title: Understanding tf.extract_image_patches for extracting patches from an image
body: <p>I found the following method <a href="https://www.tensorflow.org/versions/r0.9/api_docs/python/array_ops.html#extract_image_patches" rel="noreferrer">tf.extract_image_patches</a> in tensorflow API, but I am not clear about its functionality. </p>
  
  <p>Say the <code>batch_size = 1</code>, and an image is of size <code>225x225x3</code>, and we want to extract patches of size <code>32x32</code>. </p>
  
  <p>How exactly does this function behave? Specifically, the documentation mentions the dimension of the output tensor to be <code>[batch, out_rows, out_cols, ksize_rows * ksize_cols * depth]</code> , but what <code>out_rows</code> and <code>out_cols</code> are is not mentioned.</p>
  
  <p>Ideally, given an input image tensor of size <code>1x225x225x3</code> (where 1 is the batch size), I want to be able to get <code>Kx32x32x3</code> as output, where <code>K</code> is the total number of patches and <code>32x32x3</code> is the dimension of each patch. Is there something in tensorflow that already achieves this?</p>