Wavelet Soft-Thresholding of Time-Frequency Representations
Baraniuk, Richard G.
The high noise sensitivity of the Wigner distribution makes smoothing a necessity for producing readable time-frequency images of noise corrupted signals. Since linear smoothing suppresses noise at the expense of considerable smearing of the signal components, the author explores two nonlinear denoising techniques based on soft-thresholding in an orthonormal basis representation. Soft-thresholding provides considerable noise reduction without greatly impairing the time-frequency resolution of the denoised distribution.