Translation position extracting in incoherent pattern-illumination Fourier ptychographic photography.

• We propose a simple but efficient pre-processing algorithm capable of extracting translation positions of the structure light directly from raw images of Incoherent pattern-illumination Fourier ptychography (IFP), termed translation position extracting (TPE). • TPE removes the requirement of IFP for prior knowledge of translation positions, thus further relaxing the practical conditions. Both simulation and experiment are performed to demonstrate its effectiveness. • The calculation cost of the TPE algorithm is similar to the cross-correlation, which is far lower than the existing translation extraction algorithm based on iterative optimization. Incoherent Pattern-illuminated Fourier ptychography (IFP) is a newly developed super-resolution method, where accurate prior knowledge of translation positions is essential for image reconstruction. To release this limitation, we propose a pre-processing algorithm capable of extracting translation positions of the structure light directly from raw images of IFP, termed translation position extracting (TPE). TPE mainly involves two steps. First, the speckle parts mixed in the acquired raw images, in which the illumination motion is encoded, are isolated by intensity averaging and division. Then the cross-correlations of the speckle dataset are computed to determine the shift positions. TPE-IFP improves the previous IFP by removal of the requirement for prior knowledge of translation positions. Its effectiveness is demonstrated by obtaining high-quality super-resolution images in absence of location information in both simulations and experiments. By further relaxing the practical conditions, the proposed TPE may accelerate the applications of IFP. What's more, as a pre-processing approach, TPE might also contribute to the estimation of pattern positions for the similar speckle-based imaging. [ABSTRACT FROM AUTHOR]