photoelastimetry 0.3

Package for processing polarised images to measure stress in granular media

photoelastimetry

Package for processing polarised images to measure stress in granular media

Installation

To install the package, run the following command in the terminal:

pip install photoelastimetry

Usage

After installation, two command line scripts are available:

image-to-stress

Converts photoelastic images to stress maps using the stress-optic law and polarization analysis.

image-to-stress <json_filename> [--output OUTPUT] [--polariser-angle ANGLE]

Arguments:

• json_filename: Path to the JSON5 parameter file containing configuration (required)
• --output: Path to save the output stress map image (optional)
• --polariser-angle: Polariser angle in degrees relative to the 0 degree camera axis (default: 0.0)

Example:

image-to-stress params.json5 --output stress_map.png --polariser-angle 45.0

The JSON5 parameter file should contain:

• folderName: Path to folder containing raw photoelastic images
• C: Stress-optic coefficient in 1/Pa
• thickness: Sample thickness in meters
• wavelengths: List of wavelengths in nanometers
• crop (optional): Crop region as [y1, y2, x1, x2]
• debug (optional): If true, display all channels for debugging

stress-to-image

Converts stress field data to photoelastic fringe pattern images.

stress-to-image <json_filename>

Arguments:

• json_filename: Path to the JSON5 parameter file containing configuration (required)

Example:

stress-to-image params.json5

The JSON5 parameter file should contain:

• p_filename: Path to the photoelastimetry parameter file
• stress_filename: Path to the stress field data file
• t: Thickness of the photoelastic material
• lambda_light: Wavelength of light used in the experiment
• C: Stress-optic coefficient of the material
• scattering (optional): Gaussian filter sigma for scattering simulation
• output_filename (optional): Path for the output image (default: "output.png")

Development

To set up the development environment, clone the repository and install the package in editable mode:

git clone https://github.com/benjym/photoelastimetry.git
cd photoelastimetry
pip install -e .

Authors

• Benjy Marks
• Qianyu Fang