title: Representation of the wavelet coefficients with matlab
body: <p>I want to represent the wavelet coefficients of a 2D function using the wavelet toolbox or wavelab, but I can't manage to display a picture like this:</p>
  
  <p><img src="https://i.stack.imgur.com/mIjYi.jpg" alt="">. </p>
  
  <p>How do I do that?</p>