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 (
    square,
    rectangle,
    diamond,
    disk,
    cube,
    octahedron,
    ball,
    octagon,
    star,
)

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

struc_3d = {"cube(11)": cube(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()