Functional range of movement of the hand : declination angles to reachable space

 The measurement of the range of hand joint movement is an essential part of clinical practice and rehabilitation. Current methods use three finger joint declination angles of the metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints. In this paper we propose an alternate form of measurement for the finger movement. Using the notion of reachable space instead of declination angles has significant advantages. Firstly, it provides a visual and quantifiable method that therapists, insurance companies and patients can easily use to understand the functional capabilities of the hand. Secondly, it eliminates the redundant declination angle constraints. Finally, reachable space, defined by a set of reachable fingertip positions, can be measured and constructed by using a modern camera such as Creative Senz3D or built-in hand gesture sensors such as the Leap Motion Controller. Use of cameras or optical-type sensors for this purpose have considerable benefits such as eliminating and minimal involvement of therapist errors, non-contact measurement in addition to valuable time saving for the clinician. A comparison between using declination angles and reachable space were made based on Hume's experiment on functional range of movement to prove the efficiency of this new approach.

Sistema de supervisão aérea baseado em navegação visual para detecção de anomalias em instalações de petróleo e gás

This work deals with the development of a prototype of a helicopter quadrotor for monitoring applications in oil facilities. Anomaly detection problems can be resolved through monitoringmissions performed by a suitably instrumented quadrotor, i.e. infrared thermosensors should be embedded. The proposed monitoring system aims to reduce accidents as well as to make possible the use of non-destructive techniques for detection and location of leaks caused by corrosion. To this end, the implementation of a prototype, its stabilization and a navigation strategy have been proposed. The control strategy is based on dividing the problem into two control hierarchical levels: the lower level stabilizes the angles and the altitude of the vehicle at the desired values, while the higher one provide appropriate references signals to the lower level in order the quadrotor performs the desired movements. The navigation strategy for helicopter quadrotor is made using information provided by a acquisition image system (monocular camera) embedded onto the helicopter. Considering that the low-level control has been solved, the proposed vision-based navigation technique treats the problem as high level control strategies, such as, relative position control, trajectory generation and trajectory tracking. For the position control we use a control technique for visual servoing based on image features. The trajectory generation is done in a offline step, which is a visual trajectory composed of a sequence of images. For the trajectory tracking problem is proposed a control strategy by continuous servovision, thus enabling a navigation strategy without metric maps. Simulation and experimental results are presented to validate the proposal

Adaptação voluntária do andar em idosos com doença de Parkinson sob dica visual dinâmica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Orientação espacial em pessoas com deficiência visual: um estudo de triangulação por meio de monitoramento remoto

This study was conducted to investigate how visually impaired people perform distance estimation tasks by movement and navigation during deprivation of effective perceptual and proprioceptive information. For that they performed the task of walking three distances, being the first and second of 100 meters and the third of 140 meters (triangulation) from a point of origin in open field on a inverted L shaped trajectory and then returning to the origin. The first and second tasks were driven by means of a guide with GPS adapted to the study coordinates, and the third one was freeform with three sessions, the first without perceptual and proprioceptive restrictions, the second without auditory perception, and the third in a wheelchair, without proprioception. The objective of this study was to indicate the differences in distance reproduction in relation to accuracy and investigate the spatial representation of participants in a navigation task, in which there is active movement, but no effective perceptual and proprioceptive information. Results showed that the average participants underestimated distances producing average angles close to the value of 45°. And by means of the "t" students test no significant differences between subjects can be pointed out. To achieve these results we used remote monitoring by GPS and software TrackMaker.

Ergonomia de tablets em uso ocupacional: atividade visual e biomecânica postural sob a influência de ofuscamentos reflexivos causados pela iluminação

Pós-graduação em Design - FAAC

The Effect Of Misleading Prior Information On The Subjective Visual Vertical

When tilted sideways participants misperceive the visual vertical assessed by means of a luminous line in otherwise complete dark- ness. A recent modeling approach (De Vrijer et al., 2009) claimed that these typical patterns of errors (known as A- and E-effects) could be explained by as- suming that participants behave in a Bayes optimal manner. In this study, we experimentally manipulate participants’ prior information about body-in-space orientation and measure the effect of this manipulation on the subjective visual vertical (SVV). Specifically, we explore the effects of veridical and misleading instructions about body tilt orientations on the SVV. We used a psychophys- ical 2AFC SVV task at roll tilt angles of 0 degrees, 16 degrees and 4 degrees CW and CCW. Participants were tilted to 4 degrees under different instruction conditions: in one condition, participants received veridical instructions as to their tilt angle, whereas in another condition, participants received the mis- leading instruction that their body position was perfectly upright. Our results indicate systematic differences between the instruction conditions at 4 degrees CW and CCW. Participants did not simply use an ego-centric reference frame in the misleading condition; instead, participants’ estimates of the SVV seem to lie between their head’s Z-axis and the estimate of the SVV as measured in the veridical condition. All participants displayed A-effects at roll tilt an- gles of 16 degrees CW and CCW. We discuss our results in the context of the Bayesian model by De Vrijer et al. (2009), and claim that this pattern of re- sults is consistent with a manipulation of precision of a prior distribution over body-in-space orientations. Furthermore, we introduce a Bayesian Generalized Linear Model for estimating parameters of participants’ psychometric function, which allows us to jointly estimate group level and individual level parameters under all experimental conditions simultaneously, rather than relying on the traditional two-step approach to obtaining group level parameter estimates.

A study of 2D features for 3D visual SLAM

Paper submitted to the 43rd International Symposium on Robotics (ISR), Taipei, Taiwan, August 29-31, 2012.

Axis-based grouping reduces visual extinction

We examined the effects on extinction of grouping by collinearity of edges and grouping by alignment of internal axes of shapes, in a patient (GK) with simultanagnosia following bilateral parietal brain damage. GK’s visual extinction was reduced when items (equilateral triangles and angles) could be grouped by base alignment (i.e., collinearity) or by axis alignment, relative to a condition in which items were ungrouped. These grouping effects disappeared when inter-item spacing was increased, though factors such as display symmetry remained constant. Overall, the results suggest that, under some conditions, grouping by alignment of axes of symmetry can have an equal beneficial effect on visual extinction as edge-based grouping; thus, in the extinguished field, there is derivation of axis-based representations from the contours present.