def denoise(nblck,filename,mode='sym', wv='sym5' ):
from statsmodels.robust import mad
#noisy_coefs = pywt.wavedec(nblck, 'sym5', level=5, mode='per')
noisy_coefs = pywt.wavedec(nblck, wavelet=wv, mode=mode) #level=5, #dwt is for single level decomposition; wavedecoding is for more levels
sigma = mad(noisy_coefs[-1])
#uthresh=np.std(ca)/2
uthresh = sigma*np.sqrt(2*np.log(len(nblck)))
denoised = noisy_coefs[:]
denoised[1:] = [pywt.threshold(i, value=uthresh,mode='soft') for i in denoised[1:]]
signal = pywt.waverec(denoised, wavelet=wv, mode=mode)
from matplotlib import pyplot as plt
fig, axes = plt.subplots(1, 2, sharey=True, sharex=True,figsize=(8,4))
ax1, ax2 = axes
ax1.plot(signal)
#ax1.set_xlim(0,2**10)
ax1.set_title("Recovered Signal")
ax1.margins(.1)
ax2.plot(nblck)
ax2.set_title("Noisy Signal")
for ax in fig.axes:
ax.tick_params(labelbottom=False, top=False, bottom=False, left=False, right=False)
fig.tight_layout()
fig.savefig(filename+'_'+wv+'.pdf')
plt.clf()
return signal
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 denoise(self, series, configs):
#perform normalization
normalized = (series - series.mean()) / (series.max() - series.min())
#WaveShrink
cA, cD = pywt.dwt(normalized,
configs['preprocessing']['denoise']['wavelet'])
#threshold selection
thr = np.std(normalized) / 23
cA_shrinked = pywt.threshold(
cA, thr, mode=configs['preprocessing']['denoise']['thr_mode'])
cD_shrinked = pywt.threshold(
cD, thr, mode=configs['preprocessing']['denoise']['thr_mode'])
#reconstructs data from the given shrinked coefficients
denoised = pywt.idwt(cA_shrinked, cD_shrinked,
configs['preprocessing']['denoise']['wavelet'])
if len(denoised) > len(normalized):
denoised = denoised[:-1]
# what???!!!
if len(denoised.shape) > 1:
denoised = [x[0] for x in denoised]
self.normalized = normalized
self.denoised = denoised
def apply_threshold(output, scaler = 1., input=None):
"""
output
approx and detail coefficients, arranged in level value
exactly as output from swt:
e.g. [(cA1, cD1), (cA2, cD2), ..., (cAn, cDn)]
scaler
float to allow runtime tuning of thresholding
input
vector with length len(output). If not None, these values are used for thresholding
if None, then the vector applies a calculation to estimate the proper thresholding
given this waveform.
"""
for j in range(len(output)):
cA, cD = output[j]
if input is None:
dev = np.median(np.abs(cD - np.median(cD)))/0.6745
thresh = math.sqrt(2*math.log(len(cD)))*dev*scaler
else:
threshA = scaler*input[j][0]
threshD = scaler*input[j][1]
cA = pywt.threshold(cA, threshA, 'soft')
cD = pywt.threshold(cD, threshD, 'soft')
output[j] = (cA, cD)
def wave(arr):
return_ = np.diff(arr)
# return_=return_[1:]
# close2 / close
# print(pywt.wavelist())
#Do the Wavelet Transform for the return and inverse transformation
#return_ is a dataframe series
method = 'haar'
mode_ = "soft"
(ca, cd) = pywt.dwt(return_, method)
cat = pywt.threshold(ca, 0.3 * np.std(ca), mode=mode_)
cdt = pywt.threshold(cd, 0.3 * np.std(cd), mode=mode_)
tx = pywt.idwt(cat, cdt, method, "smooth")
# tx=pd.DataFrame(tx,index=return_.index)
#Get back to the Stock price using denoising wavelet transform
start_price = arr[0]
# txx=tx.iloc[:,0]
# txx=np.exp(tx)
# txx=np.array(txx)
temp = np.array([start_price])
np.hstack((temp, tx))
txx = np.cumsum(tx)
# txx = pd.Series(txx, index=arr.index)
# txx=pd.DataFrame(txx,index=return_.index)
return txx
def wavelet_thresholding(array_of_wavelet_coeff, image, mode_thresholding):
"""
:param array_of_wavelet_coeff: wavelet coefficients: Approximation, horizontal detail, vertical detail
and diagonal detail coefficients respectively
:param threshold: threshold for Approximation component;
:param mode_thresholding: {'soft', 'hard', 'greater', 'less'}
:return: thresholded wavelet coefficients.
"""
cA = array_of_wavelet_coeff[0]
denoise_array = [cA]
for i in range(len(array_of_wavelet_coeff) - 1):
cH = pywt.threshold(array_of_wavelet_coeff[i + 1][0],
threshold_value(
array_of_wavelet_coeff[i + 1][2],
len(array_of_wavelet_coeff[i + 1][0]), image),
mode=mode_thresholding)
cV = pywt.threshold(array_of_wavelet_coeff[i + 1][1],
threshold_value(
array_of_wavelet_coeff[i + 1][2],
len(array_of_wavelet_coeff[i + 1][1]), image),
mode=mode_thresholding)
cD = pywt.threshold(array_of_wavelet_coeff[i + 1][2],
threshold_value(
array_of_wavelet_coeff[i + 1][2],
len(array_of_wavelet_coeff[i + 1][2]), image),
mode=mode_thresholding)
denoise_array.append((cH, cV, cD))
return denoise_array
def __apply_wavelet_transform(self, x):
(ca, cd) = pywt.dwt(x, "haar")
cat = pywt.threshold(ca, np.std(ca), mode="soft")
cdt = pywt.threshold(cd, np.std(cd), mode="soft")
tx = pywt.idwt(cat, cdt, "haar")
return tx
def test_nonnegative_garotte():
thresh = 0.3
data_real = np.linspace(-1, 1, 100)
for dtype in float_dtypes:
if dtype in real_dtypes:
data = np.asarray(data_real, dtype=dtype)
else:
data = np.asarray(data_real + 0.1j, dtype=dtype)
d_hard = pywt.threshold(data, thresh, 'hard')
d_soft = pywt.threshold(data, thresh, 'soft')
d_garotte = pywt.threshold(data, thresh, 'garotte')
# check dtypes
assert_equal(d_hard.dtype, data.dtype)
assert_equal(d_soft.dtype, data.dtype)
assert_equal(d_garotte.dtype, data.dtype)
# values < threshold are zero
lt = np.where(np.abs(data) < thresh)
assert_(np.all(d_garotte[lt] == 0))
# values > than the threshold are intermediate between soft and hard
gt = np.where(np.abs(data) > thresh)
gt_abs_garotte = np.abs(d_garotte[gt])
assert_(np.all(gt_abs_garotte < np.abs(d_hard[gt])))
assert_(np.all(gt_abs_garotte > np.abs(d_soft[gt])))
def test_nonnegative_garotte():
thresh = 0.3
data_real = np.linspace(-1, 1, 100)
for dtype in float_dtypes:
if dtype in real_dtypes:
data = np.asarray(data_real, dtype=dtype)
else:
data = np.asarray(data_real + 0.1j, dtype=dtype)
d_hard = pywt.threshold(data, thresh, 'hard')
d_soft = pywt.threshold(data, thresh, 'soft')
d_garotte = pywt.threshold(data, thresh, 'garotte')
# check dtypes
assert_equal(d_hard.dtype, data.dtype)
assert_equal(d_soft.dtype, data.dtype)
assert_equal(d_garotte.dtype, data.dtype)
# values < threshold are zero
lt = np.where(np.abs(data) < thresh)
assert_(np.all(d_garotte[lt] == 0))
# values > than the threshold are intermediate between soft and hard
gt = np.where(np.abs(data) > thresh)
gt_abs_garotte = np.abs(d_garotte[gt])
assert_(np.all(gt_abs_garotte < np.abs(d_hard[gt])))
assert_(np.all(gt_abs_garotte > np.abs(d_soft[gt])))
def wavelet_denoise(self, wavelet='db1', plot='Y', level=1):
### only built for Level 1 decomp
self.Xtrans = self.XData.transpose()
self.Xnormtrans = []
self.wavecoef = []
self.thresh_wavecoef = []
self.denoisedXtrans = []
for i in range(len(self.Xtrans)):
self.maxwave = pwt.dwt_max_level(len(self.Xtrans[i]), wavelet)
if level != 'Auto':
self.level = level
self.wavecoef.append(
pwt.wavedec(self.Xtrans[i], wavelet, level=self.level))
self.thresh_A = (np.average(np.abs(
self.wavecoef[i][0]))) - (np.std(np.abs(self.wavecoef[i][0])))
self.thresh_D = (np.average(np.abs(
self.wavecoef[i][1]))) - (np.std(np.abs(self.wavecoef[i][1])))
self.thresh_wavecoef.append(
(pwt.threshold(self.wavecoef[i][0], self.thresh_A),
(pwt.threshold(self.wavecoef[i][1], self.thresh_D))))
self.denoisedXtrans.append(
pwt.idwt(self.thresh_wavecoef[-1][0],
self.thresh_wavecoef[-1][1], wavelet))
self.XDataNT = np.asarray(self.denoisedXtrans)
self.XData = self.XDataNT.transpose()
if plot != 'N':
plt.plot(self.Xtrans[plot])
plt.plot(self.denoisedXtrans[plot])
plt.show()
def encodes(self, o: TSTensor):
if self.magnitude <= 0: return o
"""
1. Adapted from waveletSmooth function found here:
http://connor-johnson.com/2016/01/24/using-pywavelets-to-remove-high-frequency-noise/
2. Threshold equation and using hard mode in threshold as mentioned
in section '3.2 denoising based on optimized singular values' from paper by Tomas Vantuch:
http://dspace.vsb.cz/bitstream/handle/10084/133114/VAN431_FEI_P1807_1801V001_2018.pdf
"""
seq_len = o.shape[-1]
# Decompose to get the wavelet coefficients
coeff = pywt.wavedec(o.cpu(), self.wavelet, mode=self.pad_mode)
if self.thr is None:
# Calculate sigma for threshold as defined in http://dspace.vsb.cz/bitstream/handle/10084/133114/VAN431_FEI_P1807_1801V001_2018.pdf
# As noted by @harshit92 MAD referred to in the paper is Mean Absolute Deviation not Median Absolute Deviation
sigma = (1 / 0.6745) * maddest(coeff[-self.level])
# Calculate the univeral threshold
uthr = sigma * np.sqrt(2 * np.log(seq_len))
coeff[1:] = (pywt.threshold(c, value=uthr, mode=self.thr_mode)
for c in coeff[1:])
elif self.thr == 'random':
coeff[1:] = (pywt.threshold(c,
value=np.random.rand(),
mode=self.thr_mode) for c in coeff[1:])
else:
coeff[1:] = (pywt.threshold(c, value=self.thr, mode=self.thr_mode)
for c in coeff[1:])
# Reconstruct the signal using the thresholded coefficients
output = o.new(
pywt.waverec(coeff, self.wavelet,
mode=self.pad_mode)[..., :seq_len])
if self.ex is not None: output[..., self.ex, :] = o[..., self.ex, :]
return output
def w2d(imArray,imagePath):
mode='db1'
(ca, cd) = pywt.dwt(imArray,mode)
cat = pywt.threshold(ca, np.std(ca)/250)
cdt = pywt.threshold(cd, np.std(cd)/250)
ts_rec = pywt.idwt(cat, cdt, mode)
return np.array(cat)
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 wavelet_tansform(raw):
(ca, cd) = pywt.dwt(raw, "haar")
cat = pywt.threshold(ca, np.std(ca), mode="soft")
cdt = pywt.threshold(cd, np.std(cd), mode="soft")
trans_raw = pywt.idwt(cat, cdt, "haar")
if np.isnan(trans_raw).any():
return raw
return trans_raw
def haar(img):
coefs = pywt.wavedec2(img, 'haar', level=2)
coefs[1] = pywt.threshold(coefs[1], 5, 'soft', 0)
coefs[2] = pywt.threshold(coefs[2], 5, 'soft', 0)
print(coefs[1], coefs[2])
con_img = pywt.waverec2(coefs, 'haar')
con_img = con_img.astype(np.uint8) # 进行类型转换
return con_img
def FISTA_Thick(P, W, K, phi, lambda2, lambda2_ref, m, n, lambda_threshold,
delta_noise, tol):
db4 = pywt.Wavelet('db4')
dirty_F = form_F_dirty(K, W, P, phi, lambda2, lambda2_ref, n)
X_temp = dirty_F
X = X_temp
t_new = 1
niter = int(np.floor(lambda_threshold / delta_noise))
for i in range(0, niter):
X_old = X_temp
t_old = t_new
#Gradient
comb = X
F_comb = form_P_meas(W, comb, phi, lambda2, lambda2_ref, m)
D = F_comb - P
if i % 1000 == 0:
objf = 0.5 * np.sqrt(np.sum(np.abs(D)**2))
print("Iteration - ", i, ": ", objf)
comb = comb - form_F_li(K, D, phi, lambda2, lambda2_ref, n)
aux_Xreal = comb.real
aux_Ximag = comb.imag
re_coeffs = pywt.wavedec(aux_Xreal, db4, level=3, mode='zpd')
im_coeffs = pywt.wavedec(aux_Ximag, db4, level=3, mode='zpd')
thres_re_coeffs = []
for j in re_coeffs:
thres_j = pywt.threshold(j, lambda_threshold, 'soft')
thres_re_coeffs.append(thres_j)
thres_im_coeffs = []
for k in im_coeffs:
thres_k = pywt.threshold(k, lambda_threshold, 'soft')
thres_im_coeffs.append(thres_k)
aux_Xreal = pywt.waverec(thres_re_coeffs, 'db4', mode='zpd')
aux_Ximag = pywt.waverec(thres_im_coeffs, 'db4', mode='zpd')
X_temp = aux_Xreal + 1j * aux_Ximag
norm = np.sum(np.abs(X_temp - X_old))
if norm <= tol:
print("Iterations: ", i)
print("Exit due to tolerance: ", norm, "<= ", tol)
break
#Step using the Lipschitz constant
t_new = (1 + np.sqrt(1 + 4 * t_old**2)) / 2
aux_Xreal = X_temp.real + (t_old - 1) / t_new * (X_temp.real -
X_old.real)
aux_Ximag = X_temp.imag + (t_old - 1) / t_new * (X_temp.imag -
X_old.imag)
X = aux_Xreal + 1j * aux_Ximag
lambda_threshold = lambda_threshold - delta_noise
print("Max iterations reached")
return X_temp
def denoise(X):
print('denoising')
X_denoised = []
for x in X:
thd = np.empty(x.shape)
thd[0] = pywt.threshold(x[0], np.median(x[0]), 'hard')
thd[1] = pywt.threshold(x[1], np.median(x[1]), 'hard')
X_denoised.append(thd)
return X_denoised
def wavelet_transformation(audio_data):
(ca, cd) = pywt.dwt(audio_data, 'haar')
cat = pywt.threshold(ca, np.std(ca) / 2, 'soft')
cdt = pywt.threshold(cd, np.std(cd) / 2, 'soft')
audio_data_transformed = pywt.idwt(cat, cdt, 'haar')
return audio_data_transformed
def DWT(series):
ca, cb = pywt.dwt(series, 'haar')
cat = pywt.threshold(ca, np.std(ca) / 2, mode='soft')
cbt = pywt.threshold(cb, np.std(cb) / 2, mode='soft')
signal = pywt.idwt(cat, cbt, 'haar')
DWT8 = ca[:, :-8] #sorted in Ascending
return DWT8
def dwt_smooth(x, wavelet):
cA, cD = pywt.dwt(x, wavelet)
def make_threshold(x):
return np.std(x) * np.sqrt(1 * np.log(x.size))
cAt = pywt.threshold(cA, make_threshold(cA), mode="soft")
cDt = pywt.threshold(cD, make_threshold(cD), mode="soft")
tx = pywt.idwt(cAt, cDt, wavelet)
return tx
def dwt_smoother(x, wavelet, smooth_factor: float = 1.) -> np.ndarray:
cA, cD = pywt.dwt(x, wavelet)
cAt = pywt.threshold(cA,
smoothing_threshold(cA, smooth_factor),
mode='soft')
cDt = pywt.threshold(cD,
smoothing_threshold(cD, smooth_factor),
mode='soft')
tx = pywt.idwt(cAt, cDt, wavelet)
return tx
def softthreshold_bandas(listpatches, umbrales, t):
listsearch = listpatches.copy()
n = 4 * t**2 # Lenght of the patches in wavelet domain (n = 4xtxt)
auxHV = range(n / 4, 3 * n / 4) # Positions of WH and WV bands
auxD = range(3 * n / 4, n) # Positions of WD band
HVbands = listsearch[:, :, auxHV, :]
listsearch[:, :, auxHV, :] = pywt.threshold(HVbands, umbrales[0], 'soft')
Dbands = listsearch[:, :, auxD, :]
listsearch[:, :, auxD, :] = pywt.threshold(Dbands, umbrales[1], 'soft')
return listsearch
def main(file_name):
d = 0
#take d also as input
#load a data y
y = []
"""
with open(file_name,'r+') as f:
reader = csv.reader(f,delimiter = ' ', quotechar='|')
for number in reader:
y.append(number[d])
ts=y
(ca, cd) = pywt.dwt(ts,'haar')
"""
series = read_csv(file_name, header=0, index_col=0, squeeze=True)
series.columns = ['a', 'b', 'c', 'd']
series['e'] = pow((series['a'] * series['a'] + series['b'] * series['b'] +
series['c'] * series['c']), 0.5)
df1 = pd.DataFrame({'$a': series['e']})
df = df1.iloc[:, 0]
#print(df)
(ca, cd) = pywt.dwt(df, 'haar')
cat = pywt.threshold(ca, np.std(ca) / 2, 'soft')
cdt = pywt.threshold(cd, np.std(cd) / 2, 'soft')
ts_rec = pywt.idwt(cat, cdt, 'haar')
plt.close('all')
plt.subplot(211)
# Original coefficients
plt.plot(ca, '--*b')
plt.plot(cd, '--*r')
# Thresholded coefficients
plt.plot(cat, '--*c')
plt.plot(cdt, '--*m')
plt.legend(['ca', 'cd', 'ca_thresh', 'cd_thresh'], loc=0)
plt.grid(True)
plt.subplot(212)
#plt.plot(ts)
plt.plot(df)
#plt.hold('on')
plt.plot(ts_rec, 'r')
plt.legend(['original signal', 'reconstructed signal'])
plt.grid(True)
plt.show()
def waveletSmooth(x,
wavelet="db4",
level=None,
sigma_type='donoho',
plot=False,
title=None,
mode='per'):
if level:
if len(x) < 2**level:
''' you don't have enough data to proceed. no smoothing'''
return x
try:
# coeff = pywt.wavedec(x, wavelet=wavelet,mode=mode)
coeff = pywt.wavedec(x, wavelet=wavelet, level=level, mode=mode)
except:
''' too little info for specific level. just default max_level and donoho'''
coeff = pywt.wavedec(x, wavelet=wavelet, mode=mode)
sigma_type = 'donoho'
if sigma_type and (sigma_type == 'donoho'):
coeff[1:] = (pywt.threshold(i, value=_sigma_est_dwt(i), mode="soft")
for i in coeff[1:])
elif sigma_type and (sigma_type == 'mad'):
sigma = mad(coeff[1])
uthresh = sigma * np.sqrt(2 * np.log(len(x)))
coeff[1:] = (pywt.threshold(i, value=uthresh, mode="soft")
for i in coeff[1:])
elif sigma_type and (sigma_type == 'SURE'):
''' Stein’s Unbiased Risk Estimate(SURE) '''
n = len(x)
uthresh = np.sqrt(2 * np.log(n * np.log2(n)))
coeff[1:] = (pywt.threshold(i, value=uthresh, mode="soft")
for i in coeff[1:])
else:
coeff[1:] = (pywt.threshold(i, value=np.std(i) / 2, mode='soft')
for i in coeff[1:])
y = pywt.waverec(coeff, wavelet=wavelet, mode=mode)
if plot:
f, ax = plt.subplots()
plt.plot(x, color="b", alpha=0.5)
plt.plot(y, color="b")
if title:
ax.set_title(title)
ax.set_xlim((0, len(y)))
return y
def wavelet_denosing_6_levels(self,data):
coeffs = pywt.wavedec(data, 'coif5', mode='symmetric',
level=6) # 将波分为6层，这行代码是一个参数是数据，第二个参数选择小波基这里选coif5，第三个点是模型默认是symmetric，第四个参数是分的层数
cA6, cD6, cD5, cD4, cD3, cD2, cD1 = coeffs
sD6 = pywt.threshold(cD6, 0.014, 'soft')
sD5 = pywt.threshold(cD5, 0.014, 'soft')
sD4 = pywt.threshold(cD4, 0.014, 'soft')
sD3 = pywt.threshold(cD3, 0.014, 'soft')
sD2 = np.zeros(len(cD2))
sD1 = np.zeros(len(cD1))
coeffs2 = [cA6, sD6, sD5, sD4, sD3, sD2, sD1]
meta = pywt.waverec(coeffs2, 'coif5')
if len(meta) > len(data):
meta = meta[:-1]
return meta
def _wavelet(diff, c):
import pywt
coeffs = pywt.wavedec2(diff, 'db1')
for index, coef in enumerate(coeffs):
if type(coef) == tuple:
coef = list(coef)
coef = [pywt.threshold(array, lambda1 * theta1) for array in coef]
coef = tuple(coef)
coeffs[index] = coef
else:
coef = pywt.threshold(coef, c)
coeffs[index] = coef
return pywt.waverec2(coeffs, 'db1')
def VISUshrink_T(filterdim, LL, HH, tscale=1 / 3):
"""
VISUShrink thresholding
:param filterdim: shape of the image
:param LL: 2x low pass
:param HH: 2x high pass
:param tscale: scaling factor for threshold
:return: updated LL(LL1) and HH(HH1)
"""
number = filterdim[0] * filterdim[1]
TLL = np.sqrt((np.std(LL)**2) * (np.log(number)))
THH = np.sqrt((np.std(HH)**2) * (np.log(number)))
LL1 = pywt.threshold(LL, TLL * tscale, 'soft')
HH1 = pywt.threshold(HH, THH * tscale, 'soft')
return LL1, HH1
def wavelet(data):
thresh = math.sqrt(2 * math.log10(len(data))) #固定阈值处理，WLSTM2
wavelet_result = []
for i in range(data.shape[1]):
if i >= 1:
data_test = data[:, i]
coeffs = pywt.wavedec(data_test, "haar", level=2) #二级小波变换
thresh1 = threshhold(coeffs[-1]) #无偏风险估计阈值
thresh2 = threshhold(coeffs[-2]) #无偏风险估计阈值
#coeffs[-2] = pywt.threshold(coeffs[-2], thresh, 'soft')
#coeffs[-1] = pywt.threshold(coeffs[-1], thresh, 'soft')
coeffs[-2] = pywt.threshold(coeffs[-2], thresh2, 'soft')
coeffs[-1] = pywt.threshold(coeffs[-1], thresh1,
'soft') #无偏风险估计阈值处理，WLSTM1
#coeffs[-2] = np.zeros_like(coeffs[-2])
#coeffs[-1] = np.zeros_like(coeffs[-1])
#x = np.arange(len(data_test))
result = pywt.waverec(coeffs, "haar") #小波重构
wavelet_result.append(result[:len(data)])
else:
result = np.zeros((len(data), ))
wavelet_result.append(result)
wavelet_result = np.array(wavelet_result)
data = np.transpose(wavelet_result)
#第二次小波变换
wavelet_result2 = []
for j in range(data.shape[1]):
if i >= 1:
data_test = data[:, j]
coeffs = pywt.wavedec(data_test, "haar", level=2)
thresh1 = threshhold(coeffs[-1])
thresh2 = threshhold(coeffs[-2])
#coeffs[-2] = pywt.threshold(coeffs[-2], thresh, 'soft')
#coeffs[-1] = pywt.threshold(coeffs[-1], thresh, 'soft')
coeffs[-2] = pywt.threshold(coeffs[-2], thresh2, 'soft')
coeffs[-1] = pywt.threshold(coeffs[-1], thresh1, 'soft')
#coeffs[-2] = np.zeros_like(coeffs[-2])
#coeffs[-1] = np.zeros_like(coeffs[-1])
result = pywt.waverec(coeffs, "haar")
wavelet_result2.append(result[:len(result)])
else:
result = np.zeros((len(data), ))
wavelet_result2.append(result)
wavelet_result2 = np.transpose(np.array(wavelet_result2))
return wavelet_result2
def lowpassfilter(signal, thresh=0.50, wavelet="db4"):
thresh = thresh * np.nanmax(signal)
coeff = pywt.wavedec(signal, wavelet, mode="per")
coeff[1:] = (pywt.threshold(i, value=thresh, mode="soft")
for i in coeff[1:])
reconstructed_signal = pywt.waverec(coeff, wavelet, mode="per")
return reconstructed_signal
def _global_threshold(self, coeffs, mode ):
threshold = self._threshold( self._sigma_image, self._image )
coeffs[1:] = [ [ pywt.threshold( detail, value=threshold, mode=mode ) for detail in coeff ] for coeff in coeffs[1:] ]
return coeffs
def _levels_threshold( self, coeffs, mode ):
thresholds = self._threshold( self._sigma_image, self._image, coeffs )
coeffs[1:] = [ tuple([ pywt.threshold( detail, value=thresholds[i][j], mode=mode ) for detail, j in zip( coeff, range(3) ) ]) for coeff, i in zip( coeffs[1:], range( len( coeffs ) - 1 ) ) ]
return coeffs
def wavelet(image, scale = 1):
# This thresholds the data based on db1 wavelet.
coeffs2 = pywt.dwt2(image[:, :, 0], 'db1')
# This assigns the directionality thresholded arrays to variables.
LL, (LH, HL, HH) = coeffs2
# This line helps eliminate the cloud but...
coeffs2 = LL * 0, (LH * 1, HL * 1, HH * 1)
# Reconstruct the image based on our removal of the LL (low frequency) component.
new_img = pywt.idwt2(coeffs2, 'db1')
# Print statements for evaluation purposes.
print("Reconstructed image parameters")
print("Standard Deviations: ", np.std(new_img))
print("Means: ", np.mean(new_img))
print("Maxima: ", np.amax(new_img))
# Thresholding based on the mean and std of the image..
thresholded_image = pywt.threshold(new_img, np.mean(new_img) + scale * np.std(new_img), substitute=0, mode='greater')
# For image viewing purposes.
# plt.subplot(131)
# plt.imshow(image[:, :, 0], cmap=plt.cm.gray)
# plt.title("Original")
# plt.subplot(132)
# plt.imshow(new_img, cmap=plt.cm.gray)
# plt.title("After")
# plt.subplot(133)
# plt.imshow(thresholded_image, cmap=plt.cm.gray)
# plt.title("Thresholded")
# plt.show()
return thresholded_image
def dwt_denoise_line_in_time(signal_in: np.ndarray,
im_index: int,
threshold_function: bool,
padding: str,
wavelet_conf) -> np.ndarray:
"""
Definition of the temporal denoising for DWT.
Parameters
----------
signal_in : np.ndarray
1D input signal.
Returns
-------
np.ndarray
Multilevel 1D inverse discrete wavelet transform.
"""
if threshold_function:
threshold_mode = 'soft'
else:
threshold_mode = 'hard'
coef = pywt.wavedec(signal_in, wavelet=wavelet_conf.m_wavelet, level=None, mode=padding)
sigma = mad(coef[-1])
threshold = sigma * np.sqrt(2 * np.log(len(signal_in)))
denoised = coef[:]
denoised[1:] = (pywt.threshold(i, value=threshold, mode=threshold_mode) for i in denoised[1:])
return pywt.waverec(denoised, wavelet=wavelet_conf.m_wavelet, mode=padding)
def apply_threshold(output, scaler = 1., input=None):
"""
output is a list of vectors (cA and cD, approximation
and detail coefficients) exactly as you would expect
from swt decomposition.
e.g. [(cA1, cD1), (cA2, cD2), ..., (cAn, cDn)]
If input is none, this function will calculate the
tresholds automatically for each waveform.
Otherwise it will use the tresholds passed in, assuming
that the length of the input is the same as the length
of the output list.
input looks like:
[threshold1, threshold2, ..., thresholdn]
scaler is a tuning parameter that will be multiplied on
all thresholds. Default = 1 (0.8?)
"""
for j in range(len(output)):
cA, cD = output[j]
if input is None:
dev = np.median(np.abs(cD - np.median(cD)))/0.6745
thresh = math.sqrt(2*math.log(len(cD)))*dev*scaler
else: thresh = scaler*input[j]
cD = pywt.threshold(cD, thresh, mode='hard')
output[j] = (cA, cD)
def denoise(noisy_img, mode, level, noiseSigma):
coeffs = pywt.wavedec2(noisy_img, mode, level=level)
# Thresholding the detail (i.e. high frequency) coefficiens
# using a Donoho-Johnstone universal threshold
threshold = noiseSigma * np.sqrt(2 * np.log2(noisy_img.size))
rec_coeffs = coeffs
rec_coeffs[1:] = (pywt.threshold(i, value=threshold, mode="soft") for i in rec_coeffs[1:])
return rec_coeffs
def thresh_median(triangle, trind):
newtri=np.zeros(triangle.shape,dtype=np.int16)
for b in range(trind.shape[0]-1):
band=get_band(triangle,trind,b)
med=np.median(np.abs(band))
thresh_band=pywt.threshold(band,med)
print med
triangle=set_band(triangle,trind,thresh_band,b)
return triangle
def wavelet(input_signal, wavelet_shape, threshold):
import pywt
# we have to pad the signal to make it a power of two
next_power_of_two = int(numpy.floor(numpy.log2(len(input_signal))) + 1)
padded_input_signal = _pad(input_signal, 2**next_power_of_two)
wt_coeffs = pywt.wavedec(padded_input_signal, wavelet_shape, level=None, mode='per')
denoised_coeffs = wt_coeffs[:]
denoised_coeffs[1:] = (pywt.threshold(i, value=threshold) for i in denoised_coeffs[1:])
recon = pywt.waverec(denoised_coeffs, wavelet_shape, mode='per')
start_offset = (len(padded_input_signal) - len(input_signal)) / 2.0
return recon[start_offset:(start_offset + len(input_signal))]
def test_threshold_firm():
thresh = 0.2
thresh2 = 3 * thresh
data_real = np.linspace(-1, 1, 100)
for dtype in float_dtypes:
if dtype in real_dtypes:
data = np.asarray(data_real, dtype=dtype)
else:
data = np.asarray(data_real + 0.1j, dtype=dtype)
if data.real.dtype == np.float32:
rtol = atol = 1e-6
else:
rtol = atol = 1e-14
d_hard = pywt.threshold(data, thresh, 'hard')
d_soft = pywt.threshold(data, thresh, 'soft')
d_firm = pywt.threshold_firm(data, thresh, thresh2)
# check dtypes
assert_equal(d_hard.dtype, data.dtype)
assert_equal(d_soft.dtype, data.dtype)
assert_equal(d_firm.dtype, data.dtype)
# values < threshold are zero
lt = np.where(np.abs(data) < thresh)
assert_(np.all(d_firm[lt] == 0))
# values > than the threshold are equal to hard-thresholding
gt = np.where(np.abs(data) >= thresh2)
assert_allclose(np.abs(d_hard[gt]), np.abs(d_firm[gt]),
rtol=rtol, atol=atol)
# other values are intermediate between soft and hard thresholding
mt = np.where(np.logical_and(np.abs(data) > thresh,
np.abs(data) < thresh2))
mt_abs_firm = np.abs(d_firm[mt])
assert_(np.all(mt_abs_firm < np.abs(d_hard[mt])))
assert_(np.all(mt_abs_firm > np.abs(d_soft[mt])))
def coeffs_process(self,coeffs):
# coeffs_out = coeffs
for level in range(len(coeffs)):
if level == 0:
continue
if level == 1:
std = np.std(coeffs[level])
#coeffs[level]=self.retain_nmax_coeffs(3,coeffs[level])
coeffs[level]=pywt.threshold(coeffs[level],std,'hard')
continue
if level == 2:
#coeffs[level] = self.retain_nmax_coeffs(3, coeffs[level])
std = np.std(coeffs[level])
coeffs[level] = pywt.threshold(coeffs[level], std*2, 'hard')
continue
# if level == 3:
# # coeffs[level] = self.retain_nmax_coeffs(3, coeffs[level])
# std = np.std(coeffs[level])
# coeffs[level] = pywt.threshold(coeffs[level], std*2, 'hard')
# continue
else:
coeffs[level] = self.retain_nmax_coeffs(0, coeffs[level])
return coeffs
def _wavelet_threshold(img, wavelet, threshold=None, sigma=None, mode='soft',
wavelet_levels=None):
"""Perform 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 BayesShrink 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.
wavelet_levels : int or None, optional
The number of wavelet decomposition levels to use. The default is
three less than the maximum number of possible decomposition levels
(see Notes below).
Returns
-------
out : ndarray
Denoised image.
Notes
-----
Reference [1]_ used four levels of wavelet decomposition. To be more
flexible for a range of input sizes, the implementation here stops 3 levels
prior to the maximum level of decomposition for `img` (the exact # of
levels thus depends on `img.shape` and the chosen wavelet). BayesShrink
variance estimation doesn't work well on levels with extremely small
coefficient arrays. This is the rationale for skipping a few of the
coarsest levels. The user can override the automated setting by explicitly
specifying `wavelet_levels`.
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
"""
wavelet = pywt.Wavelet(wavelet)
# Determine the number of wavelet decomposition levels
if wavelet_levels is None:
# Determine the maximum number of possible levels for img
dlen = wavelet.dec_len
wavelet_levels = np.min(
[pywt.dwt_max_level(s, dlen) for s in img.shape])
# Skip coarsest wavelet scales (see Notes in docstring).
wavelet_levels = max(wavelet_levels - 3, 1)
coeffs = pywt.wavedecn(img, wavelet=wavelet, level=wavelet_levels)
# Detail coefficients at each decomposition level
dcoeffs = coeffs[1:]
if sigma is None:
# Estimate the noise via the method in [2]_
detail_coeffs = dcoeffs[-1]['d' * img.ndim]
sigma = _sigma_est_dwt(detail_coeffs, distribution='Gaussian')
if threshold is None:
# The BayesShrink thresholds from [1]_ in docstring
var = sigma**2
threshold = [{key: _bayes_thresh(level[key], var) for key in level}
for level in dcoeffs]
if np.isscalar(threshold):
# A single threshold for all coefficient arrays
denoised_detail = [{key: pywt.threshold(level[key],
value=threshold,
mode=mode) for key in level}
for level in dcoeffs]
else:
# Dict of unique threshold coefficients for each detail coeff. array
denoised_detail = [{key: pywt.threshold(level[key],
value=thresh[key],
mode=mode) for key in level}
for thresh, level in zip(threshold, dcoeffs)]
denoised_coeffs = [coeffs[0]] + denoised_detail
return pywt.waverecn(denoised_coeffs, wavelet)
def test_threshold():
# soft
data = np.linspace(1, 4, 7)
soft_result = [0., 0., 0., 0.5, 1., 1.5, 2.]
assert_allclose(pywt.threshold(data, 2, 'soft'),
np.array(soft_result), rtol=1e-12)
assert_allclose(pywt.threshold(-data, 2, 'soft'),
-np.array(soft_result), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, 'soft'),
[[0, 1]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, 'soft'),
[[0, 0]] * 2, rtol=1e-12)
# hard
data = np.linspace(1, 4, 7)
hard_result = [0., 0., 2., 2.5, 3., 3.5, 4.]
assert_allclose(pywt.threshold(data, 2, 'hard'),
np.array(hard_result), rtol=1e-12)
assert_allclose(pywt.threshold(-data, 2, 'hard'),
-np.array(hard_result), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, 'hard'),
[[1, 2]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, 'hard'),
[[0, 2]] * 2, rtol=1e-12)
# greater
data = np.linspace(1, 4, 7)
assert_allclose(pywt.threshold(data, 2, 'greater'),
np.array([0., 0., 2., 2.5, 3., 3.5, 4.]), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, 'greater'),
[[1, 2]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, 'greater'),
[[0, 2]] * 2, rtol=1e-12)
# less
data = np.linspace(1, 4, 7)
assert_allclose(pywt.threshold(data, 2, 'less'),
np.array([1., 1.5, 2., 0., 0., 0., 0.]), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, 'less'),
[[1, 0]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, 'less'),
[[1, 2]] * 2, rtol=1e-12)
def test_threshold():
data = np.linspace(1, 4, 7)
# soft
soft_result = [0.0, 0.0, 0.0, 0.5, 1.0, 1.5, 2.0]
assert_allclose(pywt.threshold(data, 2, "soft"), np.array(soft_result), rtol=1e-12)
assert_allclose(pywt.threshold(-data, 2, "soft"), -np.array(soft_result), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, "soft"), [[0, 1]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, "soft"), [[0, 0]] * 2, rtol=1e-12)
# hard
hard_result = [0.0, 0.0, 2.0, 2.5, 3.0, 3.5, 4.0]
assert_allclose(pywt.threshold(data, 2, "hard"), np.array(hard_result), rtol=1e-12)
assert_allclose(pywt.threshold(-data, 2, "hard"), -np.array(hard_result), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, "hard"), [[1, 2]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, "hard"), [[0, 2]] * 2, rtol=1e-12)
# greater
greater_result = [0.0, 0.0, 2.0, 2.5, 3.0, 3.5, 4.0]
assert_allclose(pywt.threshold(data, 2, "greater"), np.array(greater_result), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, "greater"), [[1, 2]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, "greater"), [[0, 2]] * 2, rtol=1e-12)
# less
assert_allclose(pywt.threshold(data, 2, "less"), np.array([1.0, 1.5, 2.0, 0.0, 0.0, 0.0, 0.0]), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, "less"), [[1, 0]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, "less"), [[1, 2]] * 2, rtol=1e-12)
# invalid
assert_raises(ValueError, pywt.threshold, data, 2, "foo")
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))
def _wavelet_threshold(image, wavelet, method=None, threshold=None,
sigma=None, mode='soft', wavelet_levels=None):
"""Perform wavelet thresholding.
Parameters
----------
image : ndarray (2d or 3d) of ints, uints or floats
Input data to be denoised. `image` 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}``.
method : {'BayesShrink', 'VisuShrink'}, optional
Thresholding method to be used. The currently supported methods are
"BayesShrink" [1]_ and "VisuShrink" [2]_. If it is set to None, a
user-specified ``threshold`` must be supplied instead.
threshold : float, optional
The thresholding value to apply during wavelet coefficient
thresholding. The default value (None) uses the selected ``method`` to
estimate appropriate threshold(s) for noise removal.
sigma : float, optional
The standard deviation of the noise. The noise is estimated when sigma
is None (the default) by the method in [2]_.
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.
wavelet_levels : int or None, optional
The number of wavelet decomposition levels to use. The default is
three less than the maximum number of possible decomposition levels
(see Notes below).
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`
"""
wavelet = pywt.Wavelet(wavelet)
if not wavelet.orthogonal:
warn(("Wavelet thresholding was designed for use with orthogonal "
"wavelets. For nonorthogonal wavelets such as {}, results are "
"likely to be suboptimal.").format(wavelet.name))
# original_extent is used to workaround PyWavelets issue #80
# odd-sized input results in an image with 1 extra sample after waverecn
original_extent = tuple(slice(s) for s in image.shape)
# Determine the number of wavelet decomposition levels
if wavelet_levels is None:
# Determine the maximum number of possible levels for image
dlen = wavelet.dec_len
wavelet_levels = np.min(
[pywt.dwt_max_level(s, dlen) for s in image.shape])
# Skip coarsest wavelet scales (see Notes in docstring).
wavelet_levels = max(wavelet_levels - 3, 1)
coeffs = pywt.wavedecn(image, wavelet=wavelet, level=wavelet_levels)
# Detail coefficients at each decomposition level
dcoeffs = coeffs[1:]
if sigma is None:
# Estimate the noise via the method in [2]_
detail_coeffs = dcoeffs[-1]['d' * image.ndim]
sigma = _sigma_est_dwt(detail_coeffs, distribution='Gaussian')
if method is not None and threshold is not None:
warn(("Thresholding method {} selected. The user-specified threshold "
"will be ignored.").format(method))
if threshold is None:
var = sigma**2
if method is None:
raise ValueError(
"If method is None, a threshold must be provided.")
elif method == "BayesShrink":
# The BayesShrink thresholds from [1]_ in docstring
threshold = [{key: _bayes_thresh(level[key], var) for key in level}
for level in dcoeffs]
elif method == "VisuShrink":
# The VisuShrink thresholds from [2]_ in docstring
threshold = _universal_thresh(image, sigma)
else:
raise ValueError("Unrecognized method: {}".format(method))
if np.isscalar(threshold):
# A single threshold for all coefficient arrays
denoised_detail = [{key: pywt.threshold(level[key],
value=threshold,
mode=mode) for key in level}
for level in dcoeffs]
else:
# Dict of unique threshold coefficients for each detail coeff. array
denoised_detail = [{key: pywt.threshold(level[key],
value=thresh[key],
mode=mode) for key in level}
for thresh, level in zip(threshold, dcoeffs)]
denoised_coeffs = [coeffs[0]] + denoised_detail
return pywt.waverecn(denoised_coeffs, wavelet)[original_extent]
def test_threshold():
data = np.linspace(1, 4, 7)
# soft
soft_result = [0., 0., 0., 0.5, 1., 1.5, 2.]
assert_allclose(pywt.threshold(data, 2, 'soft'),
np.array(soft_result), rtol=1e-12)
assert_allclose(pywt.threshold(-data, 2, 'soft'),
-np.array(soft_result), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, 'soft'),
[[0, 1]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, 'soft'),
[[0, 0]] * 2, rtol=1e-12)
# soft thresholding complex values
assert_allclose(pywt.threshold([[1j, 2j]] * 2, 1, 'soft'),
[[0j, 1j]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1+1j, 2+2j]] * 2, 6, 'soft'),
[[0, 0]] * 2, rtol=1e-12)
complex_data = [[1+2j, 2+2j]]*2
for thresh in [1, 2]:
assert_allclose(pywt.threshold(complex_data, thresh, 'soft'),
_soft(complex_data, thresh), rtol=1e-12)
# test soft thresholding with non-default substitute argument
s = 5
assert_allclose(pywt.threshold([[1j, 2]] * 2, 1.5, 'soft', substitute=s),
[[s, 0.5]] * 2, rtol=1e-12)
# soft: no divide by zero warnings when input contains zeros
assert_allclose(pywt.threshold(np.zeros(16), 2, 'soft'),
np.zeros(16), rtol=1e-12)
# hard
hard_result = [0., 0., 2., 2.5, 3., 3.5, 4.]
assert_allclose(pywt.threshold(data, 2, 'hard'),
np.array(hard_result), rtol=1e-12)
assert_allclose(pywt.threshold(-data, 2, 'hard'),
-np.array(hard_result), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, 'hard'),
[[1, 2]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, 'hard'),
[[0, 2]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, 'hard', substitute=s),
[[s, 2]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1+1j, 2+2j]] * 2, 2, 'hard'),
[[0, 2+2j]] * 2, rtol=1e-12)
# greater
greater_result = [0., 0., 2., 2.5, 3., 3.5, 4.]
assert_allclose(pywt.threshold(data, 2, 'greater'),
np.array(greater_result), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, 'greater'),
[[1, 2]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, 'greater'),
[[0, 2]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, 'greater', substitute=s),
[[s, 2]] * 2, rtol=1e-12)
# greater doesn't allow complex-valued inputs
assert_raises(ValueError, pywt.threshold, [1j, 2j], 2, 'greater')
# less
assert_allclose(pywt.threshold(data, 2, 'less'),
np.array([1., 1.5, 2., 0., 0., 0., 0.]), rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, 'less'),
[[1, 0]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 1, 'less', substitute=s),
[[1, s]] * 2, rtol=1e-12)
assert_allclose(pywt.threshold([[1, 2]] * 2, 2, 'less'),
[[1, 2]] * 2, rtol=1e-12)
# less doesn't allow complex-valued inputs
assert_raises(ValueError, pywt.threshold, [1j, 2j], 2, 'less')
# invalid
assert_raises(ValueError, pywt.threshold, data, 2, 'foo')
import numpy as np
import math
from PIL import Image
x = []
f = open('../fft/image1.png_hor.txt', 'r')
for line in f:
x.append(float(line))
wavelet = pywt.Wavelet('bior2.8')
#levels = int( math.floor( math.log(image.shape[0], 2) ) )
WaveletCoeffs = pywt.wavedec( x, wavelet, level=None)
#threshold = noiseSigma*math.sqrt(2*math.log(image.size, 2))
threshold = 100*math.sqrt(2*math.log(len(x),2))
NewWaveletCoeffs = map (lambda x: pywt.threshold(x,threshold), WaveletCoeffs)
result = pywt.waverec( NewWaveletCoeffs, wavelet)
plt.figure(1)
plt.subplot(211)
plt.plot(x)
plt.subplot(212)
plt.plot(result)
plt.show()
'''
wavelet = pywt.Wavelet('haar')