Study of Kinematic Tracking and Monitoring of Human Movements in a Collaborative Network of Depth Sensors

通过观察运动模式来跟踪人体运动是一个具有许多潜在应用的基础研究领域，如人体步态分析、独立生活设施中的老年人监测、人机交互和监视。迄今为止，摄像机网络或可穿戴传感器已被用于捕捉人体运动。然而，视觉传感一直在努力克服光照和表面纹理特性的变化，可穿戴传感器的接受度也很低。目前正在开发一种更可行、更经济的方法，使用低成本的运动学深度传感器，这是一种新兴技术。提出的研究计划将针对通过分布式深度传感器网络对人进行鲁棒运动跟踪的方面。研究成果将有助于人类生物力学和机器人领域，并在许多方面使加拿大人受益。该研究将提供一种实用的工具，通过观察患者在自然生活环境中的运动，而无需佩戴传感器，从而用于患者康复；它还将提供一种独特的、非侵入性的方法，用于监测我们老年人口在私人或公共护理机构的活动，以确保他们的安全。这项研究将为各种深度传感技术网络开发新的校准方法，建模和理解噪声的性质以及与身体位置和肢体运动相关的测量灵敏度。提出了两种基于深度测量的运动跟踪模型：粗跟踪模型；还有一个很好的跟踪模型。在粗模型中，我们基于四肢点定义人的整体周围形状，而新方法基于横截形状定义人的整体周围形状。我们建议扩展将物理监测区域划分为更大的体积（例如立方体）的概念，并将分布式深度测量与相应的3D体积相关联。对于每一卷，我们将探索各种方法，以找到由测量深度信息规定的表面的合适表示。然后将重建的粗形状模型作为跟踪选定肢体的基础，例如手臂，脚和头部。首先，利用端点的位置信息定义端点之间网格模型的局部距离函数。对于每个占据一组立方体的肢体，将定义跟踪变量来表示肢体的底层骨架和局部简单几何形状。针对身体和肢体运动的自然不确定性，提出了一种基于智能粒子滤波框架的肢体跟踪方法。我计划开发、研究和实验跟踪变量的各种运动模型和可以表示每个时间步期望跟踪变量的知识的先验运动概率分布。然后定义一组预测跟踪变量，这些变量可以与实际测量的深度传感器信息进行比较和加权。预期的新贡献与基于模型的鲁棒切换方法的发展有关，该方法用于跟踪作为人的全局运动意图和所选肢体的局部运动模式的函数。总体目标是从跟踪一个人及其相关肢体开始，并将结果扩展到在监测区域内移动的多个人。在开发的每个阶段，增量结果将针对现有的基于标记的系统进行验证，并与其他已知的运动预测方法进行比较。

Tracking human body movement by observing motion patterns is a fundamental research area with many potential applications, such as human gait analysis, monitoring seniors in independent living facilities, human-robot interaction, and surveillance. To date, networks of cameras or wearable sensors have been utilized to capture human body movements. However, visual sensing has struggled to overcome variations in illumination and surface texture properties, and wearable sensors have faced poor acceptance. A more feasible and economical approach is currently being developed using low cost kinematic depth sensors, which are an emerging technology. The proposed research program will target the aspects of robust motion tracking of people through a network of distributed depth sensors. Research results will contribute to the field of human biomechanics and robotics and benefit Canadians in a number of ways. The research will provide a practical tool that can be used in patient rehabilitation by observing their movements in their natural living habitat without the inconvenience of wearing sensors; it will also offer a unique, non-intrusive approach for their deployment in monitoring activities of our aging population for their safety in private or public caregiving facilities. This investigation will undertake development of novel calibration methods for various networks of depth sensing technologies, modeling and understanding the nature of noise and sensitivity of measurements related to the location of bodies and movements of limbs. Two kinematic tracking models are proposed based on the depth measurements: a coarse tracking model; and a fine tracking model. In the coarse model, we define the overall surrounding shape of persons based on points at extremities and the novel method based on shapes of cross-sectional cuts. We propose to extend the notion of dividing the physical monitoring area into coarser volumes (e.g., cubes) and associate the distributed depth measurements to corresponding 3D volumes. For each volume, we will explore various approaches for finding a suitable representation of the surface prescribed by measured depth information. The reconstructed coarse shape model is then used as a basis for tracking selected limbs of the person, e.g. arms, feet, and head. First, information about the location of extremities is used to define a local distance function along the mesh model between them. For each limb occupying a set of cubes, tracking variables will be defined to represent the underlying skeleton and local simple geometrical shape of the limb. Due to natural uncertainties associated with body and limb movements, a tracking method for each limb is proposed based on a novel intelligent filter framework (intelligent particle filter). I plan to develop, study, and experiment with various motion models of the tracking variables and prior motion probability distributions that can represent the knowledge of expected tracking variables at each time step. Then a set of predicted tracking variables will be defined that can be compared and weighted with the actual measured depth sensor information. The expected novel contributions are associated with development of a robust model-based switching method for tracking as a function of global motion intentions of the person and the local motion patterns of the selected limbs. The overall objective is to start by tracking one person and their associated limbs and extend the results to multiple people moving in the monitoring area. At each stage of the development, incremental results will be validated against an existing marker-based system and compared with other known motion prediction methods.