Generate footprints (structuring elements)

This example shows how to use functions in skimage.morphology to generate footprints (structuring elements) for use in morphology operations. The title of each plot indicates the call of the function.

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D

from skimage.morphology import (
    footprint_rectangle,
    diamond,
    disk,
    octahedron,
    ball,
    octagon,
    star,
)

# Generate 2D and 3D structuring elements.
struc_2d = {
    "square 15x15": footprint_rectangle((15, 15)),
    "rectangle 15x10": footprint_rectangle((15, 10)),
    "diamond(7)": diamond(7),
    "disk(7)": disk(7),
    "octagon(7, 4)": octagon(7, 4),
    "star(5)": star(5),
}

struc_3d = {
    "cube 11x11x11": footprint_rectangle((11, 11, 11)),
    "octahedron(5)": octahedron(5),
    "ball(5)": ball(5),
}

# Visualize the elements.
fig = plt.figure(figsize=(8, 8))

idx = 1
for title, struc in struc_2d.items():
    ax = fig.add_subplot(3, 3, idx)
    ax.imshow(struc, cmap="Paired", vmin=0, vmax=12)
    for i in range(struc.shape[0]):
        for j in range(struc.shape[1]):
            ax.text(j, i, struc[i, j], ha="center", va="center", color="w")
    ax.set_axis_off()
    ax.set_title(title)
    idx += 1

for title, struc in struc_3d.items():
    ax = fig.add_subplot(3, 3, idx, projection=Axes3D.name)
    ax.voxels(struc)
    ax.set_title(title)
    idx += 1

fig.tight_layout()
plt.show()