Progress. Errrr, Sort of.

First I want to encourage everyone here to read Mike Fast's recent post about Greg Maddux. The analysis he has done on Maddux is what I am hoping my clustering algorithm can do on every pitcher. Things are moving along with the algorithm and I want to share some progress. The algorithm is still messing up Maddux's two and four seam fastballs but it now correctly identifies his cutter so that it some progress. Instead of showing you worse plots than what Mike had put together I decided to show a similar type of pitcher to Maddux in Jose Contreras. Now Contreras isn't having nearly as good of a year as Maddux but both are similar pitchers featuring several types of fastballs and a pretty small variation between pitches. Here is Contreras' horizontal and vertical movement.
What a mess we have here. Contreras is throwing a two seam fastball and what looks to be a cut fastball but also a change, a slider, and a curve. All of the pitches seem to blur together in this plot but if we add in the pitch speed they start to separate.
Here is a breakdown of horizontal break and pitch speed. I thought about adding vertical break to this plot as well but things were very messy as is. Here you can see Contreras' change break away from his fastballs and some separation between his sinker and his cutter. I was pretty impressed that the algorithm would pick up these differences. Also, even though we have much less statistics, we can see a clear speed difference between his slider and curve ball. Next the vertical movement.
Now you can see that his sinker really is sinking more than his cutter and the increased drop in his curve from his slider. What about his release point though? Contreras is known as someone who will drop down to 3/4 arm slot from time to time.
Perfect. We can see his regular arm slot and the 3/4 arm slot and it appears most of his cutters come from that 3/4 position. But hang on a second. What is with those stay points off to the right? This must be where PITCHf/x just screwed up and miss read the pitch. As crafty as Contreras is I doubt he actually threw a pitch left handed. Every time I look up it seems there is something else to the data that needs correcting. Clearly that unknown point way to the right needs to go and the change that is off by more that a foot also needs to be removed. What about that cluster of five pitches in the upper right though? Is that a crafty vet showing a different arm angle for an important pitch or just a mistake from PITCHf/x? I don't have the answer right now but hopefully will soon.

This weekend looks very busy for me but hopefully I will have some time to work on this. The order of what I am planning on doing is fixing this release point issue first. Then hopefully going back to the clustering algorithm and getting that ready to go. I feel like that is close. Seeing what a good job it did with Contreras gives me hope. The biggest thing right now is probably getting it to merge more of those unknown points into established pitches. Lastly, tackling the acceleration correction which I will almost certainly not have time for. I actually had a decent idea for a work around with it but it is going to take a long time to code up and then test.