The other is the reference beam, which does not pass through the target, and is directly captured by an area detector. Nevertheless, the image of the target is reconstructed by correlating the intensities measured by the bucket detector with the images captured by the area detector. In 1994, Ribeiro from Brazil first discovered the two-photon interference fringes by means of coincidence measurements [1]. In 1995, two-photon ghost interference and diffraction was observed by Y.H. Shih from University of Maryland [2]. These discoveries led the theoretical and experimental research on ghost imaging all over the world in last decades. There are some debates on using which theory to explain the phenomenon, the quantum theory or the statistical physics. However, attentions have been focused on how to apply the ghost imaging to practical applications to improve the conventional imaging technology