|The Pattern Emerges by Delia Derbyshire|
|Detail of start of melody and chords|
This makes it simple to score a piece accurately when only its audio survives.
It's made by warping a linear spectrogram created by the sndfile-spectrogram program in sndfile-tools using ImageMagick's -fx operator.
For further details and to listen to the above piece against its spectrogram, see
Update 2016-02-22: I've modified sndfile-spectrogram to enable it to produce log-frequency-axis spectrograms directly, now included in the master version of sndfile-tools.