Enhancing the Resolution of the Spectrogram Based on a Simple Adaptation Procedure

This work is concerned with improving the quality of signal localization for the short-time Fourier transform by properly adjusting the size of its analysis window over time. The adaptation procedure involves the estimation of an area in the time-frequency plane which is more compact than the support of the fixed-window spectrogram. Then, at each time instant, the optimal window is selected such that the signal energy is maximized within the identified area. The proposed method achieves its objectives, and can compare favorably with alternative time-adaptive spectrograms as well as with advanced quadratic representations.