def _computeTF(self, wl_min_um=1.2, wl_max_um=10.0, N=200):
"""
compute the fourier transform of the scans (A,B,C,D) and store the
results using 'TF_...' keywords. self.TF_wl contains the corresponding
wavelengths (in meters).
"""
#-- wavelength table:
self.TF_wl = 1/np.linspace(1/wl_max_um, 1/wl_min_um, N)*1e-6
for i in range(len(self.scans)):
#-- find center of the scan
try:
snr = slidop.slidingMean(self.scans[i]['TIME'],self.scans[i]['GDSNR'],
20e6/self.header['ISS PRI FSU1 FREQ'])
except:
snr,rms,xsnr= sliding_avg_rms(self.scans[i]['TIME'],self.scans[i]['GDSNR'],
20e6/self.header['ISS PRI FSU1 FREQ'])
snr = np.interp(self.scans[i]['TIME'], xsnr,snr)
opd0 = self.scans[i]['RTOFFSET'][snr.argmax()]
#-- create cos and sin waves
_cos = np.cos(2*np.pi*(self.scans[i]['RTOFFSET']-opd0)[None,:]/self.TF_wl[:,None])
_sin = np.sin(2*np.pi*(self.scans[i]['RTOFFSET']-opd0)[None,:]/self.TF_wl[:,None])
#-- apodization window (width in microns):
apod_width = np.array([50,50,50,50,50,50])*1e-6/(np.sqrt(2)/2)
apod = np.exp(-((self.scans[i]['RTOFFSET']-opd0)[:,None]/
apod_width[None,:])**2)
#-- computation for each channel (A,B,C,D)
for k in ['A', 'B', 'C', 'D']:
self.scans[i]['TF_'+k]=(apod[None,:,:]*self.scans[i][k][None,:,:]*
(_cos+1j*_sin)[:,:,None]).mean(axis=1)
if self.scans[i].has_key('DARK'+k):
self.scans[i]['TF_DARK'+k]=(self.scans[i]['DARK'+k][None,:]*
(_cos+1j*_sin)).mean(axis=1)
return
def waterFall(self, channel=0):
"""
channel is 0 for white light, 1..5 for the dispersed pixels
"""
plt.figure(0)
plt.clf()
ax1= plt.subplot(121)
ax2= plt.subplot(122, sharex=ax1, sharey=ax1)
for k in range(len(self.scans)):
tmp= self.scans[k]['A'][:,channel]-self.scans[k]['C'][:,channel]
x = self.scans[k]['RTOFFSET']
x -= x.mean()
x*=1e6
ax1.plot(x,tmp+k,
color='k', alpha=0.8)
ax2.plot(x, slidop.slidingMean(self.scans[k]['TIME'],
self.scans[k]['GDSNR'],
20e6/self.header['ISS PRI FSU1 FREQ'])/10.+k,
color='k', alpha=0.8)
ax1.set_ylim(-1,k+1)
return