生成足迹（结构元素）

这个示例展示了如何使用 skimage.morphology 中的函数来生成用于形态学操作的足迹（结构元素）。每个图的标题表示函数的调用。

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()