McAnulty College and Graduate School of Liberal Arts
audio restoration, band replication, bandwidth extension, fourier analysis, open source software, signal processing
The scope of this work is to introduce a conceptually simple yet effective algorithm for blind high-frequency bandwidth extension of audio signals, a means of improving perceptual quality for sound which has been previously low-pass filtered or downsampled (typically due to storage considerations). The algorithm combines an application of the modulation theorem for discrete Fourier transform to regenerate the missing high-frequency end of the signal spectrum with a linear-regression-driven approach to shape the spectral envelope for the regenerated band. The results are graphically and acoustically compared to those obtained with existing audio restoration software for a variety of input signals. The source code and Windows binaries of the resulting algorithm implementation are also included.
Kontsevoi, A. (2010). An Application of Spectral Translation and Spectral Envelope Extrapolation for High-frequency Bandwidth Extension of Generic Audio Signals (Master's thesis, Duquesne University). Retrieved from https://dsc.duq.edu/etd/769