title: PCA in OpenCV and how to prepare data?
body: <p>I just want to clarify something about PCA in OpenCV. Suppose, I have two rows of data (A, B). </p>
  
  <p>A   3   8   7</p>
  
  <p>B   2   4   5</p>
  
  <p>If I wanted to create a PCA model in OpenCV, what must I do to the data? Do I have to subtract the means (e.g. subtract the mean of A from its data points) or does the PCA function do this? </p>
  
  <p>Someone said that OpenCV PCA expects the data to be normalised (between 0 and 1). If so, how do I normalise?</p>
  
  <p>Hope someone can clarify this for me as PCA in OpenCV is very badly documented on the Net. </p>
  
  <p>Cheers...</p>