Tracheal Sound Acquisition Using Laser Doppler Vibrometer

Breathing is vital for human life. Respiratory diseases cause more than one million deaths annually. The sound of breathing activity can be used to assess the state of the lungs and detect adverse problems involving respiratory failure. Traditionally, mechanical stethoscopes are used for respiratory auscultation to analyse the lung sounds. Firstly, measurements are carried out on five different standard stethoscopes to assess their reliability for detecting respiratory sounds in people. Secondly, three human subjects were used for tracheal sound experiments using five stethoscopes. Thirdly, a laser doppler vibrometer was used to detect tracheal sounds on three human subjects. Five stethoscopes used for measurements give different results especially above 150 Hz. Experimental results show that mechanical stethoscopes are not reliable tools for assessing lungs sounds in people.