International
Tables for
Crystallography
Volume B
Reciprocal space
Edited by U. Shmueli

International Tables for Crystallography (2010). Vol. B, ch. 2.5, p. 371   | 1 | 2 |

Figure 2.5.6.5 

B. K. Vainshteinc and P. A. Penczekg
[Figure 2.5.6.5]
Figure 2.5.6.5

Nonuniform distribution of projections. The projection weights for the reconstruction algorithms are chosen such that the backprojection integral becomes approximated by a Riemann sum and are equal to the angular length of an arc [\Delta \Psi _i ] (2.5.6.29)[link]. In Fourier space, projections of an object with real-space radius D form rectangles with width 1/D. In the exact filter backprojection reconstruction method, the weights are derived based on the amount the overlap between projections (2.5.6.29)[link].