mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-28 02:01:40 +08:00
Tony S Yu
58 lines
1.4 KiB
Python
58 lines
1.4 KiB
Python
"""
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===============
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Radon transform
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===============
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The radon transform is a technique widely used in tomography to
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reconstruct an object from different projections. A projection is, for
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example, the scattering data obtained as the output of a tomographic
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scan.
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For more information see:
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- http://en.wikipedia.org/wiki/Radon_transform
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- http://www.clear.rice.edu/elec431/projects96/DSP/bpanalysis.html
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This script performs the radon transform, and reconstructs the
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input image based on the resulting sinogram.
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"""
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import matplotlib.pyplot as plt
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from skimage.io import imread
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from skimage import data_dir
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from skimage.transform import radon, iradon
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from scipy.ndimage import zoom
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image = imread(data_dir + "/phantom.png", as_grey=True)
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image = zoom(image, 0.4)
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plt.figure(figsize=(8, 8.5))
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plt.subplot(221)
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plt.title("Original");
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plt.imshow(image, cmap=plt.cm.Greys_r)
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plt.subplot(222)
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projections = radon(image, theta=[0, 45, 90])
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plt.plot(projections);
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plt.title("Projections at\n0, 45 and 90 degrees")
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plt.xlabel("Projection axis");
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plt.ylabel("Intensity");
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projections = radon(image)
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plt.subplot(223)
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plt.title("Radon transform\n(Sinogram)");
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plt.xlabel("Projection axis");
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plt.ylabel("Intensity");
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plt.imshow(projections)
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reconstruction = iradon(projections)
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plt.subplot(224)
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plt.title("Reconstruction\nfrom sinogram")
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plt.imshow(reconstruction, cmap=plt.cm.Greys_r)
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plt.subplots_adjust(hspace=0.4, wspace=0.5)
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plt.show()
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