Hybrid adaptive step-size strategy for full field of view measurement of ultraviolet Fourier ptychographic microscopy

This research introduces a hybrid adaptive step-size strategy for reconstructing a full field of view (FOV) image with very high resolution using a reflective Fourier ptychographic microscopy (FPM) with near ultra-violet (UV) light emitting diodes (LEDs). Hybrid adaptive step-size FPM (AS-FPM) combines the advantages of the adaptive step-size with one variable and the adaptive step-size with two variables. This approach achieves higher image quality and accuracy, while reducing processing time by eliminating the need for additional stitching algorithms such as alpha blending. To demonstrate the superior performance of hybrid AS-FPM, we constructed a reflective FPM system with UV LEDs at a wavelength of 365 nm, where the camera responsivity is significantly lower than in the visible light. We measured a United States Air Force 1951 target and a star target and compared the high-resolution images obtained using the three algorithms: hybrid AS-FPM, adaptive step-size with one-variable, and adaptive step-size with two variables. The results showed that the full FOV image reconstructed using hybrid AS-FPM had higher image quality compared to the other two algorithms, with no discontinuities between the segments. Additionally, the processing time was significantly reduced.