mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-29 03:04:42 +08:00
Neil Yager
61 lines
1.7 KiB
Python
61 lines
1.7 KiB
Python
import numpy as np
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from numpy.testing import assert_array_almost_equal
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from skimage.transform.project import _stackcopy
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from skimage.transform import homography, fast_homography
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from skimage import data
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from skimage.color import rgb2gray
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def test_stackcopy():
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layers = 4
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x = np.empty((3, 3, layers))
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y = np.eye(3, 3)
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_stackcopy(x, y)
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for i in range(layers):
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assert_array_almost_equal(x[...,i], y)
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def test_homography():
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x = np.arange(9, dtype=np.uint8).reshape((3, 3)) + 1
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theta = -np.pi/2
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M = np.array([[np.cos(theta),-np.sin(theta),0],
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[np.sin(theta), np.cos(theta),2],
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[0, 0, 1]])
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x90 = homography(x, M, order=1)
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assert_array_almost_equal(x90, np.rot90(x))
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def test_fast_homography():
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img = rgb2gray(data.lena()).astype(np.uint8)
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img = img[:, :100]
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theta = np.deg2rad(30)
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scale = 0.5
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tx, ty = 50, 50
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H = np.eye(3)
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S = scale * np.sin(theta)
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C = scale * np.cos(theta)
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H[:2, :2] = [[C, -S], [S, C]]
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H[:2, 2] = [tx, ty]
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for mode in ('constant', 'mirror', 'wrap'):
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p0 = homography(img, H, mode=mode, order=1)
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p1 = fast_homography(img, H, mode=mode)
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p1 = np.round(p1)
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## import matplotlib.pyplot as plt
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## f, (ax0, ax1, ax2, ax3) = plt.subplots(1, 4)
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## ax0.imshow(img)
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## ax1.imshow(p0, cmap=plt.cm.gray)
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## ax2.imshow(p1, cmap=plt.cm.gray)
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## ax3.imshow(np.abs(p0 - p1), cmap=plt.cm.gray)
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## plt.show()
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d = np.mean(np.abs(p0 - p1))
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assert d < 0.2
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if __name__ == "__main__":
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from numpy.testing import run_module_suite
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run_module_suite()
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