B. Haex - Academia.edu (original) (raw)

Papers by B. Haex

Research paper thumbnail of <title>Surface shape parameters and analysis of data captured with use of 4D surface scanners</title>

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 ...

Research paper thumbnail of <title>4D measurement system for automatic location of anatomical structures</title>

Biophotonics and New Therapy Frontiers, 2006

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 ...

Research paper thumbnail of A new test set-up for skull fracture characterisation

Journal of Biomechanics, 2007

Skull fracture is a frequently observed type of severe head injury. Historically, a variety of im... more Skull fracture is a frequently observed type of severe head injury. Historically, a variety of impact test set-ups and techniques have been used for investigating skull fracture. The most frequently used are the free-fall technique, the guided fall or drop tower set-up and the piston-driven impactor set-up. This document proposes a new type of set-up for cadaver head impact testing which combines the strengths of the most frequently used techniques and devices. The set-up consists of two pendulums, which allow for a 1 degree of freedom rotational motion. The first pendulum is the impactor and is used to strike the blow. The head is attached to the second pendulum using a polyester resin. Local skull deformation and impact force are measured with a sample frequency of 65 kHz. From these data, absorbed energy until skull fracture is calculated. A set-up evaluation consisting of 14 frontal skull and head impact tests shows an accurate measurement of both force and local skull deformation until fracture of the skull. Simplified mechanical models are used to analyse the different impacting techniques from literature as well as the new proposed set-up. It is concluded that the proposed test set-up is able to accurately calculate the energy absorbed by the skull until fracture with an uncertainty interval of 10%. Second, it is concluded that skull fracture caused by blunt impact occurs before any significant motion of the head. The two-pendulum set-up is the first head impact device to allow a well-controlled measurement environment without altering the skull stress distribution. r

Research paper thumbnail of Evaluation of newly developed algorithms for calculating anatomical landmarks from surface contours on the lower extremities

Journal of Biomechanics, 2006

Research paper thumbnail of Lipoatrophia semicircularis and the relation with office work

Applied Ergonomics, 1999

The relation between lipoatrophia semicircularis (LS--band-like circular depressions and isolated... more The relation between lipoatrophia semicircularis (LS--band-like circular depressions and isolated atrophy of the subcutaneous fatty tissue on the anterior thighs and sitting posture or pressure on the seat surface of office chairs was investigated in an office environment. A questionnaire was presented to 21 subjects and electromyographic measurements, video analysis and pressure measurements were performed. Remarkable posture differences between the LS group and the group without LS were found: less use of the lumbar support of the chair, static sitting postures and a too high seat surface of the office chair were characteristics of the subjects with LS. These observations were confirmed by higher pressure measurements for the subjects with LS. In addition, highly significant pressure differences were found between different chairs.

Research paper thumbnail of Customized sleeping systems

Proceedings of the …, 2005

KULeuven. ...

Research paper thumbnail of Dynamic contact-free acquisition of anatomical structures of the lower body

Proceedings of the …, 2005

KULeuven. ...

Research paper thumbnail of An anthropometrics-based design assistant for the development of optimized sleeping systems

Proceedings of the …, 2003

KULeuven. ...

Research paper thumbnail of Smart control of spinal alignment through active adjustment of mechanical bed properties during sleep

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...

Research paper thumbnail of <title>Surface shape parameters and analysis of data captured with use of 4D surface scanners</title>

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 ...

Research paper thumbnail of <title>4D measurement system for automatic location of anatomical structures</title>

Biophotonics and New Therapy Frontiers, 2006

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 ...

Research paper thumbnail of A new test set-up for skull fracture characterisation

Journal of Biomechanics, 2007

Skull fracture is a frequently observed type of severe head injury. Historically, a variety of im... more Skull fracture is a frequently observed type of severe head injury. Historically, a variety of impact test set-ups and techniques have been used for investigating skull fracture. The most frequently used are the free-fall technique, the guided fall or drop tower set-up and the piston-driven impactor set-up. This document proposes a new type of set-up for cadaver head impact testing which combines the strengths of the most frequently used techniques and devices. The set-up consists of two pendulums, which allow for a 1 degree of freedom rotational motion. The first pendulum is the impactor and is used to strike the blow. The head is attached to the second pendulum using a polyester resin. Local skull deformation and impact force are measured with a sample frequency of 65 kHz. From these data, absorbed energy until skull fracture is calculated. A set-up evaluation consisting of 14 frontal skull and head impact tests shows an accurate measurement of both force and local skull deformation until fracture of the skull. Simplified mechanical models are used to analyse the different impacting techniques from literature as well as the new proposed set-up. It is concluded that the proposed test set-up is able to accurately calculate the energy absorbed by the skull until fracture with an uncertainty interval of 10%. Second, it is concluded that skull fracture caused by blunt impact occurs before any significant motion of the head. The two-pendulum set-up is the first head impact device to allow a well-controlled measurement environment without altering the skull stress distribution. r

Research paper thumbnail of Evaluation of newly developed algorithms for calculating anatomical landmarks from surface contours on the lower extremities

Journal of Biomechanics, 2006

Research paper thumbnail of Lipoatrophia semicircularis and the relation with office work

Applied Ergonomics, 1999

The relation between lipoatrophia semicircularis (LS--band-like circular depressions and isolated... more The relation between lipoatrophia semicircularis (LS--band-like circular depressions and isolated atrophy of the subcutaneous fatty tissue on the anterior thighs and sitting posture or pressure on the seat surface of office chairs was investigated in an office environment. A questionnaire was presented to 21 subjects and electromyographic measurements, video analysis and pressure measurements were performed. Remarkable posture differences between the LS group and the group without LS were found: less use of the lumbar support of the chair, static sitting postures and a too high seat surface of the office chair were characteristics of the subjects with LS. These observations were confirmed by higher pressure measurements for the subjects with LS. In addition, highly significant pressure differences were found between different chairs.

Research paper thumbnail of Customized sleeping systems

Proceedings of the …, 2005

KULeuven. ...

Research paper thumbnail of Dynamic contact-free acquisition of anatomical structures of the lower body

Proceedings of the …, 2005

KULeuven. ...

Research paper thumbnail of An anthropometrics-based design assistant for the development of optimized sleeping systems

Proceedings of the …, 2003

KULeuven. ...

Research paper thumbnail of Smart control of spinal alignment through active adjustment of mechanical bed properties during sleep

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...