C50 (factor of clearness) determines sound clearness and clarity. It is computed as near echo/far echo ratio. The method is based on the fact, that echo reduces signal intelligibility. The near echo/far echo ratios in several frequency bands are calculated. They consider near echo (less than 33 ms) as useful signal and far echo (more than 33 ms) as disturbing signal.
Disadvantage of the approach is that the factor of clearness takes into account only one kind of the possible distortions and it is worth to apply it only as one of the speech quality estimations.
So, as promised we would like to clarify what this and the previous posts were about… It seems it’s time to develop new methods and to improve existing ones and it is caused by desire to bring together objective and subjective estimation of quality and to explicitly use in quality of service (QoS) and quality of experience (QoE) systems the knowledge about hearing, human perception and speech production, and therefore the next post will be devoted to ITU standard P.862 also known as PESQ that stands for Perceptual Evaluation of Speech QualityContinue Reading →
Speech Intelligibility is not enough – let's go for speech transmission index! The truth is out there…
Today we would like to present two more methods to measure voice quality for example degraded by using a lossy…Continue Reading →
Referring to the previous post concerning AI (Articulation Index) approach to voice quality measurement we would like to present another…Continue Reading →
In the next couple of posts we will present existing approaches to measure voice quality automatically. This is an important…Continue Reading →
General outline and the basic components of the system – signal, synchronization and analytical components
Test signal (including statistic speech model) and sound perception models
Adequacy of analytical estimations based on the results of the comparison of received analytical and subjective MOS estimations
Acoustic model further developments
System applicationsContinue Reading →
HELSINKI, Finland – March 25, 2008 – Sevana Oy today announces the immediate availability of Vocoders Quality Analyzer 2.1, a…Continue Reading →