@InProceedings{Kroschel2018_423,
author = {Kristian Kroschel and Jürgen Metzler},
booktitle = {Studientexte zur Sprachkommunikation: Elektronische Sprachsignalverarbeitung 2018},
title = {Contactless Measurement of the Respiration Frequency by Vibrometry},
year = {2018},
editor = {André Berton and Udo Haiber and Wolfgang Minker},
month = mar,
pages = {310--317},
publisher = {TUDpress, Dresden},
abstract = {The respiration frequency is currently measured by devices which need
the contact with the body of the client. For burnt clients, premature infants and
people with a contagious desease techniques with remote sensing are required. A
very promising approach is based on vibrometry with infrared lasers.
The respiration frequency of adults ranges from 8/min up to 35/min including phy-
sical stress. The raw vibrometry signal includes besides respiration also cardiac
activity and the influence of the movement of the client. Therefore a low-pass filter
separates the respiration component from the others.
Since the calculation of the respiration frequency requires processing time and there
is the demand of continuous monitoring of the frequency the filtered data are cut into
blocks, each 20 ms long. These data blocks are overlapping by 19 ms so that every
second a new value of the respiration frequency is displayed. For the calculation
of the respiration frequency three methods are discussed. The first one is based
on the fast Fourier transform (FFT), the second one exploits the properties of the
auto-correlation function and the third one is based on the zero-crossings of the
respiration signal.
Generally the vibrometer signal can be picked up on the thorax, the neck or the
forehead. The quality of the signal depends on the measuring point. Therefore the
vibrometer is directed by a pan-tilt unit to the optimal measuring point. The criterion
of optimalty depends on parameters of the correlation function calculated from the
data block and is used to control the pan-tilt unit.
Currently the new method is planned for application and test in a hospital.},
isbn = {978-3-959081-28-3},
issn = {0940-6832},
keywords = {Signal Processing in Health and Music},
url = {https://www.essv.de/pdf/pdf/2018_310_317.pdf},
}