In Situ Investigation of the 3D Mechanical Microstructure at Nanoscale: Nano-CT Imaging Method of Local Small Region in Large Scale Sample
The projection of the Shepp-Logan head phantom at was truncated and filtered by different methods. The original length of the projection is 367, but only 100 of them were preserved and the rest were set to zero. In this figure, the horizontal axis represented the index of projection line, the vertical axis represented the projection value before and after filtering. (a) Truncated projection at . (b) Projection after differentiation and Hilbert transform. (c) Filtered projection given by (7). (d) Filtered projection given by (11). (e) Comparison of the filtered projections. Only a part of projections was shown in this figure.