Fig. 4.

(a) Correlation coefficients between the 3D RI maps of a polystyrene bead, which were reconstructed using different numbers of angular projections, and the reference map. Blue curve with rectangle markers represents coefficients obtained from the conventional GP algorithm. Red curve with circle markers represents coefficients obtained from the proposed FM-GP method. The horizontal axis (number of projections) is in log scale. The inset shows the same data in normal scale on the horizontal axis. (b) Three orthogonal cross sections and the corresponding correlation coefficients of reconstructed 3D RI maps versus the projection numbers in the conventional GP algorithm. (c) Three orthogonal cross sections and the corresponding correlation coefficients of reconstructed 3D RI maps versus projection numbers in the FM-GP algorithm, showing a significant improvement in comparison to (b).