Analysis of multicomponent LFM signals using time-frequency and the gray-scale inverse hough transform

In this paper, the time-frequency distribution of multicomponent Linear-Frequency Modulation (LFM) signals, which is a function of two variables, has been treated as an "image". The gray-scale inverse Hough transform (GIHT), an image processing method, is applied for analyzing the "image". The time-frequency distribution (TFD) is computed from an optimally weighted average of multiple Hermite windowed spectrograms, which provides a better "image source" than the commonly used Wigner distribution and spectrogram for the later image analysis. By taking advantage of GIHT, more information in the time-frequency can be utilized and more accurate results have-been achieved. Several examples are provided to demonstrate and quantify the effectiveness and robustness of this method.