def test_4d_input_subpixel():
phantom = img_as_float(cp.asarray(binary_blobs(length=32, n_dim=4)))
reference_image = fft.fftn(phantom)
subpixel_shift = (-2.3, 1.7, 5.4, -3.2)
shifted_image = fourier_shift(reference_image, subpixel_shift)
result, error, diffphase = phase_cross_correlation(
reference_image, shifted_image, upsample_factor=10, space="fourier"
)
assert_allclose(result, -cp.asarray(subpixel_shift), atol=0.05)
def test_subpixel_precision():
reference_image = fft.fftn(cp.asarray(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.asarray(subpixel_shift), atol=0.05)
def test_size_one_dimension_input():
# take a strip of the input image
reference_image = fft.fftn(cp.asarray(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.asarray((-2.4, 0)), atol=0.05)
def test_correlation():
reference_image = fft.fftn(cp.asarray(camera()))
shift = (-7, 12)
shifted_image = fourier_shift(
reference_image, shift
) # TODO: replace with CUDA fourier_shift
# pixel precision
result, error, diffphase = phase_cross_correlation(
reference_image, shifted_image, space="fourier"
)
assert_allclose(result[:2], -cp.asarray(shift))
def test_3d_input():
phantom = img_as_float(cp.asarray(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.asarray(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.asarray(subpixel_shift), atol=0.05)