Depth-resolved imaging through dynamic scattering media via speckle cross-correlation under near-infrared illumination

Speckle cross-correlation imaging (SCCI) method has the depth-resolved capability, benefiting from the introduction of a reference point. However, the quality of the reconstructed image is degraded due to the background noise, which becomes more prominent when imaging through dynamic scattering media. Here, we propose a composite-differential filter-assisted (CDF-SCCI) method, allowing for effectively reducing the background noise of the reconstructed image. The signal-to-background ratios of the reconstructed images by employing the CDF-SCCI method can be enhanced by a maximum of 4.15 dB (corresponding to 2.6 times) compared to the SCCI method. Furthermore, we apply the near-infrared (NIR) illumination to the imaging system of dynamic scattering media and prove that the NIR illumination not only enhances the penetration depth of imaging, but also improves the quality of reconstructed images compared to the visible illumination. The depth-resolved imaging through various dynamic biological scattering media, including the milk and anticoagulated pig blood, further demonstrates the potential application of the proposed CDF-SCCI method in biomedical imaging.