tomopack: shift zero phase angle of psi at the centre of the detector

tools/detectSpheres.py

@@ -133,7 +133,11 @@ def tomopack(radioMM, psiMM, maxIterations=50, l=0.1, epsilon='iterative', kTrus
 
     # define the psi function and its FFT -- the structuring element for SR
     # Start with the projection of a centred sphere
-    psiMM_FFT = numpy.fft.fft2(psiMM)
+    #psiMM_FFT = numpy.fft.fft2(psiMM)
+    # 2021-10-26 OS: phase shift of psi so that zero phase angle is positioned at the centre of the detector
+    # avoids the HACK of shifting f_x later on line 187
+    psiMM_FFT = numpy.fft.fft2(numpy.fft.fftshift(psiMM))
+
 
     # This is comparable to Figure 7 in TomoPack
     # if GRAPH:
@@ -179,8 +183,8 @@ def tomopack(radioMM, psiMM, maxIterations=50, l=0.1, epsilon='iterative', kTrus
         # if GRAPH: plt.plot(f_k,'k.')
         f_k[k_trust] = f_k_naiive[k_trust]
         # if GRAPH: plt.plot(f_k,'r.')
-        #f_x = numpy.fft.ifft2(f_k)
-        f_x = numpy.fft.fftshift(numpy.fft.ifft2(f_k)) # importing HACK from 1D version
+        f_x = numpy.fft.ifft2(f_k)
+        #f_x = numpy.fft.fftshift(numpy.fft.ifft2(f_k)) # importing HACK from 1D version
         f_x = f_x + l*(_PI_projector(f_x) - f_x)
         #print(numpy.amax(numpy.abs(f_x - f_x_old)))