High-quality multi-wavelength lensfree microscopy based on nonlinear optimization

In multi-wavelength lensfree microscopy (MWLM), a laser source is usually replaced with a light-emitting diode for a low-cost and portable configuration. However, the trade-off between noise suppression and resolution enhancement puts a challenging issue for high-quality imaging. Here we propose a noise-robust multi-wavelength phase retrieval to increase the stability of MWLM. To solve the inverse problem of phase retrieval, we derive an optimization procedure to iteratively minimize the data fidelity and impose a total variation term for noise suppression. The experimental results of resolution target, stained human goblet cell, and label-free microglia cell demonstrate that our method could hold a better noise tolerance without the loss of imaging resolution. We believe that our method will become a powerful tool for a resources-limited scene.