Adaptive enhancement of Fourier spectra

An adaptive enhancement procedure is presented which emphasizes continuant spectral features such as formant frequencies, by imposing frequency and amplitude continuity constraints on a short-time Fourier representation of the speech signal. At each point in the time-frequency field, the direction of maximum energy correlation is determined by the angle of a linear window at which the energy density within it is closest in magnitude to the point under consideration. Weighted smoothing is then performed in that direction to enhance continuant features.