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2-D DVD maps

 

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2D DVD maps allow you to observe scatter plots of vocal development (or any other vocal process) as a movie. Start SAP2011 and select DVD maps. Open the table syll_R109, and click start. You should see an evolving movies (here are initial and later snapshots):
DVD10


Each red dot represents a syllable, the X axis is 'duration' by default, and the Y axis is mean FM. Note that feature units are scaled, with median at 0 and with a spread of a single MAD (median absolute deviation) unit. The beginning of the movie is also the beginning of song development, when songs syllable are relatively unstructured.

Click at the time control (long slider at the bottom), it should turn yellow, and move its thumb to the right, about ¾ of the way. The movie should now look very different as you go.
Below and to the right of the image you can select the features to be observed. Try the Goodness of pitch on the right and on the left, select 'color by cluster:
DVD11
We can see 3 dense clusters, which correspond to the 3 syllable types of the song produced. To see other features of those clusters click on the Y-axis feature choice (you can do this as the movie is playing). Clicking on the pitch shows different projections of the clusters. Moving the mouse into the movie image will show a hand pointer, indicating that you can move the image as desired. On the bottom right you will see a radio-group with 3 choices: rotate, pan and zoom - try them all during the movie play.

At this point, our notion of clusters is informal, but in the next chapter you will learn how to automatically identify the clusters. In this example, we already clustered the data. Looking at DVD maps after clustering is a useful method for validating that the outcome of the clustering is reasonable.