Pywayne Cv Geometric Hull Calculator

Geometric hull calculator for 2D point sets supporting convex hull, concave hull (concave-hull, alphashape), and minimum bounding rectangle. Use when working with pywayne.cv.geometric_hull_calculator module to compute geometric hulls, visualize results with OpenCV or matplotlib, and generate random test point sets.

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Install

openclaw skills install geometric-hull-calculator

Pywayne Geometric Hull Calculator

This module computes geometric hulls (convex and concave) for 2D point sets.

Quick Start

from pywayne.cv.geometric_hull_calculator import GeometricHullCalculator
import numpy as np

# Create calculator with random points
points = GeometricHullCalculator.generate_random_points(num_points=50)
calculator = GeometricHullCalculator(points, algorithm='concave-hull')

# Get results
print(f"MBR: {calculator.get_mbr()}")
print(f"Convex Hull: {calculator.get_convex_hull()}")
print(f"Concave Hull: {calculator.get_concave_hull()}")

# Visualize with matplotlib
calculator.visualize_matplotlib()

Initialization

# algorithm options: 'concave-hull' or 'alphashape'
# use_filtered_pts: Enable point filtering based on radius
calculator = GeometricHullCalculator(
    points=your_points,
    algorithm='alphashape',
    use_filtered_pts=True
)

Supported Algorithms

Algorithm	Description
`concave-hull`	Concave hull using concave_hull library
`alphashape`	Concave hull using alphashape library

Hull Types

Type	Method	Description
Convex Hull	`get_convex_hull()`	Outer hull containing all points
Concave Hull	`get_concave_hull()`	Inner concave boundary

Properties

Property	Description
`points`	Input 2D points (N×2 numpy array)
`algorithm`	Algorithm used for concave hull
`use_filtered_pts`	Whether filtered points were used
`box`	Minimum Bounding Rectangle corners
`center`	Center point of input points
`filter_radius`	Radius used for point filtering
`concave_hull_result`	Concave hull points or polygons

Visualization

OpenCV Visualization

calculator.visualize_opencv()

Displays: All input points, MBR, center, filter circle (if enabled), concave hull (green), convex hull (red).

Matplotlib Visualization

calculator.visualize_matplotlib()

Displays: All input points (red), MBR (blue), center, filter radius circle (if enabled), concave hull (orange), convex hull (purple).

Requirements

numpy - Array operations
cv2 (OpenCV) - For OpenCV visualization and MBR computation
matplotlib - For matplotlib visualization
scipy - For convex hull computation
concave_hull - Concave hull algorithm
alphashape - Alphashape algorithm
shapely - Polygon operations for area calculation

Notes

Point filtering uses radius = 30% of shorter MBR edge length
MBR computed using OpenCV's minAreaRect
Convex hull uses scipy's ConvexHull
Supports both single Polygon and MultiPolygon from alphashape results