Unsupervised topological analysis of polarized light microscopy: application to quantitative birefringence imaging

Area of Science:

• Geology
• Materials Science
• Optical Physics

Background:

• Birefringence determination is crucial for optical materials analysis.
• Analyzing composite samples and geological thin sections is complex and time-consuming.
• Automated methods for birefringence reconstruction are needed.

Purpose of the Study:

• To develop a partially automated procedure for reconstructing birefringence spatial distribution in geological thin sections.
• To quantitatively measure retardance and optical axis orientation.
• To correlate optical axis orientation with geological features.

Main Methods:

• Quantitative birefringence measurements on sparse points.
• Automatic boundary detection on cross-polarized light microscopy images.
• Reconstruction of retardance and optical axis orientation distributions.

Main Results:

• Successful reconstruction of spatial distributions for retardance and optical axis orientation.
• Analysis of uniaxial crystals and anisotropic grains within a geological thin section.
• Determination of optical axis orientation both in-plane and out-of-plane.

Conclusions:

• The proposed procedure offers a valuable tool for analyzing birefringence in geological samples.
• The method simplifies the complex task of birefringence mapping in composite materials.
• Future work aims to integrate thin section optical data with 3D geological orientation.