Subjective and Objective Assessment of Speech Quality

This Bachelor's thesis is focused on subjective and objective methods for evaluation of speech quality. In the first part, the quality of transmitted speech signal and its distorting effects are given. Futher, subjective and objective methods for evaluation of speech are described. The objective methods: Signal to Noise Ratio (SNR), Segmental Signal to Noise Ratio (SSNR), the methods for evaluation in spectral area (Log Likelihood Ratio Measures and Cepstral Distance) and also Perceptual Evaluation of Speech Quality (PESQ). The next part deals with the correlation analysis which is used for the comparison of subjective and objective methods. In the last part of the bachelor thesis the results of subjective and objective methods are presented. Finally on the basis of correlation analysis with the results of subjective method, the best objective method is recommended