A Survey of Applications and Human Motion Recognition with Microsoft Kinect

Microsoft Kinect, a low-cost motion sensing device, enables users to interact with computers or game consoles naturally through gestures and spoken commands without any other peripheral equipment. As such, it has commanded intense interests in research and development on the Kinect technology. In this paper, we present, a comprehensive survey on Kinect applications, and the latest research and development on motion recognition using data captured by the Kinect sensor. On the applications front, we review the applications of the Kinect technology in a variety of areas, including healthcare, education and performing arts, robotics, sign language recognition, retail services, workplace safety training, as well as 3D reconstructions. On the technology front, we provide an overview of the main features of both versions of the Kinect sensor together with the depth sensing technologies used, and review literatures on human motion recognition techniques used in Kinect applications. We provide a classification of motion recognition techniques to highlight the different approaches used in human motion recognition. Furthermore, we compile a list of publicly available Kinect datasets. These datasets are valuable resources for researchers to investigate better methods for human motion recognition and lower-level computer vision tasks such as segmentation, object detection and human pose estimation

Upper-limb Kinematic Analysis and Artificial Intelligent Techniques for Neurorehabilitation and Assistive Environments

Stroke, one of the leading causes of death and disability around the world, usually affects the motor cortex causing weakness or paralysis in the limbs of one side of the body. Research efforts in neurorehabilitation technology have focused on the development of robotic devices to restore motor and cognitive function in impaired individuals, having the potential to deliver high-intensity and motivating therapy. End-effector-based devices have become an usual tool in the upper- limb neurorehabilitation due to the ease of adapting to patients. However, they are unable to measure the joint movements during the exercise. Thus, the first part of this thesis is focused on the development of a kinematic reconstruction algorithm that can be used in a real rehabilitation environment, without disturbing the normal patient-clinician interaction. On the basis of the algorithm found in the literature that presents some instabilities, a new algorithm is developed. The proposed algorithm is the first one able to online estimate not only the upper-limb joints, but also the trunk compensation using only two non-invasive wearable devices, placed onto the shoulder and upper arm of the patient. This new tool will allow the therapist to perform a comprehensive assessment combining the range of movement with clinical assessment scales. Knowing that the intensity of the therapy improves the outcomes of neurorehabilitation, a ‘self-managed’ rehabilitation system can allow the patients to continue the rehabilitation at home. This thesis proposes a system to online measure a set of upper-limb rehabilitation gestures, and intelligently evaluates the quality of the exercise performed by the patients. The assessment is performed through the study of the performed movement as a whole as well as evaluating each joint independently. The first results are promising and suggest that this system can became a a new tool to complement the clinical therapy at home and improve the rehabilitation outcomes. Finally, severe motor condition can remain after rehabilitation process. Thus, a technology solution for these patients and people with severe motor disabilities is proposed. An intelligent environmental control interface is developed with the ability to adapt its scan control to the residual capabilities of the user. Furthermore, the system estimates the intention of the user from the environmental information and the behavior of the user, helping in the navigation through the interface, improving its independence at home.El accidente cerebrovascular o ictus es una de las causas principales de muerte y discapacidad a nivel mundial. Normalmente afecta a la corteza motora causando debilidad o parálisis en las articulaciones del mismo lado del cuerpo. Los esfuerzos de investigación dentro de la tecnología de neurorehabilitación se han centrado en el desarrollo de dispositivos robóticos para restaurar las funciones motoras y cognitivas en las personas con esta discapacidad, teniendo un gran potencial para ofrecer una terapia de alta intensidad y motivadora. Los dispositivos basados en efector final se han convertido en una herramienta habitual en la neurorehabilitación de miembro superior ya que es muy sencillo adaptarlo a los pacientes. Sin embargo, éstos no son capaces de medir los movimientos articulares durante la realización del ejercicio. Por tanto, la primera parte de esta tesis se centra en el desarrollo de un algoritmo de reconstrucción cinemática que pueda ser usado en un entorno de rehabilitación real, sin perjudicar a la interacción normal entre el paciente y el clínico. Partiendo de la base que propone el algoritmo encontrado en la literatura, el cual presenta algunas inestabilidades, se ha desarrollado un nuevo algoritmo. El algoritmo propuesto es el primero capaz de estimar en tiempo real no sólo las articulaciones del miembro superior, sino también la compensación del tronco usando solamente dos dispositivos no invasivos y portátiles, colocados sobre el hombro y el brazo del paciente. Esta nueva herramienta permite al terapeuta realizar una valoración más exhaustiva combinando el rango de movimiento con las escalas de valoración clínicas. Sabiendo que la intensidad de la terapia mejora los resultados de la recuperación del ictus, un sistema de rehabilitación ‘auto-gestionado’ permite a los pacientes continuar con la rehabilitación en casa. Esta tesis propone un sistema para medir en tiempo real un conjunto de gestos de miembro superior y evaluar de manera inteligente la calidad del ejercicio realizado por el paciente. La valoración se hace a través del estudio del movimiento ejecutado en su conjunto, así como evaluando cada articulación independientemente. Los primeros resultados son prometedores y apuntan a que este sistema puede convertirse en una nueva herramienta para complementar la terapia clínica en casa y mejorar los resultados de la rehabilitación. Finalmente, después del proceso de rehabilitación pueden quedar secuelas motoras graves. Por este motivo, se propone una solución tecnológica para estas personas y para personas con discapacidades motoras severas. Así, se ha desarrollado una interfaz de control de entorno inteligente capaz de adaptar su control a las capacidades residuales del usuario. Además, el sistema estima la intención del usuario a partir de la información del entorno y el comportamiento del usuario, ayudando en la navegación a través de la interfaz, mejorando su independencia en el hogar

A novel motion tracking system for evaluation of functional rehabilitation of the upper limbs

Upper limb function impairment is one of the most common sequelae of central nervous system injury, especially in stroke patients and when spinal cord injury produces tetraplegia. Conventional assessment methods cannot provide objective evaluation of patient performance and the tiveness of therapies. The most common assessment tools are based on rating scales, which are inefficient when measuring small changes and can yield subjective bias. In this study, we designed an inertial sensor-based monitoring system composed of five sensors to measure and analyze the complex movements of the upper limbs, which are common in activities of daily living. We developed a kinematic model with nine degrees of freedom to analyze upper limb and head movements in three dimensions. This system was then validated using a commercial optoelectronic system. These findings suggest that an inertial sensor-based motion tracking system can be used in patients who have upper limb impairment through data integration with a virtual reality-based neuroretation system

Validation of a Biomechanical Injury and Disease Assessment Platform Applying an Inertial-Based Biosensor and Axis Vector Computation

Inertial kinetics and kinematics have substantial influences on human biomechanical function. A new algorithm for Inertial Measurement Unit (IMU)-based motion tracking is presented in this work. The primary aims of this paper are to combine recent developments in improved biosensor technology with mainstream motion-tracking hardware to measure the overall performance of human movement based on joint axis-angle representations of limb rotation. This work describes an alternative approach to representing three-dimensional rotations using a normalized vector around which an identified joint angle defines the overall rotation, rather than a traditional Euler angle approach. Furthermore, IMUs allow for the direct measurement of joint angular velocities, offering the opportunity to increase the accuracy of instantaneous axis of rotation estimations. Although the axis-angle representation requires vector quotient algebra (quaternions) to define rotation, this approach may be preferred for many graphics, vision, and virtual reality software applications. The analytical method was validated with laboratory data gathered from an infant dummy leg’s flexion and extension knee movements and applied to a living subject’s upper limb movement. The results showed that the novel approach could reasonably handle a simple case and provide a detailed analysis of axis-angle migration. The described algorithm could play a notable role in the biomechanical analysis of human joints and offers a harbinger of IMU-based biosensors that may detect pathological patterns of joint disease and injury

Master of Science

thesisStroke is a leading cause of death and adult disability in the United States. Survivors lose abilities that were controlled by the affected area of the brain. Rehabilitation therapy is administered to help survivors regain control of lost functional abilities. The number of sessions that stroke survivors attend are limited to the availability of a clinic close to their residence and the amount of time friends and family can devote to help them commute, as most are incapable of driving. Home-based therapy using virtual reality and computer games have the potential of solving these issues, increasing the amount of independent therapy performed by patients. This thesis presents the design, development and testing of a low-cost system, potentially suitable for use in the home environment. This system is designed for rehabilitation of the impaired upper limb of stroke survivors. A Microsoft Kinect was used to track the position of the patient's hand and the game requires the user to move the arm over increasing large areas by sliding the arm on a support. Studies were performed with six stroke survivors and five control subjects to determine the feasibility of the system. Patients played the game for 6 to 10 days and their game scores, range of motion and Fugl-Meyer scores were recorded for analysis. Statistically significant (p<0.05) differences were found between the game scores of the first and last day of the study. Furthermore, acceptability surveys revealed patients enjoyed playing the game, found this kind of therapy more enjoyable than conventional therapy and were willing to use the system in the home environment. Future work in the system will be focused on larger studies, improving the comfort of patients while playing the game, and developing new games that address cognitive issues and integrate art and therapy

Low-cost real-time motion capturing system using inertial measurement units

Human movement modeling - also referred to as motion-capture - is a rapidly expanding field of interest for medical rehabilitation, sports training, and entertainment. Motion capture devices are used to provide a virtual 3-dimensional reconstruction of human physical activities - employing either optical or inertial sensors. Utilizing inertial measurement units and digital signal processing techniques offers a better alternative in terms of portability and immunity to visual perturbations when compared to conventional optical solutions. In this paper, a cable-free, low-cost motion-capture solution based on inertial measurement units with a novel approach for calibration is proposed. The goal of the proposed solution is to apply motion capture to the fields that, because of cost problems, did not take enough benefit of such technology (e.g., fitness training centers). According to this goal, the necessary requirement for the proposed system is to be low-cost. Therefore, all the considerations and all the solutions provided in this work have been done according to this main requirement