Python pywt.waverecn函数代码示例

def test_waverecn_empty_coeff():
    coeffs = [np.ones((2, 2, 2)), {}, {}]
    assert_equal(pywt.waverecn(coeffs, 'db1').shape, (8, 8, 8))

    assert_equal(pywt.waverecn(coeffs, 'db1').shape, (8, 8, 8))
    coeffs = [np.ones((2, 2, 2)), {}, {'daa': np.ones((4, 4, 4))}]

    coeffs = [np.ones((2, 2, 2)), {}, {}, {'daa': np.ones((8, 8, 8))}]
    assert_equal(pywt.waverecn(coeffs, 'db1').shape, (16, 16, 16))

def test_wavedecn_coeff_reshape_axes_subset():
    # verify round trip is correct when only a subset of axes are transformed:
    #   wavedecn - >coeffs_to_array-> array_to_coeffs -> waverecn
    # This is done for wavedec{1, 2, n}
    rng = np.random.RandomState(1234)
    mode = 'symmetric'
    w = pywt.Wavelet('db2')
    N = 16
    ndim = 3
    for axes in [(-1, ), (0, ), (1, ), (0, 1), (1, 2), (0, 2), None]:
        x1 = rng.randn(*([N] * ndim))
        coeffs = pywt.wavedecn(x1, w, mode=mode, axes=axes)
        coeff_arr, coeff_slices = pywt.coeffs_to_array(coeffs, axes=axes)
        if axes is not None:
            # if axes is not None, it must be provided to coeffs_to_array
            assert_raises(ValueError, pywt.coeffs_to_array, coeffs)

        # mismatched axes size
        assert_raises(ValueError, pywt.coeffs_to_array, coeffs,
                      axes=(0, 1, 2, 3))
        assert_raises(ValueError, pywt.coeffs_to_array, coeffs,
                      axes=())

        coeffs2 = pywt.array_to_coeffs(coeff_arr, coeff_slices)
        x1r = pywt.waverecn(coeffs2, w, mode=mode, axes=axes)

        assert_allclose(x1, x1r, rtol=1e-4, atol=1e-4)

def test_waverecn():
    rstate = np.random.RandomState(1234)
    # test 1D through 4D cases
    for nd in range(1, 5):
        x = rstate.randn(*(4, )*nd)
        coeffs = pywt.wavedecn(x, 'db1')
        assert_(len(coeffs) == 3)
        assert_allclose(pywt.waverecn(coeffs, 'db1'), x, rtol=tol_double)

def test_waverecn_axes_subsets():
    rstate = np.random.RandomState(0)
    data = rstate.standard_normal((8, 8, 8, 8))
    # test all combinations of 3 out of 4 axes transformed
    for axes in combinations((0, 1, 2, 3), 3):
        coefs = pywt.wavedecn(data, 'haar', axes=axes)
        rec = pywt.waverecn(coefs, 'haar', axes=axes)
        assert_allclose(rec, data, atol=1e-14)

def test_waverecn_int_axis():
    # waverecn should also work for axes as an integer
    rstate = np.random.RandomState(0)
    data = rstate.standard_normal((8, 8))
    for axis in [0, 1]:
        coefs = pywt.wavedecn(data, 'haar', axes=axis)
        rec = pywt.waverecn(coefs, 'haar', axes=axis)
        assert_allclose(rec, data, atol=1e-14)

def test_waverecn_all_wavelets_modes():
    # test 2D case using all wavelets and modes
    rstate = np.random.RandomState(1234)
    r = rstate.randn(80, 96)
    for wavelet in wavelist:
        for mode in pywt.Modes.modes:
            coeffs = pywt.wavedecn(r, wavelet, mode=mode)
            assert_allclose(pywt.waverecn(coeffs, wavelet, mode=mode),
                            r, rtol=tol_single, atol=tol_single)

def _wavelet_threshold(img, wavelet, threshold=None, sigma=None, mode='soft'):
    """Performs wavelet denoising.

    Parameters
    ----------
    img : ndarray (2d or 3d) of ints, uints or floats
        Input data to be denoised. `img` can be of any numeric type,
        but it is cast into an ndarray of floats for the computation
        of the denoised image.
    wavelet : string
        The type of wavelet to perform. Can be any of the options
        pywt.wavelist outputs. For example, this may be any of ``{db1, db2,
        db3, db4, haar}``.
    sigma : float, optional
        The standard deviation of the noise. The noise is estimated when sigma
        is None (the default) by the method in [2]_.
    threshold : float, optional
        The thresholding value. All wavelet coefficients less than this value
        are set to 0. The default value (None) uses the SureShrink method found
        in [1]_ to remove noise.
    mode : {'soft', 'hard'}, optional
        An optional argument to choose the type of denoising performed. It
        noted that choosing soft thresholding given additive noise finds the
        best approximation of the original image.

    Returns
    -------
    out : ndarray
        Denoised image.

    References
    ----------
    .. [1] Chang, S. Grace, Bin Yu, and Martin Vetterli. "Adaptive wavelet
           thresholding for image denoising and compression." Image Processing,
           IEEE Transactions on 9.9 (2000): 1532-1546.
           DOI: 10.1109/83.862633
    .. [2] D. L. Donoho and I. M. Johnstone. "Ideal spatial adaptation
           by wavelet shrinkage." Biometrika 81.3 (1994): 425-455.
           DOI: 10.1093/biomet/81.3.425

    """
    coeffs = pywt.wavedecn(img, wavelet=wavelet)
    detail_coeffs = coeffs[-1]['d' * img.ndim]

    if sigma is None:
        # Estimates via the noise via method in [2]
        sigma = np.median(np.abs(detail_coeffs)) / 0.67448975019608171

    if threshold is None:
        # The BayesShrink threshold from [1]_ in docstring
        threshold = sigma**2 / np.sqrt(max(img.var() - sigma**2, 0))

    denoised_detail = [{key: pywt.threshold(level[key], value=threshold,
                       mode=mode) for key in level} for level in coeffs[1:]]
    denoised_root = pywt.threshold(coeffs[0], value=threshold, mode=mode)
    denoised_coeffs = [denoised_root] + [d for d in denoised_detail]
    return pywt.waverecn(denoised_coeffs, wavelet)

def test_waverecn_accuracies():
    # testing 3D only here
    rstate = np.random.RandomState(1234)
    x0 = rstate.randn(4, 4, 4)
    for dt, tol in dtypes_and_tolerances:
        x = x0.astype(dt)
        if np.iscomplexobj(x):
            x += 1j*rstate.randn(4, 4, 4).astype(x.real.dtype)
        coeffs = pywt.wavedecn(x.astype(dt), 'db1')
        assert_allclose(pywt.waverecn(coeffs, 'db1'), x, atol=tol, rtol=tol)

def test_per_axis_wavelets_and_modes():
    # tests seperate wavelet and edge mode for each axis.
    rstate = np.random.RandomState(1234)
    data = rstate.randn(24, 24, 16)

    # wavelet can be a string or wavelet object
    wavelets = (pywt.Wavelet('haar'), 'sym2', 'db2')

    # The default number of levels should be the minimum over this list
    max_levels = [pywt._dwt.dwt_max_level(nd, nf) for nd, nf in
                  zip(data.shape, wavelets)]

    # mode can be a string or a Modes enum
    modes = ('symmetric', 'periodization',
             pywt._extensions._pywt.Modes.reflect)

    coefs = pywt.wavedecn(data, wavelets, modes)
    assert_allclose(pywt.waverecn(coefs, wavelets, modes), data, atol=1e-14)
    assert_equal(min(max_levels), len(coefs[1:]))

    coefs = pywt.wavedecn(data, wavelets[:1], modes)
    assert_allclose(pywt.waverecn(coefs, wavelets[:1], modes), data,
                    atol=1e-14)

    coefs = pywt.wavedecn(data, wavelets, modes[:1])
    assert_allclose(pywt.waverecn(coefs, wavelets, modes[:1]), data,
                    atol=1e-14)

    # length of wavelets or modes doesn't match the length of axes
    assert_raises(ValueError, pywt.wavedecn, data, wavelets[:2])
    assert_raises(ValueError, pywt.wavedecn, data, wavelets, mode=modes[:2])
    assert_raises(ValueError, pywt.waverecn, coefs, wavelets[:2])
    assert_raises(ValueError, pywt.waverecn, coefs, wavelets, mode=modes[:2])

    # dwt2/idwt2 also support per-axis wavelets/modes
    data2 = data[..., 0]
    coefs2 = pywt.wavedec2(data2, wavelets[:2], modes[:2])
    assert_allclose(pywt.waverec2(coefs2, wavelets[:2], modes[:2]), data2,
                    atol=1e-14)
    assert_equal(min(max_levels[:2]), len(coefs2[1:]))

def test_multilevel_dtypes_nd():
    wavelet = pywt.Wavelet('haar')
    for dt_in, dt_out in zip(dtypes_in, dtypes_out):
        # wavedecn, waverecn
        x = np.ones((8, 8), dtype=dt_in)
        errmsg = "wrong dtype returned for {0} input".format(dt_in)
        cA, coeffsD2, coeffsD1 = pywt.wavedecn(x, wavelet, level=2)
        assert_(cA.dtype == dt_out, "wavedecn: " + errmsg)
        for key, c in coeffsD1.items():
            assert_(c.dtype == dt_out, "wavedecn: " + errmsg)
        for key, c in coeffsD2.items():
            assert_(c.dtype == dt_out, "wavedecn: " + errmsg)
        x_roundtrip = pywt.waverecn([cA, coeffsD2, coeffsD1], wavelet)
        assert_(x_roundtrip.dtype == dt_out, "waverecn: " + errmsg)

def PrintReconstructions(coeffs, n):
    arr, coeff_slices = pywt.coeffs_to_array(coeffs)

    #Removing Details
    for i in range(n,len(coeff_slices)):
        arr[coeff_slices[i]['ad']] = 0
        arr[coeff_slices[i]['dd']] = 0
        arr[coeff_slices[i]['da']] = 0
        
    D1 = pywt.array_to_coeffs(arr, coeff_slices)
    dCat = pywt.waverecn(D1, wavelet)
    
    plt.figure()
    plt.title('Reconstructed with level %i of details' %(n-1))
    plt.imshow(dCat,cmap=colormap)
    return

def test_waverecn_coeff_reshape_odd():
    # verify round trip is correct:
    #   wavedecn - >coeffs_to_array-> array_to_coeffs -> waverecn
    rng = np.random.RandomState(1234)
    x1 = rng.randn(35, 33)
    for mode in pywt.Modes.modes:
        for wave in ['haar', ]:
            w = pywt.Wavelet(wave)
            maxlevel = pywt.dwt_max_level(np.min(x1.shape), w.dec_len)
            if maxlevel == 0:
                continue
            coeffs = pywt.wavedecn(x1, w, mode=mode)
            coeff_arr, coeff_slices = pywt.coeffs_to_array(coeffs)
            coeffs2 = pywt.array_to_coeffs(coeff_arr, coeff_slices)
            x1r = pywt.waverecn(coeffs2, w, mode=mode)
            # truncate reconstructed values to original shape
            x1r = x1r[[slice(s) for s in x1.shape]]
            assert_allclose(x1, x1r, rtol=1e-4, atol=1e-4)

def test_wavedecn_complex():
    data = np.ones((4, 4, 4)) + 1j
    coeffs = pywt.wavedecn(data, 'db1')
    assert_allclose(pywt.waverecn(coeffs, 'db1'), data, rtol=1e-12)

def inverse_wavelet_transform(w_coeffs_rgb, coeff_slices, x_shape):
    x_hat = np.zeros(x_shape)
    for i in range(w_coeffs_rgb.shape[0]):
        w_coeffs_list = pywt.array_to_coeffs(w_coeffs_rgb[i,:,:], coeff_slices)
        x_hat[0,:,:,i] = pywt.waverecn(w_coeffs_list, wavelet='db4', mode='periodization')
    return x_hat

def apply_dwt_filter(y, dwt_type, dwt_level, dwt_thresh_func, dwt_thresh_type):
  coeffs = pywt.wavedecn(y, dwt_type, level=dwt_level)
  for i in range(1,dwt_level+1):
    coeffs[i]["d"] = pywt.threshold(coeffs[i]["d"], thselect(coeffs[i]["d"], dwt_thresh_type), dwt_thresh_func)
  return(pywt.waverecn(coeffs, dwt_type))