Measurement of sub-shot-noise spatial correlations without subtraction   of background
  In this paper we present the first measurement of sub-shot-noise spatial correlations without any subtraction of background, a result opening the way to realize sub-shot-noise imaging of weak objects 
Giorgio Brida, Lucia Caspani, Alessandra Gatti, Marco Genovese, Alice   Meda, Ivano Ruo Berchera