Effect of the finite size of the source in correlation imaging

We investigate the impact of the finite spatial extent of the illumination source in correlation imaging systems. We shall focus, in particular, on lensless ghost imaging, and demonstrate that the finite size of the source shapes the point spread function of the system, thus influencing both the resolution and the depth of field of the image. The presented results highlight the importance of the optimal design of the illumination geometry for high-resolution correlation imaging.