Particle Filter based Speaker Tracking in Distributed Pairwise Microphone Networks

The particle filter (PF) algorithm is appropriate to solve the problem of speaker tracking in a reverberant and noisy environment using distributed pairwise microphone networks. First, complete the tracking task based on PF algorithm in centralized manner, a processing center is required to collect the signal from all microphones to carry out...

Inferring the location of reflecting surfaces from acoustic measurements: Using a compact microphone array collocated with a loudspeaker

The response of a sound system in a room primarily varies with the room itself, the position of the loudspeakers and the listening position. The room boundaries cause reflections of the sound that can lead to undesired effects such as echoes, resonances or reverberation. Knowledge of the location of these large reflecting surfaces can help to...

Privacy-preserving consensus averaging

Consensus problem has been a topic of interest for many research areas allowing multiple agents to reach an agreement through local information exchange. The explicit share of the state variables, however, may cause privacy issues due to the confidentiality of the initial values. In this work, asynchronous privacy-preserving consensus average...

Face recognition using traditional machine learning algorithms and deep neural networks with application to face verification

Biometrics authentication has been very useful and necessary nowadays due to the great developments in technology and the transaction of huge amounts of sensitive data on a daily basis. Traditionally, access to some data or service is achieved by means of some documents or a password. However, these methods are not very convenient. Alternatively...

On speech enhancement in very low SNRs for smart speakers

Human interaction with a smart speaker involves often distant automatic speech recognition (ASR). However, ASR is a rather cumbersome task at significantly high levels of noise. Most of commercial smart speakers in order to achieve high ASR accuracy they tend to reduce the playback signal once the preset keyword is detected. In an effort to...

Room Geometry Estimation from Acoustic Echoes

Estimating a room geometry using multiple microphones rises an echoes labeling problem. Two recent methods called the graph-based and the subspace-greedy methods have shown their capability in solving this problem. The graph-based method attains a good accuracy but suffers in maintaining the computational cost when the number of microphones is...

Inexact distributed optimization schemes: A convergence analysis using monotone operator theory

Distributed optimization has been an <br/>extensively studied field for years. Recent developments in the area of sensors makes it possible to create networks consisting of a large number of nodes. The focus of this thesis will be optimizing distributed problems over a decentralized network. These distributed optimization schemes operate in an...

Physical Activity Recognition using Wearable Accelerometers in Controlled and Free-Living Environments

Physical activity recognition through wearables has enabled the development of novel applications in healthcare. Most of the existing studies focus on predicting activities using wearable sensors, either in a controlled or uncontrolled environment. However, there is not a clear distinction between these two environments. Hence, this thesis aimed...

Clock-Offset Invariant Beamforming in Wireless Acoustic Sensor Networks: A Generalized Eigenvalue Decomposition Approach

Clock synchronization among the nodes of a wireless acoustic sensor network (WASN) is a significant issue that affects the performance of multi-channel noise reduction schemes. Since independent sensors are utilized, each accompanied by its internal clock, clock offsets are inevitable, even if the mismatch in the sampling frequencies is...

Estimation of Internal Delays

In this thesis report, the design of the estimation of internal delays within speakers and microphones will be covered. The estimation is done via an iterational algorithm which converges to the different delays. The design choice of the estimation of those delays follows from an initial attempt to improve synchronization of the Bosch DICENTIS...

Acoustic TDOA Propagation Time Estimation

In this report, the design of a subsystem within a localization system for the Bosch DICENTIS wireless conference system will be presented. The localization system will function by means of using acoustic Time Difference Of Arrival (TDOA) measurements to determine the location of each unit connected to the DICENTIS conference system. By unit,...