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iradon: use util.pad for sinogram padding.

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Jostein Bø Fløystad
2013-07-06 18:55:06 +02:00
parent b3746b9090
commit bea50aa608
1 changed files with 7 additions and 8 deletions
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skimage/transform/radon_transform.py
+7 -8
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@@ -182,16 +182,15 @@ def iradon(radon_image, theta=None, output_size=None,
radon_image = _sinogram_circle_to_square(radon_image)
th = (np.pi / 180.0) * theta
n = radon_image.shape[0]
img = radon_image.copy()
# resize image to next power of two for fourier analysis
# speeds up fourier and lessens artifacts
order = max(64., 2**np.ceil(np.log(2 * n) / np.log(2)))
# zero pad input image
img.resize((order, img.shape[1]))
# resize image to next power of two (but no less than 64) for
# Fourier analysis; speeds up Fourier and lessens artifacts
projection_size_padded = \
max(64, int(2**np.ceil(np.log2(2 * radon_image.shape[0]))))
pad_width = ((0, projection_size_padded - radon_image.shape[0]), (0, 0))
img = util.pad(radon_image, pad_width, mode='constant', constant_values=0)
# Construct the Fourier filter
f = fftshift(abs(np.mgrid[-1:1:2 / order])).reshape(-1, 1)
f = fftshift(abs(np.mgrid[-1:1:2 / projection_size_padded])).reshape(-1, 1)
w = 2 * np.pi * f
# Start from first element to avoid divide by zero
if filter == "ramp":