Passive acoustic diver detection
Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
This report discusses a method to detect divers in harbour environments usingpassive acoustic detection. The goal was to achieve as high detection as possiblewithout having too high false alarm rate. A short execution time was also desirable.By using the characteristic of an inhalation a band-pass filter was applied to the signalto improve the signal to noise ratio. After the filtering an energy estimation of thesignal was made. This energy estimation was later used in a frequency analysis, whichcould tell us if there were enough energy in the frequencies that correspond to adivers breathing frequency. If this energy exceeds a threshold the detector decidesthat there is a diver in the water. To get an acceptable amount of false alarms, thethreshold was set so that the energy of the breathing frequencies had to exceed 5% ofthe energy in the frequencies above the breathing frequencies. Using this method onour data we found that the detector succeeded in finding the diver and didn’t give usany false alarms.
Place, publisher, year, edition, pages
Engineering and Technology
IdentifiersURN: urn:nbn:se:uu:diva-180360OAI: oai:DiVA.org:uu-180360DiVA: diva2:549586
Master Programme in Engineering Physics
Lundberg Nordenvaad, Magnus