mirror of
https://github.com/wassname/scikit-image.git
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emmanuelle
55f5103dd8
Modified travis_script.sh to account for the new structure of the gallery Added README.txt files in directories of gallery examples Fixed references to gallery images in user guide pages Fixed broken links
43 lines
1.1 KiB
Python
43 lines
1.1 KiB
Python
"""
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===============================
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Piecewise Affine Transformation
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===============================
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This example shows how to use the Piecewise Affine Transformation.
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"""
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import numpy as np
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import matplotlib.pyplot as plt
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from skimage.transform import PiecewiseAffineTransform, warp
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from skimage import data
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image = data.astronaut()
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rows, cols = image.shape[0], image.shape[1]
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src_cols = np.linspace(0, cols, 20)
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src_rows = np.linspace(0, rows, 10)
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src_rows, src_cols = np.meshgrid(src_rows, src_cols)
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src = np.dstack([src_cols.flat, src_rows.flat])[0]
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# add sinusoidal oscillation to row coordinates
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dst_rows = src[:, 1] - np.sin(np.linspace(0, 3 * np.pi, src.shape[0])) * 50
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dst_cols = src[:, 0]
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dst_rows *= 1.5
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dst_rows -= 1.5 * 50
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dst = np.vstack([dst_cols, dst_rows]).T
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tform = PiecewiseAffineTransform()
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tform.estimate(src, dst)
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out_rows = image.shape[0] - 1.5 * 50
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out_cols = cols
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out = warp(image, tform, output_shape=(out_rows, out_cols))
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fig, ax = plt.subplots()
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ax.imshow(out)
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ax.plot(tform.inverse(src)[:, 0], tform.inverse(src)[:, 1], '.b')
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ax.axis((0, out_cols, out_rows, 0))
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plt.show()
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