mirror of
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Johannes Schönberger
35 lines
810 B
Python
35 lines
810 B
Python
"""
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====================
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Approximate Polygons
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====================
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This example shows how to approximate polygonal chains with the Douglas-Peucker
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algorithm.
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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.draw import ellipse
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from skimage.measure import find_contours, approximate_polygon
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img = np.zeros((800, 800), 'int32')
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rr, cc = ellipse(250, 250, 180, 230, img.shape)
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img[rr, cc] = 1
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rr, cc = ellipse(600, 600, 150, 90, img.shape)
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img[rr, cc] = 1
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plt.gray()
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plt.imshow(img)
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for contour in find_contours(img, 0):
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coords = approximate_polygon(contour, 4)
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plt.plot(coords[:, 1], coords[:, 0], '-r', linewidth=2)
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coords = approximate_polygon(contour, 40)
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plt.plot(coords[:, 1], coords[:, 0], '-g', linewidth=2)
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plt.axis((0, 800, 0, 800))
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plt.axis('off')
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plt.show()
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