Many image processing algorithms are taken from the signal processing world, and probably initially employed to process audio during the construction of the Bel

Many image processing algorithms are taken from the signal processing world, and probably initially employed to process audio during the construction of the Bell telephone system. There's a lot of mathematical similarity between a visual and audio signal, the differences are primarily in the human receivers. So this may well be a case of borrowing audio processing techniques from an image processing library and then using it to process audio.