The modification of magnitude spectrograms is at the core of many audio signal processing methods, from source separation to sound modification or noise canceling, and reconstructing a natural sounding signal in such situations is thus a very important issue. This article presents recent theoretical and experimental developments on the application to signal reconstruction from a modified magnitude spectrogram of the constraints that an array of complex numbers must verify to be a consistent short-time Fourier transform (STFT) spectrogram, i.e., to be the STFT spectrogram of an actual real-valued signal. We give here further theoretical insights, present several potential variations on our previously introduced algorithm, investigate various techniques to speed up the signal reconstruction process, and present a thorough experimental comparison of the performance of all the considered algorithms.

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This paper describes a novel algorithm for recovering time-domain signal from quantized amplitude and phase spectrogram, which is applicable for spectrogram-based audio coding. In order to obtain a better quality sound, a phase reconstruction technique is first applied with constraint for keeping phase in each time-frequency bin within each quantization range, and then, time-domain signal is recovered by the standard inverse short-time Fourier transform. Experimental evaluation based on the objective PEAQ measure shows that the proposed range-constrained phase reconstruction is effective for improving the sound quality.

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