Locating and classifying fluorescent tags behind turbid layers using time-resolved inversion

The use of fluorescent probes and the recovery of their lifetimes allow for significant advances in many imaging systems, in particular, medical imaging systems. Here we propose and experimentally demonstrate reconstructing the locations and lifetimes of fluorescent markers hidden behind a turbid layer. This opens the door to various applications for non-invasive diagnosis, analysis, flowmetry and inspection. The method is based on a time-resolved measurement that captures information about both fluorescence lifetime and spatial position of the probes. To reconstruct the scene, the method relies on a sparse optimization framework to invert time-resolved measurements. This wide-angle technique does not rely on coherence, and does not require the probes to be directly in line of sight of the camera, making it potentially suitable for long-range imaging. Fluorescent patches can be localized in 3D and identified behind a diffusive layer by use of streak images taken from one horizontal line on the diffusive barrier. Satat et al . show that the time-resolved inversion along with sparse prior can be used to perform this with deeper recovery range.