Segregation of concurrent speech with the reassigned spectrum

Modulation maps provide an effective method for the segregation of voiced speech sounds from competing background activity. The maps are constructed by computing modulation spectra in a bank of auditory filters. If the modulation spectra are computed using a conventional DFT, windows of 200 ms duration are necessary. The reassigned spectrum, a new time frequency representation (Kodera et al., 1978, and Auger and Flandrin, 1995), allows a reduction in the window size to 50 ms without loss of performance. The algorithm is tested on a `double vowel´ identification task that has been used extensively in psychophysical experiments