Light-field focusing and modulation through scattering media based on dual-polarization-encoded digital optical phase conjugation

Focusing through scattering media by a single polarization transmission matrix with binary polarization modulation

Wavefront distortion induced by scattering media seriously affects optical focusing. Wavefront shaping based on a transmission matrix (TM) is useful in controlling light propagation in highly scattering media. Traditional TM generally studies amplitude and phase, but the stochastic nature of the light propagation in the scattering medium also affects its polarization. Based on the binary polarization modulation, we propose a single polarization transmission matrix (SPTM) and achieve single-spot focusing through scattering media. We anticipate that the SPTM will be widely used in wavefront shaping.

3D medical images security via light-field imaging

This Letter proposes a selective encryption scheme for three-dimensional (3D) medical images using light-field imaging and two-dimensional (2D) Moore cellular automata (MCA). We first utilize convolutional neural networks (CNNs) to obtain the saliency of each elemental image (EI) originating from a 3D medical image with different viewpoints, and successfully extract the region of interest (ROI) in each EI. In addition, we use 2D MCA with balanced rule to encrypt the ROI of each EI. Finally, the decrypted elemental image array (EIA) can be reconstructed into a full-color and full-parallax 3D image using the display device, which can be visually displayed to doctors so that they can observe from different angles to design accurate treatment plans and improve the level of medical treatment. Our work also requires no preprocessing of 3D images, which is more efficient than the method of using slices for encryption.