Detector noise has a significantly negative impact on ghost imaging at low light levels, especially for existing recovery algorithm. Based on the characteristics of the additive detector noise, a method named modified compressive sensing ghost imaging is proposed to reduce the background imposed by the randomly distributed detector noise at signal path. Experimental results show that, with an appropriate choice of threshold value, modified compressive sensing ghost imaging algorithm can dramatically enhance the contrast-to-noise ratio of the object reconstruction significantly compared with traditional ghost imaging and compressive sensing ghost imaging methods. The relationship between the contrast-to-noise ratio of the reconstruction image and the intensity ratio (namely, the average signal intensity to average noise intensity ratio) for the three reconstruction algorithms are also discussed. This noise suppression imaging technique will have great applications in remote-sensing and security areas.
We present an experimental demonstration of ghost imaging of reflective objects with different surface roughness. The influence of the surface roughness, the transverse size of the test detector, and the reflective angle on the signal-to-noise ratio (SNR) is analyzed by measuring the second-order correlation of the light field based on classical statistical optics. It is shown that the SNR decreases with an increment of the surface roughness and the detector's transverse size or a decrease of the reflective angle. Additionally, the comparative studies between the rough object and the smooth one under the same conditions are also discussed.
A decline in imaging quality will occur when the sampling data of ghost imaging is recorded by binarization. Based on the Otsu binarization, a method named Otsu binary ghost imaging (OBGI) is proposed to enhance imaging quality. Both theoretical and experimental results show that, with an appropriate threshold value, OBGI can enhance imaging quality significantly when compared with ordinary binary ghost imaging, even providing better imaging quality than that of traditional ghost imaging. It is also shown the method is more applicable under the conditions of low-light level and with a complicated object.
The vibration is one of the important factors affecting imaging quality of conventional remote sensing imaging because the relative motion between the imaging system and the target can result in the degradation of imaging quality. The influence of the vibration of the detector in the test path on reflective ghost imaging (RGI) is investigated theoretically and experimentally. We analyze the effects of the vibrating amplitude and velocity. The results demonstrate that the microvibrations of the bucket detector have almost no impact on the imaging resolution and signal-to-noise ratio (SNR) of RGI, i.e., the degradation of imaging quality caused by the vibration of the detector can be overcome to some extent. Our results can be helpful for remote sensing imaging.
The inhibition effect from the cosh-Gaussian modulated incoherent source on the defocusing effect is investigated theoretically in lensless ghost imaging (LGI) and ghost diffraction (LGD) systems. The corresponding numerical simulations are presented to show the influence of the cosh-Gaussian incoherent source on the defocusing effect in LGI and LGD. Compared with the widely used Gaussian incoherent source, it is shown that the defocusing effect in LGI and LGD can be greatly weakened by properly adjusting the modulation parameter ω of the cosh-Gaussian source. To explain this phenomenon, the analytical expression for point spread function of the LGI system with the cosh-Gaussian source is derived.
Ghost imaging through inhomogeneous turbulent atmosphere along an uplink path and a downlink path is studied in detail by using the numerical simulation method. Based on the Hufnagel-Valley5/7 turbulent atmosphere profile model, the numerical imaging formula of ghost imaging through turbulent atmosphere along a slant path is derived and used to analyze the influence of turbulent atmosphere along an uplink path and a downlink path on the imaging quality, and the effect from the zenith angle is also discussed. The numerical results show that the imaging quality through turbulent atmosphere along a downlink path is better than that along an uplink one, which can be explained by the phase modulation effect.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.