An example of asymmetric comparison
Start the SA+ 'explore and score' module, make sure that the amplitude threshold is 37dB
(yellow slider) and open the sounds Example 1. Select the 'auto segment a single syllable'
radio-button and click at the second syllable:
Next click the 'Sound 2' tab, open Example 2 and click on the last syllable:
Click the 'similarity' tab and click score.
As shown, the % similarity is 100%, meaning that the similarity section captured the
entire model song (sound 1). The accuracy is moderately high, showing that the frame-to-frame similarity is reasonable. Now reverse the comparison by opening example 2 in the
'sound 1' tab and then open example 1 in 'sound 2'. Outline the appropriate syllables and
score the similarity: Note that the % similarity is now only 53% because only the second
part of the model matches with the copy. Note also that the accuracy is similar, but not
identical to the reciprocal comparison. This is because the section is cut also
asymmetrically, in reference to the model (since we do not insist on 450 but allow some
jitter, the comparison is not one on one).
We next examine the outcome of comparing two songs using either the time-course score
or mean values score. An alternative approach is comparing the means of the feature
values in contrast to comparing their curves. In this approach we do not care anymore
about the order of feature values within the interval, but rather we are looking at the
smooth estimate of the distances observed across raw feature values. Note that in contrast
to the distance across curves method, which increases the contrast (by adding more
information), here we are flattening the distances by averaging before comparing (so
those are opposite approaches so to speak).
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