Unsighted ghost imaging for objects completely hidden inside turbid media

Abstract

Ghost imaging (GI) is an unconventional imaging method that retrieves the image of an object by correlating a series of known illumination patterns with the total reflected (or transmitted) intensity. However, the patterns on the object are required to be known, which highly limits its application scenarios, especially in a strong scattering environment. We here propose a scheme that removes this basic requirement, and enables GI to non-invasively image objects through turbid media. As experimental proof, we project a set of patterns towards an object hidden inside turbid media that make the patterns falling on the object completely unknown. The spatial information of both the object and the illumination is lost. We prove that, when the source is within a memory-effect angular range of the turbid medium, the spatial frequency of the object is preserved in the correlation of GI, which can be used for image reconstruction. This scheme also circumvents the major challenge in non-invasive imaging through turbid media: the object must be small enough to fit in a field-of-view which is usually extremely small in realistic scenarios. Our method removes this limitation and is an important step towards realistic applications.

Research progress of correlation imaging under outdoor environment

“…Shi等 [61] 将自适应光学技术引入关联成像中以解 决大气湍流的问题, 其实验结果如图9所示, 图像 质量相对传统关联成像有明显提升. 2021年, Li 等 [62] 将偏振成像技术引入到关联成像中, 提出了 基于直方图预处理的水下偏振差分关联成像方法.…”

High-speed ghost imaging by an unpredictable optical phased array

“…Ghost imaging (GI) exploits the second-order correlation of two photons to reconstruct an image [1,2], which is different from the conventional imaging methods that are based on the first-order interference and typically use lenses to construct images. Its imaging architecture possesses several advantages such as less sensitivity to optical turbulence [3,4], high detection sensitivity [5,6], lensless imaging capability [7], non-invasive imaging through strong scattering media [8], and being able to easily adapt to various scenarios [9][10][11]. During the past two decades, there is a growing body of research studies on GI, invoking a lot of potential applications in various fields ranging from optical imaging [12][13][14][15], X-ray imaging [16][17][18], atomic sensing [19,20], biological diagnostics [21], and feature extraction without image reconstruction [22,23] to physical encryption [24][25][26].…”