mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-28 03:34:59 +08:00
Johannes Schönberger
318 lines
8.8 KiB
Python
318 lines
8.8 KiB
Python
from numpy.testing import (assert_almost_equal, run_module_suite,
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assert_equal, assert_raises)
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import numpy as np
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from scipy.ndimage import map_coordinates
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from skimage.transform import (warp, warp_coords, rotate, resize, rescale,
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AffineTransform,
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ProjectiveTransform,
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SimilarityTransform,
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downscale_local_mean)
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from skimage import transform as tf, data, img_as_float
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from skimage.color import rgb2gray
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from skimage._shared._warnings import expected_warnings
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from skimage._shared.testing import test_parallel
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np.random.seed(0)
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def test_warp_tform():
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x = np.zeros((5, 5), dtype=np.double)
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x[2, 2] = 1
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theta = - np.pi / 2
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tform = SimilarityTransform(scale=1, rotation=theta, translation=(0, 4))
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x90 = warp(x, tform, order=1)
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assert_almost_equal(x90, np.rot90(x))
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x90 = warp(x, tform.inverse, order=1)
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assert_almost_equal(x90, np.rot90(x))
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def test_warp_callable():
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x = np.zeros((5, 5), dtype=np.double)
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x[2, 2] = 1
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refx = np.zeros((5, 5), dtype=np.double)
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refx[1, 1] = 1
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shift = lambda xy: xy + 1
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outx = warp(x, shift, order=1)
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assert_almost_equal(outx, refx)
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@test_parallel()
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def test_warp_matrix():
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x = np.zeros((5, 5), dtype=np.double)
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x[2, 2] = 1
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refx = np.zeros((5, 5), dtype=np.double)
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refx[1, 1] = 1
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matrix = np.array([[1, 0, 1], [0, 1, 1], [0, 0, 1]])
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# _warp_fast
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outx = warp(x, matrix, order=1)
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assert_almost_equal(outx, refx)
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# check for ndimage.map_coordinates
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outx = warp(x, matrix, order=5)
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def test_warp_nd():
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for dim in range(2, 8):
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shape = dim * (5,)
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x = np.zeros(shape, dtype=np.double)
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x_c = dim * (2,)
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x[x_c] = 1
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refx = np.zeros(shape, dtype=np.double)
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refx_c = dim * (1,)
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refx[refx_c] = 1
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coord_grid = dim * (slice(0, 5, 1),)
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coords = np.array(np.mgrid[coord_grid]) + 1
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outx = warp(x, coords, order=0, cval=0)
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assert_almost_equal(outx, refx)
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def test_warp_clip():
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x = np.zeros((5, 5), dtype=np.double)
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x[2, 2] = 1
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outx = rescale(x, 3, order=3, clip=False)
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assert outx.min() < 0
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outx = rescale(x, 3, order=3, clip=True)
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assert_almost_equal(outx.min(), 0)
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assert_almost_equal(outx.max(), 1)
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def test_homography():
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x = np.zeros((5, 5), dtype=np.double)
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x[1, 1] = 1
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theta = -np.pi / 2
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M = np.array([[np.cos(theta), - np.sin(theta), 0],
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[np.sin(theta), np.cos(theta), 4],
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[0, 0, 1]])
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x90 = warp(x,
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inverse_map=ProjectiveTransform(M).inverse,
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order=1)
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assert_almost_equal(x90, np.rot90(x))
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def test_rotate():
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x = np.zeros((5, 5), dtype=np.double)
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x[1, 1] = 1
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x90 = rotate(x, 90)
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assert_almost_equal(x90, np.rot90(x))
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def test_rotate_resize():
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x = np.zeros((10, 10), dtype=np.double)
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x45 = rotate(x, 45, resize=False)
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assert x45.shape == (10, 10)
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x45 = rotate(x, 45, resize=True)
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# new dimension should be d = sqrt(2 * (10/2)^2)
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assert x45.shape == (14, 14)
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def test_rotate_center():
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x = np.zeros((10, 10), dtype=np.double)
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x[4, 4] = 1
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refx = np.zeros((10, 10), dtype=np.double)
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refx[2, 5] = 1
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x20 = rotate(x, 20, order=0, center=(0, 0))
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assert_almost_equal(x20, refx)
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x0 = rotate(x20, -20, order=0, center=(0, 0))
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assert_almost_equal(x0, x)
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def test_rotate_resize_center():
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x = np.zeros((10, 10), dtype=np.double)
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x[0, 0] = 1
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ref_x45 = np.zeros((14, 14), dtype=np.double)
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ref_x45[6, 0] = 1
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ref_x45[7, 0] = 1
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x45 = rotate(x, 45, resize=True, center=(3, 3), order=0)
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# new dimension should be d = sqrt(2 * (10/2)^2)
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assert x45.shape == (14, 14)
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assert_equal(x45, ref_x45)
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def test_rescale():
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# same scale factor
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x = np.zeros((5, 5), dtype=np.double)
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x[1, 1] = 1
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scaled = rescale(x, 2, order=0)
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ref = np.zeros((10, 10))
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ref[2:4, 2:4] = 1
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assert_almost_equal(scaled, ref)
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# different scale factors
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x = np.zeros((5, 5), dtype=np.double)
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x[1, 1] = 1
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scaled = rescale(x, (2, 1), order=0)
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ref = np.zeros((10, 5))
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ref[2:4, 1] = 1
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assert_almost_equal(scaled, ref)
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def test_resize2d():
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x = np.zeros((5, 5), dtype=np.double)
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x[1, 1] = 1
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resized = resize(x, (10, 10), order=0)
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ref = np.zeros((10, 10))
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ref[2:4, 2:4] = 1
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assert_almost_equal(resized, ref)
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def test_resize3d_keep():
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# keep 3rd dimension
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x = np.zeros((5, 5, 3), dtype=np.double)
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x[1, 1, :] = 1
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resized = resize(x, (10, 10), order=0)
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ref = np.zeros((10, 10, 3))
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ref[2:4, 2:4, :] = 1
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assert_almost_equal(resized, ref)
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resized = resize(x, (10, 10, 3), order=0)
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assert_almost_equal(resized, ref)
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def test_resize3d_resize():
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# resize 3rd dimension
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x = np.zeros((5, 5, 3), dtype=np.double)
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x[1, 1, :] = 1
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resized = resize(x, (10, 10, 1), order=0)
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ref = np.zeros((10, 10, 1))
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ref[2:4, 2:4] = 1
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assert_almost_equal(resized, ref)
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def test_resize3d_2din_3dout():
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# 3D output with 2D input
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x = np.zeros((5, 5), dtype=np.double)
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x[1, 1] = 1
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resized = resize(x, (10, 10, 1), order=0)
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ref = np.zeros((10, 10, 1))
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ref[2:4, 2:4] = 1
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assert_almost_equal(resized, ref)
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def test_resize3d_bilinear():
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# bilinear 3rd dimension
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x = np.zeros((5, 5, 2), dtype=np.double)
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x[1, 1, 0] = 0
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x[1, 1, 1] = 1
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resized = resize(x, (10, 10, 1), order=1)
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ref = np.zeros((10, 10, 1))
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ref[1:5, 1:5, :] = 0.03125
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ref[1:5, 2:4, :] = 0.09375
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ref[2:4, 1:5, :] = 0.09375
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ref[2:4, 2:4, :] = 0.28125
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assert_almost_equal(resized, ref)
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def test_swirl():
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image = img_as_float(data.checkerboard())
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swirl_params = {'radius': 80, 'rotation': 0, 'order': 2, 'mode': 'reflect'}
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with expected_warnings(['Bi-quadratic.*bug']):
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swirled = tf.swirl(image, strength=10, **swirl_params)
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unswirled = tf.swirl(swirled, strength=-10, **swirl_params)
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assert np.mean(np.abs(image - unswirled)) < 0.01
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def test_const_cval_out_of_range():
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img = np.random.randn(100, 100)
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cval = - 10
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warped = warp(img, AffineTransform(translation=(10, 10)), cval=cval)
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assert np.sum(warped == cval) == (2 * 100 * 10 - 10 * 10)
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def test_warp_identity():
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img = img_as_float(rgb2gray(data.astronaut()))
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assert len(img.shape) == 2
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assert np.allclose(img, warp(img, AffineTransform(rotation=0)))
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assert not np.allclose(img, warp(img, AffineTransform(rotation=0.1)))
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rgb_img = np.transpose(np.asarray([img, np.zeros_like(img), img]),
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(1, 2, 0))
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warped_rgb_img = warp(rgb_img, AffineTransform(rotation=0.1))
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assert np.allclose(rgb_img, warp(rgb_img, AffineTransform(rotation=0)))
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assert not np.allclose(rgb_img, warped_rgb_img)
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# assert no cross-talk between bands
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assert np.all(0 == warped_rgb_img[:, :, 1])
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def test_warp_coords_example():
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image = data.astronaut().astype(np.float32)
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assert 3 == image.shape[2]
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tform = SimilarityTransform(translation=(0, -10))
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coords = warp_coords(tform, (30, 30, 3))
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map_coordinates(image[:, :, 0], coords[:2])
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def test_downscale_local_mean():
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image1 = np.arange(4 * 6).reshape(4, 6)
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out1 = downscale_local_mean(image1, (2, 3))
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expected1 = np.array([[ 4., 7.],
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[ 16., 19.]])
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assert_equal(expected1, out1)
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image2 = np.arange(5 * 8).reshape(5, 8)
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out2 = downscale_local_mean(image2, (4, 5))
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expected2 = np.array([[ 14. , 10.8],
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[ 8.5, 5.7]])
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assert_equal(expected2, out2)
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def test_invalid():
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assert_raises(ValueError, warp, np.ones((4, 3, 3, 3)),
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SimilarityTransform())
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def test_inverse():
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tform = SimilarityTransform(scale=0.5, rotation=0.1)
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inverse_tform = SimilarityTransform(matrix=np.linalg.inv(tform.params))
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image = np.arange(10 * 10).reshape(10, 10).astype(np.double)
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assert_equal(warp(image, inverse_tform), warp(image, tform.inverse))
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def test_slow_warp_nonint_oshape():
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image = np.random.rand(5, 5)
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assert_raises(ValueError, warp, image, lambda xy: xy,
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output_shape=(13.1, 19.5))
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warp(image, lambda xy: xy, output_shape=(13.0001, 19.9999))
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def test_keep_range():
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image = np.linspace(0, 2, 25).reshape(5, 5)
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out = rescale(image, 2, preserve_range=False, clip=True, order=0)
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assert out.min() == 0
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assert out.max() == 2
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out = rescale(image, 2, preserve_range=True, clip=True, order=0)
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assert out.min() == 0
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assert out.max() == 2
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out = rescale(image.astype(np.uint8), 2, preserve_range=False,
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clip=True, order=0)
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assert out.min() == 0
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assert out.max() == 2 / 255.0
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if __name__ == "__main__":
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run_module_suite()
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