Incoherent lensless imaging via coherency back-propagation

Area of Science:

• Optical physics
• Coherence theory
• Digital optics

Background:

• The two-point complex coherence function fully describes scalar quasi-monochromatic optical fields.
• Characterizing partially coherent light is crucial for various imaging applications.

Purpose of the Study:

• To measure the complex two-point coherence function of partially coherent light scattered from objects.
• To demonstrate scene reconstruction using coherence measurements, even with occlusion and shadowing.

Main Methods:

• Utilized dynamically reconfigurable slits on a digital micromirror device (DMD).
• Measured the complex two-point coherence function for light scattering from one or two objects.
• Employed numerical back-propagation of the coherence data for scene reconstruction.

Main Results:

• Successfully measured the complex two-point coherence function for partially coherent light.
• Demonstrated that coherence measurements, unlike intensity alone, can reveal object information without a lens.
• Reconstructed object sizes and locations from the back-propagated coherence data, accounting for occlusion and shadowing.

Conclusions:

• The complex two-point coherence function provides a complete representation for scalar quasi-monochromatic optical fields.
• Numerical back-propagation of measured coherence functions enables scene reconstruction from partially coherent light.
• This technique offers a novel approach for object and scene characterization in the presence of scattering and occlusion.