A human erythrocytes hologram dataset for learning-based model training.

This manuscript presents a paired dataset with experimental holograms and their corresponding reconstructed phase maps of human red blood cells (RBCs). The holographic images were recorded using an off-axis telecentric Digital Holographic Microscope (DHM). The imaging system consists of a 40 × /0.65NA infinity-corrected microscope objective (MO) lens and a tube lens (TL) with a focal distance of 200 mm, recording diffraction-limited holograms. A CMOS camera with dimensions of 1920 × 1200 pixels and a pixel pitch of 5.86 µm was located at the back focal plane of the TL lens, capturing image-plane holograms. The off-axis, telecentric, and diffraction-limited DHM system guarantees accurate quantitative phase maps. Initially comprising 300 holograms, the dataset was augmented to 36,864 instances, enabling the investigation (i.e., training and testing) of learning-based models to reconstruct aberration-free phase images from raw holograms. This dataset facilitates the training and testing of end-to-end models for quantitative phase imaging using DHM systems operating at the telecentric regime and non-telecentric DHM systems where the spherical wavefront has been compensated physically. In other words, this dataset holds promise for advancing investigations in digital holographic microscopy and computational imaging.

Physical pupil manipulation for speckle reduction in digital holographic microscopy.

The reduction of speckle noise by physically changing the pupil of the imaging system, as first envisioned in optical holography, is experimentally applied to a digital holographic microscope (DHM). The imaging pupil of a DHM, operating in image plane telecentric-afocal architecture, is changed in a controlled way between successive recordings, allowing the shooting of multiple partially-decorrelated holograms. Averaging the numerically reconstructed holograms yields amplitude and/or phase images with reduced speckle noise. Experimental results of biological specimens and a phase-only resolution test show the feasibility to recover micron-sized features in images with reduced speckle noise.