing of radio frequency and visual markers, constructing a unique and consistent representation. In the online phase navigation and recognition of each of the internal positions are performed through the fusion representation or only by the wi-fi or visual signals when one of the sensors is strongly affected by noises or other interferences. The results showed that the recognition levels of wi-fi, visual and fusion markers were 87.59%, 90.92%, and 92.03%, respectively. The error margin after the data fusion application was 0.8 m, with an average time of 0.62 ms.

Virtual wheelchair training environments have been implemented by different authors. However, they have not accurately represented the physical world behavior. Therefore this proposal consists of creating a training environment based on teleoperation, in which the user will remotely conduct a wheelchair receiving a real-time video feedback through an HMD.

Technologies and techniques of location and navigation are advancing, allowing greater precision in locating people in complex and challenging conditions. These advances have attracted growing interest from the scientific community in using indoor positioning systems (IPSs) with a higher degree of precision and fast delivery time, for groups of people such as the visually impaired, to some extent improving their quality of life. Much research brings together various works that deal with the physical and logical approaches of IPSs to give the reader a more general view of the models. These surveys, however, need to be continuously revisited to update the literature on the features described. This paper presents an expansion of the range of technologies and methodologies for assisting the visually impaired in previous works, providing readers and researchers with a more recent version of what was done and the advantages and disadvantages of each approach to guide reviews and discussio...

Indoor navigation systems offer many application possibilities for people who need information about the scenery and the possible fixed and mobile obstacles placed along the paths. In these systems, the main factors considered for their construction and evaluation are the level of accuracy and the delivery time of the information. However, it is necessary to notice obstacles placed above the user’s waistline to avoid accidents and collisions. In this paper, different methodologies are associated to define a hybrid navigation model called iterative pedestrian dead reckoning (i-PDR). i-PDR combines the PDR algorithm with a Kalman linear filter to correct the location, reducing the system’s margin of error iteratively. Obstacle perception was addressed through the use of stereo vision combined with a musical sounding scheme and spoken instructions that covered an angle of 120 degrees in front of the user. The results obtained in the margin of error and the maximum processing time are 0...

Abstract: This paper presents a guided audio Indoor navigation system built in a wearable device designed to work with a hybrid mapping. This mapping uses radio frequency tags (RF) and visual markers located within a known environment. The system allows visually impaired users to perform a guided navigation safe and fast, and has a low computational complexity. The methodological approach chosen divides the system into two phases: an offline and another online. In the offline phase, the interior mapping is done by building markers to generate a contextual database, which increases the quality of the location indication. The online phase, where the indoor navigation is performed, is based on a proximity method, recognition of visual pattern, odometry, and ultrasonic perception of obstacles. The results showed rates higher than 90.00% for the recognition of visual and RF markers with average computation time of 0.4 seconds, and more than 95.00% of positive ultrasonic perceived barriers.

Abstract Systems based on wireless sensor have been presented as an alternative to location and navigation for visually impaired in environments where GPS is not effective. However, dealing with the information obtained from these sensors may present some challenges. The difficulties described by several authors are related mainly to the oscillation of the signals, which are susceptible to numerous interfering agents such as the scene itself, the presence of people, etc. It is necessary to increase the accuracy of the location in all the techniques observed. Therefore, this paper proposes to apply data fusion of wi-fi sensors with inertial sensors to allow visually impaired to location and navigation in indoor places using aspects of healthcare like sensor based systems embedded in wearable devices. The methodology adopted was associate redundant fusion and complementary fusion to construct a database obtained from several readings of the wi-fi sensors and an inertial sensor to construct a reference position to compare the data of the test readings to this reference and indicate the reliability in an indoor location. The results show that RSSI with SNR and magnetometer with gyroscope provide high error rates with raw and isolated data, but when fused, they show a more efficient location, decreasing the error rates observed in isolated mode. The error margins between the real position and the position indicated by the system were 0,386 m, 0,336 m and 0,148 m to RSSI with SNR, inertial and fusion application, respectively.