Comparison of subjective and objective speech quality assessment for different degradation / noise conditions

Objective speech quality assessment is done to replace the time taking and cumbersome subjective listening test to assess the quality of degraded speech processed by different speech processing algorithms. For performance evaluation, all objective speech quality assessment algorithms require the Mean Opinion Score-Listening Quality Subjective (MOS-LQS) or subjective MOS obtained from the subjective listening test for comparison with the Mean Opinion Score-Listening Quality Objective (MOS-LQO) or objective MOS. This paper gives details of the subjective database created for the different applications. In this work, subjective speech quality assessment has been done for speech utterances at different degradation/noise conditions to assign the MOS-LQS or subjective MOS and compared with MOS-LQO or the objective MOS obtained from an algorithm based on relevant auditory perception features for an illustration. Two different databases NOIZEUS-960 and NOIZEUS-2240 having 3200 speech utterances processed by different speech enhancement algorithms at different types of real life noise conditions have been used for subjective listening test by real life users. The statistical analysis of the MOS-LQS assigned by different subjects for different degraded speech utterances has been done and its details are reported in the paper. Further, the correlation coefficients are computed between the subjective MOS and the objective MOS for both the databases for an illustration and inferences are drawn regarding the usefulness of the subjective MOS in speech quality assessment algorithms.