def testFitSinc():
#make the psf a sinc function
nhalf = 512
sinc1d = np.sinc(np.linspace(-nhalf,nhalf,nhalf*2+1)/(nhalf*2+1)*np.pi*6)
psf = np.outer(sinc1d,sinc1d)
maxAt = np.argmax(psf)
maxAtCrd = np.array([maxAt % psf.shape[0], maxAt // psf.shape[0]], dtype=int)
outpars = fitter.FitCleanBeam(psf) * np.array([1, 1, 180 / np.pi])
xx, yy = np.meshgrid(np.linspace(-nhalf, nhalf, nhalf * 2 + 1), np.linspace(-nhalf, nhalf, nhalf * 2 + 1))
inpars = [1, 0, 0, outpars[0], outpars[1], outpars[2]]
cleanBeam = gauss2d(inpars, circle=0, rotate=1, vheight=0)(xx, yy)
wnd = 200
psfWnd = psf[(maxAtCrd[0] - wnd):(maxAtCrd[0] + wnd + 1),(maxAtCrd[1] - wnd):(maxAtCrd[1] + wnd + 1)]
lev, fnull = fitter.FindSidelobe(psfWnd)
assert np.isclose(lev,np.sinc(5/2.0),rtol=1e-2,atol=1e-8) # just check if it found the first sidelobe level
def restoreFittedBeam(rot):
imgSize = 256
cellSize = np.deg2rad(4./3600.)
params = (10, 5, rot) #maj, min, theta
#create input with code borrowed from Tigger:
xx,yy = np.meshgrid(np.arange(0,imgSize),np.arange(0,imgSize))
inp = gauss2d([1,imgSize/2,imgSize/2,params[1],params[0],params[2]],circle=0,rotate=1,vheight=0)(xx,yy)
inp = inp.reshape(1,1,imgSize,imgSize)
#fit
fittedParams = tuple((fitter.FitCleanBeam(inp[0, 0, :, :]) *
np.array([cellSize, cellSize, 1])).tolist())
#restore fitted clean beam with an FFT convolution:
delta = np.zeros([1, 1, imgSize, imgSize])
delta[0, 0, imgSize // 2, imgSize // 2] = 1
rest, _ = fftconvolve.ConvolveGaussianScipy(delta,
Sig=5,
GaussPar=fittedParams)
rest = fftconvolve.ConvolveGaussian(shareddict={"in":delta,
"out":delta},
field_in="in",
field_out="out",
ch=0,
CellSizeRad=cellSize,
GaussPars_ch=fittedParams,
Normalise=False)
assert np.allclose(inp, rest, rtol=1e-2, atol=1e-2)
def fitRotatedPSF(rotAngle):
nhalf = 512
xx, yy = np.meshgrid(np.linspace(-nhalf, nhalf, nhalf * 2 + 1),
np.linspace(-nhalf, nhalf, nhalf * 2 + 1))
inpars = np.array([1., 0., 0., 50., 3., rotAngle])
psf = gauss2d(inpars, circle=0, rotate=1, vheight=0)(xx, yy)
psf += np.random.randn(psf.shape[0],psf.shape[1])*1e-7
maxAt = np.argmax(psf)
maxAtCrd = np.array([maxAt % psf.shape[0], maxAt // psf.shape[0]], dtype=int)
wnd = 50
psfWnd = psf[(maxAtCrd[0] - wnd):(maxAtCrd[0] + wnd + 1), (maxAtCrd[1] - wnd):(maxAtCrd[1] + wnd + 1)]
outpars = fitter.FitCleanBeam(psfWnd) * np.array([1, 1, 180 / np.pi])
inpars = [1, 0, 0, outpars[1], outpars[0], outpars[2]]
cleanBeam = gauss2d(inpars, circle=0, rotate=1, vheight=0)(xx, yy)
assert np.allclose(psf, cleanBeam, rtol=1e-6, atol=1e-6)