1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
import numpy as np
import matplotlib.pyplot as plt
from scipy import ndimage
img = np.array([-2, -1, 0, 1, 2], float)
x = np.linspace(-2, 6, num=1000)
modes = ['constant', 'grid-constant', 'nearest', 'reflect', 'mirror', 'wrap',
'grid-wrap']
fig, axes = plt.subplots(len(modes), 3, figsize=(11, 8), sharex=True,
sharey=True)
for mode, (ax0, ax1, ax2) in zip(modes, axes):
y = ndimage.map_coordinates(img, [x], order=0, mode=mode)
ax0.scatter(np.arange(img.size), img)
ax0.plot(x, y, '-')
ax0.set_title(f'mode={mode}, order=0')
y2 = ndimage.map_coordinates(img, [x], order=1, mode=mode)
ax1.scatter(np.arange(img.size), img)
ax1.plot(x, y2, '-')
ax1.set_title(f'mode={mode}, order=1')
y3 = ndimage.map_coordinates(img, [x], order=3, mode=mode)
ax2.scatter(np.arange(img.size), img)
ax2.plot(x, y3, '-')
ax2.set_title(f'mode={mode}, order=3')
sz = len(img)
for ax in (ax0, ax1, ax2):
if mode in ['grid-wrap', 'reflect']:
ax.plot([-0.5, -0.5], [-2.5, 2.5], 'k--')
ax.plot([sz - 0.5, sz - 0.5], [-2.5, 2.5], 'k--')
elif mode in ['wrap', 'mirror']:
ax.plot([0, 0], [-2.5, 2.5], 'k--')
ax.plot([sz - 1, sz - 1], [-2.5, 2.5], 'k--')
if mode != 'constant':
for xx in range(int(x[0]), int(x[-1] + 1)):
if (xx < 0) or (xx > img.size - 1):
idx = np.argmin(np.abs(x - xx))
for y_vals, ax in zip((y, y2, y3), (ax0, ax1, ax2)):
ax.scatter(
[x[idx]], [y_vals[idx]], facecolors='none',
edgecolor='#0343df', marker='o'
)
plt.tight_layout()
plt.show()
|
