Spread spectrum ghost imaging

Abstract

Ghost imaging (GI) has attracted more and more attention due to its non-locality, however, there are still some obstacles to its practical applications. One problem is that the environmental interference, such as the time varying noise, greatly degrades the reconstructed images’ quality. In the paper, we propose a novel ghost imaging scheme based on the spread spectrum technique, named spread spectrum ghost imaging (SSGI) to overcome this problem. In the scheme, the traditional ghost imaging (TGI) system is considered as a communication system, where the light beam is regarded as a transmitter, whose intensity is first modulated by a designed direct sequence code, then followed by a spatial modulator to obtain the temporal-spatial speckle patterns. The speckle patterns are then projected onto the unknown object successively. The bucket detector in the TGI system is considered as a receiver. With the designed direct sequence code to despread the bucket value (named the computed bucket value), the image of the unknown object is finally reconstructed by the correlation between the modulated speckle patterns and corresponding computed bucket values. The numerical simulations and experimental results demonstrate that the proposed scheme has a stronger noise resistance capacity. Besides, the longer the length of the direct sequence code is, the better the performance SSGI has.