A time frequency representations of speech signals based on a modeling of the auditory system: the gammagrams

In this paper we present a study of the temporal and spectral human auditory masking phenomena for speech signal analysis. For the purpose of modeling these masking phenomena, we used a gammachirp filterbank [T. Irino and M. Unoki, Nov. 1999], [T. Irino, 1999] to model the spectral masking and a temporal window to model the temporal masking. A global model combining these two models was built for a spectro-temporal representation. We performed a comparison of two types of spectro-temporal representations called gammagrams. The first one is based only on a gammachirp filterbank and the second is based on the global model. In addition, we performed some series of tests on different speech signals for establishing examples of masking effect curves.