Android based noise measurement

OData support
Dr. Márki Ferenc
Department of Networked Systems and Services

Due to the fast technological developments, we can do an increasing number of activi-ties with our mobile phones. While ten years ago several of these tasks or activities re-quired, a computer or a dedicated device, a mobile phone is perfectly enough for them.

My thesis is closely linked to this reality as it deals with the topic of noise measurement by mobile phone. I present the MEMS microphone which is the typical microphone of the mobile phones and I describe the typical features and measurable parameters of this kind of microphone. Among these parameters I dealt more deeply with the frequency response of the microphones, because one of my goal was to compensate this. I made an inverse filter design algorithm for the compensation, which equates the frequency re-sponse within certain limits. Another purpose of the algorithm is to provide an input to a measuring application that can use the calculated filters to perform more accurate meas-urements. I describe the implementation of this application in the other half of my thesis for which I chose the Android platform. I present the structure and the functions of the application I designed, along with necessary Android-specific knowledge. I explain the sound recording possibilities, then follow up the steps of the signal processing while I also introduce the relevant acoustic measurements and calculations. Finally, I finish my thesis with the workflow of the phone calibration and with further development oppor-tunities.


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