New image processing methods and active photonics apparatus have made possible the development of... more New image processing methods and active photonics apparatus have made possible the development of relatively inexpensive optical systems for complex shape and object measurements. We present dynamic 360° scanning method for analysis of human lower body biomechanics, with an emphasis on the analysis of the knee joint. The anatomical structure (of high medical interest) that is possible to scan and
To reduce the amount of radiographs needed for patients with a scoliosis, a radiation-free method... more To reduce the amount of radiographs needed for patients with a scoliosis, a radiation-free method based on topographic images of the back was developed. An active contour model simulating spinal stiffness has been applied to video rasterstereographic (VRS) data. The aim of the present study is (a) to evaluate the applicability of active contours to improve the accuracy and the
Automated analysis of sleep apnea based on single-lead electrocardiogram would make screening and... more Automated analysis of sleep apnea based on single-lead electrocardiogram would make screening and diagnosis much more accessible. Over the years, several algorithms have been proposed in the literature. In most of them, one or several temporal averaging techniques are used to improve classifier performance. A comprehensive comparison between those techniques however has never been published. Four different temporal averaging techniques, as well as overlapping of segments, were independently assessed using a database of 70 night-time recordings, originally released for the Computers in Cardiology challenge in 2000. Classification was performed with an LDA classifier. Multiple problem-specific feature sets of 10 features were selected out of a complete set of 304 using a two-step approach. Averaging classifier input features over neighboring segments led to the highest agreement values on the test set, outperforming the best automatic entry during the original competition (90.4% vs 89...
Journal of Ambient Intelligence and Smart Environments
This study implements an algorithm for the autonomous control of spinal alignment during sleep by... more This study implements an algorithm for the autonomous control of spinal alignment during sleep by the active adjustment of mechanical bed characteristics according to the adopted sleep posture. Bed systems were used that allow active control of the mechanical stiffness in eight comfort zones by means of separately adjustable actuators. Mattress indentation measurements provide the input to detect body movement, recognize sleep posture, and --by combination with a subject specific human model --estimate spine shape. Comparison between the estimated spine shape and the desired shape results in new target values for the actuators. The control loop is repeated until the desired spine shape is reached. Results of overnight experiments revealed a significant improvement of spinal alignment during nights with active control of bed properties compared to a reference night without control. In addition, a significant improvement on subjectively perceived sleep quality was demonstrated after s...
Purpose of this study was to evaluate the reliability and validity of 4D rasterstereography under... more Purpose of this study was to evaluate the reliability and validity of 4D rasterstereography under dynamic conditions. Therefore simulated anatomical fixed points on a wooden plate were measured during different movements. Seven different motion patterns in all three angles of space were evaluated. The simulated parameter trunk length was measured with an accuracy of 3.58 mm (SD±3.29 mm) and the dimple distance was detected with an accuracy of 0.88 mm (SD±1.04 mm). With this rasterstereographic prototype it is possible to examine dynamically the spinal posture with adequate accuracy.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2014
Off-body detection of respiratory and cardiac activity presents an enormous opportunity for gener... more Off-body detection of respiratory and cardiac activity presents an enormous opportunity for general health, stress and sleep quality monitoring. The presented setup detects the mechanical activity of both heart and lungs by measuring pressure difference fluctuations between two air volumes underneath the chest area of the subject. The registered signals were characterized over four different sleep postures, three different base air pressures within the air volumes and three different mattress top layer materials. Highest signal strength was detected in prone posture for both the respiratory and heart beat signal. Respiratory signal strength was the lowest in supine posture, while heart beat signal strength was lowest for right lateral. Heart beat cycle variability was highest in prone and lowest in supine posture. Increasing the base air pressure caused a reduction in signal amplitude for both the respiratory and the heart beat signal. A visco-elastic poly-urethane foam top layer ha...
The sleep system (i.e. the combination of mattress and bed base) is an important factor of the sl... more The sleep system (i.e. the combination of mattress and bed base) is an important factor of the sleep environment since it allows physical recuperation during sleep by providing proper body support. However, various factors influence the interaction between the human body and the sleep system. Contributing factors include body dimensions, distribution of body weight and stiffness of the sleep system across the mattress surface. During the past decade, the rise of several new bedding technologies has made it increasingly difficult for the consumer to select a proper sleep system. Therefore, this study presents a method to model human-bed interaction in order to objectively predict the ideal sleep system for a particular individual. The proposed method combines a personalized anthropometric model with standardized load-deflection characteristics of mattress and bed base. Results for lateral sleep positions show a root mean square deviation of 11.9 ± 6.1 mm between modeled spine shapes ...
Advanced Biomedical and Clinical Diagnostic Systems VI, 2008
The recent development of electro-optical instrumentation allowed constructing 4D (3D+ time) stru... more The recent development of electro-optical instrumentation allowed constructing 4D (3D+ time) structure-light scanners which may be used to measure the surface of human body in motion. The main advantage of structure-light scanners is the possibility of capturing data ...
Abstract. This paper presents a novel measuring system for the detec-tion of moving skeletal stru... more Abstract. This paper presents a novel measuring system for the detec-tion of moving skeletal structures. The system uses white light raster line triangulation in combination with biomechanical modeling techniques. White light raster line triangulation visualizes surfaces (eg the back ...
New image processing methods and active photonics apparatus have made possible the development of... more New image processing methods and active photonics apparatus have made possible the development of relatively inexpensive optical systems for complex shape and object measurements. We present dynamic 360° scanning method for analysis of human lower body biomechanics, with an emphasis on the analysis of the knee joint. The anatomical structure (of high medical interest) that is possible to scan and
Orthopedics and neurosciences are fields of medicine where the analysis of objective movement par... more Orthopedics and neurosciences are fields of medicine where the analysis of objective movement parameters is extremely important for clinical diagnosis. Moreover, as there are significant differences between static and dynamic parameters, there is a strong need of analyzing the ...
New image processing methods and active photonics apparatus have made possible the development of... more New image processing methods and active photonics apparatus have made possible the development of relatively inexpensive optical systems for complex shape and object measurements. We present dynamic 360° scanning method for analysis of human lower body biomechanics, with an emphasis on the analysis of the knee joint. The anatomical structure (of high medical interest) that is possible to scan and
To reduce the amount of radiographs needed for patients with a scoliosis, a radiation-free method... more To reduce the amount of radiographs needed for patients with a scoliosis, a radiation-free method based on topographic images of the back was developed. An active contour model simulating spinal stiffness has been applied to video rasterstereographic (VRS) data. The aim of the present study is (a) to evaluate the applicability of active contours to improve the accuracy and the
Automated analysis of sleep apnea based on single-lead electrocardiogram would make screening and... more Automated analysis of sleep apnea based on single-lead electrocardiogram would make screening and diagnosis much more accessible. Over the years, several algorithms have been proposed in the literature. In most of them, one or several temporal averaging techniques are used to improve classifier performance. A comprehensive comparison between those techniques however has never been published. Four different temporal averaging techniques, as well as overlapping of segments, were independently assessed using a database of 70 night-time recordings, originally released for the Computers in Cardiology challenge in 2000. Classification was performed with an LDA classifier. Multiple problem-specific feature sets of 10 features were selected out of a complete set of 304 using a two-step approach. Averaging classifier input features over neighboring segments led to the highest agreement values on the test set, outperforming the best automatic entry during the original competition (90.4% vs 89...
Journal of Ambient Intelligence and Smart Environments
This study implements an algorithm for the autonomous control of spinal alignment during sleep by... more This study implements an algorithm for the autonomous control of spinal alignment during sleep by the active adjustment of mechanical bed characteristics according to the adopted sleep posture. Bed systems were used that allow active control of the mechanical stiffness in eight comfort zones by means of separately adjustable actuators. Mattress indentation measurements provide the input to detect body movement, recognize sleep posture, and --by combination with a subject specific human model --estimate spine shape. Comparison between the estimated spine shape and the desired shape results in new target values for the actuators. The control loop is repeated until the desired spine shape is reached. Results of overnight experiments revealed a significant improvement of spinal alignment during nights with active control of bed properties compared to a reference night without control. In addition, a significant improvement on subjectively perceived sleep quality was demonstrated after s...
Purpose of this study was to evaluate the reliability and validity of 4D rasterstereography under... more Purpose of this study was to evaluate the reliability and validity of 4D rasterstereography under dynamic conditions. Therefore simulated anatomical fixed points on a wooden plate were measured during different movements. Seven different motion patterns in all three angles of space were evaluated. The simulated parameter trunk length was measured with an accuracy of 3.58 mm (SD±3.29 mm) and the dimple distance was detected with an accuracy of 0.88 mm (SD±1.04 mm). With this rasterstereographic prototype it is possible to examine dynamically the spinal posture with adequate accuracy.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2014
Off-body detection of respiratory and cardiac activity presents an enormous opportunity for gener... more Off-body detection of respiratory and cardiac activity presents an enormous opportunity for general health, stress and sleep quality monitoring. The presented setup detects the mechanical activity of both heart and lungs by measuring pressure difference fluctuations between two air volumes underneath the chest area of the subject. The registered signals were characterized over four different sleep postures, three different base air pressures within the air volumes and three different mattress top layer materials. Highest signal strength was detected in prone posture for both the respiratory and heart beat signal. Respiratory signal strength was the lowest in supine posture, while heart beat signal strength was lowest for right lateral. Heart beat cycle variability was highest in prone and lowest in supine posture. Increasing the base air pressure caused a reduction in signal amplitude for both the respiratory and the heart beat signal. A visco-elastic poly-urethane foam top layer ha...
The sleep system (i.e. the combination of mattress and bed base) is an important factor of the sl... more The sleep system (i.e. the combination of mattress and bed base) is an important factor of the sleep environment since it allows physical recuperation during sleep by providing proper body support. However, various factors influence the interaction between the human body and the sleep system. Contributing factors include body dimensions, distribution of body weight and stiffness of the sleep system across the mattress surface. During the past decade, the rise of several new bedding technologies has made it increasingly difficult for the consumer to select a proper sleep system. Therefore, this study presents a method to model human-bed interaction in order to objectively predict the ideal sleep system for a particular individual. The proposed method combines a personalized anthropometric model with standardized load-deflection characteristics of mattress and bed base. Results for lateral sleep positions show a root mean square deviation of 11.9 ± 6.1 mm between modeled spine shapes ...
Advanced Biomedical and Clinical Diagnostic Systems VI, 2008
The recent development of electro-optical instrumentation allowed constructing 4D (3D+ time) stru... more The recent development of electro-optical instrumentation allowed constructing 4D (3D+ time) structure-light scanners which may be used to measure the surface of human body in motion. The main advantage of structure-light scanners is the possibility of capturing data ...
Abstract. This paper presents a novel measuring system for the detec-tion of moving skeletal stru... more Abstract. This paper presents a novel measuring system for the detec-tion of moving skeletal structures. The system uses white light raster line triangulation in combination with biomechanical modeling techniques. White light raster line triangulation visualizes surfaces (eg the back ...
New image processing methods and active photonics apparatus have made possible the development of... more New image processing methods and active photonics apparatus have made possible the development of relatively inexpensive optical systems for complex shape and object measurements. We present dynamic 360° scanning method for analysis of human lower body biomechanics, with an emphasis on the analysis of the knee joint. The anatomical structure (of high medical interest) that is possible to scan and
Orthopedics and neurosciences are fields of medicine where the analysis of objective movement par... more Orthopedics and neurosciences are fields of medicine where the analysis of objective movement parameters is extremely important for clinical diagnosis. Moreover, as there are significant differences between static and dynamic parameters, there is a strong need of analyzing the ...
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Papers by Bart Haex