def test_4d_input_pixel():
phantom = img_as_float(binary_blobs(length=32, n_dim=4))
reference_image = fft.fftn(phantom)
shift = (-2.0, 1.0, 5.0, -3)
shifted_image = fourier_shift(reference_image, shift)
result, error, diffphase = phase_cross_correlation(reference_image,
shifted_image,
space="fourier")
assert_allclose(result, -cp.array(shift), atol=0.05)
def test_correlation():
reference_image = fft.fftn(cp.array(camera()))
shift = (-7, 12)
shifted_image = fourier_shift(reference_image, shift)
# pixel precision
result, error, diffphase = phase_cross_correlation(reference_image,
shifted_image,
space="fourier")
assert_allclose(result[:2], -cp.array(shift))
def test_subpixel_precision():
reference_image = fft.fftn(cp.array(camera()))
subpixel_shift = (-2.4, 1.32)
shifted_image = fourier_shift(reference_image, subpixel_shift)
# subpixel precision
result, error, diffphase = phase_cross_correlation(reference_image,
shifted_image,
upsample_factor=100,
space="fourier")
assert_allclose(result[:2], -cp.array(subpixel_shift), atol=0.05)
def test_size_one_dimension_input():
# take a strip of the input image
reference_image = fft.fftn(cp.array(camera())[:, 15]).reshape((-1, 1))
subpixel_shift = (-2.4, 4)
shifted_image = fourier_shift(reference_image, subpixel_shift)
# subpixel precision
result, error, diffphase = phase_cross_correlation(reference_image,
shifted_image,
upsample_factor=20,
space="fourier")
assert_allclose(result[:2], -cp.array((-2.4, 0)), atol=0.05)
def test_real_input(dtype):
reference_image = cp.array(camera()).astype(dtype, copy=False)
subpixel_shift = (-2.4, 1.32)
shifted_image = fourier_shift(fft.fftn(reference_image), subpixel_shift)
shifted_image = fft.ifftn(shifted_image).real.astype(dtype, copy=False)
# subpixel precision
result, error, diffphase = phase_cross_correlation(reference_image,
shifted_image,
upsample_factor=100)
assert result.dtype == dtype
assert_allclose(result[:2], -cp.array(subpixel_shift), atol=0.05)
def test_3d_input():
phantom = img_as_float(binary_blobs(length=32, n_dim=3))
reference_image = fft.fftn(phantom)
shift = (-2.0, 1.0, 5.0)
shifted_image = fourier_shift(reference_image, shift)
result, error, diffphase = phase_cross_correlation(reference_image,
shifted_image,
space="fourier")
assert_allclose(result, -cp.array(shift), atol=0.05)
# subpixel precision now available for 3-D data
subpixel_shift = (-2.3, 1.7, 5.4)
shifted_image = fourier_shift(reference_image, subpixel_shift)
result, error, diffphase = phase_cross_correlation(reference_image,
shifted_image,
upsample_factor=100,
space="fourier")
assert_allclose(result, -cp.array(subpixel_shift), atol=0.05)