Physical pupil manipulation for speckle reduction in digital holographic microscopy

Area of Science:

• Optical Imaging
• Microscopy
• Holography

Background:

• Speckle noise is a common artifact in digital holographic microscopy (DHM).
• Traditional speckle reduction methods can degrade image resolution or introduce artifacts.
• Modifying the imaging pupil offers a potential avenue for noise reduction without compromising image quality.

Purpose of the Study:

• To experimentally apply pupil modification for speckle noise reduction in DHM.
• To evaluate the effectiveness of this technique in improving image quality for biological samples and resolution tests.

Main Methods:

• Physically altering the imaging pupil of a digital holographic microscope in a controlled manner.
• Acquiring multiple, partially decorrelated holograms by changing the pupil between successive recordings.
• Numerically reconstructing the holograms and averaging the results to reduce speckle noise.

Main Results:

• Successfully reduced speckle noise in reconstructed amplitude and phase images.
• Demonstrated the recovery of micron-sized features in biological specimens.
• Validated the technique using a phase-only resolution test target.

Conclusions:

• Physically changing the DHM imaging pupil is a feasible method for reducing speckle noise.
• This approach enhances the ability to resolve fine details in microscopic imaging.
• The technique shows promise for applications in biological imaging and metrology.