Optimizing nonconfigurable, transversely displaced masks for illumination patterns in classical ghost imaging

Classical ghost imaging is a new paradigm in imaging where the image of an object is not measured directly with a pixelated detector. Rather, the object is subject to a set of illumination patterns and the total interaction of the object, e.g., reflected or transmitted photons or particles, is measured for each pattern with a single-pixel or bucket detector. An image of the object is then computed through the correlation of each pattern and the corresponding bucket value. Assuming no prior knowledge of the object, the set of patterns used to compute the ghost image dictates the image quality. In the visible-light regime, programmable spatial light modulators (SLMs) can generate the illumination patterns. In many other regimes, such as x rays, electrons, and neutrons, no such dynamically configurable modulators exist, and patterns are commonly produced by employing a transversely translated mask. Moreover, in visible-light regimes, mask switching rates exceeding the fastest SLMs may often be achieved through transverse translation (e.g., rotation) of a nonconfigurable mask. In this simulations-based paper we explore some of the properties of masks or speckle that should be considered to maximize ghost-image quality, given a certain experimental classical ghost-imaging setup employing a transversely displaced but otherwise nonconfigurable mask.