Artificial Vision Algorithms for Socially Assistive Robot Applications: A Review of the Literature

Today, computer vision algorithms are very important for different fields and applications, such as closed-circuit television security, health status monitoring, and recognizing a specific person or object and robotics. Regarding this topic, the present paper deals with a recent review of the literature on computer vision algorithms (recognition and tracking of faces, bodies, and objects) oriented towards socially assistive robot applications. The performance, frames per second (FPS) processing speed, and hardware implemented to run the algorithms are highlighted by comparing the available solutions. Moreover, this paper provides general information for researchers interested in knowing which vision algorithms are available, enabling them to select the one that is most suitable to include in their robotic system applicationsBeca Conacyt Doctorado No de CVU: 64683

Touching on elements for a non-invasive sensory feedback system for use in a prosthetic hand

Hand amputation results in the loss of motor and sensory functions, impacting activities of daily life and quality of life. Commercially available prosthetic hands restore the motor function but lack sensory feedback, which is crucial to receive information about the prosthesis state in real-time when interacting with the external environment. As a supplement to the missing sensory feedback, the amputee needs to rely on visual and audio cues to operate the prosthetic hand, which can be mentally demanding. This thesis revolves around finding potential solutions to contribute to an intuitive non-invasive sensory feedback system that could be cognitively less burdensome and enhance the sense of embodiment (the feeling that an artificial limb belongs to one’s own body), increasing acceptance of wearing a prosthesis.A sensory feedback system contains sensors to detect signals applied to the prosthetics. The signals are encoded via signal processing to resemble the detected sensation delivered by actuators on the skin. There is a challenge in implementing commercial sensors in a prosthetic finger. Due to the prosthetic finger’s curvature and the fact that some prosthetic hands use a covering rubber glove, the sensor response would be inaccurate. This thesis shows that a pneumatic touch sensor integrated into a rubber glove eliminates these errors. This sensor provides a consistent reading independent of the incident angle of stimulus, has a sensitivity of 0.82 kPa/N, a hysteresis error of 2.39±0.17%, and a linearity error of 2.95±0.40%.For intuitive tactile stimulation, it has been suggested that the feedback stimulus should be modality-matched with the intention to provide a sensation that can be easily associated with the real touch on the prosthetic hand, e.g., pressure on the prosthetic finger should provide pressure on the residual limb. A stimulus should also be spatially matched (e.g., position, size, and shape). Electrotactile stimulation has the ability to provide various sensations due to it having several adjustable parameters. Therefore, this type of stimulus is a good candidate for discrimination of textures. A microphone can detect texture-elicited vibrations to be processed, and by varying, e.g., the median frequency of the electrical stimulation, the signal can be presented on the skin. Participants in a study using electrotactile feedback showed a median accuracy of 85% in differentiating between four textures.During active exploration, electrotactile and vibrotactile feedback provide spatially matched modality stimulations, providing continuous feedback and providing a displaced sensation or a sensation dispatched on a larger area. Evaluating commonly used stimulation modalities using the Rubber Hand Illusion, modalities which resemble the intended sensation provide a more vivid illusion of ownership for the rubber hand.For a potentially more intuitive sensory feedback, the stimulation can be somatotopically matched, where the stimulus is experienced as being applied on a site corresponding to their missing hand. This is possible for amputees who experience referred sensation on their residual stump. However, not all amputees experience referred sensations. Nonetheless, after a structured training period, it is possible to learn to associate touch with specific fingers, and the effect persisted after two weeks. This effect was evaluated on participants with intact limbs, so it remains to evaluate this effect for amputees.In conclusion, this thesis proposes suggestions on sensory feedback systems that could be helpful in future prosthetic hands to (1) reduce their complexity and (2) enhance the sense of body ownership to enhance the overall sense of embodiment as an addition to an intuitive control system

Upper extremity disability after stroke. Psychometric properties of outcome measures and perceived ability to perform daily hand activities.

Disability of the upper extremity is common after stroke. To be able to evaluate recovery and effects of interventions there is a need for stable and precise outcome measures. In order to design and target efficient rehabilitation interventions it is important to know which factors that affect the ability to perform daily hand activities. At the time when the studies in this thesis were planned there was limited knowledge of the psychometric properties of outcome measures for persons with mild to moderate impairments of the upper extremity after stroke. There was also a lack of knowledge of which daily hand activities these persons perceive difficult to perform and which factors are associated with the performance.The overall aim of this thesis was to evaluate the psychometric properties of outcome measures for upper extremity after stroke, and to describe which daily hand activities persons with mild to moderate impairments in upper extremity after stroke perceive difficult to perform and identify associated factors with their performance.In paper I – IV, between 43 and 45 participants were included. Muscle strength in the upper extremity, somatosensation (active touch), dexterity and self-perceived ability to perform daily hand activities were assessed twice, one to two weeks apart. In paper V, 75 participants were included and the evaluated measures of the upper extremity were used together with other stroke specific outcomes to cover important aspects of functioning and disability according to the International Classification of Functioning, Disability and Health (ICF). Test-retest analyses for continuous data were made with the Intraclass Correlation Coefficient (ICC), the Change in Mean, the Standard Error of Measurement (SEM) and the Smallest Real Difference (SRD) (Paper I, III and IV). For ordinal data the Kappa coefficient and the Elisabeth Svensson rank-invariant method were used (Paper II and III). For analyses of convergent validity the Spearman’s correlation coefficient (rho) was calculated (Paper III). The ability to perform daily hand activities and the associations with potential factors were evaluated by univariate and multivariate linear regression models (Study V). The results showed that outcome measures for isometric and isokinetic muscle strength, active touch, dexterity and self-perceived daily hand activities have high test-retest agreements and can be recommended for persons with mild to moderate impairments in the upper extremity after stroke (Paper I to IV). Isometric strength measurements had lower measurement errors than isokinetic measurements and might be preferred (Paper I). The outcomes of dexterity showed learning effects (Paper III) and the ratings of perceived daily hand activities (Paper IV) had relatively high random measurement errors which must be taken into account when recovery and effects of interventions are evaluated. The three evaluated dexterity measures were partly related and can complement each other (Paper IV). Daily hand activities that require bimanual dexterity were perceived most difficult to perform, and dexterity and participation were the strongest contributing factors for performing daily hand activities after stroke (Paper V).In conclusion, this thesis has shown that outcome measures assessing functioning and disability of upper extremity after stroke are reliable and can be used in clinical settings and research. To increase the ability to perform daily hand activities, dexterity and perceived participation, in particular, should be considered in the assessments, goal-settings and rehabilitation after stroke

Contributions to the Modelling of Auditory Hallucinations, Social robotics, and Multiagent Systems

165 p.The Thesis covers three diverse lines of work that have been tackled with the central endeavor of modeling and understanding the phenomena under consideration. Firstly, the Thesis works on the problem of finding brain connectivity biomarkers of auditory hallucinations, a rather frequent phenomena that can be related some pathologies, but which is also present in healthy population. We apply machine learning techniques to assess the significance of effective brain connections extracted by either dynamical causal modeling or Granger causality. Secondly, the Thesis deals with the usefulness of social robotics strorytelling as a therapeutic tools for children at risk of exclussion. The Thesis reports on the observations gathered in several therapeutic sessions carried out in Spain and Bulgaria, under the supervision of tutors and caregivers. Thirdly, the Thesis deals with the spatio-temporal dynamic modeling of social agents trying to explain the phenomena of opinion survival of the social minorities. The Thesis proposes a eco-social model endowed with spatial mobility of the agents. Such mobility and the spatial perception of the agents are found to be strong mechanisms explaining opinion propagation and survival

Contributions to the Modelling of Auditory Hallucinations, Social robotics, and Multiagent Systems

165 p.The Thesis covers three diverse lines of work that have been tackled with the central endeavor of modeling and understanding the phenomena under consideration. Firstly, the Thesis works on the problem of finding brain connectivity biomarkers of auditory hallucinations, a rather frequent phenomena that can be related some pathologies, but which is also present in healthy population. We apply machine learning techniques to assess the significance of effective brain connections extracted by either dynamical causal modeling or Granger causality. Secondly, the Thesis deals with the usefulness of social robotics strorytelling as a therapeutic tools for children at risk of exclussion. The Thesis reports on the observations gathered in several therapeutic sessions carried out in Spain and Bulgaria, under the supervision of tutors and caregivers. Thirdly, the Thesis deals with the spatio-temporal dynamic modeling of social agents trying to explain the phenomena of opinion survival of the social minorities. The Thesis proposes a eco-social model endowed with spatial mobility of the agents. Such mobility and the spatial perception of the agents are found to be strong mechanisms explaining opinion propagation and survival

A Biosymtic (Biosymbiotic Robotic) Approach to Human Development and Evolution. The Echo of the Universe.

In the present work we demonstrate that the current Child-Computer Interaction paradigm is not potentiating human development to its fullest – it is associated with several physical and mental health problems and appears not to be maximizing children’s cognitive performance and cognitive development. In order to potentiate children’s physical and mental health (including cognitive performance and cognitive development) we have developed a new approach to human development and evolution. This approach proposes a particular synergy between the developing human body, computing machines and natural environments. It emphasizes that children should be encouraged to interact with challenging physical environments offering multiple possibilities for sensory stimulation and increasing physical and mental stress to the organism. We created and tested a new set of computing devices in order to operationalize our approach – Biosymtic (Biosymbiotic Robotic) devices: “Albert” and “Cratus”. In two initial studies we were able to observe that the main goal of our approach is being achieved. We observed that, interaction with the Biosymtic device “Albert”, in a natural environment, managed to trigger a different neurophysiological response (increases in sustained attention levels) and tended to optimize episodic memory performance in children, compared to interaction with a sedentary screen-based computing device, in an artificially controlled environment (indoors) - thus a promising solution to promote cognitive performance/development; and that interaction with the Biosymtic device “Cratus”, in a natural environment, instilled vigorous physical activity levels in children - thus a promising solution to promote physical and mental health