Magnetic imaging with an ensemble of nitrogen-vacancy centers in diamond Mayeul Chipaux, Alexandre Tallaire, Jocelyn Achard, Sébastien Pezzagna, Jan Meijer, Vincent Jacques, Jean-François Roch and Thierry Debuisschert Eur. Phys. J. D, 69 7 (2015) 166 Published online: 02 July 2015 DOI: 10.1140/epjd/e2015-60080-1