Refocusing based on amplitude analysis in color digital holographic microscopy

Area of Science:

• Optical Microscopy
• Holography
• Image Processing

Background:

• Digital holographic microscopy (DHM) is a powerful technique for 3D imaging.
• Accurate refocusing is crucial for quantitative analysis in DHM.
• Existing monochromatic criteria may limit precision, especially with complex samples.

Purpose of the Study:

• To establish a refocusing criterion specifically adapted for red-green-blue (RGB) digital holographic microscopy.
• To enhance the accuracy of focus plane determination along the optical axis.
• To validate the method's applicability for both amplitude and phase objects.

Main Methods:

• Development of a color-based refocusing criterion derived from a monochromatic criterion using integrated modulus amplitude.
• Simulations of RGB holograms incorporating numerical apertures and noise.
• Implementation of an algorithm for exponentially reducing computation time in focus plane detection.

Main Results:

• The RGB refocusing criterion demonstrates improved accuracy in determining the focus plane position.
• Color information proved valuable even for colorless samples, enhancing precision.
• The method was successfully validated using experimental holograms.

Conclusions:

• The proposed RGB refocusing criterion offers a more accurate and robust method for digital holographic microscopy.
• The color information enhances the performance of focus detection, leading to better imaging results.
• The developed algorithm significantly reduces the computational cost of focus plane detection.