Using beamforming to maximise the detection capability of Kwintsheul’s seismic array

To run Nature’s Heat geothermal operations (Kwintsheul, The Netherlands) in a safe and efficient manner, and with the support of the local population, it is important to mitigate potential hazards. A well known potential hazard related to geothermal operations is the occurrence of induced seismicity due to injection and extraction of fluids in...

Null subtraction imaging for small aperture phased array transducers

In medical ultrasound imaging phased array transducers are used for non-invasive imaging. For 3D intra-cardiac-echography technical borders are reached since blood vessel size limits the dimensions of the array. This dimensional limitation lowers lateral resolution. To solve part of the problem, non conventional ways of lateral resolution...

Smartphone Audio Acquisition and Synchronization Using an Acoustic Beacon With Application to Beamforming

A time-domain (TD) and a frequency-domain (FD) method for time offset (TO) compensation between received audio data are presented and implemented on Android smartphones and a processing computer. Simulations show the TD method is superior in almost all applications. Real-life experiments show the TD synchronization error is below 6 samples. A...

Acoustic Enhancement via Beamforming using Smartphones

This thesis presents a comparison between two different beamforming algorithms, the delay-and-sum beamformer (DSB) and the minimum variance distortionless response (MVDR) beamformer using both objective and subjective metrics. Simulations and measurements have been performed on near-field scenarios with an ad-hoc microphone array. Microphones...

On Determining Smartphone Microphone Directivity with Application to Beamforming

An equiangular sampling scheme and accessory measurement set-up for determining the directivity gain pattern of a commercially available smartphone is presented. Determining this directivity gain pattern based on these measuremenents was not possible, because next to the impulse response of the microphone also the impulse response of the...

Verbetering van verstaanbaarheid in teleconferenties door het gebruik van beamformen

De verstaanbaarheid van de aanwezigen bij teleconferenties is minder dan bij gesprekken waarbij beide partijen zich in \'e\'en ruimte bevinden, aangezien stoorsignalen net zo goed worden opgenomen en verder de ruimtelijke informatie van de spraak verloren gaat. Een systeem werd ontworpen dat real-time bepaalt uit welke richting iemand spreekt,...

Two Sensor Array Beamforming Algorithm

Nowadays, noise reduction in mobile communication is an increasingly important topic. This thesis discusses the possibilities of using beamforming with a two microphone array for smartphone applications. The goal of the project is to realise a beamforming algorithm for smartphones to improve on current Signal to Noise ratios attained by standard...

Noise reduction application for Android smartphones

Noise reduction application for Android smartphones using a beamforming algorithm. Acquiring microphone signals, designing a user interface and hardware connectivity.