Transforming the sounds of the sea (Image: Mark Fisher/SPL)
WHALES and dolphins are accomplished vocalists, emitting complex patterns of clicks and whistles that vary in pitch, volume and length. To visualise their songs, and therefore identify species, marine biologists usually produce a spectrogram, a graph of how the frequency of their vocalisations varies over time.
Spectrograms are created using a mathematical process called the Fourier transform (FT), which can convert raw sound into a set of sinusoidal waves. However, because these waves are periodic and infinite, they are better suited to describing repetitive, continuous noises, such as the whirr…
