title: Feeding HOG into SVM: the HOG has 9 bins, but the SVM takes in a 1D matrix
body: <p>In OpenCV, there is a CvSVM class which takes in a matrix of samples to train the SVM. The matrix is 2D, with the samples in the rows.</p>
  
  <p>I created my own method to generate a histogram of oriented gradients (HOG) off of a video feed. To do this, I created a 9 channeled matrix to store the HOG, where each channel corresponds to an orientation bin. So in the end I have a 40x30 matrix of type <code>CV_32FC(9)</code>.</p>
  
  <p>Also made a visualisation for the HOG and it's working.</p>
  
  <p>I don't see how I'm supposed to feed this matrix into the OpenCV SVM, because if I flatten it, I don't see how the SVM is supposed to learn a 9D hyperplane from 1D input data.</p>