Foveated panoramic ghost imaging

Abstract

Panoramic ghost imaging (PGI) is a novel method by only using a curved mirror to enlarge the field of view (FOV) of ghost imaging (GI) to 360°, making GI a breakthrough in the applications with a wide FOV. However, high-resolution PGI with high efficiency is a serious challenge because of the large amount of data. Therefore, inspired by the variant-resolution retina structure of human eye, a foveated panoramic ghost imaging (FPGI) is proposed to achieve the coexistence of a wide FOV, high resolution and high efficiency on GI by reducing the resolution redundancy, and further to promote the practical applications of GI with a wide FOV. In FPGI system, a flexible variant-resolution annular pattern structure via log-rectilinear transformation and log-polar mapping is proposed to be used for projection, which can allocate the resolution of the region of interest (ROI) and the other region of non-interest (NROI) by setting related parameters in the radial and poloidal directions independently to meet different imaging requirements. In addition, in order to reasonably reduce the resolution redundancy and avoid the loss of the necessary resolution on NROI, the variant-resolution annular pattern structure with a real fovea is further optimized to keep the ROI at any position in the center of 360° FOV by flexibly changing the initial position of the start-stop boundary on the annular pattern structure. The experimental results of the FPGI with one fovea and multiple foveae demonstrate that, compared to the traditional PGI, the proposed FPGI not only can improve the imaging quality on the ROIs with a high resolution and flexibly remain a lower-resolution imaging on the NROI with different required resolution reduction; but also reduce the reconstruction time to improve the imaging efficiency due to the reduction of the resolution redundancy.