Changes between Version 2 and Version 3 of recipes/PCA/explanation

Timestamp:

Mar 29, 2012, 5:40:20 PM (13 years ago)

Author:

Dave Hunter

Comment:

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recipes/PCA/explanation

@@ -1 @@
-'''Mathematical Defintion''': 
+'''Mathematical Definition''': 
 > PCA is similar to Factor Analysis, in that will we decompose your data into a set of components that maximise variance in your data.
 
  
-Ok, let's take a step back. It's simple to make an average of a set templates, for each point in the template you take the sum of the x coordinates (horisontal) and devide by the number of templates, you do the same for the y coordinates (vertical). The resulting point is roughly in the middle of the original positions in all the templates. Its exact position is called the centre of gravity, in the it is biased to locations with high point density. So, now you have an average, and it still looks like a face, if it doesn't you're doing it wrong and should look at [wiki:averaging this tutorial].
+Ok, let's take a step back. It's simple to make an average of a set templates, for each point in the template you take the sum of the x coordinates (horizontal) and divide by the number of templates, you do the same for the y coordinates (vertical). The resulting point is roughly in the middle of the original positions in all the templates. Its exact position is called the centre of gravity, in the it is biased to locations with high point density. So, now you have an average, and it still looks like a face, if it doesn't you're doing it wrong and should look at [wiki:averaging this tutorial].
 
 [[Image(average.jpg)]][[BR]]Example of an average template.