A Framework for Invertible, Real-Time Constant-Q Transforms

作者：Holighaus Nicki^*; Doerfler Monika; Angelo Velasco Gino; Grill Thomas

来源：IEEE Transactions on Audio Speech and Language Processing, 2013, 21(4): 775-785.

DOI：10.1109/TASL.2012.2234114

• Audio signals
• constant-Q
• Gabor frames
• real-time
• time-frequency dictionary

Audio signal processing frequently requires time-frequency representations and in many applications, a non-linear spacing of frequency bands is preferable. This paper introduces a framework for efficient implementation of invertible signal transforms allowing for non-uniform frequency resolution. Non-uniformity in frequency is realized by applying nonstationary Gabor frames with adaptivity in the frequency domain. The realization of a perfectly invertible constant-Q transform is described in detail. To achieve real-time processing, independent of signal length, slice-wise processing of the full input signal is proposed and referred to as sliCQ transform. By applying frame theory and FFT-based processing, the presented approach overcomes computational inefficiency and lack of invertibility of classical constant-Q transform implementations. Numerical simulations evaluate the efficiency of the proposed algorithm and the method%26apos;s applicability is illustrated by experiments on real-life audio signals.

• 出版日期2013-4