title: keras custom conv2d initialization
body: <p>I been trying to figure out how to create a custom initialization for Conv2D layers in Keras. 
  Could any one show an example on how to manually create a "filter" or weights model as the starting point for training. i.e I would like to pass in a 2d matrix with weights, that can be used as a starting point, to the Conv2D layer. 
  The matrix could be a gaussian blur filter or a sharpinging filter or edge detector etc.</p>
  
  <p>JR</p>