def rangeCompression(Srx, h):
"""
Method to apply matched filter h on range dimension
"""
# pad received and emitted signals on common time stemp
# to obtain common fft
n1 = len(h)
n2 = Srx.shape[1]
Nsa = n1 + n2 - 1
## Nsa2 = int(np.power(2.0, np.ceil(np.log2( Nsa ))))
Nsa2 = Nsa if Nsa % 2 == 0 else Nsa+1
SrxMF=np.zeros((Srx.shape[0], Nsa2),dtype=complex)
hMF = np.concatenate((np.zeros(np.floor((Nsa2-n1)*0.5)), h, np.zeros(np.ceil((Nsa2-n1)*0.5))))
HMF = GC.fft(hMF)
for i in range(Srx.shape[0]):
row = Srx[i,:]
rowMF = np.concatenate((np.zeros(np.floor((Nsa2-len(row))*0.5)), row, np.zeros(np.ceil((Nsa2-len(row))*0.5))))
RowMF = GC.fft(rowMF)
RowMF = RowMF * HMF
SrxMF[i,:] = GC.ifft(RowMF)
return SrxMF
def azimuthCompression(Srx, h):
"""
Method to apply matched filter h on azimuth dimension
"""
# pad received and emitted signals on common time stemp
# to obtain common fft
n1 = len(h)
n2 = Srx.shape[0]
Nsa = n1 + n2 - 1
## Nsa2 = int(np.power(2.0, np.ceil(np.log2( Nsa ))))
Nsa2 = Nsa if Nsa % 2 == 0 else Nsa+1
SrxMF=np.zeros((Nsa2, Srx.shape[1]),dtype=complex)
hMF = np.concatenate((np.zeros(np.floor((Nsa2-n1)*0.5)), h, np.zeros(np.ceil((Nsa2-n1)*0.5))))
HMF = GC.fft(hMF)
for i in range(Srx.shape[1]):
col = Srx[:,i]
colMF = np.concatenate((np.zeros(np.floor((Nsa2-len(col))*0.5)), col, np.zeros(np.ceil((Nsa2-len(col))*0.5))))
ColMF = GC.fft(colMF)
ColMF = ColMF * HMF
SrxMF[:,i] = GC.ifft(ColMF)
return SrxMF
def compression(Srx, h, dim0):
"""
Matched filter alogorith with filter 'h' is applied on
the image 'Srx' on the dimension 'dim'
dim is 'range' or 'azimuth'
"""
dim = 1 if dim0 is 'range' else 0 if dim0 is 'azimuth' else -1
assert dim >= 0, logPrint("Parameter dim should be 'range' or 'azimuth'")
# inverse of dim
idim = np.abs(dim - 1)
# pad received and emitted signals on common time stemp
# to obtain common fft
n1 = len(h)
n2 = Srx.shape[dim]
Nsa = n1 + n2 - 1
## Nsa2 = int(np.power(2.0, np.ceil(np.log2( Nsa ))))
Nsa2 = Nsa if Nsa % 2 == 0 else Nsa + 1
## shape = (Srx.shape[0], Nsa2) if dim == 1 else (Nsa2, Srx.shape[1])
## SrxMF=np.zeros(shape,dtype=complex)
SrxMF = np.zeros(Srx.shape, dtype=complex)
hMF = np.concatenate((np.zeros(np.floor(
(Nsa2 - n1) * 0.5)), h, np.zeros(np.ceil((Nsa2 - n1) * 0.5))))
HMF = GC.fft(hMF)
m1 = np.floor((Nsa2 - n2) * 0.5)
m2 = np.ceil((Nsa2 - n2) * 0.5)
for i in range(Srx.shape[idim]):
data = Srx[i, :] if dim == 1 else Srx[:, i]
dataMF = np.concatenate((np.zeros(m1), data, np.zeros(m2)))
DataMF = GC.fft(dataMF)
DataMF = DataMF * HMF
if dim == 1:
SrxMF[i, :] = GC.ifft(DataMF)[n1 / 2:n1 / 2 + n2]
else:
SrxMF[:, i] = GC.ifft(DataMF)[n1 / 2:n1 / 2 + n2]
return SrxMF
def compression(Srx, h, dim0):
"""
Matched filter alogorith with filter 'h' is applied on
the image 'Srx' on the dimension 'dim'
dim is 'range' or 'azimuth'
"""
dim = 1 if dim0 is 'range' else 0 if dim0 is 'azimuth' else -1
assert dim >= 0, logPrint("Parameter dim should be 'range' or 'azimuth'")
# inverse of dim
idim = np.abs(dim-1)
# pad received and emitted signals on common time stemp
# to obtain common fft
n1 = len(h)
n2 = Srx.shape[dim]
Nsa = n1 + n2 - 1
## Nsa2 = int(np.power(2.0, np.ceil(np.log2( Nsa ))))
Nsa2 = Nsa if Nsa % 2 == 0 else Nsa+1
## shape = (Srx.shape[0], Nsa2) if dim == 1 else (Nsa2, Srx.shape[1])
## SrxMF=np.zeros(shape,dtype=complex)
SrxMF=np.zeros(Srx.shape,dtype=complex)
hMF = np.concatenate((np.zeros(np.floor((Nsa2-n1)*0.5)), h, np.zeros(np.ceil((Nsa2-n1)*0.5))))
HMF = GC.fft(hMF)
m1 = np.floor((Nsa2-n2)*0.5)
m2 = np.ceil((Nsa2-n2)*0.5)
for i in range(Srx.shape[idim]):
data = Srx[i,:] if dim == 1 else Srx[:,i]
dataMF = np.concatenate((np.zeros(m1), data, np.zeros(m2)))
DataMF = GC.fft(dataMF)
DataMF = DataMF * HMF
if dim == 1:
SrxMF[i,:] = GC.ifft(DataMF)[n1/2:n1/2+n2]
else:
SrxMF[:,i] = GC.ifft(DataMF)[n1/2:n1/2+n2]
return SrxMF
def rangeCompression(Srx, HMF):
"""
Range compression with freq-domain filter H(f)
"""
assert Srx.shape[1] == len(HMF), logPrint("Range dimension of the Srx is not equal to length of HMF")
SrxMF=np.zeros(Srx.shape,dtype=complex)
for i in range(Srx.shape[0]):
data = Srx[i,:]
DataMF = GC.fft(data) * HMF
SrxMF[i,:] = GC.ifft(DataMF)
return SrxMF
def rangeCompression(Srx, HMF):
"""
Range compression with freq-domain filter H(f)
"""
assert Srx.shape[1] == len(HMF), logPrint(
"Range dimension of the Srx is not equal to length of HMF")
SrxMF = np.zeros(Srx.shape, dtype=complex)
for i in range(Srx.shape[0]):
data = Srx[i, :]
DataMF = GC.fft(data) * HMF
SrxMF[i, :] = GC.ifft(DataMF)
return SrxMF
def azimuthIFFT(dataAF):
procData = np.zeros(dataAF.shape, dtype=complex)
for i in range(procData.shape[1]):
# get range fixed column
procData[:,i] = GC.ifft(dataAF[:,i])
return procData
def compressRawData(self, showProgress=True):
"""
Apply RDA on raw data
1) Range compression
2) Range Cell Migration Correction
3) Azimuth compression
Returns (compressed 2D array, azimuth positions, range time)
"""
rawData = self._rawData
assert rawData is not None, logPrint(
"Raw data should be computed ( using computeRawData() ) or provided as argument"
)
assert self._dt is not None, logPrint(
"Error : Simulator badly configured, dt is None")
assert self._dx is not None, logPrint(
"Error : Simulator badly configured, dx is None")
assert self._xArray is not None, logPrint(
"Error : Simulator badly configured, xArray is None")
assert self._tArray is not None, logPrint(
"Error : Simulator badly configured, tArray is None")
Tp = self._platform.Tp
Vsat = self._platform.Vsat
K = self._platform.K
PRF = self._platform.PRF
H = self._platform.H
Lambda = self._platform.Lambda
# 1) Range compression :
if showProgress:
logPrint(" - Range compression ...")
fRangeArray = GC.freq(rawData.shape[1], 1.0 / self._dt)
HMF = GC.rect(fRangeArray / (np.abs(K) * Tp)) * np.exp(
1j * np.pi * fRangeArray**2 / K)
# Multiply by a phase due to different range zero time
## tZero = self._tArray[len(self._tArray)/2]
## HMF = HMF * np.exp( -1j* 2.0 * np.pi * fRangeArray * tZero)
procData = rangeCompression(rawData, HMF)
HMF = None
if self.verbose:
showResponse(procData, None, 'Range compression')
# 2) Azimuth FFT :
if showProgress:
logPrint(" -- Azimuth FFT ...")
procDataAF = np.zeros(procData.shape, dtype=complex)
for i in range(procDataAF.shape[1]):
# get range fixed column
procDataAF[:, i] = GC.fft(procData[:, i])
procData = procDataAF
procDataAF = None
fArray = GC.freq(procData.shape[0], self._platform.Vsat / self._dx)
if self.verbose:
## showResponse(procData, [self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]], 'Azimuth FFT')
showResponse(procData, None, 'Azimuth FFT')
# 3) Range migration :
if showProgress:
logPrint(" --- Range migration ...")
Dfreq = np.sqrt(1.0 - (0.5 * Lambda * fArray / Vsat)**2)
procData = rangeMigration2(procData, self._tArray, Dfreq)
if self.verbose:
## showResponse(procData, [self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]], 'RCMC')
showResponse(procData, None, 'RCMC')
# 4) Azimuth compression :
if showProgress:
logPrint(" ---- Azimuth compression ...")
etaZero = self._xArray[len(self._xArray) / 2] / Vsat
for i in range(procData.shape[1]):
# Use H(f) = exp( 1j * 4 * pi * R0 * D(f) * f0 / c )
#
HMF = np.exp(2 * np.pi * 1j * GC.C * self._tArray[i] / Lambda *
Dfreq)
# Multiply by a phase due to different azimuth zero time
HMF = HMF * np.exp(-1j * 2.0 * np.pi * fArray * etaZero)
procData[:, i] = procData[:, i] * HMF
# 5) Azimuth IFFT
if showProgress:
logPrint(" ----- Azimuth IFFT ...")
procDataAF = np.zeros(procData.shape, dtype=complex)
for i in range(procDataAF.shape[1]):
# get range fixed column
procDataAF[:, i] = GC.ifft(procData[:, i])
procData = procDataAF
procDataAF = None
if self.verbose:
showResponse(
procData,
[self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]],
'Compressed image', False)
return procData, self._xArray, self._tArray
def compressRawData(self, showProgress=True):
"""
Apply RDA on raw data
1) Range compression
2) Range Cell Migration Correction
3) Azimuth compression
Returns (compressed 2D array, azimuth positions, range time)
"""
rawData = self._rawData
assert rawData is not None, logPrint(
"Raw data should be computed ( using computeRawData() ) or provided as argument"
)
assert self._dt is not None, logPrint(
"Error : Simulator badly configured, dt is None")
assert self._dx is not None, logPrint(
"Error : Simulator badly configured, dx is None")
assert self._xArray is not None, logPrint(
"Error : Simulator badly configured, xArray is None")
assert self._xSwath is not None, logPrint(
"Error : Simulator badly configured, xSwath is None")
assert self._tArray is not None, logPrint(
"Error : Simulator badly configured, tArray is None")
Tp = self._platform.Tp
Vsat = self._platform.Vsat
K = self._platform.K
PRF = self._platform.PRF
H = self._platform.H
Lambda = self._platform.Lambda
# 1) Range compression :
if showProgress:
logPrint(" - Range compression ...")
## # !!! VERY VERY SLOW !!!
## tArray0=np.arange(-Tp*0.5,Tp*0.5,self._dt)
## h = GC.chirpSignal(tArray0, Tp, -K)
## procData = compression(rawData, h, 'range')
fRangeArray = GC.freq(rawData.shape[1], 1.0 / self._dt)
HMF = GC.rect(fRangeArray / (np.abs(K) * Tp)) * np.exp(
1j * np.pi * fRangeArray**2 / K)
procData = rangeCompression(rawData, HMF)
HMF = None
if self.verbose:
showResponse(procData, None, 'Range compression')
## # TEMP
## yc = self._params[2][1]
## yArray = np.sqrt( (0.5 * GC.C * self._tArray)**2 - H**2 )
## indices = [1050]
## for index in indices:
## f = plt.figure()
## f.suptitle("Range compression")
## plt.subplot(211)
## plt.plot(yArray-yc, np.abs(rawData[index,:]))
## plt.subplot(212)
## plt.plot(yArray-yc, np.abs(procData[index,:]))
## plt.show()
## # TEMP
# 2) Azimuth FFT :
if showProgress:
logPrint(" -- Azimuth FFT ...")
procDataAF = np.zeros(procData.shape, dtype=complex)
for i in range(procDataAF.shape[1]):
# get range fixed column
procDataAF[:, i] = GC.fft(procData[:, i])
procData = procDataAF
procDataAF = None
## fArray = np.fft.fftshift(np.fft.fftfreq( procData.shape[0], self._dx / self._platform.Vsat))
fArray = GC.freq(procData.shape[0], self._platform.Vsat / self._dx)
if self.verbose:
## showResponse(procData, [self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]], 'Azimuth FFT')
showResponse(procData, None, 'Azimuth FFT')
# 3) Range migration :
if showProgress:
logPrint(" --- Range migration ...")
Dfreq = np.sqrt(1.0 - (0.5 * Lambda * fArray / Vsat)**2)
procData = rangeMigration2(procData, self._tArray, Dfreq)
if self.verbose:
## showResponse(procData, [self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]], 'RCMC')
showResponse(procData, None, 'RCMC')
# 4) Azimuth compression :
if showProgress:
logPrint(" ---- Azimuth compression ...")
## xc = self._params[2][0]
## yc = self._params[2][1]
## Rc = np.sqrt(H**2 + yc**2)
## Ka = 2.0 / Lambda * 1.0 / Rc
## h = GC.rect((self._xArray-xc)/self._xSwath) * np.exp(1j * np.pi * Ka * (self._xArray - xc)**2)
## H = GC.fft(h)
xc = self._xArray[len(self._xArray) / 2]
for i in range(procData.shape[1]):
# Small squint approximation
## Ka = 4.0 * Vsat**2 / Lambda / GC.C / self._tArray[i]
## hMF = GC.rect((self._xArray-xc)/self._xSwath) * np.exp(1j * np.pi * Ka/Vsat**2 * (self._xArray - xc)**2)
## HMF = GC.fft(hMF)
# Use H(f) = exp( 1j * 4 * pi * R0 * D(f) * f0 / c )
HMF = np.exp(2 * np.pi * 1j * GC.C * self._tArray[i] / Lambda *
Dfreq)
procData[:, i] = procData[:, i] * HMF
# 5) Azimuth IFFT
if showProgress:
logPrint(" ----- Azimuth IFFT ...")
procDataAF = np.zeros(procData.shape, dtype=complex)
for i in range(procDataAF.shape[1]):
# get range fixed column
procDataAF[:, i] = GC.ifft(procData[:, i])
procData = procDataAF
procDataAF = None
if self.verbose:
showResponse(
procData,
[self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]],
'Compressed image', False)
return procData, self._xArray, self._tArray
def compressRawData(self, showProgress=True):
"""
Apply RDA on raw data
1) Range compression
2) Range Cell Migration Correction
3) Azimuth compression
Returns (compressed 2D array, azimuth positions, range time)
"""
rawData = self._rawData
assert rawData is not None, logPrint("Raw data should be computed ( using computeRawData() ) or provided as argument")
assert self._dt is not None, logPrint("Error : Simulator badly configured, dt is None")
assert self._dx is not None, logPrint("Error : Simulator badly configured, dx is None")
assert self._xArray is not None, logPrint("Error : Simulator badly configured, xArray is None")
assert self._tArray is not None, logPrint("Error : Simulator badly configured, tArray is None")
Tp = self._platform.Tp
Vsat = self._platform.Vsat
K = self._platform.K
PRF = self._platform.PRF
H = self._platform.H
Lambda = self._platform.Lambda
# 1) Range compression :
if showProgress:
logPrint(" - Range compression ...")
fRangeArray = GC.freq(rawData.shape[1], 1.0/self._dt)
HMF = GC.rect(fRangeArray / (np.abs(K)*Tp)) * np.exp(1j*np.pi*fRangeArray**2 / K)
# Multiply by a phase due to different range zero time
## tZero = self._tArray[len(self._tArray)/2]
## HMF = HMF * np.exp( -1j* 2.0 * np.pi * fRangeArray * tZero)
procData = rangeCompression(rawData, HMF)
HMF = None
if self.verbose:
showResponse(procData, None, 'Range compression')
# 2) Azimuth FFT :
if showProgress:
logPrint(" -- Azimuth FFT ...")
procDataAF = np.zeros(procData.shape, dtype=complex)
for i in range(procDataAF.shape[1]):
# get range fixed column
procDataAF[:,i] = GC.fft(procData[:,i])
procData = procDataAF
procDataAF = None
fArray = GC.freq(procData.shape[0], self._platform.Vsat/self._dx)
if self.verbose:
## showResponse(procData, [self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]], 'Azimuth FFT')
showResponse(procData, None, 'Azimuth FFT')
# 3) Range migration :
if showProgress:
logPrint(" --- Range migration ...")
Dfreq = np.sqrt(1.0 - (0.5 * Lambda * fArray / Vsat)**2)
procData = rangeMigration2(procData, self._tArray, Dfreq)
if self.verbose:
## showResponse(procData, [self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]], 'RCMC')
showResponse(procData, None, 'RCMC')
# 4) Azimuth compression :
if showProgress:
logPrint(" ---- Azimuth compression ...")
etaZero = self._xArray[len(self._xArray)/2] / Vsat
for i in range(procData.shape[1]):
# Use H(f) = exp( 1j * 4 * pi * R0 * D(f) * f0 / c )
#
HMF = np.exp( 2*np.pi*1j * GC.C * self._tArray[i] / Lambda * Dfreq)
# Multiply by a phase due to different azimuth zero time
HMF = HMF * np.exp( -1j* 2.0 * np.pi * fArray * etaZero)
procData[:,i] = procData[:,i] * HMF
# 5) Azimuth IFFT
if showProgress:
logPrint(" ----- Azimuth IFFT ...")
procDataAF = np.zeros(procData.shape, dtype=complex)
for i in range(procDataAF.shape[1]):
# get range fixed column
procDataAF[:,i] = GC.ifft(procData[:,i])
procData = procDataAF
procDataAF = None
if self.verbose:
showResponse(procData, [self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]], 'Compressed image', False)
return procData, self._xArray, self._tArray
def compressRawData(self, showProgress=True):
"""
Apply RDA on raw data
1) Range compression
2) Range Cell Migration Correction
3) Azimuth compression
Returns (compressed 2D array, azimuth positions, range time)
"""
rawData = self._rawData
assert rawData is not None, logPrint("Raw data should be computed ( using computeRawData() ) or provided as argument")
assert self._dt is not None, logPrint("Error : Simulator badly configured, dt is None")
assert self._dx is not None, logPrint("Error : Simulator badly configured, dx is None")
assert self._xArray is not None, logPrint("Error : Simulator badly configured, xArray is None")
assert self._xSwath is not None, logPrint("Error : Simulator badly configured, xSwath is None")
assert self._tArray is not None, logPrint("Error : Simulator badly configured, tArray is None")
Tp = self._platform.Tp
Vsat = self._platform.Vsat
K = self._platform.K
PRF = self._platform.PRF
H = self._platform.H
Lambda = self._platform.Lambda
# 1) Range compression :
if showProgress:
logPrint(" - Range compression ...")
## # !!! VERY VERY SLOW !!!
## tArray0=np.arange(-Tp*0.5,Tp*0.5,self._dt)
## h = GC.chirpSignal(tArray0, Tp, -K)
## procData = compression(rawData, h, 'range')
fRangeArray = GC.freq(rawData.shape[1], 1.0/self._dt)
HMF = GC.rect(fRangeArray / (np.abs(K)*Tp)) * np.exp(1j*np.pi*fRangeArray**2 / K)
procData = rangeCompression(rawData, HMF)
HMF = None
if self.verbose:
showResponse(procData, None, 'Range compression')
## # TEMP
## yc = self._params[2][1]
## yArray = np.sqrt( (0.5 * GC.C * self._tArray)**2 - H**2 )
## indices = [1050]
## for index in indices:
## f = plt.figure()
## f.suptitle("Range compression")
## plt.subplot(211)
## plt.plot(yArray-yc, np.abs(rawData[index,:]))
## plt.subplot(212)
## plt.plot(yArray-yc, np.abs(procData[index,:]))
## plt.show()
## # TEMP
# 2) Azimuth FFT :
if showProgress:
logPrint(" -- Azimuth FFT ...")
procDataAF = np.zeros(procData.shape, dtype=complex)
for i in range(procDataAF.shape[1]):
# get range fixed column
procDataAF[:,i] = GC.fft(procData[:,i])
procData = procDataAF
procDataAF = None
## fArray = np.fft.fftshift(np.fft.fftfreq( procData.shape[0], self._dx / self._platform.Vsat))
fArray = GC.freq(procData.shape[0], self._platform.Vsat/self._dx)
if self.verbose:
## showResponse(procData, [self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]], 'Azimuth FFT')
showResponse(procData, None, 'Azimuth FFT')
# 3) Range migration :
if showProgress:
logPrint(" --- Range migration ...")
Dfreq = np.sqrt(1.0 - (0.5 * Lambda * fArray / Vsat)**2)
procData = rangeMigration2(procData, self._tArray, Dfreq)
if self.verbose:
## showResponse(procData, [self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]], 'RCMC')
showResponse(procData, None, 'RCMC')
# 4) Azimuth compression :
if showProgress:
logPrint(" ---- Azimuth compression ...")
## xc = self._params[2][0]
## yc = self._params[2][1]
## Rc = np.sqrt(H**2 + yc**2)
## Ka = 2.0 / Lambda * 1.0 / Rc
## h = GC.rect((self._xArray-xc)/self._xSwath) * np.exp(1j * np.pi * Ka * (self._xArray - xc)**2)
## H = GC.fft(h)
xc = self._xArray[len(self._xArray)/2]
for i in range(procData.shape[1]):
# Small squint approximation
## Ka = 4.0 * Vsat**2 / Lambda / GC.C / self._tArray[i]
## hMF = GC.rect((self._xArray-xc)/self._xSwath) * np.exp(1j * np.pi * Ka/Vsat**2 * (self._xArray - xc)**2)
## HMF = GC.fft(hMF)
# Use H(f) = exp( 1j * 4 * pi * R0 * D(f) * f0 / c )
HMF = np.exp( 2*np.pi*1j * GC.C * self._tArray[i] / Lambda * Dfreq)
procData[:,i] = procData[:,i] * HMF
# 5) Azimuth IFFT
if showProgress:
logPrint(" ----- Azimuth IFFT ...")
procDataAF = np.zeros(procData.shape, dtype=complex)
for i in range(procDataAF.shape[1]):
# get range fixed column
procDataAF[:,i] = GC.ifft(procData[:,i])
procData = procDataAF
procDataAF = None
if self.verbose:
showResponse(procData, [self._tArray[0], self._tArray[-1], fArray[0], fArray[-1]], 'Compressed image', False)
return procData, self._xArray, self._tArray