DCTNet and PCANet for acoustic signal feature extraction
This work addresses signal processing problems like underwater acoustics, but it is incremental as it adapts an existing method (PCANet) with a known approximation (DCT).
The paper tackled acoustic signal classification by introducing DCTNet as an efficient alternative to PCANet, showing improved classification rates on whale vocalization data.
We introduce the use of DCTNet, an efficient approximation and alternative to PCANet, for acoustic signal classification. In PCANet, the eigenfunctions of the local sample covariance matrix (PCA) are used as filterbanks for convolution and feature extraction. When the eigenfunctions are well approximated by the Discrete Cosine Transform (DCT) functions, each layer of of PCANet and DCTNet is essentially a time-frequency representation. We relate DCTNet to spectral feature representation methods, such as the the short time Fourier transform (STFT), spectrogram and linear frequency spectral coefficients (LFSC). Experimental results on whale vocalization data show that DCTNet improves classification rate, demonstrating DCTNet's applicability to signal processing problems such as underwater acoustics.