Rafal Samborski

Monitoring of the condition of the fetus, early detection of its threats and correct response to these threats are the basic tasks of modern prena- tal medicine. Decision-making implies serious health effects and should therefore be based on the most accu- rate clinical data and results of possi- bly objective measures. With the con- tinuous develo...

Playback attacks constitute one of the biggest threats in biometric speaker verification systems, in which a previously recorded passphrase is played back by an unprivileged person in order to gain access. This paper features a description of the playback attack detection (PAD) algorithm, designed to protect text-dependent speaker verification syst...

Some of existing conference system employ a distant microphone array instead of microphones dedicated for each user. This approach is much more convenient although suffers from much higher noise sensitivity. One of the possible solutions is employing beamforming techniques to focus on the user that is speaking at the moment. However, beamformer nee...

In this paper filer-based model of sound propagation combined with a model of multimicrophone array is presented. Simple operations employed in the model such as sum and linear convolution allows one to implement it easily using numerical methods. Additionally, described solution was discussed in connection with filter-based model of multimicrophon...

The paper presents successful experiments on combining two speaker recognition methods into a hybrid system. The �rst branch of recognition is an innovative approach based on discrete wavelet-Fourier transform. The second one is classic, based on HTK and classi�cation into voice and unvoice segments. The hybrid solution outperforms both on a small...

This paper suggests a speech enhancement approach to an eavesdropping audio system. Speech signal is disturbed by non-stochastic noise. The algorithm is based on recordings from dual-microphone system. The Wiener filter was applied for speech extraction. The algorithm is designed to capture dialogues in noisy environment as well. It uses the small...

This paper presents two different methods of speech ex-traction: cross-correlation analysis and adaptive filtering. Algorithms are designed to extract conversations in noisy environment. Such situations can appear in police inves-tigations' materials or multi-speaker environment. Noise can be added intentionally by suspects or not intentionally (e....

This paper presents a model of a system which is able to support Police investigations. The listening in system acquires audio signals from two microphones located around one meter to each other. System is designed to record suspect conversations under disadvantageous conditions like the loud music or the car machine noise. The presented method use...