Effect of partial coherent illumination on Fourier Ptychography

Abstract

Fourier Ptychography is a computational imaging technique able to decouple high resolution from wide field of view, bypassing the diffraction limit of the microscope. Since it does not rely on high precision mechanics or fluorescent imaging, it is of practical interest for implementation in low scale devices. Despite its gains, realizing a functional low-cost setup working at the theoretical limits is challenging due to many factors causing discrepancies between theory and practice. Misalignment of the light emitting diode array (LED-array), optical system aberrations and use of partial coherent sources are common issues which have been addressed with calibration algorithms. However, physical interpretation of how these factors influence the algorithm and cause mismatches between theory and practice has had little attention so far. This work provides a discussion based on simulation results on the effect of the partial coherence of the source. From obtained results, an optimal set of LEDs for data acquisition is described which avoids degeneracy caused by partial coherence and is based on the numerical aperture (NA) of the objective and source parameters such as bandwidth and size.

Target product profiles for devices to diagnose urinary schistosomiasis in Nigeria

“…Within the INSPiRED project, there are two types of optical diagnostic methods under development (Schistoscope and SODOS) where an optical system is combined with an algorithm to automatically detect and count S. haematobium ova in a urine sample [9,[15][16][17][18]. Since the procedure rules out human error, the test can reach a higher level of sensitivity and is not dependent on scarce skilled healthcare staff.…”