On time-frequency correlation in spectrogram samples with application to target detection

This paper investigates the time-frequency correlation of spectrogram samples when overlapping windows are considered in the computation of the short-time Fourier transform (STFT). Specifically, a general closed-form formula is derived and its properties analyzed. Moreover, the practical usefulness is demonstrated on both simulated and real data, for the problem of small-drones detection based on FMCW radar. Results show that a pre-whitening filter compensating for the correlation can significantly improve the detection performance.