Figure 5: The reconstruction results of the dental phantom. From left to right: the first one is the reconstructed from 720 projections by FBP, the second one is the reconstructed from 70 projections by FBP, the third one is the results by PICCS from 15 projections, and the last one is the results of PPFC. The grey scale windows for the low and high-energy images are [0, 0.85] and [0, 0.65]. All the results are reconstructed from the noisy projections.