Non-invasive Monitoring of Elderly Persons

This book covers the results of a study concerning systems for healthcare-oriented monitoring of elderly persons. It is focused on the methods for processing data from impulse-radar sensors and depth sensors, aimed at localisation of monitored persons and estimation of selected quantities informative from the healthcare point of view. It includes mathematical descriptions of the considered methods, as well as the corresponding algorithms and the results of their testing in a real-world context. Moreover, it explains the motivations for developing healthcare-oriented monitoring systems and specifies the real-world needs which may be addressed by such systems. The healthcare systems, all over the world, are confronted with challenges implied by the ageing of population and the lack of adequate recruitment of healthcare professionals. Those challenges can be met by developing new technologies aimed at improving the quality of life of elderly people and at increasing the efficiency of public health management. Monitoring systems may contribute to this strategy by providing information on the evolving health status of independently-living elderly persons, enabling healthcare personnel to quickly react to dangerous events. Although these facts are generally acknowledged, such systems are not yet being commonly used in healthcare facilities and households. This may be explained by the difficulties related to the development of technological solutions which can be both acceptable for monitored persons and capable of providing healthcare personnel with useful information. The impulse-radar sensors and depth sensors, considered in this book, have a potential for overcoming those difficulties since they are not cumbersome for the monitored persons - if compared to wearable sensors - and do not violate the monitored person's privacy - if compared to video cameras. Since for safety reasons the level of power, emitted by the radar sensors, must be ultra-low, the task of detection and processing of signals is a research challenge which requires more sophisticated methods than those developed for other radar applications. This book contains descriptions of new Bayesian methods, applicable for the localisation of persons by means of impulse-radar sensors, and an exhaustive review of previously published ones. Furthermore, the methods for denoising, regularised numerical differentiation and fusion of data from impulse-radar sensors and depth sensors are systematically reviewed in this book. On top of that, the results of experiments aimed at comparing the performance of various data-processing methods, which may serve as guidelines for related future projects, are presented.

Auteur

Jakub Wagner, born in 1988 (Poland), received the M.Sc. degree in biomedical engineering in 2013, and the Ph.D. degree in electronics in 2020, both from Warsaw University of Technology (Poland) where he is currently employed as Assistant Professor. His scientific activities are focused on biomedical and healthcare applications of mathematical tools for analysis of measurement data. He has participated in a series of research projects devoted to healthcare-oriented monitoring of independently-living elderly persons. Pawel Mazurek, born in 1989 (Poland), received the M.Sc. degree in telecommunications, in 2014, and Ph.D. degree in electronics in 2019, from Warsaw University of Technology (Poland) where he is currently employed as Assistant Professor. His research interests include the preprocessing and integration of measurement data acquired by means of impulse-radar sensors and infrared depth sensors when applied for unobtrusive monitoring of elderly persons. Roman Z. Morawski, born in 1949 (Poland), Professor of Measurement Science at Warsaw University of Technology, has fifty-year research experience in the field of measurement data modelling and processing, including the development and implementation of algorithms for processing data from various kinds of spectrometric, optoelectronic, acoustic and microwave sensors. He has also considerable experience related to industrial research and development, comprising: the development of algorithms for seismic signal processing applied in petroleum industry (Shell Company, 1987); the algorithms for optical performance monitoring of telecommunication channels (Bookham Technology, 2001); the algorithms of spectrometric data processing for analytical spectrophotometry (Measurement Microsystems, 1998-2008). Since 2014 he has been involved in the projects concerning healthcare-oriented monitoring of elderly persons.

Contenu

1. Introduction to healthcare-oriented monitoring of persons1.1. Objectives of healthcare-oriented monitoring

1.2. Systems for healthcare-oriented monitoring

1.2.1. Monitoring techniques

1.2.2. Commercially available monitoring systems

1.3. Semantic and mathematical modelling of monitoring systems

1.3.1. Semantic modelling of monitoring systems

1.3.2. Mathematical modelling of monitoring systems

1.4. Overview of measurement-data processing in healthcare-oriented monitoring systems

1.4.1. Localisation of persons by means of impulse-radar sensors

1.4.2. Localisation of persons by means of depth sensors

1.4.3. Denoising and differentiation of persons' movement trajectories

1.4.4. Fusion and postprocessing of data from impulse-radar sensors and depth sensors

2. Localisation of persons by means of impulse-radar sensors - basic methods

2.1. Methods for extraction of signal from impulse-radar data

2.1.1. Mathematical model of impulse-radar data

2.1.2. Method based on arithmetic averaging

2.1.3. Method based on exponential averaging

2.1.4. Method based on singular-value decomposition

2.2. Methods for estimation of impulse-radar signal parameters

2.2.1. Mathematical model of impulse-radar data

2.2.2. Method based on time-domain template matching

2.2.3. Method based on frequency-domain template matching

2.2.4. Method based on maximum-envelope matching

2.3. Methods for estimation of two-dimensional trajectories 2.3.1. Methods for smoothing of distance trajectories

2.3.2. Methods for conversion of two distance trajectories into movement trajectory

2.4. Chapter conclusions

3. Localisation of persons by means of impulse-radar sensors - advanced methods

3.1. Principles of Bayesian inference

3.1.1. Bayesian methods for measurand reconstruction

3.1.2. Key role of a priori information

3.1.3. Recent applications of Bayesian inference in data processing

3.2. Extraction of signal from impulse-radar data 3.2.1. Method #1

3.2.2. Method #2 3.2.3. Method #3

3.3. Estimation of impulse-radar signal parameters

3.3.1. Dealing with varying number of echoes

3.3.2. Dealing with fixed number of echoes

3.4. Estimation of two-dimensional trajectories

3.4.1. Smoothing of distance trajectories

3.4.2. Conversion of two distance trajectories into movement trajectory

4. Localisation of persons by means of impulse-radar sensors - comparison of methods

4.1. Extraction of signal from impulse-radar data

4.1.1. Methodology of numerical experimentation based on semi-synthetic data

4.1.2. Numerical experiments based on semi-synthetic data 4.1.3. Numerical experiments based on real-world data

4.1.4. Section conclusions

4.2. Estimation of impulse-radar signal parameters

4.2.1. Methodology of numerical experimentation based on semi-synthetic data

4.2.2. Numerical experiments based on semi-synthetic data

4.2.3. Methodology of numerical experimentation based on real-world data

4.2.4. Numerical experiments based on real-world data 4.2.5. Section conclusions

4.3. Estimation of two-dimensional trajectories

4.3.1. Methodology of numerical experimentation based on real-world data

4.3.2. Numerical experiments based on real-world data

4.3.3. Section conclusions

5. Denoising and differentiat…