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https://github.com/wassname/scikit-image.git
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Tony S Yu
45 lines
911 B
Python
45 lines
911 B
Python
"""
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============
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Thresholding
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============
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Thresholding is used to create a binary image. This example uses Otsu's method
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to calculate the threshold value.
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Otsu's method calculates an "optimal" threshold by maximizing the variance
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between the two classes of pixels, which are separated by the threshold.
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Equivalently, the optimal threshold minimizes the intra-class variance.
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.. [1] http://en.wikipedia.org/wiki/Otsu's_method
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"""
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import matplotlib.pyplot as plt
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from skimage.data import camera
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from skimage.filter import threshold_otsu
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image = camera()
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thresh = threshold_otsu(image)
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binary = image > thresh
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plt.figure(figsize=(10, 3.5))
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plt.subplot(1, 3, 1)
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plt.imshow(image)
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plt.title('original')
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plt.axis('off')
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plt.subplot(1, 3, 2)
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plt.hist(image)
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plt.title('histogram')
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plt.axvline(thresh, color='r')
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plt.subplot(1, 3, 3)
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plt.imshow(binary)
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plt.title('thresholded')
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plt.axis('off')
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plt.show()
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