|
|
Multi-channel Methods of Speech Enhancement
Zitka, Adam ; Balík, Miroslav (referee) ; Smékal, Zdeněk (advisor)
This thesis deals with multi-channel methods of speech enhancement. Multichannel methods of speech enhancement use a few microphones for recording signals. From mixtures of signals, for example, individual speakers can be separated, noise should be reduced etc. with using neural networks. The task of separating speakers is known as a cocktail-party effect. The main method of solving this problem is called independent component analysis. At first there are described its theoretical foundation and presented conditions and requirements for its application. Methods of ICA try to separate the mixtures with help of searching the minimal gaussian properties of signals. For the analysis of independent components are used different mathematical properties of signals such as kurtosis and entropy. Signals, which were mixed artificially on a computer, can be relatively well separated using, for example, FastICA algorithm or ICA gradient ascent. However, difficult is situation, if we want to separate the signals created in the real recording enviroment, because the separation of speech people speaking at the same time in the real environment affects other various factors such as acoustic properties of the room, noise, delays, reflections from the walls, the position or the type of microphones, etc. Work presents aproach of independent component analysis in the frequency domain, which can successfully separate also recordings made in the real environment.
|
|
|
Implemetation of algorithms for blind source separation in C/C++ language
Funderák, Marcel ; Malý, Jan (referee) ; Míča, Ivan (advisor)
This thesis is describing one of the methods of Blind Source Separation (BSS) which is Independent Component Analysis. There is shown some brief introduction to the theory behind in which there are explained some basic findings. These findings are important for understanding the theory behind algorithms of ICA. These theoretical findings include primarily explanations of basic knowledge of statistics science. In next part there are described methods which are advisable for preprocessing of input signals – mainly Principal Component Analysis (PCA) and whitening of signals. Mainly whitening is very important part of solution of ICA algorithms. Then there are described different ICA algorithm solutions and especially introduction in this problematic. FastICA algorithm description is mainly depicted because it is very good for computer processing since it is strong and it is less computer demanding than other algorithms. After that follows implementation of one of the ICA algorithm in C++ programming language. FastICA algorithm for complex valued signal was chosen.
|
|
|
Implemetation of algorithms for blind source separation in C/C++ language
Funderák, Marcel ; Malý, Jan (referee) ; Míča, Ivan (advisor)
This thesis is describing one of the methods of Blind Source Separation (BSS) which is Independent Component Analysis. There is shown some brief introduction to the theory behind in which there are explained some basic findings. These findings are important for understanding the theory behind algorithms of ICA. These theoretical findings include primarily explanations of basic knowledge of statistics science. In next part there are described methods which are advisable for preprocessing of input signals – mainly Principal Component Analysis (PCA) and whitening of signals. Mainly whitening is very important part of solution of ICA algorithms. Then there are described different ICA algorithm solutions and especially introduction in this problematic. FastICA algorithm description is mainly depicted because it is very good for computer processing since it is strong and it is less computer demanding than other algorithms. After that follows implementation of one of the ICA algorithm in C++ programming language. FastICA algorithm for complex valued signal was chosen.
|
|
|
Multi-channel Methods of Speech Enhancement
Zitka, Adam ; Balík, Miroslav (referee) ; Smékal, Zdeněk (advisor)
This thesis deals with multi-channel methods of speech enhancement. Multichannel methods of speech enhancement use a few microphones for recording signals. From mixtures of signals, for example, individual speakers can be separated, noise should be reduced etc. with using neural networks. The task of separating speakers is known as a cocktail-party effect. The main method of solving this problem is called independent component analysis. At first there are described its theoretical foundation and presented conditions and requirements for its application. Methods of ICA try to separate the mixtures with help of searching the minimal gaussian properties of signals. For the analysis of independent components are used different mathematical properties of signals such as kurtosis and entropy. Signals, which were mixed artificially on a computer, can be relatively well separated using, for example, FastICA algorithm or ICA gradient ascent. However, difficult is situation, if we want to separate the signals created in the real recording enviroment, because the separation of speech people speaking at the same time in the real environment affects other various factors such as acoustic properties of the room, noise, delays, reflections from the walls, the position or the type of microphones, etc. Work presents aproach of independent component analysis in the frequency domain, which can successfully separate also recordings made in the real environment.
|
guest ::
