Multiple hidden-targets recognizing and tracking based on speckle correlation method

The light beam is diffused and scattered randomly when it passes through turbid media. Imaging through inhomogeneous samples, like ground glass, is regarded as a difficult challenge. Here, we propose a method to estimate the number of hidden targets and the pose of multi-targets hidden behind scattering medium by analyzing the distribution of autocorrelation of multi-targets speckle. The autocorrelation of multi-targets includes two parts, the autocorrelation of each sub-target and the cross-correlation among all targets. When multi-targets locate in the same row, the speckle autocorrelation shows a line shape. The autocorrelation of each sub-target overlaps on the center position and the crosscorrelations among them symmetrically distribute at both sides. When multi-targets distribute in different rows and columns, the speckle autocorrelation arranges symmetrically around the center. The autocorrelation of each sub-target overlaps on the center, and the cross-correlations among sub-targets symmetrically distribute around. The relative location among multi-targets can be estimated by calculating the distance from the cross-correlations of two sub-targets. Both simulation and experiment results successfully prove that our method possesses the ability to reconstruct multitargets in different column and cow within optical memory effect (OME) range. The method is expected to be applied to multi-targets recognizing, tracking and imaging through scattering medium in practical applications, such as biomedical imaging, astronomical observations and military detection.