import numpy as np
from numpy.testing import run_module_suite, assert_raises

from skimage import filter, data, color, img_as_float


lena = img_as_float(data.lena()[:256, :256])
lena_gray = color.rgb2gray(lena)


def test_denoise_tv_chambolle_2d():
    # lena image
    img = lena_gray
    # add noise to lena
    img += 0.5 * img.std() * np.random.random(img.shape)
    # clip noise so that it does not exceed allowed range for float images.
    img = np.clip(img, 0, 1)
    # denoise
    denoised_lena = filter.denoise_tv_chambolle(img, weight=60.0)
    # which dtype?
    assert denoised_lena.dtype in [np.float, np.float32, np.float64]
    from scipy import ndimage
    grad = ndimage.morphological_gradient(img, size=((3, 3)))
    grad_denoised = ndimage.morphological_gradient(
        denoised_lena, size=((3, 3)))
    # test if the total variation has decreased
    assert grad_denoised.dtype == np.float
    assert (np.sqrt((grad_denoised**2).sum())
            < np.sqrt((grad**2).sum()) / 2)


def test_denoise_tv_chambolle_float_result_range():
    # lena image
    img = lena_gray
    int_lena = np.multiply(img, 255).astype(np.uint8)
    assert np.max(int_lena) > 1
    denoised_int_lena = filter.denoise_tv_chambolle(int_lena, weight=60.0)
    # test if the value range of output float data is within [0.0:1.0]
    assert denoised_int_lena.dtype == np.float
    assert np.max(denoised_int_lena) <= 1.0
    assert np.min(denoised_int_lena) >= 0.0


def test_denoise_tv_chambolle_3d():
    """Apply the TV denoising algorithm on a 3D image representing a sphere."""
    x, y, z = np.ogrid[0:40, 0:40, 0:40]
    mask = (x - 22)**2 + (y - 20)**2 + (z - 17)**2 < 8**2
    mask = 100 * mask.astype(np.float)
    mask += 60
    mask += 20 * np.random.random(mask.shape)
    mask[mask < 0] = 0
    mask[mask > 255] = 255
    res = filter.denoise_tv_chambolle(mask.astype(np.uint8), weight=100)
    assert res.dtype == np.float
    assert res.std() * 255 < mask.std()

    # test wrong number of dimensions
    assert_raises(ValueError, filter.denoise_tv_chambolle,
                  np.random.random((8, 8, 8, 8)))


def test_denoise_tv_bregman_2d():
    img = lena_gray
    # add some random noise
    img += 0.5 * img.std() * np.random.random(img.shape)
    img = np.clip(img, 0, 1)

    out1 = filter.denoise_tv_bregman(img, weight=10)
    out2 = filter.denoise_tv_bregman(img, weight=5)

    # make sure noise is reduced
    assert img.std() > out1.std()
    assert out1.std() > out2.std()


def test_denoise_tv_bregman_float_result_range():
    # lena image
    img = lena_gray
    int_lena = np.multiply(img, 255).astype(np.uint8)
    assert np.max(int_lena) > 1
    denoised_int_lena = filter.denoise_tv_bregman(int_lena, weight=60.0)
    # test if the value range of output float data is within [0.0:1.0]
    assert denoised_int_lena.dtype == np.float
    assert np.max(denoised_int_lena) <= 1.0
    assert np.min(denoised_int_lena) >= 0.0


def test_denoise_tv_bregman_3d():
    img = lena
    # add some random noise
    img += 0.5 * img.std() * np.random.random(img.shape)
    img = np.clip(img, 0, 1)

    out1 = filter.denoise_tv_bregman(img, weight=10)
    out2 = filter.denoise_tv_bregman(img, weight=5)

    # make sure noise is reduced
    assert img.std() > out1.std()
    assert out1.std() > out2.std()


def test_denoise_bilateral_2d():
    img = lena_gray
    # add some random noise
    img += 0.5 * img.std() * np.random.random(img.shape)
    img = np.clip(img, 0, 1)

    out1 = filter.denoise_bilateral(img, sigma_range=0.1, sigma_spatial=20)
    out2 = filter.denoise_bilateral(img, sigma_range=0.2, sigma_spatial=30)

    # make sure noise is reduced
    assert img.std() > out1.std()
    assert out1.std() > out2.std()


def test_denoise_bilateral_3d():
    img = lena
    # add some random noise
    img += 0.5 * img.std() * np.random.random(img.shape)
    img = np.clip(img, 0, 1)

    out1 = filter.denoise_bilateral(img, sigma_range=0.1, sigma_spatial=20)
    out2 = filter.denoise_bilateral(img, sigma_range=0.2, sigma_spatial=30)

    # make sure noise is reduced
    assert img.std() > out1.std()
    assert out1.std() > out2.std()


if __name__ == "__main__":
    run_module_suite()

@@ -69,16 +69,30 @@
 t_raises
+, assert_equal
 %0A%0Afrom s
@@ -1009,24 +1009,270 @@
 m()) / 2)%0A%0A%0A
+def test_denoise_tv_chambolle_multichannel():%0A    denoised0 = filter.denoise_tv_chambolle(lena%5B..., 0%5D, weight=60.0)%0A    denoised = filter.denoise_tv_chambolle(lena, weight=60.0, multichannel=True)%0A    assert_equal(denoised%5B..., 0%5D, denoised0)%0A%0A%0A
 def test_den

Add test case for multi-channel chambolle denoising