High dynamic range lensless on-chip microscopy via an overexposure inverse-projection operator

Lensless on-chip microscopy (LoM) enables high-throughput, label-free imaging with a compact setup and high numerical aperture. Its performance is limited by sensor saturation, which distorts high-intensity measurements and degrades reconstruction of the complex field. We report a high-dynamic-range inverse-projection reconstruction (HDR-IPR) framework that models saturation via an overexposure operator and jointly reconstructs the complex object field without multiple acquisitions at each predefined exposure duration. Using an approximate inverse-projection operator and alternating direction projection with complex total variation regularization, HDR-IPR effectively restores saturated signals while suppressing noise. Experiments demonstrate superior reconstruction quality, cleaner backgrounds, and enhanced reconstruction of fine structural details, providing a practical solution for HDR lensless imaging with standard sensors.