Influence of detector response speed on the contrast-to-noise ratio of reflective ghost imaging

• An expression for the CNR of reflective ghost imaging (RGI) with added speckle patterns is derived.
• In a computational ghost imaging system, the RGI based on added speckle patterns is studied experimentally.
• The image quality of RGI is insensitive to the detector response speed as long as the detector noise can be neglected.

The influence of detector response speed on the contrast-to-noise ratio (CNR) of reflective ghost imaging (RGI) is studied. To mimic the situation of a slow response detector, the illuminating speckle patterns are replaced with the sum of uncorrelated speckle patterns for each measurement. An expression for the CNR of RGI with added speckle patterns is derived. By employing a light projector to provide spatially incoherent structured illumination in a computational ghost imaging system, we perform computational RGI based on added speckle patterns. The experimental results show that when up to 40 uncorrelated speckle patterns are added together in each measurement, the CNR of computational RGI obtained from 5000 effective measurements remains almost the same as the conventional computational ghost imaging. The reason for this is that the image quality of RGI depends on the kurtosis of intensity fluctuation of speckle field instead of the contrast ratio of speckle pattern. The experimental results agree with the theoretical prediction.