def PCreateFFT(image, dir):
"""
Create an FFT object suitable for FFTing an image
Create an FFT for an efficient size equal to or larger than image
One needed for each direction to be FFTed.
returns Python FFT object
* image = Image to be FFTed
* dir = FFT direction 1 -> R2C, 2 -> C2R
"""
################################################################
# Checks
if not Image.PIsA(image):
raise TypeError("image MUST be a Python Obit Image")
#
# Get image info from descriptor
desc = image.Desc
descDict = desc.Dict
rank = 2 # Only 2D FFTs
dim = descDict["inaxes"]
# Compute size to be efficient
i = 0
effDim = []
for x in dim:
effDim.append(FFT.PSuggestSize(x))
i = i+1
effDim
name = "FFT for " + Image.PGetName(image)
out = FFT.FFT(name, dir, 2, rank, effDim)
return out
def PTimeFilterResize (filter, nTime):
""" Resize Filter
Change number of time samples in filter
Note: the actual size will be the result of FFT.PSuggestSize(nTime)
filter = time filter
nTime = minimum number of time elements
"""
################################################################
# Checks
if not PIsA(filter):
print "Actually ",filter.__class__
raise TypeError,"filter MUST be a Python Obit TimeFilter"
n = FFT.PSuggestSize(nTime); # How many actual points?
Obit.TimeFilterResize (filter.me, n)
def PImageFFT(inImage, outAImage, outPImage, err):
"""
FFTs an Image
FFT inImage and write as real and imaginary as full plane (hermetian)
* inImage = input Obit Python Image 1
Any BLC and/or TRC set will be honored
* outAImage = output Obit Python Amplitude image of FFT
must be defined but not instantiated
* outPImage = output Obit Python Phase (deg) image of FFT
must be defined but not instantiated
* err = Python Obit Error/message stack
"""
################################################################
# Checks
if not Image.PIsA(inImage):
raise TypeError("inImage MUST be a Python Obit Image")
if not Image.PIsA(outAImage):
raise TypeError("outAImage MUST be a Python Obit Image")
if not Image.PIsA(outPImage):
raise TypeError("outPImage MUST be a Python Obit Image")
if not err.IsA():
raise TypeError("err MUST be an OErr")
#
# Clone output images
inImage.Clone(outAImage, err)
inImage.Clone(outPImage, err)
OErr.printErrMsg(err, "Error initializing images")
# Size of FFT
inImage.Open(Image.READONLY, err)
inImage.Read(err)
OErr.printErrMsg(err, "Error reading input")
inHead = inImage.Desc.Dict
FFTdim = [
FFT.PSuggestSize(inHead["inaxes"][0]),
FFT.PSuggestSize(inHead["inaxes"][1])
]
# Create float arrays for FFT size
inFArray = FArray.FArray("inF", naxis=FFTdim)
outFArray = FArray.FArray("outF", naxis=FFTdim)
# Create FFT for full complex FFT
FFTfor = FFT.FFT("FFT", 1, 1, 2, FFTdim)
# Create complex arrays for FFT size
inCArray = CArray.CArray("inC", naxis=FFTdim)
outCArray = CArray.CArray("outC", naxis=FFTdim)
#Loop over planes
nplane = inImage.Desc.Dict['inaxes'][2]
for iax in range(1, nplane + 1):
inImage.GetPlane(None, [iax, 1, 1, 1, 1], err)
OErr.printErrMsg(err, "Error reading input")
# Pad input into work FArray
FArray.PPad(inImage.FArray, inFArray, 1.0)
# and God said "The center of an FFT will be at the corners"
FArray.PCenter2D(inFArray)
# Zero output FArray and use as imaginary part
FArray.PFill(outFArray, 0.0)
# Copy input to scratch CArray
CArray.PComplex(inFArray, outFArray, inCArray)
# FFT
FFT.PC2C(FFTfor, inCArray, outCArray)
# Extract amplitude, write
CArray.PAmp(outCArray, outFArray)
# and God said "The center of an FFT will be at the corners"
FArray.PCenter2D(outFArray)
outAImage.FArray = FeatherUtil.PExtract(FFTfor, outFArray,
outAImage.FArray, err)
OErr.printErrMsg(err, "Error extracting output amplitude plane")
outAImage.PutPlane(outAImage.FArray, [iax, 1, 1, 1, 1], err)
# Extract phase, write
CArray.PPhase(outCArray, outFArray)
# To degrees
FArray.PSMul(outFArray, 57.2956)
# and God said "The center of an FFT will be at the corners"
FArray.PCenter2D(outFArray)
outPImage.FArray = FeatherUtil.PExtract(FFTfor, outFArray,
outPImage.FArray, err)
OErr.printErrMsg(err, "Error extracting output phase plane")
outPImage.PutPlane(outPImage.FArray, [iax, 1, 1, 1, 1], err)
# Error?
OErr.printErrMsg(err, "Error writing output phase image")
# end loop over planes
# Fix headers
outAImage.Open(Image.READWRITE, err)
FFTHeaderUpdate(outAImage, FFTdim, err)
outAImage.Close(err)
OErr.printErrMsg(err, "Error writing output amplitude image")
outPImage.Open(Image.READWRITE, err)
FFTHeaderUpdate(outPImage, FFTdim, err)
outPImage.Close(err)
OErr.printErrMsg(err, "Error writing output phase image")
# get any BLC, TRC for history
info = inImage.List.Dict
blc = [1, 1, 1, 1, 1, 1, 1]
if 'BLC' in info:
blc = info["BLC"][2]
trc = [0, 0, 0, 0, 0, 0, 0]
if 'TRC' in info:
trc = info["TRC"][2]
# Write history
i = 0
imtype = ("Amplitude", "Phase")
for outImage in (outAImage, outPImage):
inHistory = History.History("history", inImage.List, err)
outHistory = History.History("history", outImage.List, err)
# Copy History
# FITS? - copy header
if ("FileType" in info) and (info["FileType"][2][0] == 0):
History.PCopyHeader(inHistory, outHistory, err)
#Not needed History.PCopy(inHistory, outHistory, err)
# Add this programs history
outHistory.Open(History.READWRITE, err)
outHistory.TimeStamp(" Start Obit PImageFFT", err)
outHistory.TimeStamp(OSystem.PGetPgmName() + " BLC = " + str(blc), err)
outHistory.TimeStamp(OSystem.PGetPgmName() + " TRC = " + str(trc), err)
outHistory.TimeStamp(OSystem.PGetPgmName() + " type = " + imtype[i],
err)
i += 1
outHistory.Close(err)
outPDisk = 1
# Convert files into Images
inImage = Image.newPFImage(inFile, inFile, inDisk, True, err)
outAImage = Image.newPFImage(outAFile, outAFile, outADisk, False, err)
inImage.Clone(outAImage,err)
outPImage = Image.newPFImage(outPFile, outPFile, outPDisk, False, err)
inImage.Clone(outPImage,err)
OErr.printErrMsg(err, "Error initializing images")
# Size of FFT
inImage.Open(Image.READONLY, err)
inImage.Read(err)
OErr.printErrMsg(err, "Error reading input")
inHead = inImage.Desc.Dict
FFTdim = [FFT.PSuggestSize(inHead["inaxes"][0]), FFT.PSuggestSize(inHead["inaxes"][1])]
# Create float arrays for FFT size
inFArray = FArray.FArray("inF", naxis=FFTdim)
outFArray = FArray.FArray("outF", naxis=FFTdim)
# Pad input into work FArray
FArray.PPad(inImage.FArray, inFArray, 1.0)
# and God said "The center of an FFT will be at the corners"
FArray.PCenter2D(inFArray)
# Zero output FArray and use as imaginary part
FArray.PFill(outFArray, 0.0)
# Create FFT for full complex FFT
FFTfor = FFT.FFT("FFT", 1, 1, 2, FFTdim)
