Fast Signal Reconstruction from Magnitude Spectrogram of Continuous Wavelet Transform based on Spectrogram Consistency

Contributors: Tomohiko Nakamura (The University of Tokyo) and Hirokazu Kameoka (The University of Tokyo/NTT Communication Science laboratories).

Demonstration of signal reconstruction

You will be aware of reconstructing the signal as same as the original signal iteration by iteration.

Original acoustic signal Magnitude CWT spectrogram with random phases Estimation results by the proposed algorithm
After 1 iterations
After 10 iterations
After 20 iterations
After 50 iterations
After 100 iterations

Demonstration of pitch tranposition

You can see that only shifting the complex CWT spectrogram is not enough to obtain the pitch-transposed signals, and the pitch transposition is realized by the proposed phase estimation.

Original acoustic signal Shifting complex CWT spectrogram Shifting magnitude CWT spectrogram and zero phases Shifting magnitude CWT spectrogram and estimated phases
Convert the original into low pitch
Convert the original into high pitch