Noninvasive object imaging with single-shot low-resolution speckle pattern through strongly-scattering turbid layers

摘要

Noninvasive object imaging through strongly-scattering turbid layers has attracted the attention of many experts due tothe potential application in the biomedical imaging and bioscience. The traditional speckle correlation method withGerchberg-Saxton (GS) algorithm is used to restore object in a single-shot speckle pattern. However, this method suffersfrom the problems of convergence to local minimums, many iterations and cannot determine the object direction, due tothe randomly assign initial value to GS algorithm. Bispectrum analysis method enables the directional Fourier phaseretrieved using single-shot speckle pattern, but there are the problems of requiring high-resolution speckle pattern, lowSNR and selecting the size of filter window. Therefore, we report an effective noninvasive imaging method throughstrongly-scattering turbid layers on the basis of bispectrum analysis and GS algorithm to restore the object in a lowresolutionspeckle pattern. Meanwhile, the new expression of Gaussian filter function is introduced contribute todetermine the window size of filter in the processes of bispectrum analysis. In this proposed approach, the window sizeof filter is determined by the adjust factor according to the new form of Gaussian filter function, and the initial Fourierphase with directional information is generated by bispectrum analysis in a low-resolution speckle pattern. Then theinitial Fourier phase is used as the randomly assign initial value to retrieve Fourier phase of object. Hence, the proposedmethod required no high-resolution, multiple iterations, nor randomly assign initial values to restore directional object.This work carries out simulations and experiments to demonstrates noninvasive object imaging in the low-resolutionspeckle pattern through strongly-scattering turbid layers.