pendantdroppy 1.0.1

pendantdroppy - Tensiometry software for droplet shape analysis using Young-Laplace fitting

pendantdroppy - Tensiometry Analysis Software

A PyQt6-based GUI application for analyzing droplet shape using Young-Laplace equation fitting and Bond number calculation.

Installation

Prerequisites

• Python 3.8 or higher
• pip (Python package manager)

From PyPI

pip install pendantdroppy

From Source

# Clone the repository
git clone https://github.com/pendantdroppy/pendantdroppy.git
cd pendantdroppy

# Install in development mode
pip install -e .

# Or install normally
pip install .

Manual Installation

# Install dependencies
pip install opencv-python PyQt6 numpy

# Run the GUI
python droppy.py

Usage

GUI Application

droppy

Or run directly:

python droppy.py

Workflow

1. Select Image - Browse for droplet image (PNG, JPG, etc.)
2. Draw Geometry - Interactive cv2 window to define:
   • ROI (Region of Interest)
   • Needle line (for diameter calibration)
3. Configure Parameters - Adjust processing and analysis settings across tabs
4. Save Settings - Button to save current configuration to droppy.conf
5. Run Analysis - Click "RUN ANALYSIS" to:
   • Run low clarity fit
   • Run high clarity fit
   • Average Bond numbers
6. View Results - See overlaid YL curve, plateau points, and extrema

Settings File

Configuration is automatically saved to droplet_out/droppy.conf.

On startup, the program loads from this file if it exists, otherwise uses defaults.

Example droppy.conf:

{
  "droplet_type": "rising",
  "needle_diameter_mm": 0.72,
  "sigma": 2.0,
  "canny1": 40,
  "canny2": 120,
  "plateau_width": 100,
  "lensing_factor": 1.0,
  "low_clarity_ratio": 0.1,
  "high_clarity_ratio": 0.01
}

Output Files

Analysis generates:

• result_yl_overlay.png - Young-Laplace curve fitted to droplet
• edges.png - Edge detection result
• summary.json - Numerical results (Bond numbers, calibration)
• droplet_edge_results.csv - Detailed point-by-point analysis

Parameters Explained

Image Processing

• Blur Sigma - Gaussian blur for noise reduction
• Canny Low/High - Edge detection thresholds

Contour Analysis

• Num Points - Number of contour points to sample
• Direction - Traversal direction (+1 or -1)
• Min r', z' - Minimum thresholds to avoid numerical blowup

Analysis

• Plateau Width - Number of points centered on equator
• Lensing Factor - Optical correction (1.0 = no correction)
• Clarity Ratios - Window fractions for low/high clarity runs
• Bo Wiggle Room - Expansion of Bond number search range

Visualization Colors

• Red - Young-Laplace theoretical curve (averaged Bond number)
• Yellow - Plateau region (fitting region around equator)
• Grey - Extrema points (tip, center, left, right)

Troubleshooting

"No contours found" - Adjust Canny thresholds or sigma "Bo ~0 for rising droplets" - Ensure plateau is centered on equator, edit sigma, or redraw needle line, it honestly can be pixels in it. Config not loading - Check droppy.conf is valid JSON in output directory

Contributing

Contributions welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Submit a pull request

Support

For issues, feature requests, or questions:

• Open an issue on GitHub
• Check existing documentation
• Review analysis parameters

Acknowledgments

Based on Young-Laplace equation analysis for axisymmetric droplets.

References:

• Bashforth, F., & Adams, J. C. (1883). "An attempt to test the theories of capillary action"
• Rotenberg, Y., Boruvka, L., & Neumann, A. W. (1983). "Determination of surface tension and contact angle from the shapes of axisymmetric fluid interfaces"