def resize(r, d):
# resizes the reconstruction to the desired size
# r is the reconstruction
# d is the desired size
resized = np.zeros((d, d))
start = int((r.shape[0] - d) / 2)
resized = r[start + 2:start + d + 2, start:start + d]
return resized
if __name__ == "__main__":
# make offset jet
ofsj = phantoms.offset_jet(48, 55)
graphs.colourmap(ofsj)
plt.title('Original phantom')
# take projections and make sinogram
offsino = astra1.sinogram(ofsj, np.pi / 2, 90)
graphs.colourmap(offsino)
plt.title('90 degrees sinogram')
# straighten
offsino = centre_sino(offsino) #, np.pi/2, 48, 55)
graphs.colourmap(offsino)
plt.title('Line of symmetry through axis of rotation')
# mirror
offsino = mirror_sinogram(offsino)
return sino_mirr
def resize(r, d):
# resizes the reconstruction to the desired size
# r is the reconstruction
# d is the desired size
resized = np.zeros((d, d))
start = int((r.shape[0] - d) / 2)
resized = r[start + 2:start + d + 2, start:start + d]
return resized
if __name__ == "__main__":
j = phantoms.offset_jet(0, 0)
sino = astra1.sinogram(j, np.pi / 2, 180)
# make offset jet
ofsj = phantoms.offset_jet(48, 55)
graphs.colourmap(ofsj)
plt.title('Original phantom')
# take projections and make sinogram
offsino = astra1.sinogram(ofsj, np.pi / 2, 180)
graphs.colourmap(offsino)
plt.title('90 degrees sinogram')
# straighten
offsino = centre_sino(offsino) #, np.pi/2, 48, 55)
graphs.colourmap(offsino)
# find difference and only keep values where phantom greater than 0.1
diff = abs(p - r)
for i in range(len(p)-1, -1, -1):
if p[i] < 0.1:
diff = np.delete(diff, i)
p = np.delete(p, i)
# calculate relative error as a percentage (relative to phantom)
rel_err = diff / p * 100
return np.mean(rel_err) # return the mean so that it can be plotted
# create the original phantom
phant = phantoms.offset_jet(48, 55)
phant_centr = phantoms.offset_jet(0, 55)
# the range of number of projections to reconstruct for:
n_projections = [int(a) for a in np.linspace(3,90,9)]
n_iterations = 40
# all six types to plot
fbp_noise_err = []
sirt_noise_err = []
fbp_clean_err = []
sirt_clean_err = []
fbp_90_err = []
sirt_90_err = []
fbp_90_noise_err = []