No abstract

The Chirplet Transform (CT) is effective in the characterization of IF for mono-component linear-frequency-modulated signal. However, During the initialization process, using the peak of the time-frequency map of the short-time Fourier transform to fit the line is greatly affected by noise. For the multi-component signals, it is more difficult to distinguish and fit different IF lines. Since the Hough is good at a common algorithm for the line detection, the ridge edge fitting is replaced by the Hough transform in this paper. The experiment results show significant improvement in the obtained time-frequency representation.

Direction of arrival algorithms which exploit the eigenstructure of the spatial covariance matrix (such as MUSIC) encounter difficulties in the presence of strongly correlated sources. Since the broadband polynomial MUSIC is an extension of the narrowband version, it is unsurprising that the same issues arise. In this paper, we extend the spatial smoothing technique to broadband scenarios via spatially averaging polynomial space-time covariance matrices. This is shown to restore the rank of the polynomial source covariance matrix. In the application of the polynomial MUSIC algorithm, the spatially smoothed space-time covariance matrix greatly enhances the direction of arrival estimate in the presence of strongly correlated sources. Simulation results are described shows the performance improvement gained using the new approach compared to the conventional non-smoothed method.

Two efficient techniques are proposed in this study for the multiple pitch estimation of polyphonic music. The partial magnitude rearrangement separates the overlapped partials into their possible pitches. The harmonic error can be corrected by harmonic relation confirmation. Random combinations of up to six notes at different pitches are analysed statically within one frame over the samples from 21 pitched instruments. The accuracy, efficiency, and robustness of the method using these two techniques are verified by three groups of experiments. The results show that the proposed techniques achieve a better balance between the higher accuracy and the lower computation cost.