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ZeroCrossLibrary.py
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Sun, Apr 28, 15:04

ZeroCrossLibrary.py
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#!~/anaconda3/bin python
'''script that includes all functions related to the use of the AZC feature'''
__authors__ = "Una Pale, Renato Zanetti, and Tomas Teijeiro"
__license__ = "LGPL"
__version__ = "1.0"
__email__ = "{una.pale, renato.zaneti} at epfl.ch"
import os
import glob
# import csv
import matplotlib
matplotlib.use('Agg') #to do not show figures
from scipy.io import loadmat
from scipy.signal import decimate
from VariousFunctionsLib import *
########################################################
#global variables for multi-core operation
files_processed=[]
n_files_per_patient=[]
number_free_cores = 0
number_free_cores_pat = 0
n_cores_semaphore = 1
###########################################################################
##defining functions needed
def polygonal_approx(arr, epsilon):
"""
Performs an optimized version of the Ramer-Douglas-Peucker algorithm assuming as an input
an array of single values, considered consecutive points, and **taking into account only the
vertical distances**.
"""
def max_vdist(arr, first, last):
"""
Obtains the distance and the index of the point in *arr* with maximum vertical distance to
the line delimited by the first and last indices. Returns a tuple (dist, index).
"""
if first == last:
return (0.0, first)
frg = arr[first:last+1]
leng = last-first+1
dist = np.abs(frg - np.interp(np.arange(leng),[0, leng-1], [frg[0], frg[-1]]))
idx = np.argmax(dist)
return (dist[idx], first+idx)
if epsilon <= 0.0:
raise ValueError('Epsilon must be > 0.0')
if len(arr) < 3:
return arr
result = set()
stack = [(0, len(arr) - 1)]
while stack:
first, last = stack.pop()
max_dist, idx = max_vdist(arr, first, last)
if max_dist > epsilon:
stack.extend([(first, idx),(idx, last)])
else:
result.update((first, last))
return np.array(sorted(result))
def zero_crossings(arr):
"""Returns the positions of zero-crossings in the derivative of an array, as a binary vector"""
return np.diff(np.sign(np.diff(arr))) != 0
def calculateMovingAvrgMeanWithUndersampling_v2(data, winLen, winStep):
lenSig=len(data)
index = np.arange(0, lenSig - winLen, winStep)
segmData = np.zeros(len(index))
for i in range(len(index)): #-1
x = data[index[i]:index[i] + winLen]
segmData[i]=np.mean(x)
return(segmData)
def calculateFeaturesPerEachFile_CLFAndAZCFeatures_CHB(parallelize, perc_cores, EPS_thresh_arr,folderIn, folderOutFeatures, patients, SigInfoParams, ZeroCrossFeatureParams, calculateOtherFeat, calculateZCFeat):
global files_processed
global n_files_per_patient
global number_free_cores
print('Extracting features from all subjects files')
numFeat = len(EPS_thresh_arr) + 1
if parallelize:
n_cores = mp.cpu_count()
n_cores = ceil(n_cores*perc_cores)
print('Number of cores: ' + str(n_cores))
pool = mp.Pool(n_cores)
number_free_cores = n_cores
files_processed=np.zeros(len(patients))
n_files_per_patient = np.zeros(len(patients))
# go through all patients
for patIndx, pat in enumerate(patients):
filesIn=np.sort(glob.glob(folderIn + 'chb' + pat+ '/chb' + pat + '*.csv.gz')) #only the data files
numFiles=len(filesIn)
n_files_per_patient[patIndx]=numFiles
print('Pat: ' + str(pat) + ' Nfiles: ' + str(numFiles))
folderOutFeaturesSub = folderOutFeatures + 'chb' + pat + '/'
if not os.path.exists(folderOutFeaturesSub):
try:
os.mkdir(folderOutFeaturesSub)
except OSError:
print("Creation of the directory %s failed" % folderOutFeaturesSub)
for fileIndx, file in enumerate(filesIn):
pom, fileName1 = os.path.split(file)
fileName2 = fileName1[:-7]
print('File: '+ fileName2 + ' NFilesprocessed: '+ str(files_processed[patIndx]) + ' Out of: ' + str(n_files_per_patient[patIndx]))
fileName3 = fileName2.split('_')
file_number_str = fileName3[1].zfill(3) #for file-reading proper ordering
if '+' in fileName2 and pat=='02': #chb02_16+
file_number_str = '0'+ file_number_str
numFeat = len(EPS_thresh_arr) + 1
# reading data
data = readDataFromFile(file)
# separating to data and labels
X = data[:, SigInfoParams.chToKeep]
y = data[:, -1]
(lenData, numCh) = X.shape
labels = y[0:lenData - 2]
index = np.arange(0, lenData - int(ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winLen),
int(ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winStep))
labelsSegm = calculateMovingAvrgMeanWithUndersampling_v2(labels, int(
ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winLen), int(
ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winStep))
labelsSegm = (labelsSegm > 0.5) * 1
if parallelize:
pool.apply_async(readFileCalculateFeatures, args=(patIndx, data, labelsSegm, index, numCh, numFeat, ZeroCrossFeatureParams, EPS_thresh_arr, calculateOtherFeat, calculateZCFeat, folderOutFeaturesSub, fileName3, file_number_str), callback=collect_result)
number_free_cores = number_free_cores -1
if number_free_cores==0:
while number_free_cores==0: #synced in the callback
time.sleep(0.1)
pass
else:
readFileCalculateFeatures(patIndx, data, labelsSegm, index, numCh, numFeat, ZeroCrossFeatureParams, EPS_thresh_arr, calculateOtherFeat, calculateZCFeat, folderOutFeaturesSub, fileName3, file_number_str)
if parallelize:
while number_free_cores < n_cores: #wait till all subjects have their data processed
time.sleep(0.1)
pass
pool.close()
pool.join()
def calculateFeaturesPerEachFile_CLFAndAZCFeatures_SWEC(parallelize, perc_cores, EPS_thresh_arr,folderIn, folderOutFeatures, patients, SigInfoParams, ZeroCrossFeatureParams, calculateOtherFeat, calculateZCFeat):
global files_processed
global n_files_per_patient
global number_free_cores
print('Extracting features from all subjects files')
numFeat = len(EPS_thresh_arr) + 1
diff_files_seiz=0
if parallelize:
n_cores = mp.cpu_count()
n_cores = ceil(n_cores*perc_cores)
print('Number of cores: ' + str(n_cores))
pool = mp.Pool(n_cores)
number_free_cores = n_cores
files_processed=np.zeros(len(patients))
n_files_per_patient = np.zeros(len(patients))
# go through all patients
for patIndx, pat in enumerate(patients):
filesIn=np.sort(glob.glob(folderIn + 'ID' + pat + '/'+ 'ID' + pat + '*h.mat')) #only the data files
numFiles=len(filesIn)
n_files_per_patient[patIndx]=numFiles
print('Pat: ' + str(pat) + ' Nfiles: ' + str(numFiles))
f = loadmat(folderIn + 'ID' + pat + '/'+ 'ID' + pat +'_info.mat', simplify_cells=True)
seizure_begin = np.array(f['seizure_begin']) #given in seconds
seizure_end = np.array(f['seizure_end'])
fs = np.array(f['fs']).astype(int)
file_index = (seizure_begin/3600 + 1).astype(int) #sum 1 to fit calculate index to files indexes
print('file_index: ' + str(file_index))
seiz_count=0
folderOutFeaturesSub = folderOutFeatures + 'ID' + pat + '/'
if not os.path.exists(folderOutFeaturesSub):
try:
os.mkdir(folderOutFeaturesSub)
except OSError:
print("Creation of the directory %s failed" % folderOutFeaturesSub)
for fileIndx, file in enumerate(filesIn):
pom, fileName1 = os.path.split(file)
fileName2 = os.path.splitext(fileName1)[0]
print('File: '+ fileName2 + ' NFilesprocessed: '+ str(files_processed[patIndx]) + ' Out of: ' + str(n_files_per_patient[patIndx]))
fileName3 = fileName2.split('_')
file_number_str = fileName3[1][:-1]
file_number = int(file_number_str)
file_number_str = file_number_str.zfill(3) #for file-reading proper ordering
numFeat = len(EPS_thresh_arr) + 1
# reading data
reader = loadmat(file, simplify_cells=True)
data0 = np.array(reader['EEG']).astype("float").T
#
data = decimate(data0, int(fs/ZeroCrossFeatureParams.samplFreq), axis=0, zero_phase=True)
(lenData, numCh) = data.shape
y=np.zeros((lenData,))
if diff_files_seiz: #previous file had a seizure which spams till the current file
y[old_beg:old_end]=1
diff_files_seiz=0
idx_seiz = np.where(file_index==file_number)[0]
for i, v in enumerate(idx_seiz):
print('Seizure found at file: ' + str(file_index[v]))
beg = int((seizure_begin[v]%3600*fs)*(ZeroCrossFeatureParams.samplFreq/fs))
end = int((seizure_end[v]%3600*fs)*(ZeroCrossFeatureParams.samplFreq/fs))
if end < beg: #seizures in different files
diff_files_seiz = 1
old_end = end
old_beg = 0
end = int((3600*fs)*(ZeroCrossFeatureParams.samplFreq/fs))
y[beg:end]=1
labels = y[0:lenData - 2]
# windowing the data: 'index' contains start:stop indexes
index = np.arange(0, lenData - int(ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winLen),
int(ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winStep))
#'labels' contains one value per datapoint. 'labelsSegm' contains one value per window (> 50% ictal data --> ictal label)
labelsSegm = calculateMovingAvrgMeanWithUndersampling_v2(labels, int(
ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winLen), int(
ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winStep))
labelsSegm = (labelsSegm > 0.5) * 1
if parallelize:
pool.apply_async(readFileCalculateFeatures, args=(patIndx, data, labelsSegm, index, numCh, numFeat, ZeroCrossFeatureParams, EPS_thresh_arr, calculateOtherFeat, calculateZCFeat, folderOutFeaturesSub, fileName3, file_number_str), callback=collect_result)
number_free_cores = number_free_cores -1
if number_free_cores==0:
while number_free_cores==0: #synced in the callback 'collect_result'
time.sleep(0.1)
pass
else:
readFileCalculateFeatures(patIndx, data, labelsSegm, index, numCh, numFeat, ZeroCrossFeatureParams, EPS_thresh_arr, calculateOtherFeat, calculateZCFeat, folderOutFeaturesSub, fileName3, file_number_str)
if parallelize:
while number_free_cores < n_cores: #wait till all subjects have their data processed
time.sleep(0.1)
pass
pool.close()
pool.join()
def readFileCalculateFeatures(patIndx, data, labelsSegm, index, numCh, numFeat, ZeroCrossFeatureParams, EPS_thresh_arr, calculateOtherFeat, calculateZCFeat, folderOutFeaturesSub, fileName3, file_number_str):
sos = signal.butter(4, [1, 20], 'bandpass', fs=ZeroCrossFeatureParams.samplFreq, output='sos')
allsigFilt = signal.sosfiltfilt(sos, data, axis=0)
del data
zeroCrossStandard = np.zeros((len(index), numCh))
zeroCrossApprox = np.zeros((len(index), numCh))
zeroCrossFeaturesAll = np.zeros((len(index), numFeat * numCh))
for ch in range(numCh):
# t=time.time()
sigFilt=allsigFilt[:,ch]
# calculate CLF
if (calculateOtherFeat==1):
featOther = calculateOtherMLfeatures_oneCh(np.copy(sigFilt), ZeroCrossFeatureParams)
if (ch == 0):
AllFeatures = featOther
else:
AllFeatures = np.hstack((AllFeatures, featOther))
#AZC
if (calculateZCFeat==1):
# Zero-crossing of the original signal, counted in 1-second continuous sliding window
# zeroCrossStandard[:,ch] = np.convolve(zero_crossings(sigFilt), np.ones(ZeroCrossFeatures.samplFreq), mode='same')
x = np.convolve(zero_crossings(sigFilt), np.ones(ZeroCrossFeatureParams.samplFreq), mode='same')
# zeroCrossStandard[:,ch] =calculateMovingAvrgMeanWithUndersampling_v2(x, ZeroCrossFeatureParams.samplFreq)
zeroCrossStandard[:, ch] = calculateMovingAvrgMeanWithUndersampling_v2(x, int(
ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winLen), int(
ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winStep))
zeroCrossFeaturesAll[:, numFeat * ch] = zeroCrossStandard[:, ch]
for EPSthrIndx, EPSthr in enumerate(EPS_thresh_arr):
# Signal simplification at the given threshold, and zero crossing count in the same way
sigApprox = polygonal_approx(sigFilt, epsilon=EPSthr)
# axs[0].plot(sigApprox, sigFilt[sigApprox], alpha=0.6)
sigApproxInterp = np.interp(np.arange(len(sigFilt)), sigApprox, sigFilt[sigApprox])
# zeroCrossApprox[:,ch] = np.convolve(zero_crossings(sigApproxInterp), np.ones(ZeroCrossFeatures.samplFreq), mode='same')
x = np.convolve(zero_crossings(sigApproxInterp), np.ones(ZeroCrossFeatureParams.samplFreq),
mode='same')
# zeroCrossApprox[:, ch] = calculateMovingAvrgMeanWithUndersampling_v2(x, ZeroCrossFeatureParams.samplFreq)
zeroCrossApprox[:, ch] = calculateMovingAvrgMeanWithUndersampling_v2(x, int(
ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winLen), int(
ZeroCrossFeatureParams.samplFreq * ZeroCrossFeatureParams.winStep))
# save to matrix with all features that will be saved
zeroCrossFeaturesAll[:, numFeat * ch + EPSthrIndx + 1] = zeroCrossApprox[:, ch]
if (calculateZCFeat == 1):
# save for this file Zero cross features
df = pd.DataFrame(data=zeroCrossFeaturesAll)
outputName = folderOutFeaturesSub + fileName3[0]+ '_' + file_number_str+ 'h_ZCFeat.csv.gz'
#to read from disk: df = pd.read_csv('dfsavename.csv.gz', compression='gzip')
df.to_csv(outputName, index=False, compression='gzip')
# np.savetxt(outputName, zeroCrossFeaturesAll, delimiter=",")
if (calculateOtherFeat == 1):
# save for this file all other features
df = pd.DataFrame(data=AllFeatures)
outputName = folderOutFeaturesSub + fileName3[0]+ '_' + file_number_str+ 'h_OtherFeat.csv.gz'
df.to_csv(outputName, index=False, compression='gzip')
# np.savetxt(outputName, AllFeatures, delimiter=",")
# save for this file labels
df = pd.DataFrame(data=labelsSegm)
outputName = folderOutFeaturesSub + fileName3[0]+ '_' + file_number_str+ 'h_Labels.csv.gz'
df.to_csv(outputName, index=False, compression='gzip')
# np.savetxt(outputName, labelsSegm, delimiter=",")
return (patIndx)
#callback for the apply_async process paralization
def collect_result(result):
global files_processed
global number_free_cores
global n_cores_semaphore
global n_files_per_patient
while n_cores_semaphore==0: #block callback in case of multiple accesses
pass
if n_cores_semaphore:
n_cores_semaphore=0
files_processed[result] += 1
number_free_cores = number_free_cores+1
n_cores_semaphore=1
if __name__ == "__main__":
pass

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