Abstract
Non-line-of-sight (NLOS) imaging makes it possible to reconstruct hidden objects around corners, which is of fundamental importance in various fields. Despite recent advances, NLOS imaging has not been studied in certain typical random scenarios, such as tortuous corridors filled with random media. We dub such a category of complex environment “random corridor”, and propose a reduced spatial- and ensemble-speckle intensity correlation (RSESIC) method to image a moving object obscured by a random corridor. Experimental results show that the method can reconstruct image of a centimeter-sized hidden object with a sub-millimeter resolution by a low-cost digital camera. The imaging capability depends on three system parameters and can be characterized by the correlation fidelity (CF). Furthermore, the RSESIC method is able to recover the image of objects even for a single pixel containing the contribution of about $10^2$ speckle grains, which overcomes the theoretical limitation of traditional speckle imaging methods. Last but not least, when the power attenuation of speckle intensity leads to the serious deterioration of CF, the image of hidden objects can still be reconstructed by the corrected intensity correlation.
Low-cost SPAD sensing for non-line-of-sight tracking, material classification and depth imaging